Strengthen the Immune System to Prevent COVID-19
COVID-19
As of September 21, 2020, there have been 30,949,804 confirmed cases of coronavirus disease (COVID-19) worldwide, including 959,116 deaths (13). At least 200,000 of those deaths have been in the United States, and COVID-19 is now one of the leading causes of death in the country with around 1,000 people dying every day (4). Although possible vaccines are currently being tested, it could be months or even years before one becomes widely available to the public.
For these reasons, it becomes crucial to do everything we can to improve our health and prevent this highly contagious disease. Social distancing, frequent hand washing, covering coughs, and wearing a mask are still the best ways to reduce the spread of disease. However, strengthening the immune system could be a useful additional step to help prevent infection. Also, for those who become infected with COVID-19, it is possible that having a stronger and healthier immune system could lessen the severity and duration of the disease (9).
Here are some dietary and lifestyle suggestions that may strengthen the immune system and reduce the risk of infection.
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Nutrition and Immune Function
Nutrition plays a vital role in supporting a healthy immune system. Individuals consuming a nutritious diet are healthier and have a stronger immune system.
Consumption of the typical “Western Diet” (marked by high intakes of saturated fat, refined carbohydrates, and sugar) leads to chronic inflammation and a reduced immune defense against viruses (1).
Inflammation is a natural part of immunity and the healing process. However, chronic inflammation can hamper the body’s ability to heal itself and fight infection. Nutritional deficiencies in anti-inflammatory foods may result in delayed or suboptimal resolution of inflammation and a weakened immune system (2).
For optimal immune function, it is essential to consider both micronutrients (i.e. vitamins and minerals) and macronutrients (i.e. protein, carbohydrates, and fats).
Micronutrients: Vitamins and Minerals
Proper vitamin and mineral intake is key to a healthy immune system. Micronutrient deficiencies can negatively affect the immune system and decrease the body’s resistance to infections (2).
The following vitamins and minerals may help to regulate the immune system and reduce the risk of infection: vitamins A, B6, B12, C, D, E, folate, zinc, iron, selenium, magnesium, and copper (2, 6)
Ideally, nutrient intake should come from a well-balanced and diverse diet. However, a multivitamin supplement is a great way to eliminate nutritional gaps and support optimal immune function.
Macronutrients: Protein, carbohydrates, and fat
Protein
Sufficient protein intake is essential for immune health and low protein status can increase the risk of an infection (6).
It is recommended to consume at least 0.8 g of protein per kg of body weight (8).
However, the average American consumes well over this amount. Many common protein sources in the U.S. (i.e. processed meats, red meat, cheese) are high in saturated fats and can promote inflammation and reduce immune function (6).
In contrast, protein from plant sources (i.e. beans, nuts, whole grains) has anti-inflammatory properties.
Carbohydrates and Fiber
Carbohydrates in the diet should come from whole grains and processed carbohydrates should be greatly limited.
Dietary fiber (found in whole grains, vegetables, fruits, legumes, nuts, and seeds) ferments in the gut and has been shown to have anti-inflammatory properties (6).
Dietary fiber intake has been inversely linked to the risk of death from respiratory and infectious diseases in American adults (6).
Recommended fiber intake is 25 g and 38 g per day for women and men, respectively (6). However, the average American consumes around half that amount. Even a small increase (i.e. 5 g additional fiber per day) can help to reduce inflammation in the body.
Fats
Omega-3 and unsaturated fatty acids (FAs) are believed to contribute to a stronger immune system due to their anti-inflammatory effects (6).
Conversely, saturated and trans-FAs are known to increase inflammation and may negatively affect immune system strength (1).
Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play important roles in immune system health (2).
Try to obtain dietary fat in the diet from unsaturated sources (i.e. olive oil, avocados, olives, nuts, and seeds) and those high in omega-3 FAs (i.e. salmon, herring, halibut, walnuts, and flaxseeds).
Foods to Enjoy in Abundance
All vegetables and fruits
Whole grains: oats, brown rice, barley, quinoa, sorghum, cornmeal
Legumes and beans: green beans, peas, lentils, soy beans, chickpeas, kidney beans, black beans
Nuts and seeds
Fish high in omega-3 FAs: salmon, sardines, herring, mackerel, and tuna
Chicken, whey protein, and other lean protein sources (5)
Foods to Avoid
Saturated fat sources: beef, lamb, pork, butter, whole fat dairy products, and lard
Trans-fat sources: fried foods, margarine, donuts, shortening, packaged cakes, and anything with “partially hydrogenated oils” on the label
Processed meats: bacon, beef jerky, salami, sausage, smoked meat, and hot dogs
Processed carbohydrates: white rice, white bread, white pasta, crackers, and pretzels
Excess salt/sodium intake
Sugar (5)
Physical Health
Regular exercise is believed to enhance immune system function (3).
Exercise can also reduce the risk of various conditions that increase susceptibility to COVID-19, such as high blood pressure, stroke, heart disease, and type 2 diabetes (14).
It is important for your physical health to stay active during the pandemic. If you are spending more time at home, even short periods of activity will benefit your health. Consider taking a short walk outside, going up and down the stairs, stretching, dancing, skipping rope, or taking an online yoga class.
Make sure you’re getting enough sleep each night to keep your immune system strong.
Drinking enough water is essential to the elimination of waste from the body and absorption of nutrients (8). A minimum of 6-8 glasses (48-64 oz) is recommended, but 8-12 glasses (64-96 oz) may be better for optimal health.
Reduce Stress
Stress has a significant impact on the functioning of the immune system. It has been shown to negatively impact the immune system and contribute to poor health and disease (10).
It has been suggested that high stress and anxiety levels may increase an individual’s risk of COVID-19 infection due to immune system depression (11).
If you are prone to stress, consider adopting relaxation techniques such as yoga, meditation, tai chi, exercise, spending time in nature, and listening to music.
Stop Smoking
Smoking is known to be harmful to the immune system and its ability to respond to infections (12). It causes oxidative stress and an inflammatory response in the lung, which could make smokers more vulnerable to bacterial and viral infections (7).
It is believed that smoking cigarettes could be associated with the negative progression and adverse outcomes of COVID-19 infection (12).
Although more research is necessary, indirect studies have shown that smokers (and vapers) may be at a higher risk of severe COVID-19 symptoms and need for mechanical ventilation compared to non-smokers (7).
References
Butler, M.J. & Barrientos, R.M. (2020). The impact of nutrition on COVID-19 susceptibility and long-term consequences. Brain, Behavior, and Immunity. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7165103/
Calder, P.C., Carr, A.C., Gombart, A.F., & Eggersdorfer, M. (2020). Optimal nutritional status for a well-functioning immune system is an important factor to protect against viral infections. Nutrients. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230749/
Campbell, J.P. & Turner, J.E. (2018). Debunking the myth of exercise-induced immune suppression: Redefining the impact of exercise on immunological health across the lifespan. Frontiers in Immunology. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5911985/
Chappell, B. (2020). ‘Enormous and tragic’: U.S. has lost more than 200,000 people to COVID-19. NPR. Retrieved from: https://www.npr.org/sections/coronavirus-live-updates/2020/09/22/911934489/enormous-and-tragic-u-s-has-lost-more-than-200-000-people-to-covid-19
Chowdhury, M.A., Hossain, N., Kashem, M.A., Shahid, M.A., & Alam, A. (2020). Immune response in COVID-19: A review. Journal of Infection and Public Health. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359800/
Iddir, M., Brito, A., Dingeo, G., Sosa Fernandez Del Campo, S., Samouda, H., La Frano, M.R., & Bohn, T. (2020). Strengthening the immune system and reducing inflammation and oxidative stress through diet and nutrition: Considerations during the COVID-19 crisis. Nutrients. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352291/
Kaur, G., Lungarella, G., & Rahman, I. (2020). SARS-CoV-2 COVID-19 susceptibility and lung inflammatory storm by smoking and vaping. Journal of Inflammation. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284674/
Murray, M., Pizzorno, J., & Pizzorno, L. (2005). The encyclopedia of healing foods. New York, NY: Atria Books.
Paces, J., Strizova, Z., Smrz, D., & Cerny, J. (2020). COVID-19 and the immune system. Physiological Research. Retrieved from: http://www.biomed.cas.cz/physiolres/pdf/69/69_379.pdf
Pizzorno, J.E. & Murray, M.T. (2013). Textbook of natural medicine (4th ed.). St. Louis, MO: Elsevier Churchill Livingstone.
Ramezani, M., Simani, L., Karimialavijeh, E., Rezaei, O., Hajiesmaeili, M., & Pakdaman, H. (2020). The role of anxiety and cortisol in outcomes of patients with Covid-19. Basic and Clinical Neuroscience. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368100/
Vardavas, C.I. & Nikitara, K. (2020). COVID-19 and smoking: A systematic review of the evidence. Tobacco Induced Diseases. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083240/
WHO coronavirus disease (COVID-19) dashboard. (updated 9/21/2020). Retrieved from: https://covid19.who.int/
WHO #HealthyAtHome: Physical Activity. (n.d.). Retrieved from: https://www.who.int/news-room/campaigns/connecting-the-world-to-combat-coronavirus/healthyathome/healthyathome---physical-activity