Folic Acid Prevents High Blood Pressure in WomenWomen who get lots of folic acid from both diet and supplements have less chance of developing high blood pressure than women who get very little, according to a study in
Journal of
American Medical Association (2005;293:320-9) that re-analyzed data from two previous studies.
Hypertension (HTN) is defined as blood pressure higher than 140/90 mm Hg. HTN affects approximately 65 million people in
United States, and
prevalence is increasing as
population ages. Blood pressure is influenced by
openness and elasticity of
blood vessels; HTN indicates loss of elasticity, narrowing of
vessels, or both. It is frequently caused by plaque formation along
inner vessel walls (atherosclerosis). Because
heart pumps against
resistance (pressure) of
arteries, HTN increases
work
heart must do to keep blood flowing to all parts of
body. Chronic HTN can therefore cause thickening of
heart muscle and eventual heart failure. HTN also increases
risk of stroke and kidney failure. Preventing HTN is critical to reducing
incidence of heart disease,
leading cause of death in
US. Public health recommendations are based on evidence that a diet rich in fruits and vegetables and low in saturated fats, combined with regular moderate exercise, can protect against HTN.
Folic acid, one of
B vitamins, occurs naturally in many plant foods (such as beans and green leafy vegetables) and is commonly found in multivitamins and B-complex supplements. Due to its role in preventing some birth defects, a number of foods are now fortified with folic acid, such as cold cereals and other grain products. Along with vitamins B6 and B12, folic acid lowers blood levels of homocysteine, an amino acid that has been found to be a heart disease risk factor. Several small studies have suggested that folic acid supplements might improve
health of
vessel walls and lower blood pressure.
Data from two previous studies of health and disease patterns in women in
US, known as
Nurses' Health Study I and II, were used in
current study to examine
effect of dietary and supplemental folic acid intake on HTN.
More than 238,000 women participated in
two studies. One study included women between 25 and 42 years old and
other included women between 30 and 55 years old. Women in both studies answered questionnaires about health and dietary habits upon enrollment. For both studies, follow-up health questionnaires were filled out every two years for eight years, and a follow-up diet questionnaire was answered after four years.