Foods To Boost the Immune System
As coronavirus (COVID-19) has impacted communities around the world, many people have wondered whether there are steps they can take to stay healthy. Everyday preventive measures—such as hand washing, avoiding contact with sick individuals, and good hygiene - can go a long way in reducing your risk for viruses, bacteria, and other pathogens.
Studies have also shown that healthful diet can help boost the body’s natural defenses:
Diet
Eating a low-fat, plant-forward anti-inflammatory diet may help give the immune system a boost. The immune system relies on white blood cells that produce antibodies to combat bacteria, viruses, and other invaders. People who eat a plant forward diet have been shown to have more effective white blood cells when compared to those who eat less vegetables, due to a high intake of vitamins and low intake of fat. [1]
Eating a low-fat diet may also be protective. Studies have shown that limiting dietary fat helps strengthen immune defenses. Research also shows that diets high in saturatared fats such as found in land animal meats may alter the gut microbiota that aid in immunity. [2,3]
Maintaining a healthy weight can also benefit the immune system. Obesity has been linked to increased risk for influenza and other infections such as pneumonia.[4] Plant-forward diets are effective for weight loss, because they are rich in fiber, which helps fill you up, without adding extra calories. Fiber can also lower BMI, which is linked to improved immunity.[5] A plant-forward diet has also been shown to reduce inflammatory biomarkers.[6]
Vitamins, Minerals, and Antioxidants
Studies have shown that fruits and vegetables provide nutrients—like beta-carotene, vitamin C, and vitamin E—that can boost immune function. Because many vegetables, fruits, and other plant-based foods are also rich in antioxidants, they help reduce oxidative stress.[7]
Beta-Carotene: Beta-carotene is a powerful antioxidant that can reduce inflammation and boost immune function by increasing disease-fighting cells in the body. Excellent sources include sweet potatoes, carrots, and green leafy vegetables.
Vitamins C and E: Vitamins C and E are antioxidants that help to destroy free radicals and support the body’s natural immune response. Sources of vitamin C include red peppers, oranges, strawberries, broccoli, mangoes, lemons, and other fruits and vegetables. Vitamin E sources include nuts, seeds, spinach, and broccoli.
Vitamin D: Research shows vitamin D supplementation may reduce the risk for viral infections, including respiratory tract infections, by reducing production of proinflammatory compounds in the body. Increased vitamin D in the blood has been linked to prevention of other chronic diseases including tuberculosis, hepatitis, and cardiovascular disease. Food sources of vitamin D include fortified cereals and plant-based milks and supplements.[8]
Zinc: Zinc is a mineral that can help boost white blood cells, which defend against invaders. Sources include nuts, pumpkin seeds, sesame seeds, beans, and lentils.
Berenbaum, F.; van den Berg,W.B. Inflammation in osteoarthritis: Changing views. Osteoarthritis Cartilage 2015, 23, 1823–1824.
McAnulty, L.S.; Nieman, D.C.; Dumke, C.L.; Shooter, L.A.; Henson, D.A.; Utter, A.C.; Milne, G.; McAnulty, S.R. Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running. Appl. Physiol. Nutr. Metab. 2011, 36, 976–984.
Rinninella E, Cintoni M, Raoul P, et al. Food Components and Dietary Habits: Keys for a Healthy Gut Microbiota Composition. Nutrients. Published online October 7, 2019; SoldatiL , Di Renzo L, Jirillo E, Ascierto PA, Marincola FM, De Lorenzo A. The influence of diet on anti-cancer immune responsiveness. J Transl Med. 2018;16:75-93.
Alwarawrah Y, Kiernan K, MacIver NJ. Changes in nutritional status impact immune cell metabolism and function. Front Immunol. 2018;9:1055-1069.
Haddad EH, Berk LS, Kettering JD, Hubbard RW, Peters WR. Dietary intake and biochemical, hematologic, and immune status of vegans compared with nonvegetarians. Am J Clin Nutr. 1999;70(3 Suppl):586S-593S.
Eichelmann F , Schwingshackl L, Fedirko V, Aleksandrova K. Effect of plant-based diets on obesity-related inflammatory profiles: A systematic review and meta-analysis of intervention trials. Obes Rev.
Barnard ND, Goldman DM, Loomis JF, et al. Plant-based diets for cardiovascular safety and performance in endurance sports. Nutrients. Published online January 10, 2019.
Grant WB, Lahore H,. McDonnell SL, et al. Vitamin D supplementation could prevent and treat influenza, coronavirus, and pneumonia Infections. Preprints. 2020;2020030235; Chung C, Silwal P, Kim I, Modlin RL, Jo EK. Vitamin D-cathelicidin axis: at the crossroads between protective immunity and pathological inflammation during infection. Immune Netw. 2020;20:e12-38.