What should we be eating to help us resist the coronavirus?

Submitted by By David St-Jules, University of Nevada, Reno | Feature Image: Crystal Momii, University of Nevada, Reno Extension

Our current attitudes and beliefs toward healthy eating are largely shaped by nutrition research and marketing designed to address the long-standing epidemics of obesity, and obesity-related chronic diseases in the U.S., not deal with infectious diseases such as COVID-19. When faced with the threat of a currently untreatable, potentially fatal disease, it is common for us to look to diet for a potential cure.

However, we must realize that foods and supplements are not drugs, and diet is necessarily limited in what it can achieve. Arguably the best thing that people can do to help combat coronavirus is to follow the evidence-based guidelines for healthy eating designed to provide adequate nutrition, including adequate nutrition to help ensure our immune systems are properly functioning. Here are some clarifications surrounding our efforts to fend off COVID-19 with our food and nutrition choices.

Can I get infected from food?

Current evidence indicates that the coronavirus is primarily transmitted person-to-person via respiratory droplets produced through coughing and sneezing.
No evidence supports the transmission of coronavirus from food or food packaging. Although the virus may be transmitted from surfaces and objects through contact with the mouth, nose and eyes, this is not thought to be the main route of transmission. See the U.S. Food and Drug Administration website: https://www.fda.gov/food/food-safety-during-emergencies/food-safety-and-coronavirus-disease-2019-covid-19.

Are there specific foods and nutrients that will reduce my risk of infection?

Yes and No.
Yes – Nutrients are required in adequate amounts to support our body functions, including those that help our immune system to work properly and help protect us against viruses such as the coronavirus. Nutrient deficiencies can therefore impair our immune system., but there is no evidence that nutrient excess will enhance our immune system.
No – There is no evidence that specific foods or nutrients prevent viral infections such as COVID-19 in healthy adults who are meeting their daily nutrient needs.

What can people do from a diet perspective to reduce the risk of harm from COVID-19?

Follow the USDA MyPlate food recommendations. MyPlate is the current nutrition guide designed to provide the required amounts of essential nutrients for healthy adults and children. It is published on the U.S. Department of Agriculture’s website at https://www.choosemyplate.gov/. In order to prevent nutrient imbalances (deficiency or toxicity), people are advised to consume the recommended balance of food groups, and choose a variety of foods within each food group.
Beware of misleading claims. The U.S. Food and Drug Administration and Federal Trade Commission have already issued warning letters to numerous companies for claims related to COVID-19 – claims regarding foods, test kits, vaccinations, pills, potions, lotions and more. People should be wary of unsubstantiated claims related to improving immune function. More information on coronavirus scams, what the Federal Trade Commission is doing about them, and what you can do to avoid falling prey to them be found at https://www.consumer.ftc.gov/features/coronavirus-scams-what-ftc-doing.

What about supplements?

By design, dietary and herbal supplements are not required to show that they are safe or effective (that would be drugs), nor are they able to claim the ability to prevent, treat or cure a disease (that would also be drugs). But, supplement manufacturers can craft messages that imply health benefits such as, “boosts immunity,” and consumers often interpret these messages to be hard facts. Such claims are not subject to the standard of significant scientific agreement among experts, and are not vetted by the U.S. Food and Drug Administration.
For most adults, a multivitamin/multimineral supplement is unnecessary, and unlikely to provide any additional protection in those consuming the balanced, varied diet recommended in MyPlate.
Beware of costs. Supplements can be very expensive. Unless you are certain of the benefits, this money may be better spent on foods to support a healthy diet.
Beware of claims. The potential benefits of supplements are often based on basic research, such as cell culture research and animal studies. Often these effects are not substantiated by more in-depth scientific research on humans, and therefore these effects are not known to translate to humans.
Beware of unintended consequences. Taking a given supplement can have multiple effects on our bodies, including effects with negative consequences. For example, we know that zinc is an important nutrient for immune function, and this could be the basis for an “immune-boosting” claim, encouraging zinc supplements. However, taking too many zinc supplements can reduce the absorption of other nutrients, such as iron, which is also important for immune function. Thus, taking mega-doses of any certain nutrient is not recommended for the general public.

Where are we today, really?

What we know is that diet is one of the most important factors we can control to improve our health, including our immune systems. Nutrients in food are like fuel for our immune engines, necessary to make them run properly. Putting in excess fuel doesn’t make the engine run better.

But, it is equally important to recognize: while it is possible that nutritional science will one day identify specific dietary patterns that will reduce the risk of infection in otherwise healthy, well-nourished adults, the field is relatively young, and we simply aren’t there yet. Just because there is a gap in our understanding does not mean that we should fill it with foods or supplements that have undemonstrated benefits, and uncertain consequences.

For now, we need to focus on what we do know, which is that a balanced, varied diet is the best way to supply the nutritional fuel that our immune engines need. No diet will guarantee protection. Plenty of apparently well-nourished people have already been infected. But, nutrient deficiencies can certainly impair our immunity and increase our risk of infection.

Finally, more recommendations on food- and nutrition-related practices during the coronavirus outbreak are provided by the Academy of Nutrition and Dietetics on their website at https://www.eatright.org/coronavirus. These recommendations are in line with recommendations from the Centers for Disease Control and Prevention. Contact me with questions at [email protected].

David St-Jules is an assistant professor at the University of Nevada, Reno’s College of Agriculture, Biotechnology & Natural Resources who conducts research on how nutrition affects various diseases and medical conditions.

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