Extra Vitamin E May Thwart Infections in the Elderly
May 6, 1997
WASHINGTON, May 6--An extra 200 milligrams of vitamin E
every day can go a long way toward reducing infections and potential cancers in
older people, according to findings of a U.S.
Department of Agriculture study to be published tomorrow (May 7) in the
Journal of the American Medical Association.
Men and women over age 65 who took daily vitamin E supplements had
clinically relevant improvements in their immune system's response to foreign
antigens, substances that cause the body to produce antibodies. Those getting
the 200-milligram dose--equivalent to 200 International Units (I.U.)--had the
strongest responses, said study leader Simin Nikbin Meydani.
The ability of vitamin E to boost a flagging immune system is
further supported by an animal study that Meydani and colleagues are reporting
in the July issue of Journal of Infectious Diseases. Older mice that
received high doses of vitamin E suppressed the influenza virus far better than
their counterparts getting the recommended level of vitamin.
"Together, these findings give hope for reducing infections and
possibly cancer in the elderly," said USDA Undersecretary for Research,
Education and Economics Cathie Woteki. "It's well established that the immune
system declines with aging, contributing to an increase in infections and
cancer rates. Until now, very few nutritional interventions have enhanced the
immune response of older people."
Eighty men and women participated in the six-month study at the
USDA Human Nutrition Research Center on
Aging at Tufts in Boston. Meydani, a nutritionist and immunologist, and
colleagues divided the volunteers into four groups to test three different
levels of vitamin E--60, 200 or 800 milligrams--versus a placebo.
"It surprised us that 200 milligrams of vitamin E was the optimal
level, not 800 milligrams," said Meydani, who had earlier tested the higher
dose on elders with positive results. "Even those taking 60 milligrams daily
had improvements in some tests."
Each person who received vitamin E was given a DTH skin test, in
which seven antigens are injected into the skin. The group taking 200
milligrams of vitamin E had a stronger response to the test than the other two
supplemented groups, Meydani said, although the difference wasn't statistically
"The DTH test measures the body's reaction to the antigens," she
explained. "It indicates how well T cells remember antigens they have seen
before and how to respond to them."
Compared with the placebo group, the volunteers taking 200
milligrams of vitamin E daily had a 65 percent increase in DTH response. Those
taking 800 milligrams had a 49 percent increase.
The 200-milligram group also produced the highest levels of
antibodies against three vaccines. For example, their antibodies to hepatitis B
virus were six times greater than the placebo group, compared with 2.5 times
greater in the 800-milligram group.
"It appears that 200 milligrams was a threshold level for these
volunteers," Meydani noted. "They got no added benefit from taking more."
The researchers also ran tests to see if supplemental vitamin E
prompted the volunteers to produce antibodies against their own proteins, which
can lead to autoimmune diseases such as rheumatoid arthritis. They did not,
Meydani said, adding that no side effects were seen from taking the extra
Good food sources of vitamin E include nuts, seeds, whole grains,
fortified cereals, vegetable oils, margarine, seafoods, liver and leafy green
Scientific contact: Simin Nikbin Meydani, DVM, PhD, chief,
Nutritional Immunology Laboratory, USDA Human Nutrition Research Center on
Aging at Tufts, Boston, Mass. 02111, phone (617) 556-3129, fax 556-3224, e-mail
Until 12 noon May 7, Dr. Meydani can be reached at the Emory
Conference Center Hotel, Atlanta, Ga., phone (404) 712-6000, room 4412.