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Garlic, which botanically is a vegetable but practically is used more like a spice, is a worthy addition to your diet if you struggle with high blood pressure. This condition is incredibly common, affecting 1 in every 3 U.S. adults,[i] but only 54% of those affected have their blood pressure under control.
This is dangerous, since high blood pressure increases your risk of heart disease and stroke -- often causing no symptoms until the damage has already been done. Hence, this "silent killer" can truly sneak up on you when you least expect it; in fact, about 13 million Americans have high blood pressure but don't know it.[ii] Importantly, there are many natural treatment options, garlic being among them.
What's So Great About Garlic for High Blood Pressure?
Garlic (Allium sativum L.) is a therapeutic food capable of increasing nitric oxide synthase activity in your cells.[iii] Nitric oxide synthase is an enzyme that catalyzes the production of nitric oxide (NO) from l-arginine. NO, in turn, is a vasodilator, meaning it helps your blood vessels to dilate, or widen, an important component in healthy blood flow.
NO is important for regulating blood pressure, and impaired NO bioavailability is a risk factor for high blood pressure (and heart disease).[iv] Garlic may also act as an angiotensin converting enzyme (ACE) inhibitor, similar to popular blood pressure drugs. Angiotensin is a hormone that narrows arteries, which is why ACE inhibitor drugs, which block angiotensin's effects, help to keep blood vessels from narrowing.
Garlic, however, is a natural ACE inhibitor. In 1998, researchers identified seven dipeptides in garlic with ACE inhibitory properties, noting:[v]
"[T]he presence of these dipeptides in garlic suggests that these compounds may, at least in part, be responsible for the observed antihypertensive effect of garlic (or garlic extracts) in animals and humans. Further, long-term use of dietary garlic may have a protective effect against rise in blood pressure."
There's more, too. Garlic provides organic polysulfides to your red blood cells, which use the sulfur compounds to produce hydrogen sulfide, a compound that promotes the relaxation of blood vessels.[vi] So when you eat a garlic-rich diet, it works to keep your blood pressure in check via a number of different mechanisms.
Garlic Lowers Blood Pressure
A number of studies support what traditional cultures seemed to be aware of for centuries -- that garlic exerts powerful benefits to human health. As early as the 9th century, it's believed that garlic was used to prevent blood vessel aging,[vii] and modern research affirms its benefits for blood pressure.
In a 2013 study, researchers looked at the effects of garlic tablets on blood pressure in patients with high blood pressure. Significant reductions in both systolic and diastolic blood pressure were noted in groups that consumed garlic tablets, with higher doses leading to greater reductions. The garlic treatment worked better than both placebo or atenolol, a blood pressure drug.[viii]
Aged garlic extract also proved to be effective in reducing blood pressure in people with uncontrolled high blood pressure, with researchers suggesting "aged garlic extract to be an effective and tolerable treatment in uncontrolled hypertension, and may be considered as a safe adjunct treatment to conventional antihypertensive therapy."[ix]
A meta-analysis on the effect of garlic on blood pressure, which included 20 trials with 970 participants, also revealed favorable results, with decreases in both systolic and diastolic blood pressure.[x]
How Much Garlic Is Best?
The active compounds in garlic, like allicin, are activated when the cloves are chewed, chopped or crushed. But, being highly unstable, allicin breaks down into organosulfur compounds rapidly, and the benefit of any garlic supplement you take, including whether or not it delivers those beneficial compounds to you, is dependent on how it's processed.
One of the best ways to consume garlic is in its fresh, raw form, just after you've chopped or crushed it (or chewed it up with your teeth). The downside is that raw garlic has a strong bite, but it's one that can be tamed by adding it to a small amount of avocado, tomato sauce or olive oil (such as in a salad dressing).
The exact amount of raw garlic needed to lower blood pressure is unclear, but an experiment run by Kings College London and the BBC suggests that two cloves of garlic, daily, may be just what the doctor ordered. When 28 adults with high blood pressure ate two cloves of garlic every day for a week, their blood pressure decreased from an average of 133.6 mmHg to 129.3 mmHg.[xi]
What's even better? When you eat garlic, you get benefits to your blood pressure plus so much more. Garlic has been researched for its potential role in 275 diseases, with 101 pharmacological actions. Everything from Type 2 diabetes to cancer to gallstones may benefit from this popular food, so use it liberally in your daily meals.
For the best therapeutic potential, eat it raw, but if you're planning to cook with it, letting it sit for 10 minutes after chopping before adding it to heat may help to preserve some of its health benefits.[xii] And don't worry about garlic breath -- there are natural remedies for that too (like chewing on apples, mint leaves or lettuce).[xiii]
For more on the wonderful benefits of Garlic, visit our database on the topic.