News Release

Postmenopausal Women Reap Heart Benefits From Foods Containing Vitamin E

Peer-Reviewed Publication

American Heart Association

ORLANDO, Fla., March 26 -- Postmenopausal women may reduce their risk of cardiovascular disease by eating more foods rich in vitamin E, according to a study presented today at the American Heart Association epidemiology and prevention meeting.

Lead author of the study, Lori Mosca, M.D., Ph.D., at the University of Michigan in Ann Arbor, says, "The prevailing wisdom has been that you need more vitamin E to protect against heart disease than you can get from food, but our data suggest that the potential benefits of antioxidant nutrient intake may be derived from food alone."

In a study of 54 postmenopausal women, a higher intake of vitamin E from food was linked to reduced oxidation of low-density lipoprotein cholesterol (LDL or "bad" cholesterol). This antioxidant benefit occurred only in women who did not use supplements.

When LDL becomes oxidized it can damage blood vessels, which may lead to atherosclerosis. Some vitamins, including vitamin E, are called antioxidants because they inhibit oxidation.

"When a fat such as LDL undergoes oxidation, it is more prone to collect in blood vessels to form plaque. Over time, the plaque narrows the blood vessels, or unleashes a blood clot, which can result in a heart attack or stroke. When LDL is not oxidized, it does not seem to cause problems," says Mosca, director of preventive cardiology research and education at the University of Michigan.

Although many people take supplements, the researchers wanted to know whether food was a better source of antioxidants. A previous study had shown that vitamin E intake from food, but not supplements, was associated with lower rates of cardiovascular disease in women.

"We wanted to study a potential biological mechanism to explain this," says Mosca.

Researchers suspected that vitamins in foods might be better than vitamin pills in inhibiting LDL oxidation, thus protecting against heart disease and stroke. In this observational study, the women listed everything they ate and the vitamin pills they took for six days. During this period, their intake of vitamin E was measured. LDL oxidation was evaluated in a laboratory test that measured the time it took the women's LDL to become oxidized by copper ions (natural oxidants). The time, called the lag time, is used as an indicator of LDL oxidation.

Researchers found increased intake of vitamin E was associated with decreased susceptibility of LDL to oxidation among women whose only source of vitamin E was food. There was no benefit in supplement users. In fact, the study showed that the higher the vitamin intake in supplement users, the higher the susceptibility of LDL to oxidation.

"It's possible that vitamins taken in supplement form may block some of the benefits of vitamins taken from food," Mosca says.

"The best scientific evidence we have is that eating a diet rich in fruits and vegetables is protective against heart disease," says Mosca. "We can never be sure exactly which nutrient is providing the benefits, and it is likely that several different nutrients are involved. That's why we recommend getting vitamin E from foods."

Rich sources of vitamin E include nuts, vegetable oils, whole grains and wheat germ.

The researchers also investigated the relationship between the intake of vitamin C, beta-carotene and folic acid -- from both food and supplements -- and LDL oxidation. None of these nutrients protected against oxidation.

"The reason may be because these nutrients may not be as good of an antioxidant as vitamin E. Also, the majority of women in this study who were taking supplements were using a multivitamin, which contains smaller amounts of vitamin E than a supplement," says Mosca. "We can't rule out the possibility that higher doses of vitamin E in pills may be protective."

Reducing the risk of developing heart disease and stroke is not the only reason to eat a vitamin-E-rich diet, says Mosca. This nutrient also has been linked to a reduced risk of developing certain cancers, skin disorders, cataracts and muscular degeneration. Studies also show that getting plenty of vitamin E improves immunity and promotes wound healing.

Mosca's co-authors are Thomas Tarshis, M.D., Kathy Rhodes, Ph.D., R.D., Melvyn Rubenfire, M.D., and Gilbert S. Omenn, M.D., Ph.D.

The research was presented at the American Heart Association 39th Annual Conference on Cardiovascular Disease Epidemiology and Prevention.

###

Media advisory: Dr. Mosca can be reached at 734-998-6301. (Please do not publish telephone number.)



Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.