Garlic has some amazing health benefits, one of them being its ability to significantly decrease blood pressure and reduce the risk of stroke and heart attacks. They call high blood pressure a ‘silent killer’ because the symptoms aren’t obvious. So how can you protect yourself using garlic and what is the best way to take it?
Garlic is an ingredient used a lot in different types of food. The problem is that the garlic is often cooked at high temperatures and the allicin, which is one of the main sulfur compounds in garlic, is significantly reduced to non-existent in the end product.
Garlic contains around 33 sulfur compounds in total, many of them have been identified as having positive effects on the human body. Allicin is really the star though, but it breaks down into various other compounds quite rapidly once ingested.
So the first rule of getting the most out of garlic is to simply eat it raw, and consume within about 10-15 minutes of it being crushed.
But now you run into another problem: if you eat a lot of garlic to really get the amazing benefits garlic has to offer, you will end up smelling like garlic. So garlic supplements are one ideal way you can take garlic for high blood pressure without the smell.
I personally consume two garlic cloves per day as well as taking 2-4 garlic capsules containing allicin.
How does garlic help blood pressure?
Garlic has been extensively studied for its cardiovascular health benefits for a long time. Even as far back as the 1940s, researchers were investigating garlic’s health benefits.
Garlic, including Aged-garlic extracts which contain S-alllylcysteine, have been shown to lower both diastolic and systolic blood pressure in humans. One of the ways that garlic is thought to work is by stimulating vascular hydrogen sulfide production and enhancing endothelial nitric oxide, which helps the blood vessels relax.
Even small decreases in blood pressure of just 10-20 mmHg can have massive effects on reducing the risk of heart attacks and strokes, especially in those with a systolic blood pressure of >140 mmHg and a diastolic of >90 mmHg.
It a meta-analysis of 61 prospective studies and over 1 million patients, it’s estimated that reducing blood pressure by that amount would reduce the number of deaths by 50%! 
Taking garlic either in the raw form of capsules may help reverse high blood pressure by restoring redox balances for eNOS-dependent pathways to promote vascular relaxation and lower blood pressure.
Garlic can promote vascular health in several ways
- Garlic may act as a natural ACE-inhibitor, similar to medications that are used to treat high blood pressure
- Garlic may help reduce inflammation and oxidative damage to the vascular wall
- Aged Garlic Extract has potent antiglycation effects, thereby helping reduce crosslinking and stiffening of the arteries with age
- Garlic is a potent antimicrobial and may prevent and manage inflammatory conditions which raise levels of inflammatory cytokines and proteins which cause dysfunction to the vascular system
What is the evidence?
Garlic powder Supplements
According to research, garlic appears to be especially useful for people who are hypertensive. A meta-analysis was published in 2008 which looked at studies published between 1955 and 2007 showed that by examining 25 studies, they were able to show that garlic was able to reduce blood pressure significantly.
- They showed that there was a mean decrease in systolic blood pressure (SBP) of 4.6 +/- 2.8 mmHg for the group consuming garlic compared to the placebo
- They showed that there was a mean decrease in the hypertensive subgroup of 8.4 +/- 2.8 mmHg for SBP
- They also showed that garlic was able to reduce diastolic blood pressure by 7.3 +/- 1.5 mmHg compared to the placebo
Read more on the meta-analysis here.
Another more recent meta-analysis was also performed and published in the Journal of Nutrition shows that Garlic lowers blood pressure in hypertensive individuals and lowers cholesterol.
The looked at 20 clinical trials with 970 patients and showed in the hypertensive subgroups there was a systolic blood pressure decrease of 8.7 +/0 2.2 mmHg and diastolic blood pressure decrease of 6.1 +/- 1.3 mmHg.
Cholesterol was also looked at and they saw a decrease of 10% if the garlic supplement was taken for at least 2 months and baseline cholesterol was over 200 mg/dL.
In another study published in 2013, researchers used Aged Garlic Extract in a double-blind randomized placebo-controlled trial for 12 weeks.
There were 79 patients in the study who had uncontrolled systolic hypertension.
Three groups took different doses of garlic: 240 mg, 480 mg, and 960 mg.
The 4th group took the placebo.
The group who took 480 mg of Aged Garlic Extract per day over the 12 weeks appeared to benefit most from the garlic.
In the group taking 480 mg of garlic, systolic blood pressure was reduced by 11.8 +/- 5.4 mmHg compared to the placebo. The group taking just one garlic capsule a day did not show any significant benefit in lowering blood pressure. .
Kwai garlic in these meta-analyses did not show any improvement in blood pressure. This is a popular garlic tablet that many people take for heart health, but it appears that it is not effective for reducing hypertension in humans.
Fresh garlic intake has been linked to lower blood pressure but the evidence is weak. People who tend to include garlic in their diet also have healthier diets in general.
To match the doses of garlic used in these studies to treat high blood pressure, one would have to consume between 1-3 fresh cloves of garlic per day or more.
This is quite easy to do, and 2 cloves of garlic a day shouldn’t be a problem. If you start increasing your garlic consumption to 3-4 per day or more, you might begin to smell of garlic. 🙂
Flaws in some garlic studies
Some of the studies performed on garlic are quite old and did not utilize more effective garlic supplements with stabilized allicin.
The amount of garlic one gets from certain garlic tablets can vary dramatically depending on the conditions of the stomach and how the powder is encapsulated.
Nevertheless, garlic has many wonderful health properties and should be consumed on a regular basis! Research suggests that overall, fresh garlic is healthy for you and that taking garlic supplement may be a convenient and easy way (without the smell) of getting those beneficial compounds.
Garlic appears to be effective for blood pressure, especially when taken as a supplement. However, if you are fine with consuming a few cloves of garlic each day, then you may be able to replicate these effects as seen in the studies on blood pressure by consuming up to 3 cloves per day.
I like to consume both fresh garlic and take garlic supplements and get the benefits of both.
And finally, for people who have a sensitive stomach, I would recommend taking a garlic supplement instead of eating raw garlic every day. Raw garlic can cause burning and stomach upset, especially if consumed with little food.
More tips for lowering blood pressure with diet by Dr. Michael Greger
- Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lewington S, Clarke R, Qizilbash N, Peto R, Collins R, Prospective Studies Collaboration. Lancet. 2002 Dec 14; 360(9349):1903
- Effect of garlic on blood pressure: A systematic review and meta-analysis BMC Cardiovasc Disord. 2008; 8: 13. Published online 2008 Jun 16: 10.1186/1471-2261-8-13
- Aged garlic extract reduces blood pressure in hypertensives: a dose-response trial Eur J Clin Nutr. 2013 Jan; 67(1): 64–70. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3561616/