There’s more to keeping well than washing your hands
frequently, getting vaccines on schedule and eating five fruit and
vegetable servings a day (though that can certainly help!). Scientists
in the fledgling field of nutritional immunology are zeroing in on the specific nutrients and other dietary components that keep the immune system strong.
The goal: “To help establish the guidelines for food
intake and supplement use for reducing the risk of diseases in which disordered
immune function plays a role,” says Dayong Wu, M.D., Ph.D., a scientist at the
USDA Human Nutrition Research Center on Aging at Tufts University in Boston.
That’s particularly important as people age. Older people tend
to have lower defenses against potentially harmful viruses and bacteria,
increasing their risks for infectious diseases,
Wu says. Plus many experience the kind of low level, chronic
inflammation in the body’s cells and tissues that contributes to
cardiovascular woes, diabetes and Alzheimer’s disease.
Often a deficiency of a critical vitamin is the culprit behind
lackluster immunity. “Vitamins like A and D function in ways that
directly turn genes on or off,” says Adrian Gombart, Ph.D., principal
investigator at the Linus Pauling Institute at Oregon State University.
“The lack of these nutrients can lead
to changes in gene expression that can impair immune cell function.”
Here are some initial findings that he and other scientists have
identified about specific nutrients and the body’s disease-defense
Zinc:Research shows a deficiency of this mineral,
which is common in older people, triggers a tsunami of molecular
changes that ultimately decreases natural killer cells, the immune
system’s first line of defense again viruses, bacteria and cancer cells.
Vitamin E:Dietary Vitamin E
supplementation can help “reduce the risk of acquiring upper respiratory
infections in nursing home residents,” Wu says.
Vitamin D:“There is some evidence that
vitamin D supplementation may reduce the incidence of flu, though such studies
are relatively small,” Gombart says. “Because vitamin D is important for
proper immune function, it is important to make sure that individuals have
sufficient levels so that if an infection occurs, then it is countered with an
optimal immune response.” Like most of the emerging science of
nutritional immunology, more research is needed before firm recommendations can