We've all heard about the apple a day, and maybe you’ve sought out the proverbial chicken soup in the throws of a cold – but can food itself prevent a cold in the first place? That’s a complicated question that needs further scientific evidence, but the good news is that eating nutrient-dense foods can certainly give your immune system the upper hand. 1,2
Your immune system is an intricate defense network built to fight invading pathogens like unfriendly bacteria and viruses, which, left unchecked, could lead to illnesses and disease. Because it, too, is made up of cells – T-cells, B-cells and the like – these cells are prone to oxidative stress, making them susceptible to attacks by wily pathogens.4 This is where antioxidants come in, which help fight against the damage of free radicals which defines oxidative stress. Furthermore, your gut microbiome is fundamental to your immune function. 3 While there is still a lot to uncover regarding the interconnectedness of nutrition and immunity, having a healthy digestive tract may help the friendly bacteria and your immune system fight those unfriendly pathogens. To bolster your defenses, supply your immune system with all its essential nutrients. 1, 2
Foods that Support Immune Function
Protein. You’re probably savvy to the role of protein and its function in the development of lean body mass by now – but did you know that protein is also important to the maintenance of healthy immune function in your body? 2 Your body uses the amino acids that comprise proteins to build antibodies, interferons, and complement proteins, which attack infectious foreign bodies. 2 Good sources of protein that may also support your fitness goals include nuts, seeds, legumes, seafood, eggs, tofu, and lean meats like chicken and turkey.
Vitamin A. Micronutrient deficiencies are correlated with an altered immune response. 1,4 Vitamin A plays a role in maintaining the integrity of the skin as well as the lining of the gut. 1 Good sources of vitamin A include carrots, sweet potatoes, kale, red bell peppers, spinach, apricots, and eggs.
Vitamin C. This micronutrient is a sturdy modulator of the immune system.1 It is thought to decrease viral production and help form antibodies.1,4 Good sources of vitamin C include citrus fruits (oranges, grapefruits), red bell pepper, strawberries, and papaya.
Vitamin E. As an antioxidant, this micronutrient neutralizes free radicals thereby protecting the body’s cells against oxidative damage. 4 Good sources of vitamin E include almonds, sunflower seeds, vegetable oils, hazelnuts, and peanut butter.
Zinc. This micronutrient is vital for wound healing and is also integral to the proper functioning of the immune system. 4 Good sources of zinc include whole grain products, lean meats, poultry, seafood, milk, seeds, and nuts. 4
Prebiotics and Probiotics. These are important in their role of maintaining a healthy gut microbiome and properly absorbing nutrients. Together, they are a dream team. Prebiotics help the body absorb calcium and can be found in bananas, onions, garlic, leeks, asparagus, artichokes, soybeans, whole-wheat foods. Probiotics are live cultures that balance the gut flora. You will find these in fermented dairy foods, like kefir, yogurt, aged cheeses, as well as kimchi, miso, tempeh, and cultured non-dairy yogurts. 5
Other Considerations
While a diet that includes a lot of fruits, vegetables, lean proteins, and whole grains will set you up for success, remember that staying active and getting enough sleep is also vital to maintaining a strong immune system! Researchers believe that exercise helps boost the immune system by promoting healthy circulation, allowing cells and components of the immune system to encompass the body more fully and do their job more efficiently. 2 Other general immune-supporting recommendations are to avoid smoking, getting adequate hydration, and practicing proper stress management techniques.
Note: Please talk to your doctor or Registered Dietitian before making changes to your diet or physical activity. Any mentions of diets or products here or anywhere on this site should not be taken as an endorsement, medical diagnosis, or medical advice.
References
1 Gershwin, ME et al (2004). Handbook of Nutrition and Immunity. Totowa,
New Jersey: Humana Press. http://sasing.unimus.ac.id/files/disk1/138/
jtptunimus-gdl-mericgersh-6854-1-ebookscl-y.pdf
2 Harvard Health Publications (2016). “How to Boost Your Immune System.”
Web. https://www.health.harvard.edu/staying-healthy/how-to-boost-your-
immune-system
3 Round, J. L., & Mazmanian, S. K. (2009). The gut microbiome shapes intestinal
immune responses during health and disease. Nature Reviews. Immunology, 9(5),
313–323. http://doi.org/10.1038/nri2515
4 Wolfram, T. (2017) “Protecting Your Health With Immunity-Boosting
Nutrition.” Academy of Nutrition and Dietetics. http://www.eatright.org/
resource/health/wellness/preventing-illness/protect-your-health-with-
immune-boosting-nutrition
5 Wolfram, T. (2017) “Prebiotics and Probiotics: Creating a Healthier You..”
Academy of Nutrition and Dietetics. http://www.eatright.org/resource/food/
vitamins-and-supplements/nutrient-rich-foods/prebiotics-and-probiotics-the-
dynamic-duo