Food to Boost the Immune System
Posted on by Neal Barnard, MD, FACC
Give your immune system a boost with healthful, plant-based foods. 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.
But studies have also shown that healthful diet and lifestyle habits can help boost the body’s natural defenses.
Eating a low-fat, plant-based 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. Vegetarians have been shown to have more effective white blood cells when compared to non-vegetarians, 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 oil may impair white blood cell function and that high-fat diets 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-based 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-based 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.
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.
Our bodies need sleep to rest and recharge. Without a sufficient amount of sleep, we increase our risk for developing serious health problems – like heart disease, Alzheimer’s disease and obesity. Inadequate sleep has also been linked to suppressed immune function. One study found that those who sleep fewer than 5 hours per night are more likely to have recently suffered a recent cold compared with those who sleep more.
Need help falling asleep? Try adding healthful fruits, vegetables, grains, and beans to your diet. One study found that diets rich in fiber and low in saturated fat can lead to deeper, more restorative sleep. Learn more about how a plant-based diet can lead to better sleep.
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- 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.
; Hutchison, A.T.; Flieller, E.B.; Dillon, K.J.; Leverett, B.D. Black currant nectar reduces muscle damage and inflammation following a bout of high-intensity eccentric contractions. J. Diet. Suppl. 2016, 13, 1–15. ; Tarazona-Díaz, M.P.; Alacid, F.; Carrasco, M.; Martínez, I.; Aguayo, E. Watermelon juice: Potential functional drink for sore muscle relief in athletes. J. Agric. Food Chem. 2013, 61, 7522–7528. ; Ley, S.H.; Sun, Q.; Willett, W.C.; Eliassen, A.H.; Wu, K.; Pan, A.; Grodstein, F.; Hu, F.B. Associations between red meat intake and biomarkers of inflammation and glucose metabolism in women. Am. J. Clin. Nutr. 2014,99, 352–360.
- 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.
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Paula is a highly qualified and experienced nutrition counselor on the staff at Village Green.
Margo's impressive knowledge base is the result of a unique blend of educational and professional experience.
Dr. Neal Barnard
Dr. Barnard leads programs advocating for preventive medicine, good nutrition, and higher ethical standards in research.
Dr. Joseph Pizzorno
Dr. Joseph Pizzorno, ND is a pioneer of integrative medicine and a leading authority on science-based natural medicine.
Debi is a registered dietitian with a master’s degree in nutrition, a personal trainer, and whole health coach.
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Dr. Rav Ivker is a holistic family physician, health educator, and best-selling author.
Susan writes about the connection between plant-based diets and a reduced risk of chronic diseases.
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Dr. Brown's blended perspective of healthcare includes a deeply rooted passion for wellness and spiritual exploration.