NEW ORLEANS—Increasing dietary folate may reduce the risk of stroke and cardiovascular events. Research presented at the American Heart Association's 73rd Scientific Sessions supports a strong, inverse correlation between dietary intake of folate, which affects homocysteine levels, and the subsequent risk of stroke and cardiovascular disease.

High plasma homocysteine has been suggested as a potentially important risk factor for cardiovascular disease. Folate is required to metabolize homocysteine, and at least one large prospective study has shown an inverse association between the dietary intake of folic acid and the risk of cardiovascular disease.

In order to examine this relationship, Dr. Lydia A. Bazzano from the Department of Epidemiology at Tulane School of Public Health in New Orleans and her colleagues reviewed data from the first National Health and Nutritional Examination Survey (NHANES I) Epidemiologic Follow-up Study. The analysis included 9,776 men and women who were free of cardiovascular disease at baseline, between 1971 and 1975.

FOOD FOR FOLATE

In addition to a medical history and a physical examination, participants filled out a 24-hour dietary recall questionnaire and a food frequency questionnaire covering the preceding three months. Important risk factor measures were also taken, including serum cholesterol, blood pressure, body mass index, and smoking history.

Information on the folate content of foods was not available in the NHANES I nutrient dataset, Dr. Bazzano noted, but food items were matched by name and nutrient content to those found in ESHA Research's Nutrient Database.

Follow-up data on the incidence of stroke and cardiovascular disease events were collected in 1982, 1983, 1984, 1986, 1987, and 1992 by interview with the patient or a proxy, hospital or nursing home records, and death certificate.

MORE FOLATE, LESS RISK

After an average of 19 years' follow-up, 928 incident strokes, and 3,762 incident cardiovascular disease events were recorded. After adjustment for a variety of established cardiovascular disease risk factors, the researchers found that those subjects who reported dietary folate consumption in the top quartile, that is, greater than 300.6 µg per day, had a 13% lower risk of a cardiovascular disease event compared to those in the lowest quartile, or with intakes lower than 136.6 µg per day.

Stroke was also significantly reduced in the highest quartile of intake compared to the lowest, with a multivariate adjusted relative risk of 0.79. However, the incidence of coronary heart disease was not significantly affected by increasing dietary folate intake.

"Our findings indicate a strong, inverse relationship between dietary intake of folate and the subsequent risk of stroke and cardiovascular disease," Dr. Bazzano concluded. Increasing folate intake from foods, therefore, may be an important approach to reducing stroke risk in the community, she added.

The amount of folate in the highest quartile would not be difficult to achieve, Dr. Bazzano noted. About 300 µg of folate are present, for example, in one cup of cooked spinach. Presently, 400 µg per day of dietary folate is the amount recommended for pregnant women to prevent neural tube defects.

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