Stay healthy with these 3 immune boosters.
You already know you need to eat well to stay healthy, but scientists are now zeroing in on specific diet strategies that can
help bolster immunity. With cold and flu season right around the corner, here are three to add to your arsenal.
1. Fill Your Vitamin D Tank.
You may have fewer health problems—ranging from colds to cancer—if you get enough vitamin D. Your body naturally makes
vitamin D from sunlight. You can also get it—albeit in smaller doses—from fatty fish, such as salmon, and fortified milk. But
because Americans don’t get enough vitamin D, most experts recommend a D supplement. New research in the American Journal of
Clinical Nutrition suggests that taking such a supplement may help boost your immune system. In a study of more than 300
Japanese children, those who took daily vitamin D supplements (1,200 IU) were 40 percent less likely to get a common flu
virus than kids who took a placebo. Laboratory studies indicate that the nutrient may help immune cells identify and destroy
bacteria and viruses that make us sick, says Adit Ginde, M.D., M.P.H., a public health researcher at the University of
Colorado School of Medicine in Denver. Aim to get at least 1,000 IU of vitamin D daily (check with your doctor before taking
2. Get a Daily Dose of Soluble Fiber.
Mice that ate a diet rich in soluble fiber for six weeks recovered from a bacterial infection in half the time it took mice
that chowed on meals containing mixed fiber, according to a recent study in the journal Brain, Behavior and Immunity. Soluble
fiber—abundant in citrus fruits, apples, carrots, beans and oats—helps fight inflammation, says lead author Christina Sherry,
Ph.D., R.D., of the University of Michigan, Ann Arbor. Insoluble fiber—found in wheat, whole grains, nuts and green leafy
vegetables—is still important for overall health, but it doesn’t seem to have the same impact on immunity. Strive for 25 to
38 grams of total fiber a day, Sherry says, paying extra attention to getting the soluble kind.
3. Stay Lean.
Overweight adults who cut their daily calorie intake by nearly a third saw a 50 percent boost in immunity, according to a
six-month study out of Tufts University. (Those who cut calories by 10 percent had smaller improvements.) Restricting
calories may reduce levels of compounds in the body that depress your immune response, says Tufts nutritional immunologist
Simin Meydani, D.V.M., Ph.D. Animal studies suggest that calorie restriction could work in normal-weight individuals too.
“Try to maintain your body weight at what is considered ideal,” Meydani says, because eating more than what you need drags
the immune system down. And remember: when you cut back on quantity, you need to be even more vigilant about the quality of
your diet. Aim to eat more fruits and vegetables—and choose lean protein sources, such as fish, chicken and low-fat dairy.