Folic Acid Shows Promise for Lowering Blood Pressure
Women who take folic acid supplements during their childbearing years to prevent certain birth defects could also be lowering their risk for high blood pressure, according to a study reported in the Journal of the American Medical Association.
Researchers found that women who consumed high levels of the B vitamin from food and supplements significantly reduced their risk of developing hypertension.
"This is the first major study to demonstrate that higher folate intake may be able to lower the risk of developing high blood pressure," says Dr. John P. Forman, a Brigham and Women's Hospital researcher.
"This is especially exciting, given the safety and ready availability of folic acid supplements," adds Dr. Forman, who is the lead author of the study.
Hypertension affects an estimated 65 million US adults. Because it typically strikes without symptoms, it is often called the "silent killer." But treatment is critical because elevated blood pressure puts people at increased risk of cardiovascular disease and renal failure.
Folate, also known as folic acid, is necessary for proper cell growth and is thought to lower blood pressure by improving blood vessel function.
Folic acid supplements are widely recommended to women who are pregnant or trying to become pregnant. Studies show folate can decrease the risk for neural tube birth defects such as spina bifida.
In addition to supplements, good dietary sources of folate include leafy green vegetables, such as spinach and turnip greens, fruits, dried beans, and peas.
To see whether there was a link between folate intake and blood pressure, the authors evaluated detailed dietary and health information for more than 150,000 women over eight years.
One group included 62,260 women aged 43 to 70 from the Nurses' Health Study, a prospective study of the risk factors for major chronic disease in women. The other group included 93,803 women, aged 27 to 44, from the Nurses' Health Study II, which involves younger women.
Among younger women who consumed at least 1,000 micrograms per day of folate from dietary and supplemental sources, there was a 46 percent reduction in risk of hypertension compared to women whose folate intake was less than 200 micrograms per day. Older women had an 18 percent reduction in risk of hypertension.
Women who consumed a low amount of folate from foods - less than 200 micrograms per day - but still managed to achieve a total daily folate intake of more than 800 micrograms through supplementation also lowered their risk of developing hypertension. Younger women reduced their risk by 45 percent; older women cut their risk by 39 percent.
Among women who did not use supplements, folate from foods alone did not lower their risk of high blood pressure, the study found.
Dr. Forman cautioned that more research is needed to confirm the findings.
"It is important to emphasize that our study, although providing evidence of the link between folate and blood pressure, is not proof that folate can be used clinically to lower blood pressure," he says.
A large randomized, controlled clinical trial involving women treated with folic acid supplements or a placebo is needed to confirm the findings before any recommendations could be made, he explains.
Dr. Norman M. Kaplan, a clinical professor in the hypertension division at the University of Texas Southwestern Medical Center in Dallas, agrees that the study is observational, as opposed to a more rigorous prospective study comparing outcomes of people taking folate with a control group.
"They clearly took more folate, but we have no idea what else they did," Dr. Kaplan notes.
The authors stopped short of recommending that women boost their folate intake. So what dietary change can they make to avoid high blood pressure?
"The bottom line is people should eat a good diet," Dr. Kaplan says. "They should eat lots of fruits and vegetables, just like their grandmother told them."
Always consult your physician for more information.
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According to the National Institutes of Health (NIH), research has shown that following a healthy eating plan can both reduce the risk of developing high blood pressure and lower an already elevated blood pressure.
For an overall eating plan, the NIH suggests the DASH eating plan. "DASH" stands for "Dietary Approaches to Stop Hypertension," a clinical study that tested the effects of nutrients in food on blood pressure.
Study results indicated that elevated blood pressures were reduced by an eating plan that emphasizes fruits, vegetables, and lowfat dairy foods, and is low in saturated fat, total fat, and cholesterol. The DASH eating plan includes whole grains, poultry, fish, and nuts and has reduced amounts of fats, red meats, sweets, and sugared beverages.
A second clinical study, called "DASH-Sodium," looked at the effect of a reduced dietary sodium intake on blood pressure as people followed either the DASH eating plan or a typical American diet. The NIH points to results that show that reducing dietary sodium lowered blood pressure for both the DASH eating plan and the typical American diet. The biggest blood pressure-lowering benefits were for those eating the DASH eating plan at the lowest sodium level (1,500 milligrams per day).
A key to healthy eating is choosing foods lower in salt and sodium. Most Americans consume more salt than they need. The current recommendation is to consume less than 2.4 grams (2,400 milligrams[mg]) of sodium a day, states the NIH. That equals 6 grams (about 1 teaspoon) of table salt a day. The 6 grams include all salt and sodium consumed, including that used in cooking and at the table.
For someone with high blood pressure, a physician may advise eating less salt and sodium, as recent research has shown that people consuming diets of 1,500 mg of sodium had even better blood pressure lowering benefits. These lower-sodium diets also can keep blood pressure from rising and help blood pressure medicines work better.
Being overweight increases a person's risk of developing high blood pressure. In fact, blood pressure rises as body weight increases. Losing even 10 pounds can lower blood pressure, and it has the greatest effect for those who are overweight and already have hypertension.
Being overweight or obese are also risk factors for heart disease. They increase the chance for developing high blood cholesterol and diabetes -two more major risk factors for heart disease.
Being physically active is one of the most important steps a person can take to prevent or control high blood pressure. It also helps reduce risk of heart disease. It does not take a lot of effort to become physically active, the NIH states.
Drinking too much alcohol can raise blood pressure. It also can harm the liver, brain, and heart. Alcoholic drinks also contain calories, which matter if an individual is trying to lose weight. The NIH suggests that if a person drinks alcoholic beverages, have only a moderate amount - one drink a day for women; two drinks a day for men.
Smoking injures blood vessel walls and speeds up the process of hardening of the arteries. This applies even to filtered cigarettes. So even though it does not cause high blood pressure, smoking is bad for anyone, especially those with high blood pressure, according to the NIH.
Always consult your physician for more information.
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