NEW YORK, May 06 (Reuters) -- Vitamin E, already much in the news for its benefits in combating heart disease and Alzheimer's disease, may help boost the waning immune system of the elderly, a new study shows.
A group of people over age 65 who took 200 milligrams (mg) of vitamin E a day for eight months showed large improvements in their bodies' ability to produce antibodies that fight off a variety of infectious diseases, including hepatitis B and tetanus.
The new findings appear this week in The Journal of the American Medical Association.
Dr. Simin Nikbin Meydani, nutritionist and immunologist at the U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, says the discovery is important because it suggests that elderly people ought to be taking about 20 times more vitamin E daily than the current recommended amount of 8 to 10 mgs.
"What we've been trying to do is see if there are dietary factors that can reverse the decline in the immune system with aging," she says.
"Many studies have shown that with aging, there is a dysregulation in parts of the immune system which contributes to an increase in infectious diseases, an increase in tumors, and to immune diseases like arthritis. It is a big problem for the elderly," she adds, noting that infections such as pneumonia and influenza are among the leading causes of death in older people.
The researcher points out that although they get flu vaccinations in the fall, "it is only 60% as effective in older people as it is in younger people. They don't develop as much antibody."
Meydani and her colleagues from Harvard and Boston universities divided 88 study participants into four groups, who were then given daily doses of either 60, 200, or 800 milligrams (mg) of vitamin E or given an inactive placebo. All participants were in good health and lived in the community rather than in institutions.
The subjects were given a skin sensitivity (DTH) test to observe their immune reactions to a number of infectious agents, including tetanus, diphtheria, and streptococcus bacteria. They also received a series of vaccinations and booster shots against pneumonia, hepatitis B, and tetanus/diphtheria. Blood samples were later evaluated for antibodies against these diseases and compared with blood samples taken when the study began.
While participants showed improved immune response no matter how large a dose of vitamin E they took, the optimal results were observed in the group taking the 200 mg supplements.
Specifically, people consuming 200 mg of vitamin E had a 65% increase in DTH and a sixfold increase in antibody levels to hepatitis B compared with those taking the placebo. The DTH increases for 60 mg and 800 mg vitamin E were 41% and 49%, respectively. And the antibody increases were 3-fold and 2.5-fold. People taking 200 mg vitamin E also showed significant antibody increases in response to the tetanus vaccine.
The improvement in antibody response associated with the antioxidant vitamin E did not come as a surprise to the researchers, says Meydani. But the optimal amount did.
"The problem with a lot of studies in nutrition is that you find something, and people think more must be better," she says. "But what this points out is that you don't really have to go above 200 mg to see the results. What it's saying is there is an optimal level, and people shouldn't be thinking more is better."
For most people, however, getting 200 mg of vitamin E a day probably requires taking a vitamin supplement, Meydani says. The vitamin is found in large amounts in oils and nuts, which means diets high in the nutrient also tend to be high in fat.
"It is possible for a dietitian to put together a diet that includes this much vitamin E," Meydani notes, "but it isn't easy."
SOURCE: The Journal of the American Medical Association (1997;277(17):1380-1386)
