How Folic Acid Affects High Blood Pressure

Folic acid is a water-soluble form of vitamin B9. It is the synthetic form of folate, a nutrient found in certain foods, and is used in vitamin supplements. Folic acid is an important nutrient that the body uses to generate, replicate and repair cells, including DNA.

Folic acid pills on wooden surface
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Deficiencies in folic acid are particularly problematic during pregnancy when the body must quickly produce lots of new cells. Red blood cell production is also very sensitive to folic acid levels, and low levels of this nutrient can lead to certain types of anemia. It is believed that folic acid and its derivatives also play an important role in repairing DNA damage that could otherwise lead to cancer.

The Affect of Folic Acid on High Blood Pressure

Several large studies have examined the role of folic acid in the prevention of high blood pressure and found that it provides benefit in reducing the risk of the condition. A study published in the Journal of the American Medical Association (JAMA) found that women with hypertension who took folate were able to significantly reduce their blood pressure. By taking more than 1,000 mcg a day of folic acid there was a 46% reduction in high blood pressure of women who participated in the study.

Folic Acid Shown to Reduce the Risk of Stroke

According to a study appearing in JAMA in April 2015, folic acid was found to significantly reduce the risk of stroke in people with high blood pressure.

The study included more than 20,000 adults in China with high blood pressure, but without a history of stroke or heart attack. A portion of the participants used enalapril, a hypertension medication, with folic acid, others were treated with enalapril alone.

During a treatment period of 4.5 years, the first stroke occurred in 282 participants (2.7%) in the enalapril-folic acid group compared with 355 participants (3.4%) in the enalapril group, representing a risk reduction of 0.7% and a relative risk reduction of 21%.

Taking Supplements

It is worthwhile to consider taking a folic acid supplement (400 to 500 micrograms per day). As with any supplement, you should ask your healthcare provider before starting. Folate supplements may not be recommended for those with certain conditions.

Because folic acid is water-soluble, it is very difficult to consume dangerous amounts. That means that whatever your body doesn't use is filtered by the kidneys and excreted in the urine. Though excess folic acid consumption isn't likely to cause serious harm, it can cause side effects. Too much folic acid can cause headaches, stomach upset, diarrhea, and other discomfort.

Good Dietary Sources

Many prepared bowls of cereal, canned goods, and bread are fortified with the nutrient. Green leafy vegetables and legumes (beans) are the best natural sources of folic acid. Some wise choices:

  • Lentils: 1 cup, boiled = 386 micrograms
  • Chickpeas: 1 cup, boiled = 282 micrograms
  • Spinach: 1 cup, raw = 210 micrograms
  • Cauliflower: 1 cup = 180 micrograms
  • Lettuce: 1 cup = 156 micrograms

While folic acid is an important part of a healthy high blood pressure diet, it is only one component. Healthy eating is one of the most important steps towards the prevention of high blood pressure, and overall balance is the key.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Craig O. Weber, MD
Craig O. Weber, MD, is a board-certified occupational specialist who has practiced for over 36 years.