What you eat has a huge impact on how well your immune system is able to function. Eating whole, nutrient-dense foods offers your body the building blocks it needs for optimal immunity and optimal health in any season and is especially important during cold and flu season.

10 Top Immune Boosting Foods

  1. Garlic – This potent onion relative contains the active ingredient allicin, which fights infection and bacteria.
  2. Ginger – A warming antioxidant and antimicrobial, ginger is a powerful immune boosting food.
  3. Shellfish – Selenium, plentiful in shellfish such as oysters, lobsters, crabs, and clams, helps white blood cells produce cytokines, proteins that help clear flu viruses out of the body. Salmon, mackerel, and herring are rich in omega-3 fats, which reduce inflammation, increasing airflow and protecting lungs from colds and respiratory infections.
  4. Chicken Soup – When University of Nebraska researchers tested 13 brands, they found that all but one (chicken-flavored ramen noodles) blocked the migration of inflammatory white cells-an important finding, because cold symptoms are a response to the cells’ accumulation in the bronchial tubes. The amino acid cysteine, released from chicken during cooking, chemically resembles the bronchitis drug acetylcysteine, which may explain the results. The soup’s salty broth keeps mucus thin the same way cough medicines do. Added spices, such as garlic and onions, can increase soup’s immune-boosting power.
  5. Tea – Recent research shows that tea primes the immune system to fight some kinds of bacteria. Furthermore, in a recent Harvard study people who drank 5 cups a day of black tea for 2 weeks had 10 times more virus-fighting interferon in their blood than others who drank a placebo hot drink. The amino acid that’s responsible for this immune boost, L-theanine, is abundant in both black and green tea; decaf versions have it, too.
  6. Sweet Potatoes (and winter squashes) – Vitamin A plays a crucial role in the immune system. One of the best ways to get vitamin A into your diet is from foods containing beta-carotene (like sweet potatoes), which your body turns into vitamin A.
  7. Mushrooms – For centuries, people around the world have turned to mushrooms for a healthy immune system. Contemporary researchers now know why. “Studies show that mushrooms increase the production and activity of white blood cells, making them more aggressive.” says Douglas Schar, DipPhyt, MCPP, MNIMH, director of the Institute of Herbal Medicine in Washington, DC.
  8. Grass-fed Beef – Zinc deficiency is one of the most common nutritional shortfalls among American adults, especially for vegetarians and those who’ve cut back on beef, a prime source of this immunity-bolstering mineral. Even mild zinc deficiency can increase your risk of infection. “Zinc in your diet is very important for the development of white blood cells, the intrepid immune system cells that recognize and destroy invading bacteria, viruses, and assorted other bad guys,” says William Boisvert, PhD, an expert in nutrition and immunity at The Scripps Research Institute in La Jolla, CA.
  9. Oats and Barley – These grains contain beta-glucan, a type of fiber with antimicrobial and antioxidant capabilities more potent than echinacea, reports a Norwegian study. When animals eat this compound, they’re less likely to contract influenza, herpes, even anthrax; in humans, it boosts immunity, speeds wound healing, and may help antibiotics work better.
  10. Citrus and Red Bell Peppers – These foods are high in Vitamin C which is used by white blood cells to combat viruses.