Can Garlic Beat High Blood Pressure?

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

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). Garlic is one of the herbs most commonly used to fight high blood pressure.

Since high blood pressure is a major risk factor for heart disease (the leading cause of death in the U.S.), many people consume garlic in an effort to keep their blood pressure in check. 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). 

Garlic seems to be able to modestly reduce blood pressure, according to the National Institutes of Health (NIH).

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.

In another report published in the Annals of Pharmacotherapy the same year, researchers reviewed 10 clinical trials evaluating garlic's effects on blood pressure. Results revealed that use of garlic was associated with a decrease in blood pressure among patients with elevated systolic blood pressure. However, use of garlic was not associated with decreased blood pressure in study participants without elevated systolic blood pressure.

(The top number on a blood pressure reading, systolic blood pressure is a measure of the pressure while your heart is beating. Diastolic blood pressure, on the other hand, is the lower number on a blood pressure reading and a measure of the pressure when your heart relaxes between beats.)

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

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.

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.

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. 

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.

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.

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.

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.