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Tuesday 11 January 2022

can garlic lower blood pressure?

How garlic lowers blood pressure (MUST LEARN)



Traditionally, garlic has a long history as a remedy for improving strength, reducing fatigue, and increasing immunity both in prevention and treatment of infectious diseases and gastrointestinal function (1). In modern times, garlic has also been linked to improved cardiovascular health, including blood pressure, cholesterol, and other cardiovascular markers (2, 3). We updated our previously published meta-analysis on the effect of garlic on blood pressure (2) with the inclusion of several more recent trials, reviewed our meta-analysis on the effect of garlic on cholesterol, and summarized the effect of garlic on the immune system.


Effect of garlic on blood pressure.

High blood pressure is an important risk factor for cardiovascular disease and is attributed to an estimated 70% of heart attacks, strokes, and chronic heart failure, leading to 37% of cardiovascular deaths in Western countries and 13.5% globally (4, 5).3 Epidemiologic studies describe a continuous association between blood pressure and cardiovascular disease risk, suggesting a reduction in high systolic blood pressure (SBP; >140 mm Hg) by 20 mm Hg and a reduction in high diastolic blood pressure (DBP; >90 mm Hg) by 10 mm Hg to be associated with a 50% risk reduction in developing cardiovascular disease (6). Hypertension affects ∼30% of adults in Western countries, with 68 million adults in the United States alone (7). Although management of blood pressure in family practice has increased in the past 20 y, a large proportion of adults (23%) have uncontrolled blood pressure (7, 8), 9% have untreated blood pressure, and half of those treated do not achieve optimal control (7, 9).


Current medical treatment of hypertension.

Approximately 40% of hypertensive patients can achieve the target blood pressure of <140/90 mm Hg with monotherapy, independent of the type of antihypertensive medication used. Approximately 40% require combination therapy with 2 agents, and 20% need to take ≥3 antihypertensive medications to achieve blood pressure control (10). In Australia, for example, the most commonly prescribed class of antihypertensive medications (56%) are angiotensin-converting enzyme inhibitors, followed by angiotensin II receptor antagonists (27%), calcium channel blockers, diuretics, and β-blockers (11). Adverse reactions from antihypertensive medications may occur in a significant number of patients and are more likely when multiple drugs are prescribed (12). Adverse reactions include fatigue, dizziness, cough, headache, myalgia, angioedema, renal impairment, gastrointestinal upset, and hyperglycemia (12).


Garlic supplements have shown promise in lowering blood pressure in several meta-analyses (2, 13, 14), and the blood pressure–lowering action of garlic is biologically plausible. Garlic contains a number of active sulfur compounds (15) that have been reported to modulate endothelium-relaxing and -constricting factors, leading to blood pressure reduction. Specifically, garlic has been shown to stimulate the production of NO and hydrogen sulphide (H2S), both gasotransmitters leading to vasorelaxation (16–18). In addition, others reported that garlic reduced the production of the vasoconstricting factors endothelin 1 and angiotensin II (19, 20). This meta-analysis and review updates our previously published meta-analyses on the effect of garlic on blood pressure with the inclusion of recent trials.


Methods

We included trials selected in previous meta-analyses by Silagy and Neil (13), Reinhart et al. (14), and Ried et al. (2) and extended the search by using the search terms “garlic” and “hypertension” or “blood pressure” in Medline for published trials between 2008 and 2013. We included studies with placebo control groups, that used garlic-only supplements, and that reported mean SBP and/or DBP and SDs (Table 1).




TABLE 1Characteristics of trials included in the meta-analysis of the effect of garlic on blood pressure1

Baseline mean SBP/DBP, mm Hg

Authors, year (reference) Garlic/control, n Study design Garlic type Brand2 Dosage, mg/d Dosage of active ingredient, mg/d Duration, wk Garlic Control

Kandziora, 1988 (22) 20/20 p GP Kwai 600 7.8, alliin 12 174/99 175/98 

Auer et al., 1990 (23) 24/23 p GP Kwai 600 7.8, alliin 12 171/102 161/97 

Vorberg and Schneider, 1990 (24) 20/20 p GP Kwai 900 11.7, alliin 16 144.5/91 144/88 

Holzgartner et al., 1992 (25) 47/47 p GP Kwai 900 11.7, alliin 12 143/83 141/82 

Jain et al., 1993 (26) 20/22 p GP Kwai 900 11.7, alliin 12 129/82 128/83 

DeASantos and Gruenwald, 1993 (27) 25/27 p GP Kwai 900 11.7, alliin 24 143/89 144/89 

Kiesewetter et al., 1993 (28) 32/32 p GP Kwai 800 10.4, alliin 12 NR/85 NR/83 

Saradeth et al., 1994 (29) 31/37 p GP Kwai 600 7.8, alliin 15 125/81 125/82 

Simons et al., 1995 (30) 28/28 c GP Kwai 900 11.7, alliin 12 127/80 127/80 

Steiner et al., 1996 (31) 41/41 p AGE Kyolic 2400 NR 23 134/84 134/85 

Adler and Holub, 1997 (32) 12/11 p GP Kwai 900 11.7, alliin 12 123/83 118/79 

Isaacsohn et al., 1998 (33) 28/22 p GP Kwai 900 11.7, alliin 12 119/73 123/72 

Zhang et al., 2000 (34) 14/13 p GO Cardiomax 12.3 NR 16 114/72 109/64 

Williams et al., 2005 (35) 15/15 c AGE Kyolic 2400 2, SAC 2 132/82 132/82 

Macan et al., 2006 (36) 22/26 p AGE Kyolic 3050 14.7, SAC 12 122/74 127/82 

Sobenin et al., 2008 (37) 23/19 p GP Allicor 600 7.8, allicin pt 12 143/89 140/88 

Sobenin et al., 2009 (38) G1: 30/P: 20 p GP G1: Allicor G1: 600 G1: 7.8, allicin 8 G1: 156/96 150/94 

  G2:18 p GP G2: Allicor G2: 2400 G2: 31.2, allicin 8 G2: 153/95 150/94 

  G3: 16 P GP G3: Kwai G3: 900 G3: 11.7, alliin 8 G3: 152/96 150/94 

Ried et al., 2010 (39) 25/25 p AGE Kyolic 960 2.4, SAC 12 135/74 141/76 

Ried et al., 2013 (40) G1:18/P: 17 p AGE Kyolic G1: 240 G1: 0.6, SAC 12 G1: 151/77 149/76 

  G2:20 p AGE Kyolic G2: 480 G2: 1.2, SAC 12 G2: 149/76 149/76 

  G3: 19 p AGE Kyolic G3: 960 G3: 2.4, SAC 12 G3: 149 /76 149/76 

Nakasone et al., 2013 (41) HT: 23/24 p GPjpn Dentou-ninniku-ranwo 188 NR 12 HT: 142/91 HT: 142/92 

  NT: 16/18 p GPjpn Dentou-ninniku-ranwo 188 NR 12 NT: 134/83 NT: 134/82 

1

AGE, aged garlic extract; c, crossover trial; G1–3, garlic groups 1–3; GO, garlic oil; GP, garlic powder; GPjpn, Japanese garlic powder containing egg yolk; HT, hypertensive group; NR, not reported; NT, normotensive group; p, parallel trial; P, placebo group; pt, potential; SAC, S-allylcysteine; SBP/DBP, systolic blood pressure/diastolic blood pressure.


2

Manufacturers' details of brands: Allicor: INAT-Farma, Moscow, Russia; Cardiomax: Seven Seas, Hull, United Kingdom; Dentou-ninniku-ranwo: Kenkoukazou Inc, Kagoshima, Japan; Kwai: Lichtwer Pharma GmbH, Berlin, Germany; Kyolic: Wakunaga of America Co Ltd, Mission Viejo, USA & Wakunaga Pharmaceuticals Co Ltd, Hiroshima, Japan.


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Changes in mean SBP or DBP in garlic and control groups before and after intervention were entered into the meta-analysis by using a random-effects model in Review Manager, version 5.2 (21). In addition, we performed a subgroup meta-analysis of trials in hypertensive subjects at the start of treatment (mean SBP ≥140 mm Hg or mean DBP ≥90 mm Hg) and a subgroup analysis of trials in normotensive subjects at the start of treatment (mean SBP <140 mm Hg or mean DBP <90 mm Hg).


Results

Meta-analysis

A total of 20 trials in >900 participants were identified as meeting the inclusion criteria (22–41), including 5 recent trials (37–41) that were not included in previous meta-analyses (2, 13, 14). Two trials (39, 41) included hypertensive and normotensive participants in the garlic and placebo groups. We undertook a meta-analysis that included all patients as well as a subgroup meta-analysis by baseline blood pressure (hypertensive or normotensive at baseline). Two trials (38, 40) featured 4-group, parallel, randomized controlled trials, with 3 active garlic groups of different dosages and a placebo group. In the main meta-analysis, we included only one active group compared with placebo from each of the 2 trials: the Allicor (INAT-Farma, Moscow, Russia) 400-mg group (38) and the garlic 2-capsule group (40). In addition, we tested the other active garlic groups of the 2 trials in sensitivity analysis.


Meta-analyses of all 20 trials (25 trial arms) suggested that garlic supplements significantly lower SBP by a mean (±SE) difference of 5.1 ± 2.2 mm Hg (P < 0.001; n = 19) and DBP by a mean difference of 2.6 ± 1.6 mm Hg (P < 0.001; n = 20) (Figures 1 and 2). Subgroup meta-analysis of trials and trial arms involving hypertensive participants revealed a larger significant reduction in SBP (mean difference for SBPhypertensive: −8.6 ± 2.2 mm Hg; P < 0.001; n = 10) and DBP (mean difference for DBPhypertensive: −6.1 ± 1.3 mm Hg; P < 0.001; n = 6) (Figures 3 and 4). In contrast, subgroup meta-analyses of trials involving participants with blood pressure in the prehypertensive and normal range at baseline (SBP/DBP <140/90 mm Hg) did not reveal a significant effect (mean difference for SBPnormotensive: −1.5 ± 1.9 mm Hg; n = 11; mean difference for DBPnormotensive: −0.4 ± 1.2 mm Hg; n = 14).

EX-e: Garlic reduces Blood Pressure in Hypertensive Individuals



FIGURE 1

Forest plot showing the effect of garlic on systolic blood pressure; n = 19 trials (25 trial arms) including only 1 of 3 trial arms in 2 trials that tested different dosages of garlic compared with placebo [Sobenin 2009 (38): a2400 group; Ried 2013 (40): g2 group]. Other trial arms were tested in sensitivity analyses. Values are weighted mean differences (95% CIs) comparing changes in systolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; g1, g2, g4, garlic 1-, 2-, 4-capsule group; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg; NTSG, normotensive subgroup.

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Forest plot showing the effect of garlic on systolic blood pressure; n = 19 trials (25 trial arms) including only 1 of 3 trial arms in 2 trials that tested different dosages of garlic compared with placebo [Sobenin 2009 (38): a2400 group; Ried 2013 (40): g2 group]. Other trial arms were tested in sensitivity analyses. Values are weighted mean differences (95% CIs) comparing changes in systolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; g1, g2, g4, garlic 1-, 2-, 4-capsule group; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg; NTSG, normotensive subgroup.



FIGURE 2

Forest plot showing the effect of garlic on diastolic blood pressure; n = 20 trials (25 trial arms). Values are weighted mean differences (95% CIs) comparing changes in diastolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; g1, g2, g4, garlic 1-, 2-, 4-capsule group; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg; NTSG, normotensive subgroup.

Open in new tabDownload slide

Forest plot showing the effect of garlic on diastolic blood pressure; n = 20 trials (25 trial arms). Values are weighted mean differences (95% CIs) comparing changes in diastolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; g1, g2, g4, garlic 1-, 2-, 4-capsule group; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg; NTSG, normotensive subgroup.



FIGURE 3

Forest plot showing the effect of garlic on systolic blood pressure in hypertensive subjects. Values are weighted mean differences (95% CIs) comparing changes in systolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; g1, g2, g4, garlic 1-, 2-, 4-capsule group; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg; SBP, systolic blood pressure.

Open in new tabDownload slide

Forest plot showing the effect of garlic on systolic blood pressure in hypertensive subjects. Values are weighted mean differences (95% CIs) comparing changes in systolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; g1, g2, g4, garlic 1-, 2-, 4-capsule group; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg; SBP, systolic blood pressure.



FIGURE 4

Forest plot showing the effect of garlic on diastolic blood pressure in hypertensive subjects. Values are weighted mean differences (95% CIs) comparing changes in diastolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; DBP, diastolic blood pressure; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg.

Open in new tabDownload slide

Forest plot showing the effect of garlic on diastolic blood pressure in hypertensive subjects. Values are weighted mean differences (95% CIs) comparing changes in diastolic blood pressure over time between treatment and control groups. a600, Allicor-600 mg; a2400, Allicor-2400 mg; DBP, diastolic blood pressure; HTSG, hypertensive subgroup; IV, inverse variance; k900, Kwai-900 mg.



The majority of trials included in the meta-analysis used standard garlic powder (GP) supplements (n = 13), 5 trials used aged garlic extract (AGE), 1 trial used garlic oil (GO), and 1 trial used an egg yolk–enriched GP. Results of subgroup analysis by type of garlic were similar between GP (n = 13) and AGE (n = 5) (Table 2). In addition, we conducted sensitivity analyses excluding the trial by Nakasone et al. (41), because this trial used a modified GP, and the influence of the egg yolk on blood pressure cannot be ruled out. These and other sensitivity analyses that used alternate trial arms with different dosages of garlic in Sobenin et al. (38) and Ried et al. (38) did not change the results appreciably (Table 2).




TABLE 2Subgroup and sensitivity analyses1

SBP/DBP

Subgroup Authors, year (reference) Group Trials, n Subjects, n SBP DBP

By type of garlic All2 19/20 908/940 −5.1 ± 2.2 −2.6 ± 1.6 

  GP 12/13 576/640 −5.8 ± 3.2 −3.2 ± 2.0 

  AGE 5/5 233 −4.1 ± 3.1 0.02 ± 2.9 

Sensitivity analysis  

 With trial arm a600 Sobenin et al., 2009 (38) All 19/20 920/952 −4.9 ± 2.0 −2.6 ± 1.7 

 With trial arm k900 Sobenin et al., 2009 (38) All 19/20 906/938 −4.7 ± 2.0 −2.4 ± 1.7 

 With trial arm g1 Ried et al., 2013 (40) All 19/20 905/941 −4.7 ± 2.2 −2.5 ± 1.7 

 With trial arm g4 Ried et al., 2013 (40) All 19/20 905/942 −4.9 ± 2.2 −2.5 ± 1.8 

 Excluding trial Nakasone et al., 2013 (41) All 18/19 836/900 −5.2 ± 2.4 −2.5 ± 1.7 

1

Values are means ± SEs unless otherwise indicated. a600, Allicor-600 mg group; AGE, aged garlic extract; DBP, diastolic blood pressure; g1, garlic 1-capsule group; g4, garlic 4-capsule group; GP, garlic powder; k900, Kwai-900 mg group; SBP, systolic blood pressure.


2

Includes the a2400 (Allicor-2400 mg) arm of trial in reference 38 and the g2 (garlic 2)-capsule group of trial in reference 40.


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Table 3 summarizes the results of our updated meta-analysis and earlier meta-analyses on the effect of garlic on blood pressure, illustrating blood pressure status at baseline (hypertensive or normotensive) to be a strong predictor of the magnitude of blood pressure reduction. Side effects of garlic supplements, reported by approximately one-third of participants in the trials, were generally mild and included burping, flatulence, and reflux in the first few weeks of the trial (39, 40). A small percentage of the population (4–6%) may experience more severe gastrointestinal disturbances with therapeutic dosages of garlic supplements (39, 40, 42, 43). The lower tolerance of sulfur-containing foods such as garlic and onion has been linked to genetic variation in detoxification pathways of sulfur-transferase enzymes, as well as inflammatory status, and concentrations of molybdenum and vitamin B-12 (44, 45).



TABLE 3Comparison of meta-analyses on the effect of garlic on blood pressure1

SBP difference (garlic vs. placebo), mm Hg DBP difference (garlic vs. placebo), mm Hg

Authors, year (reference) Trials, n Subjects, n All Hypertensive subgroup Normotensive subgroup Trials, n Subjects, n All Hypertensive subgroup Normotensive subgroup

Silagy and Neil, 1994 (13) 5 347 −7.7 ± 3.4 5 347 −5.0 ± 2.1 — 

  2 87 −11.1 ± 6.1 2 87 −6.5 ± 3.1 — 

Reinhart et al., 2008 (14) 10 444 −3.9 ± 4.4 10 444 −2.8 ± 2.4 — 

  3 139 −16.3 ± 10.1 3 139 −9.3 ± 4.0 — 

  7 305 −0.5 ± 2.6 7 305 −0.9 ± 1.8 

Ried et al., 2008 (2) 10 503 −4.6 ± 2.8 11 567 −2.4 ± 2.5 — 

  4 221 −8.4 ± 2.8 3 127 −7.3 ± 1.5 — 

  6 282 −2.3 ± 2.3 8 440 −0.1 ± 1.3 

Ried (this article) 19 908 −5.1 ± 2.2 20 972 −2.6 ± 1.6 — 

  10 440 −8.7 ± 2.2 8 257 −6.1 ± 1.3 — 

  11 468 −1.5 ± 1.9 14 641 −0.4 ± 1.2 

1

Values are means ± SEs unless otherwise indicated. DBP, diastolic blood pressure; SBP, systolic blood pressure.


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Despite the general medical advice, evidence is weak for garlic supplements, including GP, GO, and AGE, to cause harmful interactions if taken in addition to blood-thinning, blood sugar–regulating, or anti-inflammatory medications (36, 46, 47). Physicians and patients need to be mindful, however, of a potentially harmful interaction of garlic with protease inhibitors in antiretroviral therapy (46).

1 Crushed Garlic Clove a Day...Your Heart & Arteries Will Thank You in Many Ways | Dr Mandell



Other cardiovascular-protective effects of garlic

Effect of garlic on cholesterol.

Several meta-analyses demonstrated a cholesterol-lowering effect of garlic supplements. A recent and most comprehensive meta-analysis including 39 trials and almost 2300 subjects suggested that garlic moderately but significantly lowers total serum cholesterol (−17 ± 6 mg/dL) and LDL cholesterol (9 ± 6 mg/dL) if taken for >2 mo by patients with slightly elevated cholesterol (>200 mg/dL, >5.5 mmol/L) (3). The 8% reduction in serum cholesterol is of clinical relevance and has been associated with a 38% risk reduction in coronary events at age 50 y (48, 49). Trials in the meta-analysis used GP (n = 31), GO (n = 6), AGE (n = 6), and raw garlic (n = 3). Nine of the trials ran between 2 and 8 wk, and 30 trials lasted >8 wk.


Side effects with garlic supplements were minimal, with one-third of participants complaining about odor and 7% experiencing mild gastrointestinal discomfort (3). In comparison, mild gastrointestinal complaints were also described by 7% in the placebo group. In contrast, current standard pharmacologic treatment for cholesterol with statins may trigger adverse effects in a considerable number of patients, including myalgia (muscle pain), muscle weakness, neuropathy, cognitive impairment, mood disorders, anxiety, and an increased risk of diabetes (50–53).


Cholesterol is essential for normal body functions that include preserving the integrity of cell membranes, facilitating cell signaling, maintaining the myelin sheath, and synthesizing steroid hormones, vitamin D, and coenzyme Q10. The inhibition of cholesterol synthesis by statin drugs may interfere with these essential pathways, resulting in detrimental effects for some patients (50–53).


In addition, there is cumulative evidence to suggest that lipoproteins also have a role in the immune response to infection as part of the innate immune system (54). Although HDL cholesterol plays a role in the immune response to viral and parasitic infections, LDL cholesterol appears to be involved in the host defense to bacterial infections (54). Oxidized LDL cholesterol, on the other hand, has been associated with plaque formation and increased risk of heart attack and stroke when accumulated in the endothelium (55). The oxidization of LDL cholesterol may be generated by free radicals through dietary factors, such as consumption of trans fats, deep-fried foods, smoking, or the presence of high blood sugar (56). However, chemical analyses have found oxidized LDL cholesterol to consist of many heterogeneous components, suggesting multiple origins, possibly including interaction with pathogens and their toxins (57).


Because of the many purposes of cholesterol and serum lipoproteins in the human body, some of which are undoubtedly still incompletely understood, cholesterol concentrations need to be adjusted with care. Indeed, there is a growing list of clinical trials in which interference with serum cholesterol led to disappointing—and in some cases detrimental—results (58).


In contrast, garlic supplements have been linked to moderate reduction in cholesterol concentrations, therefore providing an alternative cholesterol-regulating agent with a higher safety profile than statins in patients with slightly elevated cholesterol.


Effect of garlic on immunity.

Historically, garlic has been used for its anti-infective activities, immune-boosting properties, and general strengthening actions (1). In vitro and cell culture studies showed garlic to have antibacterial, antivirus, antifungal, and antiparasitic properties. Garlic was shown to stall growth of food pathogens such as Salmonella, Listeria, Escherichia coli, the stomach bacteria Helicobacter pylori, and the tuberculosis-causing pathogen Mycobacterium tuberculosis (59, 60). In addition, garlic inhibits biofilm formation by bacterial pathogens from burn wounds (61). Garlic's antiviral actions include the human rhinovirus, cytomegalovirus, herpes simplex, and influenza (62). Garlic is effective in the treatment of common yeast and fungal infections such as Candida albicans and Aspergillus flavus (63). Furthermore, garlic shows promise as an antiparasitic agent, helping in the treatment of Cryptosporidium, Toxoplasma, Giardia, and Plasmodium (64).


Garlic is a prebiotic, containing fructans and oligosaccharides, which stimulate the growth of “friendly” bacteria in the digestive tract (65, 66) that in turn make up the microbiome, which contributes to ∼80% of the immune system (67). Garlic was shown to stimulate activation of the humoral and inert immune system, including the activation of macrophages by NO production and T and B cell production (68–70).


Clinical trials have shown garlic to have a beneficial effect in the prevention, duration, and severity of upper respiratory infections. A randomized, double-blind, placebo-controlled trial in 146 participants testing the effect of 180 mg GP/d over 3 mo found a 37% reduction in the number of colds (garlic compared with placebo: n = 24 compared with n = 65; P < 0.001) and a 30% reduction in the duration of illness (garlic compared with placebo: 1.5 compared with 5 d; P < 0.001) in the group taking garlic compared with the placebo group (71).


A recent trial in 120 participants that tested the effect of 2.56 g AGE/d over 3 mo found a 61% reduction in the number of days (garlic compared with placebo: 53 compared with 126 d; P < 0.001) and a 21% reduction in symptoms (garlic compared with placebo: 584 compared with 126; P < 0.001) (70). In this trial, a significant increase in γδ-T cells (P = 0.039) and NK cells (P = 0.043) was shown in the garlic group after 45 d compared with placebo.


In addition, garlic contains the immunomodulatory proteins lectins or agglutinins [allium sativum agglutinin (ASA) I and ASA II] (66, 72). Furthermore, garlic was shown to reduce inflammatory markers, including C-reactive protein and TNF-α (73, 74). A high concentration of inflammatory C-reactive protein has been associated with greater odds of developing coronary artery disease (OR: 1.45; 95% CI: 1.25, 1.68) (75). Therefore, the beneficial effects of garlic on the immune system, including C-reactive protein and cytokines such as ILs and TNF-α, are also associated with improved cardiovascular health.


In conclusion, garlic has the potential to improve cardiovascular health on several levels. First, there is consistent evidence that garlic supplements lower blood pressure in hypertensive individuals. Second, there is strong evidence that garlic modulates cholesterol concentrations when slightly elevated. Third, garlic has several immune system–enhancing properties that directly and indirectly benefit cardiovascular health. Garlic supplements have a high safety profile and are generally well tolerated. Therefore, garlic supplements may be considered as an alternative or complementary treatment in addition to standard medication for cardiovascular health. Further long-term trials are needed to elucidate the effect of garlic supplementation on cardiovascular morbidity and mortality.

Garlic may be useful in addition to medication to treat high blood pressure, a study suggests.


Australian doctors enrolled 50 patients in a trial to see if garlic supplements could help those whose blood pressure was high, despite medication.


Those given four capsules of garlic extract a day had lower blood pressure than those on placebo, they report in scientific journal Maturitas.


The British Heart Foundation said more research was needed.


Garlic has long been thought to be good for the heart.


Garlic supplements have previously been shown to lower cholesterol and reduce high blood pressure in those with untreated hypertension.


In the latest study, researchers from the University of Adelaide, Australia, looked at the effects of four capsules a day of a supplement known as aged garlic for 12 weeks.


They found systolic blood pressure was around 10mmHg lower in the group given garlic compared with those given a placebo.


Researcher Karin Ried said: "Garlic supplements have been associated with a blood pressure lowering effect of clinical significance in patients with untreated hypertension.

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Drink a Glass of Garlic Water Every Day, See What Happens to You



"Our trial, however, is the first to assess the effect, tolerability and acceptability of aged garlic extract as an additional treatment to existing antihypertensive medication in patients with treated, but uncontrolled, hypertension."


Experts say garlic supplements should only be used after seeking medical advice, as garlic can thin the blood or interact with some medicines.


Ellen Mason, senior cardiac nurse at the British Heart Foundation, said using garlic for medicinal purposes dates back thousands of years, but it is essential that scientific research proves that garlic can help conditions such as raised blood pressure.


She said: "This study demonstrated a slight blood pressure reduction after using aged garlic supplements but it's not significant enough or in a large enough group of people to currently recommend it instead of medication.


"It's a concern that so many people in the UK have poorly controlled blood pressure, with an increased risk of stroke and heart disease as a consequence. So enjoy garlic as part of your diet but don't stop taking your blood pressure medication."

A post shared on Facebook in Nigeria claims that garlic can be used to lower high blood pressure.


It also credits the World Health Organization (WHO) with saying garlic helps to reduce blood pressure in patients with moderate hypertension.


“Garlic works in a way to increase the size of the arteries, which makes it easier for blood to pass. In addition, due to its diuretic properties, it reduces the volume of water in the body and therefore blood pressure,” reads part of the post.


The post does include an unusual warning: “Be careful, even regular consumption of garlic does not exempt from appropriate treatment, especially in people with severe hypertension.” 


But is there any scientific evidence that the bulbous flowering plant can be used to manage high blood pressure? 


We checked.


Garlicbloodpressure_False


High blood pressure leads to 9.4 mn deaths annually

According to the WHO, high blood pressure, also called hypertension, is when the force exerted by blood pushing against the walls of the arteries is higher than what is considered normal.


“Hypertension is diagnosed if, when it is measured on two different days, the systolic blood pressure readings on both days are greater than 140 mmHg and/or the diastolic blood pressure readings on both days are greater than 90 mmHg,” says a WHO fact sheet on hypertension.


Blood pressure is measured in units of millimeters of mercury, or mmHg. It is recorded as two numbers, the systolic or upper value first, followed by the diastolic or lower value. 


About 1.13 billion people around the world have high blood pressure, with the majority living in low- and middle-income countries. This leads to about 9.4 million deaths annually, says the WHO.


‘Not approved by health authorities’ – expert

Some studies have documented the potential of garlic in lowering high blood pressure in a similar way to standard medication. A review of trials involving garlic concludes that the vitamin B status of an individual is “an important factor for the responsiveness of high blood pressure to garlic”.


But Basden Onwubere, a professor of medicine at the University of Nigeria in southeastern Nigeria, was sceptical. He told Africa Check: “Such prescriptions cannot be made by doctors.” 


“There are studies that have been published about the use of garlic in managing some health conditions but I am not aware of any traditional medicine that has been approved officially by Nafdac for use in managing high blood pressure,” he said.


Nafdac is Nigeria’s National Agency for Food and Drug Administration and Control, responsible for regulating and controlling drugs, among other substances.


Onwubere said: “Until that [approval] becomes available, what we are using now is the orthodox way of managing hypertension. This is medication and advice on managing the patient’s diet.”


Africa Check has also checked claims on Facebook that ginger or ginger tea can prevent heart attack and stroke, and that mixing lemon, ginger and garlic cures high blood pressure. 


Like this claim, we found no conclusive evidence to support these. Experts advise those with high or elevated blood pressure to ignore miracle cures promoted on social media and seek proper medical care.

Garlic is an herb sometimes used to protect against high blood pressure. Proponents suggest that consuming garlic as food or taking garlic extract in dietary supplement form can help treat high blood pressure or stop high blood pressure from setting in.1




Truth about garlic and diabetes | Garlic and blood sugar



Also known as hypertension, high blood pressure affects about one in three adults in the United States, according to the Centers for Disease Control and Prevention (CDC).2 Garlic is one of the herbs most commonly used to fight high blood pressure.



Garlic Tablets

Jennifer A Smith / Getty Images

How It Works

High blood pressure is a major risk factor for heart disease (the leading cause of death in the U.S.).2 Garlic seems to be able to modestly reduce blood pressure, according to the National Institutes of Health (NIH).3


It's thought that garlic may help lower blood pressure in part by stimulating the production of nitric oxide (a compound that plays a key role in the widening of your blood vessels).1


What Research Says

The available research on garlic and blood pressure includes a report published in BMC Cardiovascular Disorders in 2008. For the report, scientists analyzed 11 previously published clinical trials and found that garlic was superior to placebo in reducing blood pressure among people with hypertension.4


In a 2008 review of 10 clinical trials, results revealed that the use of garlic was associated with a decrease in blood pressure among patients with elevated systolic blood pressure. However, the use of garlic was not associated with decreased blood pressure in study participants without elevated systolic blood pressure.5



A clinical trial published in the European Journal of Clinical Nutrition in 2013 involved 79 people with uncontrolled high systolic blood pressure, each of whom was given either garlic extract at a dose of 240 milligrams (mg), 480 mg, or 960 mg daily, or a placebo, for 12 weeks.1



By the end of the treatment period, those who took either 480 mg or 960 mg of garlic extract daily showed a significant reduction in systolic blood pressure. However, those given 240 mg of garlic extract did not experience a significant decrease in systolic blood pressure.1


Possible Side Effects

Although garlic in normal amounts in food is likely safe for most people, the supplement can cause a number of side effects (including heartburn, nausea, and diarrhea). People with bleeding disorders and pregnant or nursing women shouldn't take garlic.6


Since garlic may slow blood clotting, consuming garlic along with blood-thinning medications (including aspirin and warfarin) or supplements (such as ginkgo) could raise your risk of adverse effects like bleeding and bruising.6


Other Natural Alternatives

A number of lifestyle practices are crucial for controlling your blood pressure. These practices include following a balanced diet, limiting your intake of sodium and alcohol, achieving and/or maintaining a healthy weight, exercising regularly, avoiding smoking, and incorporating stress-reducing techniques into your daily routine.7


There's also some evidence that getting your fill of omega-3 fatty acids, maintaining optimal levels of vitamin D, and consuming cocoa extract on a regular basis may help keep your blood pressure in check.7


 How Hypertension Is Treated

Using Garlic to Lower Your Blood Pressure

While increasing your intake of garlic may help enhance your health and protect against high blood pressure, garlic supplements should not be used as a substitute for standard care of hypertension.


In addition to raising your risk of heart disease, heart attack, and stroke, uncontrolled high blood pressure may lead to major health issues like kidney damage and vision loss. Uncontrolled high blood pressure is also linked to memory impairment.8


If you're considering the use of garlic in the treatment of high blood pressure, make sure to consult your physician prior to starting your supplement regimen.

How many cloves garlic a day?

Garlic is a popular ingredient enjoyed for both its unique flavor and powerful health benefits.


However, garlic is usually sautéed, roasted, or baked before being added to recipes.


For this reason, many people are unsure whether raw garlic is safe to consume.


This article takes a closer look at whether you can eat raw garlic, along with the potential benefits and downsides of doing so.


Sofia Roncero/Addictive Creative/Offset Images

Can you eat raw garlic?

In most recipes, garlic is typically cooked or used in powdered form.


Cooking garlic alters its taste and texture, making it softer, milder, and creamier and giving it a more subtle flavor and aroma.


However, it can also be enjoyed raw rather than cooked.


Although raw garlic tends to have a stronger, more pungent flavor, it can be consumed safely and makes a great addition to many dishes.


In fact, raw garlic is often added to dips, dressings, and sauces like aioli or pesto.


What’s more, raw garlic may even retain more beneficial compounds than cooked garlic and improve several aspects of your health.


SUMMARY

Although raw garlic has a stronger, more pungent flavor than cooked garlic, it’s safe to consume and can be added to various recipes.



Health benefits of raw garlic

Garlic is a great source of allicin, a sulfur-containing compound associated with many health benefits (1Trusted Source).


Allicin, which is responsible for the distinct taste and smell of garlic, is produced when fresh garlic is crushed or chopped (1Trusted Source).


Interestingly, some research suggests that allicin could help enhance the function of your immune system and may offer some protection against conditions like heart disease and cancer (1Trusted Source).


However, studies show that roasting, boiling, heating, or pickling garlic can significantly reduce its allicin content (2Trusted Source, 3Trusted Source).


Therefore, while consuming cooked garlic can be beneficial, opting for raw garlic instead may help maximize its nutritional value.


Here are a few of the potential health benefits of raw garlic:

14 Amazing FOODS THAT LOWER BLOOD PRESSURE!



Improves immunity. Several studies show that garlic may help decrease inflammation and boost immune function, which may be due to its content of antioxidants and sulfur-containing compounds like allicin (4Trusted Source, 5Trusted Source).

Supports heart health. Some research suggests that garlic may help lower blood pressure and decrease cholesterol levels to support heart health (6Trusted Source).

Stabilizes blood sugar levels. Garlic may help reduce fasting blood sugar levels and improve blood sugar management, which may be beneficial for managing type 2 diabetes (7Trusted Source, 8Trusted Source).

Protects brain health. Although research in humans is limited, animal studies show that consuming high amounts of fresh garlic or aged garlic extract could improve memory and support brain health (9Trusted Source, 10Trusted Source, 11Trusted Source).

SUMMARY

Raw garlic retains higher amounts of allicin, a beneficial sulfur-containing compound. Garlic has been shown to improve immunity, stabilize blood sugar levels, and support heart and brain health.


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Potential downsides of eating raw garlic

Although raw garlic may be associated with several health benefits, there are a few potential drawbacks to consider.


First, raw garlic has a much stronger taste and smell than cooked garlic, which some people may find unappetizing.


Additionally, those with gastroesophageal reflux disease (GERD) are often advised to limit their consumption of garlic to prevent heartburn.


In fact, certain compounds found in raw garlic may irritate the digestive tract, which could cause a burning sensation in the chest or stomach (12Trusted Source).


Garlic may also increase the risk of bleeding by preventing the formation of blood clots.


While enjoying raw garlic in moderation is unlikely to cause any issues for most healthy adults, people taking blood thinners should check with their doctor before consuming large amounts of garlic or using garlic supplements (13Trusted Source).


SUMMARY

Garlic could trigger heartburn and irritate the digestive tract. It may also increase the risk of bleeding, especially if consumed in large amounts or used in supplement form.


How much should you eat?

There’s no official recommended dosage for garlic. However, most studies have found that around 1–2 cloves per day could be beneficial (13Trusted Source).


In supplement form, doses of up to 3,600 mg of aged garlic extract have also been shown to be effective (13Trusted Source).


Be sure to talk to your doctor before using garlic supplements, especially if you have any underlying health conditions or are taking medications.


Consider reducing your intake or discontinuing consumption if you notice any negative side effects after eating raw garlic.


Switching to cooked garlic instead of eating it raw may also help ease digestive side effects like heartburn or acid reflux (12Trusted Source).


SUMMARY

Eating 1–2 cloves of raw garlic per day may be beneficial. In supplement form, doses of up to 3,600 mg of aged garlic extract per day have been shown to be effective.


The bottom line

Although raw garlic has a stronger flavor and more pungent smell than cooked garlic, it’s safe to consume.


Raw garlic also retains more allicin, which is the sulfur-containing compound responsible for many of garlic’s beneficial health effects.


For best results, aim for around 1–2 cloves per day and reduce your intake if you experience any side effects, such as heartburn, acid reflux, or increased bleeding.

What home remedy can I use to lower my blood pressure?

High blood pressure is a dangerous condition that can damage your heart. It affects one in three people in the US and 1 billion people worldwide (1Trusted Source, 2).


If left uncontrolled, high blood pressure raises your risk of heart disease and stroke.


But there’s good news. There are a number of things you can do to lower your blood pressure naturally, even without medication.


Here are 15 natural ways to combat high blood pressure.

Lower Blood Pressure with These 3 Foods



1. Walk and exercise regularly

Regular exercise can help lower your blood pressure.

Exercise is one of the best things you can do to lower high blood pressure.


Regular exercise helps make your heart stronger and more efficient at pumping blood, which lowers the pressure in your arteries.


In fact, 150 minutes of moderate exercise, such as walking, or 75 minutes of vigorous exercise, such as running, per week, can help lower blood pressure and improve your heart health (3Trusted Source, 4Trusted Source).


What’s more, doing even more exercise than this reduces your blood pressure even further, according to the National Walkers’ Health Study (5Trusted Source).


Bottom line: Walking just 30 minutes a day can help lower your blood pressure. More exercise helps reduce it even further.



2. Reduce your sodium intake

Salt intake is high around the world. In large part, this is due to processed and prepared foods.


For this reason, many public health efforts are aimed at lowering salt in the food industry (6Trusted Source).


Many studies have linked high salt intake with high blood pressure and heart events, including stroke (7Trusted Source, 8Trusted Source).


However, more recent research indicates that the relationship between sodium and high blood pressure is less clear (9Trusted Source, 10).


One reason for this may be genetic differences in how people process sodium. About half of people with high blood pressure and a quarter of people with normal levels seem to have a sensitivity to salt (11Trusted Source).


If you already have high blood pressure, it’s worth cutting back your sodium intake to see if it makes a difference. Swap out processed foods with fresh ones and try seasoning with herbs and spices rather than salt.


Bottom line: Most guidelines for lowering blood pressure recommend reducing sodium intake. However, that recommendation might make the most sense for people who are salt-sensitive.


3. Drink less alcohol

Drinking alcohol can raise blood pressure. In fact, alcohol is linked to 16% of high blood pressure cases around the world (12Trusted Source).


While some research has suggested that low-to-moderate amounts of alcohol may protect the heart, those benefits may be offset by adverse effects (12Trusted Source).


In the U.S., moderate alcohol consumption is defined as no more than one drink a day for women and two for men. If you drink more than that, cut back.


Bottom line: Drinking alcohol in any quantity may raise your blood pressure. Limit your drinking in line with the recommendations.


4. Eat more potassium-rich foods

Potassium is an important mineral.


It helps your body get rid of sodium and eases pressure on your blood vessels.


Modern diets have increased most people’s sodium intake while decreasing potassium intake (13Trusted Source).


To get a better balance of potassium to sodium in your diet, focus on eating fewer processed foods and more fresh, whole foods.


Foods that are particularly high in potassium include:


vegetables, especially leafy greens, tomatoes, potatoes, and sweet potatoes

fruit, including melons, bananas, avocados, oranges, and apricots

dairy, such as milk and yogurt

tuna and salmon

nuts and seeds

beans

Bottom line: Eating fresh fruits and vegetables, which are rich in potassium, can help lower blood pressure.


Use Aged Garlic for High Blood Pressure



5. Cut back on caffeine

If you’ve ever downed a cup of coffee before you’ve had your blood pressure taken, you’ll know that caffeine causes an instant boost.


However, there’s not a lot of evidence to suggest that drinking caffeine regularly can cause a lasting increase (14Trusted Source).


In fact, people who drink caffeinated coffee and tea tend to have a lower risk of heart disease, including high blood pressure, than those who don’t drink it (15Trusted Source, 16Trusted Source, 17Trusted Source, 18Trusted Source).


Caffeine may have a stronger effect on people who don’t consume it regularly (19).


If you suspect you’re caffeine-sensitive, cut back to see if it lowers your blood pressure (20Trusted Source).


Bottom line: Caffeine can cause a short-term spike in blood pressure, although for many people, it does not cause a lasting increase.


6. Learn to manage stress

Listening to soothing music may help lower stress.

Stress is a key driver of high blood pressure.


When you’re chronically stressed, your body is in a constant fight-or-flight mode. On a physical level, that means a faster heart rate and constricted blood vessels.


When you experience stress, you might also be more likely to engage in other behaviors, such as drinking alcohol or eating unhealthful food that can adversely affect blood pressure.


Several studies have explored how reducing stress can help lower blood pressure. Here are two evidence-based tips to try:


Listen to soothing music: Calming music can help relax your nervous system. Research has shown it’s an effective complement to other blood pressure therapies (21Trusted Source, 22Trusted Source).

Work less: Working a lot, and stressful work situations, in general, are linked to high blood pressure (23Trusted Source, 24Trusted Source).

Bottom line: Chronic stress can contribute to high blood pressure. Finding ways to manage stress can help.


7. Eat dark chocolate or cocoa

Here’s a piece of advice you can really get behind.


While eating massive amounts of dark chocolate probably won’t help your heart, small amounts may.


That’s because dark chocolate and cocoa powder are rich in flavonoids, which are plant compounds that cause blood vessels to dilate (25Trusted Source).


A review of studies found that flavonoid-rich cocoa improved several markers of heart health over the short term, including lowering blood pressure (25Trusted Source).


For the strongest effects, use non-alkalized cocoa powder, which is especially high in flavonoids and has no added sugars.


Bottom line: Dark chocolate and cocoa powder contain plant compounds that help relax blood vessels, lowering blood pressure.


8. Lose weight

In people with overweight, losing weight can make a big difference to heart health.


According to a 2016 study, losing 5% of your body mass could significantly lower high blood pressure (26Trusted Source).


In previous studies, losing 17.64 pounds (8 kilograms) was linked to lowering systolic blood pressure by 8.5 mm Hg and diastolic blood pressure by 6.5 mm Hg (27Trusted Source).


To put that in perspective, a healthy reading should be less than 120/80 mm Hg (4Trusted Source).


The effect is even greater when weight loss is paired with exercise (27Trusted Source).


Losing weight can help your blood vessels do a better job of expanding and contracting, making it easier for the left ventricle of the heart to pump blood.


Bottom line: Losing weight can significantly lower high blood pressure. This effect is even more significant when you exercise.


9. Quit smoking

Among the many reasons to quit smoking is that the habit is a strong risk factor for heart disease.


Every puff of cigarette smoke causes a slight, temporary increase in blood pressure. The chemicals in tobacco are also known to damage blood vessels.


Surprisingly, studies haven’t found a conclusive link between smoking and high blood pressure. Perhaps this is because smokers develop a tolerance over time (28Trusted Source).


Still, since both smoking and high blood pressure raise the risk of heart disease, quitting smoking can help lessen that risk.


Bottom line: There’s conflicting research about smoking and high blood pressure, but what is clear is that both increase the risk of heart disease.


10. Cut added sugar and refined carbs

There’s a growing body of research showing a link between added sugar and high blood pressure (29Trusted Source, 30, 31).


In the Framingham Women’s Health Study, women who drank even one soda per day had higher levels than those who drank less than one soda per day (32Trusted Source).


Another study found that having one less sugar-sweetened beverage per day was linked to lower blood pressure (33Trusted Source).


And it’s not just sugar — all refined carbs, such as the kind found in white flour — convert rapidly to sugar in your bloodstream and may cause problems.


Some studies have shown that low carb diets may also help reduce blood pressure.


One study on people undergoing statin therapy found that those who went on a 6-week, carb-restricted diet saw a greater improvement in blood pressure and other heart disease markers than people who did not restrict carbs (34Trusted Source).


Bottom line: Refined carbs, especially sugar, may raise blood pressure. Some studies have shown that low carb diets may help reduce your levels.

Reversing High Blood Pressure in 30 Days with Dr. David DeRose



11. Eat berries

Berries are full of more than just juicy flavor.


They’re also packed with polyphenols, natural plant compounds that are good for your heart.


Polyphenols can reduce the risk of stroke, heart conditions, and diabetes, as well as improving blood pressure, insulin resistance, and systemic inflammation (34).


One study assigned people with high blood pressure to a low-polyphenol diet or a high-polyphenol diet containing berries, chocolate, fruits, and vegetables (35).


Those consuming berries and polyphenol-rich foods experienced improved markers of heart disease risk.


Bottom line: Berries are rich in polyphenols, which can help lower blood pressure and the overall risk of heart disease.


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12. Try meditation or deep breathing

While these two behaviors could also fall under “stress reduction techniques,” meditation and deep breathing deserve specific mention.


Both meditation and deep breathing may activate the parasympathetic nervous system. This system is engaged when the body relaxes, slowing the heart rate, and lowering blood pressure.


There’s quite a bit of research in this area, with studies showing that different styles of meditation appear to have benefits for lowering blood pressure (36Trusted Source, 37Trusted Source).


Deep breathing techniques can also be quite effective.


In one study, participants were asked to either take six deep breaths over the course of 30 seconds or simply sit still for 30 seconds. Those who took breaths lowered their blood pressure more than those who just sat (38Trusted Source).


Try guided meditation or deep breathing. Here’s a video to get you started.


Bottom line: Both meditation and deep breathing can activate the parasympathetic nervous system, which helps slow your heart rate and lower blood pressure.


13. Eat calcium-rich foods

People with low calcium intake often have high blood pressure.


While calcium supplements haven’t been conclusively shown to lower blood pressure, calcium-rich diets do seem linked to healthful levels (39Trusted Source, 40Trusted Source).


For most adults, the calcium recommendation is 1,000 milligrams (mg) per day. For women over 50 and men over 70, it’s 1,200 mg per day (41).


In addition to dairy, you can get calcium from collard greens and other leafy greens, beans, sardines, and tofu. Here is a list of calcium-rich plant-based foods.


Bottom line: Calcium-rich diets are linked to healthy blood pressure levels. You can get calcium through eating dark leafy greens and tofu, as well as dairy.


14. Take natural supplements

Some natural supplements may also help lower blood pressure. Here are some of the main supplements that have evidence behind them:


Aged garlic extract: Researchers have used aged garlic extract successfully as a stand-alone treatment and along with conventional therapies for lowering blood pressure (42Trusted Source, 43Trusted Source).

Berberine: Traditionally used in Ayurvedic and Chinese medicine, berberine may increase nitric oxide production, which helps decrease blood pressure (44Trusted Source, 45Trusted Source).

Whey protein: A 2016 study found that whey protein improved blood pressure and blood vessel function in 38 participants (46Trusted Source).

Fish oil: Long credited with improving heart health, fish oil may benefit people with high blood pressure the most (47Trusted Source, 48).

Hibiscus: Hibiscus flowers make a tasty tea. They’re rich in anthocyanins and polyphenols that are good for your heart and may lower blood pressure (49Trusted Source).

Read more about supplements for high blood pressure here.


Bottom line: Researchers have investigated several natural supplements for their ability to lower blood pressure.


15. Eat foods rich in magnesium

Magnesium is an important mineral that helps blood vessels relax.


While magnesium deficiency is pretty rare, many people don’t get enough.


Some studies have suggested that getting too little magnesium is linked with high blood pressure, but evidence from clinical studies has been less clear (50Trusted Source, 51Trusted Source).


Still, eating a magnesium-rich diet is a recommended way to ward off high blood pressure (51Trusted Source).


You can incorporate magnesium into your diet by consuming vegetables, dairy products, legumes, chicken, meat, and whole grains.

Natural Ways to Lower Blood Pressure



Bottom line: Magnesium is an essential mineral that helps regulate blood pressure. Find it in whole foods, such as legumes and whole grains.


Take home message

High blood pressure affects a large proportion of the world’s population.


While drugs are one way to treat the condition, there are many other natural techniques, including eating certain foods that can help.


Read more about foods that help lower blood pressure here.


Controlling your blood pressure through the methods in this article may, ultimately, help you lower your risk of heart disease.

Can garlic cure BP?

High blood pressure, also known as hypertension, is a condition that affects about one in three adults in Western countries. It often comes with no symptoms yet significantly increases a person’s risk of heart disease and stroke (1Trusted Source).


Blood-pressure-lowering drugs often cause a range of unpleasant side effects, which helps explain the growing interest in potentially effective natural remedies, such as garlic.


This article discusses whether garlic is a safe and effective way to naturally lower your blood pressure, and if so, which forms are most effective.


Cavan Images/Offset Images


What is garlic’s effect on blood pressure?

Garlic (Allium sativum) is a vegetable that has been used as a natural blood-pressure-lowering remedy since ancient times (2Trusted Source).


Recent research suggests this may be for good reason, as garlic appears to be a very effective remedy against high blood pressure. In fact, some studies report it to be as effective as standard blood-pressure-lowering medications — with much fewer side effects (3Trusted Source).


One review of randomized controlled trials (RCT) — the gold standard in research — reported that garlic supplements may reduce systolic and diastolic blood pressure (the top and bottom numbers of a reading) by 6.7 and 4.8 mmHg, respectively, with no serious side effects.


The studies included in the review provided participants with 188–2,400 mg of garlic powder supplements or aged garlic extracts per day and lasted 8–12 weeks (4Trusted Source).


Several other recent reviews support these results, with many reporting blood pressure reductions ranging from 2.5–11.2 mm Hg following taking 600–2,400 mg of garlic powder per day for 8–24 weeks (3Trusted Source, 5Trusted Source, 6).


It’s noteworthy that although garlic’s blood-pressure-lowering effects appear universal, they seem greatest in people with elevated blood pressures, compared with those with blood pressures within the normal range (5Trusted Source).


SUMMARY

Garlic may help reduce systolic and diastolic blood pressure levels by up to 11.2 mm Hg. In some instances, garlic supplements may work as effectively as standard blood-pressure-lowering medications, with much fewer side effects.


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How does it work?

Allicin, the main active compound in garlic, is thought to be largely responsible for garlic’s blood-pressure-lowering properties.


Research suggests that allicin may prevent the production of angiotensin II, a compound responsible for increasing blood pressure by causing your blood vessels to tighten up or contract (1Trusted Source, 2Trusted Source).


By preventing the production of angiotensin II, allicin’s effects make it easier for your blood to flow freely, in turn, reducing your blood pressure.


Allicin also appears to increase the production or availability of hydrogen sulfide and nitric oxide, two compounds crucial for regulating blood pressure levels (1Trusted Source, 7Trusted Source).


Moreover, experts believe that garlic’s anti-inflammatory and antioxidant properties may further contribute to garlic’s ability to reduce or prevent rises in blood pressure levels (1Trusted Source, 2Trusted Source, 7Trusted Source).


SUMMARY

Garlic may help reduce blood pressure by preventing the production of angiotensin II, enhancing the availability of nitric oxide, or increasing the production of hydrogen sulfide. Its anti-inflammatory and antioxidant properties may further help.


Safety

Garlic has been used for over 5,000 years to prevent and treat disease, with few reports of side effects (1Trusted Source).


To date, the majority of studies suggest that garlic supplements are very safe. The most commonly reported side effects include garlic breath, taste, or body odor.


Stomach upset, gas, reflux, or abdominal pain are also somewhat common, but complaints generally remain minor (6).


Other side effects may include hypersensitivity, headaches, dry mouth, coughs, hot flushes, mouth ulcers, and drowsiness, but these are considered rare (6).


Side effects appear to be most common when eating large quantities of garlic, and less common when garlic powder supplements or aged garlic extracts are used (1Trusted Source).


Large intakes of garlic, whether through diet or supplements, may thin the blood and increase the risk of bleeding when combined with anti-coagulant medication. If you’re currently taking medications, speak with your healthcare provider before drastically increasing your garlic intake (8Trusted Source).


SUMMARY

Garlic is generally considered safe. Side effects appear minor or rare and may be most likely to occur upon consuming raw garlic rather than aged garlic extracts or garlic powder supplements.


Effective dosages and forms

So far, most studies reporting blood-pressure-lowering effects have provided participants with the following forms and amounts of garlic (3Trusted Source, 4Trusted Source, 5Trusted Source, 6):

Blood Pressure: How High is Too High and How Do I Lower it Safely?



188 mg of egg-yolk-containing garlic powder per day for 12 weeks

400 mg of raw garlic per day for 6 months

240–2,400 mg of aged garlic extracts per day for 2–23 weeks

600–2,400 mg of garlic powder per day for 8–24 weeks

12.3 mg of garlic oil per day for 16 weeks

Although blood pressure reductions have been observed with all of the forms above, some suggest that aged garlic extracts may be the most beneficial (6).


In any case, speak with your healthcare provider before trying garlic as a blood-pressure-lowering remedy. They can help you figure out the best form and most effective dosage.


SUMMARY

Raw garlic, garlic powder, aged garlic extracts, or garlic oil all appear to help lower blood pressure. Effective dosages range from 12.3–2,400 mg per day for 2–24 weeks, depending on the form taken.



Other natural blood pressure remedies

In addition to garlic, other potentially effective natural blood-pressure-reducing remedies include (2Trusted Source, 9Trusted Source, 10Trusted Source):


coenzyme Q10

vitamin C

long-chain omega-3s

ginseng

probiotics

lipoic acid

whole grains

potassium

vitamin E

polyphenols

vanadium

Keep in mind that although the use of many of these supplements to treat hypertension is supported by a large body of evidence, it’s always important to check with your doctor before adding any dietary supplement to your diet (11Trusted Source).


SUMMARY

Other natural blood-pressure-lowering remedies exist. That said, it’s always best to consult your doctor before adding any dietary supplement to your diet.


The bottom line

Garlic is a safe and effective natural blood-pressure-lowering remedy.


It can be consumed in various forms, including raw garlic, garlic oil, aged garlic extracts, and garlic powder supplements.


Relatively large doses are needed before effects are noticeable, but these remedies appear to be as effective as conventional blood pressure medications, with much fewer side effects. Therefore, using garlic as a natural blood-pressure-lowering remedy may be worth a try.


Still, be sure to speak with your healthcare provider before adding a garlic supplement to your routine, especially if you’re taking medications or have an underlying health condition.

How long does it take for garlic to lower blood pressure fast?

Garlic supplements have shown effectiveness in reducing blood pressure in hypertensive patients, similarly to first-line standard anti-hypertensive medications. Kyolic garlic has also shown promise in improving cardiovascular health by reducing arterial stiffness, elevated cholesterol levels and blood ‘stickiness’. In addition, the prebiotic properties in garlic increase gut microbial richness and diversity. This article systematically reviews previously published trials investigating the effects of garlic on blood pressure, and provides an updated meta-analysis of hypertensive participants. In addition, we summarise the findings of recent clinical trials investigating the effects of Kyolic aged garlic extract on arterial stiffness, and gut microbiota in hypertensive subjects. We searched online electronic databases, including PubMed and Google Scholar for randomised controlled trials (RCTs) published between 1955 and December, 2018 examining the effects of garlic on high blood pressure. The meta-analysis of 12 trials and 553 hypertensive participants confirmed that garlic supplements lower systolic blood pressure (SBP) by an average of 8.3±1.9 mmHg and diastolic blood pressure (DBP, n=8 trials, n=374 subjects) by 5.5±1.9 mmHg, similarly to standard anti-hypertensive medications. This reduction in blood pressure was associated with a 16–40% reduction in the risk of suffering from cardiovascular events. Additionally, this review summarises new evidence for the vitamin B12 status playing an important role in the responsiveness of blood pressure to garlic. Furthermore, Kyolic aged garlic extract significantly lowered central blood pressure, pulse pressure, pulse wave velocity and arterial stiffness, and improved the gut microbiota, evidenced by higher microbial richness and diversity, with a marked increase in the numbers of Lactobacillus and Clostridia species found following 3 months of supplementation. Thus, Kyolic aged garlic extract is considered to be highly tolerable with a high safety profile either as a stand-alone or adjunctive anti-hypertensive treatment, with multiple benefits for cardiovascular health.


Keywords: aged garlic extract, blood pressure, hypertension, meta-analysis, pulse wave velocity, arterial stiffness, gut microbiome

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Introduction

Previous meta-analyses and recent clinical trials have demonstrated that garlic supplements, including Kyolic aged garlic extract, are effective in reducing blood pressure in patients with uncontrolled hypertension, similar to first-line standard anti-hypertensive medications (1–8). Uncontrolled hypertension, defined as systolic blood pressure (SBP) ≥140 mmHg and/or a diastolic blood pressure (DBP) ≥90 mmHg, including treated and untreated hypertensive patients, is prevalent in about a quarter (25%) of the adult population in Western countries (9). Up to 62% of patients on standard blood pressure medication experience adverse effects, such as fatigue, cold hands/feet, dry mouth, dizziness, headaches, muscular cramp/myalgia (10), thus highlighting the need for a more tolerable alternative therapeutic option.


A recent meta-analysis on the effects of garlic supplements on blood pressure, including 20 trials and >900 participants, revealed a significant effect of garlic on blood pressure, with an average decrease in SBP of 8.6 mm and 6.1 mm in DBP in hypertensive subjects (n=14 trial arms, n=468 participants) (4).


To date, our group has conducted a number of clinical trials investigating the effects of Kyolic on blood pressure (5–8). Our first clinical trial including a pre-hypertensive group of adults (SBP ≥130 mmHg) revealed that Kyolic garlic significantly reduced blood pressure in the hypertensive subgroup (SBP ≥140 mmHg), but not in the normotensive subgroup (SBP <140 mmHg) (5). This suggests that Kyolic aged garlic extract normalises blood pressure, in contrast to standard blood pressure medications, including angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), beta blockers (BBs), calcium channel blockers (CCBs), diuretics (Ds), which may sometimes lead to hypotension.


Our second dose-response trial revealed that a dose of 2 capsules/day of Kyolic aged garlic extract was sufficient to achieve an average blood pressure-lowering effect of 10 mmHg systolic and 5 mmHg diastolic, within 2–3 months (6). By contrast, 1 capsule per day was insufficient, whereas 4 capsules/day were not superior to 2 capsules/day. Two capsules of the High Potency Formula of Kyolic (Wagner/Nutralife available in Australia/New Zealand) contains 480 mg of concentrated aged garlic extract powder and 1.2 mg S-allyl cysteine (SAC), and are equivalent to 2 capsules of the Reserve Formula of Kyolic (Wakunaga of America available in the USA), containing 1.2 g of aged garlic extract powder and 1.2 mg of SAC.


In our third ‘AGE at Heart’ trial we found Kyolic to be effective in reducing peripheral blood pressure, as well as central blood pressure, central pulse pressure, pulse wave velocity and arterial stiffness (7). Central hemodynamic measures, such as central blood pressure, pulse wave velocity, pulse pressure and arterial stiffness, are regarded as more important predictors than peripheral blood pressure for cardiovascular disease risk (11,12). Arterial stiffness, an indicator of the flexibility of the arteries, increases with age through the loss of intact elastin and collagen fibres in the arterial wall (13,14), which also contributes to increased blood pressure (15). Kyolic aged garlic extract has been shown to be effective in reducing arterial stiffness, which in turn is related to better heart health and aerobic fitness, while the risk of cardiovascular disease is reduced (7,8,12).


While in the ‘AGE at Heart’ trial (7), the average blood pressure reduction observed in the garlic group (n=50) compared to the placebo (n=38) was statistically significant and comparable to that of previous studies (5,6), in a subgroup of participants, blood pressure was not appreciably altered (SBP ≤5 mmHg, DBP ≤3 mmHg) over the 3 months course of the study (n=21 non-responders). We hypothesised that this non-response of blood pressure to garlic may be related to a deficiency in co-factors, including the B vitamins, and in particular folate, vitamin B2, vitamin B6 and vitamin B12, as these are essential co-factors in the mechanisms of action of garlic as regards the reduction of blood pressure (16).


Briefly, the mechanisms of action through which garlic influences blood pressure involve two main signalling pathways via nitric oxide (NO) and hydrogen sulphide (H2S) production (16). Garlic, a sulphur donor, provides an important component for the trans-sulphuration pathway, which is linked to the methylation pathway, with both requiring several co-factors, such as vitamin B12, folate, vitamin B2 and vitamin B6. In addition, known genetic variants for the cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) enzymes influence the efficiency of H2S production, and thus are considered to play an important role in the susceptibility to developing hypertension, in conjunction with deficiencies in B vitamins. We have previously identified a potentially large proportion (80%) of healthy adults in Australia with sub-optimal vitamin B12 levels (<500 pg/l) (17). Therefore, deficiencies in co-factors, such as vitamin B12, may explain the individual responsiveness of blood pressure to garlic observed in our clinical trials.


Furthermore, as high blood pressure has been linked to the dysbiosis of gut microbiota, both in animal and human studies, with a significant lower microbial richness and diversity in hypertensive subjects compared to normotensive subjects (18), we investigated the effects of Kyolic garlic on the microbiome in our most recent clinical study, the GarGIC trial (8). In general, a higher relative abundance/bacterial mass/microbial richness and a diversity of microbial species is associated with better health (18–20).


With its prebiotic properties, and the source of intracellular H2S (16,21), garlic has the potential to modulate the gut microbiota (22), and to restore the microbiota biofilm and mucus production (23). The timeframe for changes to be observed in the composition of the gut microbiota with dietary supplementation is relatively short, as shown in a 4-week study of patients with irritable bowel syndrome taking probiotics daily (24). In addition, the consumption of probiotics has been shown to significantly reduce blood pressure, in particular in trials of >8 weeks duration (meta-analysis of 9 RCTs involving 534 patients) (25).


In this study, we revise the meta-analyses on garlic and blood pressure in hypertensive subjects, including additional recent clinical trials. In addition, we review the role of B vitamins in the responsiveness of blood pressure to garlic, and summarise the effects of Kyolic aged garlic extract on arterial stiffness and gut microbiota.

How to Lower Your Blood Pressure with Garlic Pills



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Data and methods

For the meta-analysis of the effects of garlic on blood pressure in hypertensive subjects, we included randomised double-blind placebo-controlled trials on garlic for blood pressure with a minimum of 2 months duration, identified in previous meta-analyses: Specifically, Silagy and Neil, 1994 (26), Reinhart et al, 2008 (2), Ried et al, 2008 (1), Rohner et al, 2014 (3) and Ried, 2016 (4). We extended the search in Medline for trials published between 1955 and December, 2018 with no language restrictions, using the search terms ‘garlic’ AND ‘blood pressure’ OR ‘hypertension’.


We included studies with adults with uncontrolled hypertension [mean ± standard deviation (SD): SBP, ≥140±2 mmHg and/or DBP, ≥90±2 mmHg], using garlic-only supplements, and reporting the mean SBP and/or DBP with SD or standard error (SE) at baseline and at end of the intervention. We included hypertensive subjects on an established plan of blood pressure medication, or subjects who were not taking any blood pressure medication at time of the trial. We excluded trials and trial arms with normotensive subjects, trials or trial arms using garlic-combination products, and trials with a very high attrition rate (loss to follow-up, >30%).


For the meta-analysis, we entered the mean SBP and DBP into the Review Manager 5.3 program (27) using the inverse variance method and a random effects model. When blood pressure measurements were reported in >1 position, the order of preference was as follows: i) Sitting; ii) standing; and iii) in the supine position. When both clinical and ambulatory blood pressure measurements were available, the order of preference was as follows: i) clinical; and ii) ambulatory. If results were reported for several periods of follow-up, we selected the longest follow-up from each study for comparison with the baseline. The outcomes were calculated as mean differences in SBP and DBP between the garlic and control groups at the final follow-up adjusted for baseline. We assessed heterogeneity by the I2 statistic, and overall significance with a P-value using the Review Manager program, as outlined in the Cochrane Handbook (27).


The risk of bias for each trial included the assessment of random sequence generation (selection bias), allocation concealment (selection bias), incomplete outcome data (attrition bias), selective reporting (reporting bias), blinding of participants and personnel (performance bias), and the blinding of outcome assessment (detection bias) (27).


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Results

A total of 12 trials involving 553 participants with hypertension were identified as meeting the inclusion criteria (5–8,28–34), including 2 new trials (7,8) that were not part of the most recently published meta-analyses (4). For trials with multiple intervention arms (6,34), only the main arm was included in this updated meta-analysis, in order to avoid the double-counting of placebo groups. For trials with hypertensive and normotensive subgroups (5,7,35), only the hypertensive subgroup was included in this updated meta-analysis (Table I).


Table I.

Characteristics of trials included in the meta-analysis of garlic on blood pressure in hypertensives (SBP ≥140 mmHg, DBP ≥90 mmHg at baseline).


Author/(Refs.), year No. of subjects (garlic/control group) Garlic type Brand Country of manufacture Dosage (mg/day) Dosage of active ingredient per day Duration (weeks) Garlic Baseline mean SBP/DBP (mmHg) Control Baseline mean SBP/DBP (mmHg)

Kandziora et al (28), 1988 20/20 GP Kwai Germany 600 7.8 mg alliin 12 174/99 175/98

Auer et al (29), 1990 24/23 GP Kwai Germany 600 7.8 mg alliin 12 171/102 161/97

Vorberg and Schneider (30), 1990 20/20 GP Kwai Germany 900 11.7 mg alliin 16 144.5/91 144/88

Holzgartner et al (31), 1992 47/47 GP Kwai Germany 900 11.7 mg alliin 12 143/83 141/82

Santos and Gruenwald (32), 1993 25/27 GP Kwai Germany 900 11.7 mg alliin 24 143/89 144/89

Sobenin et al (33), 2008 23/19 GP Allicor Russia 600 7.8 mg allicin pt 12 143/89 140/88

Sobenin et al (34), 2009 G2: 18/20 GP Allicor Russia 2400 31.2 mg allicin 8 153/95 150/94

Ried et al (5), 2010 HT: 6/10 AGE Kyolic High Potency USA for Australia/NZ 960 (4 caps) 2.4 mg SAC 12 135/74 141/76

Ried et al (6), 2013 G2: 20/17 AGE Kyolic High Potency USA for Australia/NZ 480 (2 caps) 1.2 mg SAC 12 149/76 149/76

Nakasone et al (35), 2013 HT: 23/24 GPjpn Dentou ninniku ranwo™ Japan 188 NR 12 HT: 142/91 HT: 142/92

Ried et al (7), 2016 HT: 38/26 AGE Kyolic Reserve USA 1200 (2 caps) 1.2 mg SAC 12 HT: 154/96 HT: 146/93

Ried et al (8), 2018 23/26 AGE Kyolic Reserve USA 1200 (2 caps) 1.2 mg SAC 12 153/93 144/90

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AGE, aged garlic extract; GP, garlic powder; GPjpn, Japanese garlic powder containing egg yolk; G2, main garlic group, P, placebo group; HT, hypertensive subgroup; RG, raw garlic; mg; milligram; mg/dl, milligram per decilitre; mmHg, millimetre of mercury; NA, not applicable; NR, not reported; NZ, New Zealand; pt, potential; SAC, S-allylcysteine; SBP/DBP, systolic/diastolic blood pressure.


Not all participants of the trials included in the meta-analysis on systolic hypertension also suffered from diastolic hypertension. Eight out of the 12 trials involving 374 subjects met the inclusion criteria for the meta-analysis of diastolic hypertension (7,8,28–30,32,34,35).


A further two trials published between 2013 and 2018, examining the effects of a garlic product on blood pressure, were excluded from the meta-analysis, as one trial testing patients with severe coronary artery disease did not include hypertensive subjects (36), and the other trial was not of sufficient quality (37). The latter trial of 80 participants and 4 groups investigated a combination of garlic and coriander seed powder (details of active ingredients or production were not provided), did not report on compliance or loss-to-follow-up, and provided no placebo supplement to the control group (37).


The meta-analysis of 12 trials involving adults with hypertension confirmed that the garlic supplements significantly lowered SBP by 8.32±1.93 mmHg (n=12 trials, n=553 participants, P<0.00001), and DBP by 5.48±1.92 mmHg (n=8 trials, n=374 participants, P<0.00001) (Figs. 1 and ​and22).


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Figure 1.

Meta-analysis of the effects of garlic on systolic blood pressure (SBP) in hypertensive adults. a2400, Allicor-2400mg group; g2, Kyolic garlic-2-capsule group; h, hypertensive subgroup; IV, inverse variance method; SD, standard deviation; I2 statistic of Heterogeneity; Weight; influence of study on meta-analysis depending on sample size and 95% CI.


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Figure 2.

Meta-analysis of the effects of garlic on diastolic blood pressure (DBP) in hypertensive adults. a2400, Allicor-2400mg group; h, hypertensive subgroup; IV, inverse variance method; SD, standard deviation.


The included trials were of high quality with a minimal risk of bias (Figs. 1 and ​and2).2). An unclear risk of attrition bias was encountered in 2 trials (28,29), which did not report on the loss to follow-up, one trial (32) reported 20% attrition in the garlic group and 11% in the placebo group, and another trial (33) reported 27% attrition in the garlic group, and none in the placebo group. No details on blood pressure measurements were reported in 2 trials (32,33), leading to an unclear risk of detection bias, and no details on allocation concealment were reported in another trial (30). Resulting in an unclear risk of selection bias.

HOW TO EAT GARLIC TO REDUCE BP/ELIMINATE BAD BREATH



Eight out of the 12 trials used garlic powder, either Kwai manufactured in Germany (n=5) (28–32), Allicor from Russia (n=2) (33,34), or a garlic powder manufactured in Japan (n=1) (35), while 4 trials investigated Kyolic aged garlic extract (5–8). Kyolic aged garlic extract powder is manufactured from organically grown garlic bulbs, which has undergone a 20-month aging process in 70% ethanol at room temperature. During the aging process, volatile sulphur components found in raw garlic, such as allicin, are chemically converted into stable and standardisable components, including the main vasoactive component, SAC (38–40).


In two of our clinical trials, Ried et al, 2010 (5) and Ried et al, 2013 (6), we used the ‘Kyolic High Potency Formula’ available in Australia and New Zealand (240 mg of concentrated aged garlic extract containing 600 µg SAC per capsule). In our 2 previous trials [Ried et al, 2016 (7) and Ried et al, 2018 (8)], we used the ‘Kyolic Reserve Formula’ (600 mg of aged garlic extract powder containing 600 µg SAC per capsule). Both Kyolic formulas are comparable by dosage of the active ingredient SAC (Table I). The majority of trials used between 600–900 mg of garlic powder per day or 1,200 mg of Kyolic aged garlic extract for a median trial period of 12 weeks (Table I).


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Discussion

Our meta-analyses on the effects of garlic on hypertension, including 12 trials and 553 adults with high blood pressure, suggested that garlic supplements significantly lower SBP by an average of 8.3±1.9 mmHg and DBP (n=374) by 5.5±1.9 mmHg.


The average reduction in SBP of 8–10 mmHg induced by garlic supplements, alone or in combination with other blood pressure medications, is comparable to that of conventional standard blood pressure drug therapeutics, estimated to reduce the risk of cardiovascular events, such as heart attack, coronary artery disease, or stroke by 16–40% (41,42).


In our clinical trials, in a proportion of participants, blood pressure was not appreciably altered (>5 mmHg SBP and >3 mmHg DBP; 30 or 17%, respectively), possibly owing to a suboptimal B vitamin status (7,8). Some B vitamins are important co-factors in the mechanisms of action through which sulphur components in garlic are transformed into H2S, serving as signalling molecules for smooth muscle cell relaxation and vasodilation, leading to a reduction in blood pressure (16,43).


In addition to the beneficial effects of garlic supplements on blood pressure, we, as well as others have found that Kyolic aged garlic extract is effective in rejuvenating the arteries, as evidenced by a reduction in pulse wave velocity (7,8,12). While arterial stiffness increases naturally with age by an average of 1.43 m/sec pulse wave velocity in 10 years (13,14), our findings suggested that Kyolic aged garlic extract has the potential to reverse the ageing of the arteries and therefore, arterial stiffness by approximately 5 years, as evidenced by a mean reduction in pulse wave velocity by 0.7 m/sec within 3 months (8).


Furthermore, previous research suggests that garlic is effective in normalising blood cholesterol levels. A meta-analysis of 39 trials and 2,300 participants demonstrated an improvement in total cholesterol and low-density-lipoprotein (LDL) in adults with slightly elevated levels at baseline (44).


Moreover, Kyolic aged garlic extract has demonstrated to be able to normalise blood thickness. The blood thinning effect of garlic, of any type, is well known, decreasing the risk of blood clotting and thrombosis. Garlic is thought to interfere with platelet function by altering thromboxane production, preventing degranulation and interfering with the binding of fibrinogen with glycoprotein IIa/IIIa (45).


Importantly, Kyolic aged garlic extract does NOT increase the risk of bleeding, in contrast to other garlic products. A randomised double-blind placebo-controlled trial by Macan et al (2006) (46) administered warfarin (an anti-coagulant medication) to 52 patients at a dose of 10 g of liquid Kyolic aged garlic extract daily for 12 weeks, and assessed their increased risk of bleeding by the standard International Normalised Ratio (INR) test, finding no increased risk of bleeding in both the Kyolic garlic and the placebo group. Importantly, this trial demonstrated that Kyolic aged garlic extract differed from other garlic products, e.g., dietary garlic, and in particular raw garlic, and any warnings with regard to the increased risk of haemorrhaging are not warranted for Kyolic aged garlic extract. To the contrary, Kyolic aged garlic extract can be safely consumed before any planned surgery, and may even reduce the risk of thrombosis.


In addition to the beneficial effects of garlic on cardiovascular markers, our latest trial demonstrated a beneficial prebiotic effect on the microbiome by increasing microbial richness and microbial diversity, with the particular growth stimulation of the Lactobacillus and Clostridia species (8). Lactobacillus bacteria are generally regarded as beneficial (47), while common Clostridia species colonization in the gut has been found to activate innate immune-related genes in intestinal epithelial cells, and to prevent sensitization to food allergens in mice (48,49).


In summary, this meta-analysis of 12 trials involving 553 adults with uncontrolled hypertension consolidated current evidence for garlic to be effective in reducing blood pressure by 8–10 mmHg systolic and by 5–6 mmHg diastolic, similarly to standard blood pressure medication. This decrease in blood pressure is associated with a 16–40% risk reduction of cardiovascular events, such as heart attack and stroke. The B vitamin status is an important factor for the responsiveness of high blood pressure to garlic in each individual. Kyolic aged garlic extract in particular is highly tolerable, and can safely be consumed, in addition to other standard blood pressure medication.


Latest research has provided new evidence for Kyolic aged garlic extract to improve central haemodynamic measures, including central blood pressure and pulse pressure, and pulse wave velocity, a measure for arterial stiffness, regarded as important predictors for cardiovascular disease. Kyolic aged garlic extract has the potential to reverse the ageing of the arteries and therefore, arterial stiffness by approximately 5 years, as evidenced by a mean reduction in pulse wave velocity by 0.7 m/sec within 3 months.


In conjunction with the normalising effects of Kyolic aged garlic extract on blood pressure, cholesterol levels and blood stickiness, Kyolic aged garlic extract provides beneficial effects on several levels important for cardiovascular health. Furthermore, prebiotic Kyolic aged garlic extract improves microbial richness and diversity in the gut, with a marked increase in the numbers of beneficial and immune-stimulating bacteria, such as Lactobacillus and Clostridia species, within a 3-month period.


Further larger and longer-term studies are warranted to assess the potential of Kyolic aged garlic extract on the gut microbiota. Moreover, it would be of interest to explore the responsiveness of high blood pressure to aged garlic extract in each individual, by investigating underlying dietary and genetic factors, such as vitamin B6 and folate levels, in addition to vitamin B12.


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Acknowledgements

Not applicable.


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Glossary

Abbreviations

DBP diastolic blood pressure

SBP systolic blood pressure

H2S hydrogen sulphide

PWV pulse wave velocity

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Funding

This research was presented at the 2019 International Garlic Symposium in Hiroshima, Japan, supported by Wakunaga Pharmaceuticals Japan. KR received a travel sponsorship from Wakunaga Ltd. to attend the 2019 International Garlic Symposium. The sponsor was not involved in the study design, data collection, analysis and preparation of the manuscript.


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Availability of data and materials

All data generated or analysed during this study are included in this published article or are available from the corresponding author on reasonable request.

How To Lower Blood Pressure Naturally, How To Reduce Blood Pressure Naturally



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Authors' contributions

KR was the chief investigator of 4 trials (5–8). Trials (5,6) were conducted at Adelaide University, South Australia, and trials (7,8) were conducted at NIIM Melbourne, Australia. KR undertook the meta-analysis, prepared the manuscript and approved the final version for publication.


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Ethics approval and consent to participate

Not applicable.


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Patient consent for publication

Not applicable.


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Competing interests

The author declares that this research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Garlic supplements have shown effectiveness in reducing blood pressure in hypertensive patients, similarly to first-line standard anti-hypertensive medications. Kyolic garlic has also shown promise in improving cardiovascular health by reducing arterial stiffness, elevated cholesterol levels and blood 'stickiness'. In addition, the prebiotic properties in garlic increase gut microbial richness and diversity. This article systematically reviews previously published trials investigating the effects of garlic on blood pressure, and provides an updated meta-analysis of hypertensive participants. In addition, we summarise the findings of recent clinical trials investigating the effects of Kyolic aged garlic extract on arterial stiffness, and gut microbiota in hypertensive subjects. We searched online electronic databases, including PubMed and Google Scholar for randomised controlled trials (RCTs) published between 1955 and December, 2018 examining the effects of garlic on high blood pressure. The meta-analysis of 12 trials and 553 hypertensive participants confirmed that garlic supplements lower systolic blood pressure (SBP) by an average of 8.3±1.9 mmHg and diastolic blood pressure (DBP, n=8 trials, n=374 subjects) by 5.5±1.9 mmHg, similarly to standard anti-hypertensive medications. This reduction in blood pressure was associated with a 16-40% reduction in the risk of suffering from cardiovascular events. Additionally, this review summarises new evidence for the vitamin B12 status playing an important role in the responsiveness of blood pressure to garlic. Furthermore, Kyolic aged garlic extract significantly lowered central blood pressure, pulse pressure, pulse wave velocity and arterial stiffness, and improved the gut microbiota, evidenced by higher microbial richness and diversity, with a marked increase in the numbers of Lactobacillus and Clostridia species found following 3 months of supplementation. Thus, Kyolic aged garlic extract is considered to be highly tolerable with a high safety profile either as a stand-alone or adjunctive anti-hypertensive treatment, with multiple benefits for cardiovascular health.


Keywords: aged garlic extract; arterial stiffness; blood pressure; gut microbiome; hypertension; meta-analysis; pulse wave velocity.

Background: Hypertension affects 30% of adults worldwide. Garlic supplements have shown promise in the treatment of uncontrolled hypertension, and the mechanism of action is biologically plausible. Our trial is the first to assess the effect of aged garlic extract on central blood pressure and arterial stiffness, regarded as important risk factors for cardiovascular morbidity.


Subjects and methods: A total of 88 general practice patients and community members with uncontrolled hypertension completed a double-blind randomized placebo-controlled trial of 12 weeks investigating the effect of daily intake of aged garlic extract (1.2 g containing 1.2 mg S-allylcysteine) or placebo on blood pressure, and secondary outcome measures of central-hemodynamics and other cardiovascular markers, including cholesterol, homocysteine, platelet function, and inflammatory markers.


Results: Mean blood pressure was significantly reduced by 5.0±2.1 mmHg (P=0.016) systolic, and in responders by 11.5±1.9 mmHg systolic and 6.3±1.1 mmHg diastolic compared to placebo (P<0.001). Central hemodynamic-measures tended to improve in the garlic group more than in the placebo group, including central blood pressure, central pulse pressure, mean arterial pressure, augmentation pressure, pulse-wave velocity, and arterial stiffness. While changes in other cardiovascular markers did not reach significance due to small numbers in subgroups with elevated levels, trends in beneficial effects of garlic on the inflammatory markers TNFα, total cholesterol, low-density lipid cholesterol, and apolipoproteins were observed. Aged garlic extract was highly tolerable and acceptable, and did not increase the risk of bleeding in patients on blood-thinning medication.


Conclusion: Our trial suggests that aged garlic extract is effective in reducing peripheral and central blood pressure in a large proportion of patients with uncontrolled hypertension, and has the potential to improve arterial stiffness, inflammation, and other cardiovascular markers in patients with elevated levels. Aged garlic extract was highly tolerable with a high safety profile as a stand-alone or adjunctive antihypertensive treatment.


Keywords: aged garlic extract; arterial stiffness; cardiovascular risk factors; central blood pressure; hypertension.

How much garlic should I take for high blood pressure?

The pungent smelling herb garlic has been used for many purposes since ancient times. Including garlic in your diet can help prevent many chronic health conditions. Garlic has natural antibacterial and antifungal properties. It helps in lowering cholesterol, prevents cancer and several cardiovascular diseases and simultaneously acts as a blood thinner. It can even treat gastritis. Perhaps one of the most promising actions of this natural "wonder drug" is its ability to lower blood pressure. Garlic contains sulphur containing compounds like allicin, one of the most beneficial high blood pressure natural remedies. Allinase is an enzyme that is released when we crush, chop or chew raw garlic. It then undergoes a series of reactions, resulting in the formation of allicin.

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Garlic is one of the most beneficial high blood pressure natural remedies.

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Also read: 10 Amazing Home Remedies For High Blood Pressure


Here's how you can include garlic can lower your blood pressure:

1. Raw garlic: Eating fresh, raw garlic is one among the herbal remedies for controlling high blood pressure. Chewing raw garlic will activate allinase for releasing maximum allicin. It should be consumed within one to two hours of activating allicin for added health benefits. You can eat this regularly to control your blood pressure.

High Blood Pressure 8 HOME REMEDIES Start Today



2. Garlic powder: Including garlic in your daily diet can lower your blood pressure. About 600-900 mg of garlic powder will give about 9-12% reduction in the increased blood pressure. A 600 mg dose of garlic powder contains 3.6 mg allicin and 900 mg contain 5.4 mg of allicin.


Also read: Pulses Can Control High Blood Pressure: Here's How


3. Salads: You can also add thin slices of garlic directly to your favourite salads. Minced raw garlic is also a good option to make your salads delicious yet healthy. Make this grated garlic salad a part of your daily diet and forget about other costly herbs for high blood pressure.



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4. Garlic milk: This drink works as a medicine and is beneficial for your overall health. To prepare this drink you need ten to twelve peeled and minced cloves of garlic. Add the cloves of garlic into warm milk. You can even add a tablespoon of honey into the drink for better results.

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