The Immunity Diet

Cold and flu season is upon us in the U.S. and many parts of the world. Here I’ve outlined quite a few things below that you can do to build up your immune defenses and decrease your chances of getting sick. 

While it’s difficult to enhance an already healthy immune system, there are steps you can take to strengthen it during flu season or periods of illness, or if you have a chronic disease. Three important ways to protect and enhance your immune system are through diet and nutrition, exercise, and stress reduction.

Diet and Nutrition: Healthful Fats

High-fat diets apparently can weaken the immune system by decreasing the function of the immune cells called T-lymphocytes, a major class of immune cells. Conversely, eating less fat is believed to boost immune function by enhancing T-lymphocyte function. But remember that the type of fat in your diet is as important as the amount you eat. For example, trans fats (found in margarines and many commercial baked goods) can contribute to chronic, low-grade inflammation in the body, which increases the risk of cells and tissues being damaged.

Diet and Nutrition: Antioxidants

Antioxidants are vitamins and minerals that help neutralize and remove harmful chemicals from the bloodstream—culprits such as free radicals, which are found in pollution, cigarette smoke, and other environmental factors. Antioxidants, which are found in foods as well as in supplements, include beta carotene (the non-toxic form of vitamin A), vitamin C, vitamin E, and some minerals, including selenium.

Beta carotene is a powerful antioxidant that can help protect your body from oxidative stress. Some studies have linked its consumption with lowering the risk of developing some forms of cancer, although it’s not been shown to be potent enough to overcome cancers among smokers.

Vitamin C is a another potent antioxidant, and although quite a few studies suggest daily ingestion of C does little to protect you from catching the common cold, a consensus seems to be building that it might help reduce a cold’s severity. In addition, some research cites vitamin C as able to help fight the deleterious effects of heavy stress.


Exercise is believed to protect and even strengthen the immune response. Studies have demonstrated that a regular exercise program of brisk walking can bolster several elements of the immune system, including the antibody response and the natural killer T-cell response.

Surprisingly, the intensity and duration of exercise needed to support the immune system are not as great as those needed to strengthen the cardiovascular system—even relatively low levels of aerobic exercise are believed to protect your immune system. For example, 20 to 30 minutes of brisk walking 5 days a week is believed to be enough to maintain a healthy immune response, and such exercise might also improve mental well-being. Regular aerobic exercise can help alleviate mild-to-moderate depression, anxiety, and feelings of loneliness and anger, and will further lower one’s risk for a depressed immune response.

Stress Reduction

Mood states such as depression, anxiety, and panic are all harmful to the body’s immune system and to overall health, and can even result in secondary symptoms such as fatigue, problems with memory and concentration, aches and pains, and sleep and mood disorders, all potentially harmful to our ability to fight off sickness.

Stress management techniques include deep-breathing, meditation, yoga, and tai chi. Therapies such as massage and acupuncture might also be extremely helpful.


  • Decrease or eliminate dietary intake of sources of unhealthy fats in your diet, including red meat, fried foods, and trans fats in donuts, baked goods, and margarine.
  • Include healthy omega-3 fats in your diet by eating salmon and sardines, for example. Flaxseed and walnuts are vegetarian sources.
  • Eat more fruits and vegetables—ideally, at least total 9 servings per day—and, in terms of antioxidants, the more colorful the better.
  • Drink plenty of water—ideally, filtered.
  • Manage stress.
  • Get moderate physical activity--daily, if possible. If you’re currently sedentary, however, always check with your doctor before starting an exercise regimen.
  • Get the flu vaccine.


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