According to the American Heart Association (AHA), nearly half of all adults in the United States have high blood pressure, also called hypertension. Having hypertension increases a person’s risk of heart failure, heart attacks, and strokes. Leading a healthful lifestyle can reduce blood pressure. This includes eating a healthful, low-salt diet, getting regular exercise, maintaining a healthy weight, not smoking, and limiting the intake of alcohol. For some people, doctors also recommend medication that lowers blood pressure. According to some sources, natural treatments and dietary supplements can help reduce hypertension. Do these supplements work, and are they safe? In this article, we investigate the research into supplements for lowering blood pressure, exploring their effectiveness, risks, and alternatives.

Do supplements work?

Some evidence suggests that certain supplements could help lower blood pressure. However, most of the relevant studies have been of low quality or included small sample sizes. Doctors do not routinely recommend supplements for hypertension. According to the AHA, “There are no special pills, vitamins, or drinks that can substitute for prescription medications and lifestyle modifications.” The AHA recommend talking to a doctor before taking any supplement to lower blood pressure because supplements may not work as advertised, and some can raise blood pressure. The following sections look at the evidence behind some common supplements that people take to reduce high blood pressure.

Potassium

Potassium is a mineral that plays a key role in regulating blood pressure. When too much salt, or sodium, in food increases a person’s blood pressure, potassium clears the sodium from the body. Sodium causes high blood pressure because it stops the kidneys from removing water from the body efficiently. Carrying excess water leads to a hike in blood pressure. Potassium helps reduce blood pressure in two ways:

• by causing the body to get rid of more sodium in the urine
• by relaxing the walls of blood vessels

Authors of a 2017 review of studies report that potassium supplements could help decrease both systolic and diastolic blood pressure. The effect was strongest in people who had high-sodium diets, people who had a low intake of potassium before the study, and people who were not taking blood pressure medication. However, potassium supplements can be harmful for people with kidney disorders. As with any supplement, it is a good idea to consult a doctor before trying a potassium supplement. The AHA do recommend eating high-potassium foods to help manage blood pressure. These include:

• dried apricots
• spinach
• tomatoes
• avocados
• mushrooms
• prunes or prune juice
• fat-free or low-fat yogurt or milk

Magnesium

Magnesium is another mineral that plays an important role in regulating blood pressure. It supports many processes in the body, including muscle and nerve function, the immune system, and protein synthesis. Authors of a 2016 review conclude, after having analyzed the results of 34 trials, that magnesium supplements can reduce blood pressure. They say that taking 300 milligrams (mg) of magnesium per day for 1 month may increase magnesium levels enough to lower high blood pressure. The recommended dietary allowance of magnesium for adults is 310–420 mg. According to the Office of Dietary Supplements (ODS) a diet rich in magnesium may also reduce the risk of stroke, heart disease, and type 2 diabetes. Foods rich in magnesium include:

• almonds
• spinach
• cashews
• peanuts
• black beans
• avocados
• potatoes
• brown rice
• fat-free or low-fat yogurt

Dietary fiber

Dietary fiber is important for keeping the heart and gut healthy. Eating enough dietary fiber can help lower:

• cholesterol levels
• blood pressure
• the risk of cardiovascular disease

A 2018 review reports that some dietary fiber supplements may lower both diastolic and systolic blood pressure. A 2005 review suggests that supplementing the diet with about 12 grams of fiber per day could help reduce blood pressure by a small amount. The Food and Drug Administration (FDA) recommend consuming 25 grams of fiber per day and note that most people in the U.S. do not eat this amount. Adding plenty of healthful high-fiber foods to the diet can help, and fiber supplements can be a good alternative.

Folic acid

High blood pressure can be particularly harmful during pregnancy, when doctors call it gestational hypertension. If a woman does not receive treatment for this issue, it can lead to complications such as preeclampsia, stroke, preterm delivery, and low birth weight. A 2018 study found that taking supplements containing folic acid lessened the risk of gestational hypertension and preeclampsia. Folic acid is a B vitamin, and getting enough of this vitamin during pregnancy can help prevent birth abnormalities. The Centers for Disease Control and Prevention (CDC) recommend that women who may become pregnant take 400 micrograms of folic acid per day. Many prenatal vitamins contain folic acid, which is also available as a standalone supplement. In people who are not pregnant, researchers have yet to determine whether folic acid has any effect on high blood pressure.

Coenzyme Q10

Coenzyme Q10 (CoQ10) is a natural substance that occurs in the body and plays an important role in cell chemistry. It helps the cells produce energy. Some scientists believe that this supplement can reduce blood pressure by acting as an antioxidant and preventing fatty deposits from forming in the arteries. However, according to the ODS, “The small amount of evidence currently available suggests that CoQ10 probably doesn’t have a meaningful effect on blood pressure.” Also, the organization notes, research into the benefits for heart disease has been inconclusive. A 2016 Cochrane review found that taking CoQ10 supplements did not significantly affect blood pressure, compared with placebo. The researchers conclude that definitively determining the effects will require further well-conductedcoq10 studies.

Other supplements

According to the National Center for Complementary and Integrative Health, several other supplements may help lower blood pressure, including:

• cocoa
• garlic
• flaxseed
• green or black tea
• probiotics
• roselle (Hibiscus sabdariffa)
• fish oil, or others that include omega-3 fatty acids

The authors note, however, that evidence for the effects of these supplements is limited, and they may lower blood pressure only slightly, if at all.

What to avoid

People should be wary of any claim that a supplement can significantly lower high blood pressure. Supplements are not regulated by the FDA, and their quality and contents can vary. Speak to a doctor before taking any dietary supplement. Some can have adverse effects and may interact with medications, including those for high blood pressure. A doctor can advise about possible benefits and side effects, and they may recommend a more reliable brand. A person with hypertension will benefit from avoiding substances that can raise blood pressure, including:

• alcohol
• caffeine
• oral contraceptives nonsteroidal anti-inflammatory drugs, or NSAIDs, such as ibuprofen
• systemic corticosteroids
• antidepressants
• some antipsychotics

Alternatives

In most cases, high blood pressure is preventable and controllable. People can often manage their blood pressure by:

• consuming less sodium
• eating less fat, especially saturated fat
• having a diet rich in fresh fruits and vegetables
• staying physically active
• avoiding smoking
• treating sleep apnea, if present

If these changes are not enough, a doctor may recommend taking medication that will help reduce high blood pressure.

Summary

High blood pressure is a common issue. Some scientific evidence suggests that certain supplements, including potassium, magnesium, and folic acid, could lower blood pressure. However, official organizations recommend lifestyle changes and, when appropriate, antihypertension medication instead. Talk to a doctor before taking any nutritional supplements.