4 Ways to Strengthen Your Immune System

What multiplies as fast as a flu virus? Claims about immune boosters, most of which just boost a few bucks from your wallet. But a few study-backed moves really can help you fight infection.

By Christopher Woolston from Reader's Digest | July 2009

What multiplies as fast as a flu virus? Claims about immune boosters, most of which just boost a few bucks from your wallet. But a few study-backed moves really can help you fight infection. Worth a try:

  • 1

    Go nuts for E.

    Immune cells can’t function without proper nutrition, says Simin Meydani, PhD, director of the USDA Human Nutrition Research Center at Tufts University. “In an outbreak, a deficiency of nutrients can be as dangerous as not washing your hands,” she says. But many people don’t get enough vitamin E, a proven immune enhancer, says Patricia Sheridan, PhD, at the University of North Carolina at Chapel Hill. You need at least 15 mg of E daily, she says, which you can get in a generous handful of almonds (7 mg of E per ounce). The elderly and people with weakened immune systems may need a supplement of 200 mg of E, Meydani believes.

    In her study of nursing home residents, supplementing with that amount cut the risk of colds and flu by about 20 percent. Don’t take more, though: One highly publicized study suggested that high doses (400 mg per day or more) can increase the risk of death.

  • 2.

    Don't stint on selenium.

    This trace mineral helps build immune system enzymes. Most people in the United States aren’t deficient but could use a little extra to sharpen their immune systems, Sheridan says. She recommends about 55 micrograms, which you can get in a tuna sandwich.

  • 3.

    Consider popping the sunshine vitamin.

    Vitamin D is needed to produce certain germ-killing proteins (a recent study suggests that low levels raise the risk of respiratory infection by more than 35 percent). But many people fall short, says Michael Holick, MD, professor of medicine at Boston University. You can’t get much vitamin D from food, so Holick recommends that adults supplement with 1,000 IU a day, plus a multivitamin containing another 400 IU.

  • 4.

    Work out (but don’t burn out).

    Even a little exercise can wake up the immune system, says Thomas Lowder, PhD, at the University of Houston. (Exercise that wrecks you for days can actually make you more vulnerable, though.) In a 2006 study, women either exercised moderately five times a week or stretched once a week. By study’s end, the exercisers were only one third as likely as the stretchers to be sniffling and sneezing. “Nobody can say for sure how much exercise it takes to improve the immune system,” Lowder says. “But it’s not much, and it happens very quickly.”

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