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Foods for Boosting Your Immune System

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Updated June 27, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Certain foods are helpful for boosting your immune system and warding off common ailments like colds and the flu. Here's a look at five types of foods shown to be useful in boosting your immune system:

1) Foods High in Vitamin C

An essential nutrient, vitamin C acts as an antioxidant. Antioxidants help fight free radicals, a type of unstable molecule known to damage the immune system. There's some evidence that vitamin C may be particularly helpful in boosting the immune systems of people under major stress. To increase your vitamin C intake, add these foods to your diet:

  • citrus fruits and juices (such as orange and grapefruit)
  • kiwi fruit
  • red and green peppers
  • broccoli
  • strawberries

2) Foods High in Vitamin E

Like vitamin C, vitamin E is a powerful antioxidant. Research suggests maintaining ample levels of vitamin E is crucial for maintaining a healthy immune system, especially among older people. To get your fill of vitamin E, look to these foods:

  • wheat germ oil
  • almonds
  • sunflower seeds
  • hazelnuts
  • peanut butter

3) Foods High in Zinc

Zinc is an essential mineral involved in the production of certain immune cells. The National Institutes of Health (NIH) caution that even mildly low levels of zinc may impair your immune function. Here are some top food sources of zinc:

  • oysters
  • baked beans
  • cashews
  • raisin bran
  • chickpeas

4) Foods High in Carotenoids

Another type of antioxidant, carotenoids are a class of pigments found naturally in a number of plants. When consumed, carotenoids are converted into vitamin A (a nutrient that helps regulate the immune system). Look to these foods to boost your carotenoids:

  • carrots
  • kale
  • apricots
  • papaya
  • mango

5) Foods High in Omega-3 Fatty Acids

Omega-3 fatty acids are a type of essential fatty acid known to suppress inflammation and keep the immune system in check. Although it's not known whether omega-3s can help fight off infections (such as the common cold), research suggests that omega-3s can protect against immune system disorders like Crohn's disease, ulcerative colitis, and rheumatoid arthritis. Try these omega-3-rich foods:

  • oily fish (including mackerel, tuna, salmon, sardines, herring, and trout)
  • flaxseed
  • walnuts

More Foods for Boosting the Immune System

To keep your immune system healthy, it's important to get sufficient sleep, exercise regularly, and manage your stress. Although supplements containing high doses of antioxidants and other nutrients found in whole foods are often touted as natural immune-boosters, some research indicates that taking dietary supplements may have limited benefits for the immune system.

For more foods that may help boost your immune system, try adding garlic, foods high in probiotics (such as yogurt and kefir), and green tea to your diet.

Sources:

Calder PC, Kew S. "The immune system: a target for functional foods?" Br J Nutr. 2002 Nov;88 Suppl 2:S165-77.

Chew BP, Park JS. "Carotenoid action on the immune response." J Nutr. 2004 Jan;134(1):257S-261S.

Gill H, Prasad J. "Probiotics, immunomodulation, and health benefits." Adv Exp Med Biol. 2008;606:423-54.

Hughes DA. "Effects of dietary antioxidants on the immune function of middle-aged adults." Proc Nutr Soc. 1999 Feb;58(1):79-84.

Kyo E, Uda N, Kasuga S, Itakura Y. "Immunomodulatory effects of aged garlic extract." J Nutr. 2001 Mar;131(3s):1075S-9S.

Simopoulos AP. "Omega-3 fatty acids in inflammation and autoimmune diseases." J Am Coll Nutr. 2002 Dec;21(6):495-505.

Wintergerst ES, Maggini S, Hornig DH. "Immune-enhancing role of vitamin C and zinc and effect on clinical conditions." Ann Nutr Metab. 2006;50(2):85-94.

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