With the flu season upon us, many of us are worried about the next cycle of increase in COVID-19 cases. We know that our body is able to fight and ward off many viruses. COVID-19 is a bit of an exception since it is a novel virus and health experts know less about its virulence. Even so, some people who have tested positive for COVID-19 have been asymptomatic, as their immune system appears to have been able to contain the infection.
What you eat and how you take care of yourself is a supplemental protection and of course not a replacement for other safety measures to prevent COVID-19 such as vigilant mask wearing, social distancing, avoiding crowds, and frequent sanitizing and hand washing.
How can diet and nutrition play a role in offering added protection?
Many nutrients are naturally beneficial for our immune system. In many cases, the supplements for these nutrients, such as zinc, vitamin C, and vitamin D, are administered to patients with COVID-19. But we can increase our intake of the foods containing these vitamins and minerals, and by doing so improve the status of the reservoirs of these nutrients in our bodies. Overall, zinc, iron, vitamin D, vitamin C, carotenoids (lycopene and beta-carotene), vitamin E, manganese, and selenium, as well as Phenolic compounds (e.g., flavonoids, polyphenols), and protein have been shown to support immunity or have antioxidant and anti-inflammatory effects [1,2]. This is especially important, as our bodies experience inflammation during acute and chronic illnesses.
Aside from targeted nutrients, an overall healthy and balanced dietary pattern not only provides us with these immune-supporting nutrients, but they also ensure that we maintain a healthy body weight during a time that access to food and gym is limited. After all, a healthy weight has also been associated with better prognosis for COVID-19. The Western Diet, characterized by being high in saturated fat (e.g., processed and red meats), refined carbohydrates and sugar (e.g., white bread, cakes, cookies), and being low in foods that contain fiber, unsaturated fats, and antioxidants.
A healthier alternative is the Mediterranean diet, characterized as being high in whole grains, fruits, vegetables, and legumes, which all contribute to a diet filled with fiber and antioxidants. This diet also focuses on fulfilling protein needs primarily from vegetable sources, such as legumes and nuts and seeds, as well as lean protein (e.g., fish, chicken, low-fat dairy) a few times a week. The consumption of red meat and sweets are very scarce and limited to a few times a month.
Now, let’s see what foods you should be eating to support your immune response and potentially manage a speedy recovery if you are tested positive for COVID-19. Keep in mind that many of these nutrients, especially antioxidants, tend to work better with the other natural compounds found in whole foods. Therefore, it is preferable to try to consume whole and real foods rather than take these nutrients in form of supplements. Here’s a review of the food sources for each of the nutrients that help our immune system [1,2,3,4, 5]:
1. Zinc: Red meat, poultry, seafood (e.g., oysters, crab, lobster, shrimp), beans and legumes (e.g., chickpeas, lentils), nuts and seeds (e.g., sesame, pumpkin), whole grains, fortified cereals.
2. Iron: Lean meat, seafood, poultry, beans, iron-fortified cereals and breads.
3. Vitamin D: Fatty fish (e.g., salmon, tuna, mackerel), fortified milk and yogurt. The best source is sunlight!
4. Vitamin C: Citrus fruit (e.g., oranges, grapefruit, lemon) and their juices, bell peppers, kiwi, broccoli, strawberries, baked potatoes, tomatoes, cantaloupe, honeydew, leafy greens.
5. Carotenoids: Leafy greens, orange and yellow vegetables (e.g., carrots, sweet potatoes), tomato products, broccoli, Brussels sprouts, cantaloupe, winter squash, apricots, mangoes.
6. Vitamin E: vegetable oils (e.g., sunflower, safflower, corn, soybean), nuts and seeds (e.g., almonds, peanuts, peanut butter, sunflower), green vegetables (e.g., spinach, broccoli), red peppers, avocado, wheat germ.
7. Manganese: Legumes
8. Selenium: Brazil nuts, beef, poultry, fish, shellfish, barley, brown rice.
9. Phenolic compounds: apples, tea, berries, grapes, peanuts, cocoa (e.g., dark chocolate), spices (ginger, garlic, turmeric, chili peppers).
10. Protein: meats, poultry, seafood, eggs, low fat dairy, beans and legumes, nuts and seeds.
11. Pre- and Pro-biotics: The gut microbiome is involved in immune activity, making our gut health important in fighting diseases and infection. We can improve our gut health by eating fiber-rich foods, such as whole grains, fruits, vegetables, and legumes [2]. Probiotic and Prebiotic foods also help maintain healthy gut bacteria. These foods include kefir and yogurt, fermented and pickled foods and vegetables (e.g., sauerkraut, tempeh, kombucha, kimchi, miso), garlic, onion, leeks, asparagus, artichokes, bananas, and seaweed.
Healthy Eating During COVID-19
Now you might ask, what should my diet look like and what should I do?
1. Eat a balanced diet. Fruits (especially citrus fruit such as oranges, grapefruit, lemon/lime), vegetables, legumes (e.g., lentils, beans), lean proteins (e.g., fish, chicken breast, eggs, low-fat dairy), and whole grains (e.g., unprocessed oats, wheat, brown rice). This is similar to the Mediterranean Diet.
2. Choose healthy fats. Consume unsaturated fats (e.g., olive oil, nuts, soy, canola, sunflower oil) and omega-3 fatty acids (oily fish, walnuts). Dial back on saturated fats (e.g., fatty meat, butter, coconut oil, ghee, lard, full fat dairy). Avoid processed meats (e.g., sausage, bacon), as they are high in saturated fat and salt.
3. Focus on fruits and vegetables. Eat 2 cups of fruit (4 servings) and 2.5 cups of vegetables (5 servings). Do not overcook vegetables to preserve their vitamins. When using canned fruit or vegetable, choose the ones without added salt or sugar.
4. Drink plenty of water, especially if you do contract COVID-19. Water will help with the prevention of dehydration in case of fever and diarrhea. Tea is also recommended as it contains antioxidants. Every day, drink 8-10 cups of primarily water, or tea. You can mix it up, by choosing carbonated water or adding lemon slices to your water.
5. Limit sugar intake. Limit soft drinks, sodas, energy drinks, sweetened store-bought coffee or tea, fruit juice, flavored milk and yogurt drinks, syrups, cookies, cakes, chocolate.
6. Limit salt intake. Limit salt intake to 5 g (1 tsp) a day. Try to steer away from overly processed foods and snacks and limit or avoid salting your food at the table.
7. Drink alcohol in moderation. Alcohol weakens your immune system and undermines your body’s ability in fighting infectious diseases. While red wine is a good option, as it contains antioxidants, any type of alcoholic products is NOT a preventive or treatment measure against COVID-19. Alcohol can also cause dehydration, which is not helpful in case of fever or diarrhea.
Mediterranean Diet
Healthy Pandemic Practices
Keep active. Perform moderate and regular exercise. Even walking for 20-30 minutes every day is helpful. But keep a 6-ft distance from other people. Follow online exercise classes, many of which are free on YouTube. Take breaks from sitting every 30 minutes and stretch for a few minutes.
Wash hands. Wash hands throughout the day: when coming from the outdoors, before and after preparing and eating food, after using the toilet, after coughing or sneezing or blowing your nose.
Be mindful when eating at restaurant. Wear a mask when dining inside and outside – when you are not eating. Use the Ozzi container at dining halls. If you order takeout, recycle the containers from restaurants.
Buy only what you need. Panic buying can ultimately increase food prices and lead to overconsumption of food.
Use fresh ingredients. Frozen fruits and vegetables are also good alternatives as they have similar nutrient content to fresh fruits and vegetables, if you are concerned about storing perishable foods
Follow my Instagram page: @Happy.Eatz.with.Deniz
Deniz received her PhD in Nutritional Epidemiology from University of Massachusetts at Amherst. She has conducted research on anti-inflammatory diets, and is passionate about promoting a healthy lifestyle, including the Mediterranean Diet.
References:
1. Antioxidants. Harvard School of Public Health: The Nutrition Source. Accessed on Oct 13, 2020. Available at: https://www.hsph.harvard.edu/nutritionsource/antioxidants/
2. Nutrition and immunity. Harvard School of Public Health: The Nutrition Source. Accessed on Oct 13, 2020. Available at: https://www.hsph.harvard.edu/nutritionsource/nutrition-and-immunity/#:~:text=Examples%20of%20nutrients%20that%20have,including%20the%20amino%20acid%20glutamine)
3. Fact Sheet for Professionals. National Institute of Health (NIH): Office of the Dietary Supplements. Accessed on Oct 13, 2020. Available at: https://ods.od.nih.gov/factsheets/list-all/#
4. Antioxidants - Protecting Healthy Cells. Academy of Nutrition and Dietetics. Accessed on Oct 13, 2020. Available at: https://www.eatright.org/food/vitamins-and-supplements/types-of-vitamins-and-nutrients/antioxidants-protecting-healthy-cells
5. 5 immune boosters to help keep you healthy amid COVID-19 outbreak. UC Davis Health Blog. Accessed on Oct 13, 2020. Available at: https://health.ucdavis.edu/good-food/blog/nutrients-to-help-prevent-illness.html
6. Eating during COVID-19: Improve your mood and lower stress. Harvard Health Blog. Accessed on Oct 13, 2020. Available at: https://www.health.harvard.edu/blog/eating-during-covid-19-improve-your-mood-and-lower-stress-2020040719409
7. Diet Review: Mediterranean Diet. Harvard Health Blog. Accessed on Oct 13, 2020. Available at: https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/mediterranean-diet/
8. Nutrition advice for adults during the COVID-19 outbreak. World Health Organization (WHO), Regional Office for the Eastern Mediterranean. Accessed on Oct 9, 2020. Available at: http://www.emro.who.int/nutrition/nutrition-infocus/nutrition-advice-for-adults-during-the-covid-19-outbreak.html
9. Food and nutrition tips during self-quarantine. World Health Organization (WHO), Regional Office for Europe. Accessed on Oct 9, 2020. Available at: https://www.euro.who.int/en/health-topics/health-emergencies/coronavirus-covid-19/publications-and-technical-guidance/food-and-nutrition-tips-during-self-quarantine
10. Oliviero, F., Punzi, L., & Spinella, P. (2009). Mediterranean food pattern in rheumatoid arthritis. Current Rheumatology Reviews, 5(4), 233-240.
11. PrevenT2 Curriculum. Centers for Disease Control and Prevention (CDC): National Diabetes Prevention Program. Accessed on Sep 23, 2020. Available at: https://www.cdc.gov/diabetes/prevention/resources/curriculum.html