What can I do to strengthen my immune system?

Zinc: One of the most important nutrients for maintaining strong immune function, zinc can be found in high-protein foods. A good multivitamin usually contains 15 to 25 mg of zinc.

Vitamin C: Taking vitamin C actually does make you less likely to catch a cold. This is especially true for people who are undergoing high levels of stress. A review of the medical literature published in the Journal of Military Medicine in 2004 showed that, in five studies, participants in the vitamin C group experienced a 45 to 91 percent reduction in common cold incidence. Three other trials found an 80 to 100 percent reduction in the incidence of pneumonia in the vitamin C group. It is hard to get more than 60 to 100 mg a day from your diet, and many food sources high in vitamin C (like fruit juices) are also high in sugar, making them more problematic than helpful. For most people, 500 mg a day of vitamin C in a good multivitamin is plenty for prevention. During an infection, taking higher doses can help you recover more quickly.

Stay hydrated: Your body’s first line of defense against most respiratory infections (such as colds and flu) is the moist surface linings in your nose, mouth, throat, and lungs called mucosal linings. Your body generates special “troops” (called IgA antibodies) that work best in moist environments. When you’re dehydrated and these surfaces are dry, you are essentially putting your troops out of action. The solution? Occasionally check your mouth and lips. If they are dry, so are the rest of the mucosal linings in your respiratory system. Drink some water.

Get proper rest: You may have noticed that during an infection, a fever increases while you are sleeping (this is especially noticeable in children). This is because much of your defense operation occurs at night, during sleep. Research by Professor Carol Everson at the Medical College of Wisconsin has shown that depriving an animal of sleep severely suppresses its immune system. People are no different.

Wash your hands: When a flu or other bug is going around, wash your hands often. Although being in a crowded space with someone who’s hacking and sneezing might worry you, you are much more likely to catch a bug that has found its way onto a surface that someone else with the infection has touched. The virus then catches a ride from your hands to your mouth or nose. By simply washing your hands regularly you’ll wash these hitchhikers right down the drain.