Taking B vitamins prevents heart disease, study shows
BY DENISE MANN
Medical TribuneCONSUMING higher-than-recommended amounts of folate and vitamin B6
—whether from dietary supplements or foods such as green leafy vegetables may substantially reduce the risk of heart disease, new research suggests.An ongoing Boston-based nurses’ health study of more than 80,000 women over 14 years found that those who consumed the highest amounts of folate and 136 enjoy about hail the risk of heart disease as women who consume less of these two B vitamins. And the more folate and vitamin 136 the women consumed, the less likely they are to have a heart attack or die from heart disease. The highest amounts taken were 400 micrograms a day of folate and three milligrams a day of 136. A microgram is a one-millionth of a gram.
The study also found that the benefits of folate intake were most pronounced among women who drank alcohol each day.
"This is pretty good evidence that suggests that there is something else out there besides cholesterol that affects heart-disease risk," says study author Dr. Eric Rimm, an epidemiologist at the Harvard School of Public Health in Boston.
Alcohol, which raises the level of protective high-density lipoprotein (HDL) cholesterol
in the blood, has been linked in numerous studies to a decreased risk of heart attack in men and women. However, alcohol consumption has a negative effect on folate. Even in moderate amounts, alcohol inactivates folate and decreases its availability to the body."If you drink alcohol and consume low levels of folate, you’re not going to get much benefit from folate," Dr. Rirnm says. "A woman who drinks may need to consume more folate to lower homocysteine levels."
The recommended dietary allowance (RDA) for folate is 180 micrograms per day for women and 200 micrograms a day for men, while the RDA for vitamin 136 is 1.6 mg for women and 2 mg for men. The findings question whether the current RDAs for these nutrients are adequate.
Found in green leafy vegetables, fortified cold cereals and legumes, folate staves off anemia and certain birth defects. Vitamin 136— found in poultry, fish and potatoes
— prevents anemia and certain skin conditions. It also helps the brain to function properly.High blood levels of the B vitamins are believed to lower levels of homocysteine, an amino acid implicated in heart disease, says Dr. Rinim. Homocysteine is thought to contributeto fatty plaque buildup in heart arteries.
The new findings add to a growing body of research suggesting that high levels of homecysteine are an important and independent risk factor for heart disease, he says. While the study did not measure homocysteine levels, previous research shows that increased amounts of vitamin 136 and folate can lower homocysteine levels.
"Our results suggest that any widespread in-crease in folate intake will have a favourable impact on heart-disease rates, but the maximum benefit would be achieved at folate in-take of at least 400 micrograms a day," he says.
The researchers report that some studies in men have found similar results.
While there is little danger in taking too much folate or vitamin 136, excessive intake of folate can mask a deficiency in vitamin 1312, another B vitamin which prevents anemia and maintains the nervous system, they say.
The study involved nurses whose diets and health status were first evaluated in 1980 and then periodically reevaluated for the next 14 years. During that time, 658 of the women had nonfatal heart attacks and 281 died of heart attacks. The women were classified in one of five groups, depending on how much of each vitamin they routinely consumed through foods and supplements in 1980. Dr. Rimm says there was relatively little change in the women’s diets during the follow-up period. The researchers took all major and many minor risk factors for heart disease into account in analyzing their data.
Kilmer McCully, a pathologist at the Veterans Affairs Medical Center in Providence, Rhode lsland, and a pioneer in research linking homocysteine to heart disease, wrote an editorial accompanying the study. It says people should "eat an optimal diet that provides the folate and vitamin 136 needed to keep homocysteine levels low."
Increased homocysteine levels are comparable to smoking, high-blood pressure and high cholesterol levels in predicting heart disease, he says. Up to 40 per cent of people with heart disease have elevated levels of homocysteine. The U.S. Food and Drug Administration recently authorized the fortification of flour with folic acid, which is the form of folate used by the body and the form found in supplements.
The study by researchers at the Harvard School of Public Health, Brigham and Women’s Hospital and Harvard Medical School in Boston appears in the latest issue of the Journal of the American Medical Association.
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