Dr. Karin Ried and colleagues from the University of Adelaide did an analysis of 14 previous studies on using garlic to treat hypertension as well as doing their own study. Garlic has been shown to stimulate nitric oxide, which has been shown to relax blood vessel walls.
The 14 trials included a total of 673 individuals. Among individuals in those 14 trials the use of garlic resulted in an 8 point reduction of systolic blood pressure as well as a 7 point reduction of diastolic blood pressure. See my earlier post for an explanation of systolic and diastolic blood pressure measurements.
The most effective treatment was the use of aged garlic extract (Kyolic), followed by garlic powder. The use of garlic only had a blood pressure reduction impact in those individuals who were hypertensive.
Conclusion of the researchers
Aged garlic is effective in reducing blood pressure in individuals with hypertension.
Aged garlic was well tolerated and can be taken with other blood pressure medications.
The effective dose in their trial was 4 tablets of Kyolic High Potency formula.
According to the National Health Service of the UK, the authors noted that the reductions in blood pressure were similar to that seen by common blood pressure medications.
Aged garlic extract is effective, but more is not necessarily better
In another study published in the Natural Medicine Journal (June 2013), a group of 79 participants were divided into 4 groups. Each group received different amounts of aged garlic extract or a placebo. Blood pressure reduction reached 11.8 points in the group receiving 480 milligrams of aged garlic extract.
An interesting note is that the group receiving 960 milligrams of aged garlic extract experienced blood pressure reduction less than the group receiving 480 milligrams. This goes to show you that more is not necessarily better.
Blood Pressure Reduction (BPR)
The results of the two studies above indicate that the higher the starting blood pressure, the greater the blood pressure reduction. The following chart combines the results of the two studies:
|Systolic BPR||Diastolic BPR|
|Garlic Powder, Aged Garlic Extract or Oil*||4.6-11.8 points||0-7.3 points|
|Placebo Group||1 point||0.5 points|
|Avg. Blood Pressure Medication||5-9 points||3-5 points|
* Garlic powder was used in doses from 600mg to 900mg daily. 2-4 capsules of aged garlic extract is the equivalent of approx. 1 clove of fresh garlic.
Note that the placebo group results remain the same as some of my previous charts (hibiscus tea for high blood pressure), as does the average blood pressure medication – which is a standard measurement. Collectively, the studies I reviewed gave a range of results for garlic displayed above.
As always, consult with a licensed health practitioner if you are taking medications or are being treated for any medical condition.
- NHS Choices: “Garlic and high blood pressure”
- U.S. National Library of Medicine / National Institutes of Health / PubMed: Dr. Karin Ried’s study, “Aged garlic extract reduces blood pressure in hypertensives: a dose-response trial” (European Journal of Clinical Nutrition)
- Natural Integrative Medicine Institute, The University of Adelaide, Australia: Karin Ried, O Frank, P Fakler, N Stocks: “Garlic, Chocolate & Tomatoes good for blood pressure or cholesterol?” (PDF of presentation slides)