What to know about nutrition and immunity during COVID-19

Editor’s note: As what we know about COVID-19 evolves, so could the information contained in this story. Find our most recent COVID-19 blog posts here, and learn the latest in COVID-19 prevention at the Centers for Disease Control and Prevention.

The relationship between nutrition and the immune system has been a topic of interest for many with the increasing impacts of the COVID-19 pandemic. There are many articles, interviews and social media posts detailing various foods, supplements and diets to help prevent getting this virus. But does anything actually help?

There are definite connections between getting enough nutrition and immune function. It’s well understood that people who are malnourished or who don’t get enough nutrients can have a weakened immune system. Some individuals who may be at a higher risk for a weak immune system are those with chronic diseases and the elderly. However, most healthy people can stay nourished and avoid deficiency with a healthful diet.

According to the Academy of Nutrition and Dietetics, here’s how these major nutrients promote a healthy immune system:

• Protein plays a role in the body's immune system, especially for healing and recovery. Eat a variety of protein foods, including seafood, lean meat, poultry, eggs, beans and peas, soy products, and unsalted nuts and seeds. Avoid highly processed meats like hot dogs, bacon and chicken nuggets, since these don’t have as many nutrients.
• Vitamin A helps protect against infections by keeping skin and tissues in the mouth, stomach, intestines and respiratory system healthy. It’s found in sweet potatoes, carrots, broccoli, spinach, red bell peppers, apricots, eggs or foods labeled "vitamin A fortified," such as milk and some cereals.
• Vitamin C supports the immune system by stimulating the formation of antibodies. Include more sources of this healthy vitamin by choosing bell peppers, oranges, grapefruit and tangerines, papaya, strawberries, broccoli and tomatoes.
• Vitamin E works as an antioxidant and helps boost immune function. Include vitamin E in your diet with fortified cereals, sunflower seeds, almonds, vegetable oils (such as sunflower and safflower oil), hazelnuts and peanut butter.
• Zinc helps the immune system work properly and may help wounds heal. Zinc can be found in lean meat, poultry, seafood, whole grain products, beans, seeds and nuts.
• Selenium is an important mineral for immune function and your metabolism. Get it from nuts, especially Brazil nuts and walnuts, fish, meat, poultry and whole grains.
• Other nutrients, including vitamin B6, B12, copper, folate and iron also may support your immune system and play a role in a healthful eating style.
• Phytochemicals from plant foods can act as antioxidants to help neutralize free-radicals that can cause harm to the body. Phytochemicals come from plants like fruits and vegetables and some beverages like tea and coffee.

To get the recommended servings of each food group, the United States Department of Agriculture’s MyPlate is a great resource to show what to include at meals to achieve a general, healthful diet that provides the nutrients we need to keep our immune systems strong.

Does taking supplements help protect against COVID-19 and other viruses?

There are no dietary supplements that can prevent or cure COVID-19. Many unregulated supplements are being sold and advertised as curative for COVID-19. Unregulated supplements can be dangerous to your health, especially when taken with prescription medications for chronic health conditions. Check with your physician before beginning any type of nutrition supplement. The best way to get the necessary nutrients is from whole foods.

There are many dietary supplements that advertise as being able to fight off the common cold or rhinovirus. However, there’s no solid evidence that supplements can prevent disease caused by viruses. Unfortunately, supplements can be sold with labeling that may make you think otherwise. Vitamin C is a good example of this. In a review discussing the use of vitamin C supplementation in prevention and treatment of the common cold, vitamin C supplementation prior to the start of cold symptoms wasn’t found to prevent getting a cold, and had only a small effect on the length of illness or severity of symptoms. There was no reduction in symptoms/severity found in those who supplemented at the start of their cold. 

In times like these when there are many mixed messages out there, it’s important to remember there are no good or bad foods. Frozen, canned and packaged foods are good options to help you keep nourished and shop less frequently, so you can stay safely at home.

Samantha Cochrane is a registered dietitian at The Ohio State University Wexner Medical Center.