With every breath you take and bite of food you eat, potentially hazardous viruses and bacteria go along for the ride. But the human body doesn’t welcome these hitchhikers. It wields an arsenal of defenses—the immune system—to ward off intruders.
Some factors (age, genetics) that influence how well your immune system responds to gate-crashers are out of your control. But researchers are finding that the nutrients you eat have a powerful effect on immunity. For example, vitamin A is key to maintaining the protective barriers that line the mouth, lungs and intestines and filter out marauding microbes.
How Much Is Enough? Research shows you don’t need megadoses of vitamins and minerals to maintain a well-functioning immune system. Simply meeting recommended levels for most nutrients may be enough. In fact, excesses of some nutrients, especially minerals, can be harmful. For example, excessive iron can exacerbate the infectious process as much as too little. Likewise for copper. Too much copper creates nasty free radicals in cell membranes, causing DNA damage.
Even zinc—the nutrient of the hour for fending off colds—can be too much of a good thing in large amounts. Too much zinc can deplete the body of copper, suppressing immunity.
A varied diet is the ideal way to ensure the correct balance of nutrients for optimal immune functioning. At least one study, however, has shown that a daily multivitamin/mineral can boost immune function, especially if your diet is less than optimal to start.
Can Vitamin E Keep You Flu-Free? Of all the nutrients being studied, vitamin E shows the most promise as a single supplement. A recent study of 80 healthy older people found that supplementing with E improved immunity. Volunteers supplementing with the vitamin reported fewer infections than those receiving a placebo.
Simin N. Meydani, Ph.D., of the Human Nutrition Research Center on Aging at Tufts University in Boston, found that 200 milligrams of vitamin E was the optimal amount to produce a positive immune response. Higher doses provided no further benefit.
Which Fat Fights Infection? If there is a downside to the current craze of extremely-low-fat diets, it may be impaired immune function, say some experts. Because the body cannot make them, we need to ingest small amounts of two essential fatty acids: linoleic acid (an omega-6 fat found in most vegetable oils and margarines) and alpha-linolenic acid (an omega-3 fat found in fish, uuflaxseed, walnuts and canola oil). Not getting enough of these essential fats can delay wound healing, one measure of immune function. The average American has no trouble getting omega-6’s. It’s our omega-3 intake that could use a boost.
EN Sums Up. Keeping your immune system in tip-top working order does not require Herculean efforts, or even scads of supplements. (Perhaps just a basic multivitamin/mineral and a vitamin E supplement.) A lifetime of intelligent eating undoubtedly provides the base to build on and is a logical place to start.
EN’s Blueprint for a Strong Immune System
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