Nutrition in the Time of COVID-19

The Role of Diet and Supplements

Dietary surveys in the U.S. and elsewhere show most people are consuming diets that do not meet national guidelines —often because of availability or cost— and such diets may not provide optimal quantities of essential
vitamins and minerals. Currently, the ongoing COVID-19 pandemic is likely to put many more individuals at risk of food insecurity and make consuming a healthy diet even more difficult. This becomes increasingly likely if the infection risk-mitigation strategies do not include approaches to ensure essential supplies are effectively distributed and accessible, or if the pandemic affects productivity of the agricultural sector.

Although we are not aware of good data on the effects of nutritional supplements on risk or severity of COVID-19, existing evidence indicates that supplements of several nutrients can reduce risk or severity of some viral infections, particularly among people with inadequate dietary sources. Therefore, prudence suggests inadequate intakes of essential minerals and vitamins be avoided at this time, and supplements can help fill some gaps. Some key points:

• Taking a standard (RDA) multivitamin/multimineral supplement as a nutritional safety net is reasonable. These supplements are relatively inexpensive (should cost less than $40 USD for a six- month supply) and convenient way to replenish and maintain micronutrient stores.

• Maintaining adequate levels of vitamin D is particularly important. Vitamin D is normally produced in our skin when exposed to sunlight, and in the late winter and spring, blood levels of vitamin D tend to be low because of reduced sun exposure. Staying indoors will further reduce blood levels. Although we do not have evidence at this time whether vitamin D supplements will reduce the severity of COVID-19, they might, especially among people with low levels. Because the cost of blood testing is usually more than the cost of supplements (and not appropriate while our health care system is seriously stressed), and because there are other benefits from maintaining adequate vitamin D, taking supplemental vitamin D would be reasonable for most people to consider.

• Many of the commonly available multivitamin/ multimineral supplements do contain 1,000 or 2,000 IU of vitamin D, which is a good target. People with darker skin (who tend to have lower blood levels because melanin in the skin blocks ultraviolet light) may need more vitamin D; up to 4,000 IU per day is considered safe. Vitamin D is a commonly available multivitamin/multimineral supplement.

• If vitamin D supplements are not available, a backup option is to take advantage of some sunlight, which is now intense enough to produce vitamin D. Expose as much skin as possible in the middle of the day and begin for short periods, being careful to avoid burns; 15 minutes can produce a large amount of vitamin D in light skin; 3 or 4 times longer will likely be needed for dark skin. Note that this is short-term guidance related to limited vitamin D supplement availability during the current pandemic; and not advisable long-term. Because sun exposure can contribute to skin cancers, it is important to avoid excessive sun exposure or use of tanning beds.

• At this time, megadose supplements (many times the recommended dietary allowance, or RDA) do not appear justified, and these can sometimes be harmful. Avoid any supplements promoting wild health claims. The U.S. Food and Drug Administration has been monitoring and warning companies offering fraudulent products claiming to prevent, diagnose, treat, or cure COVID-19.

Nutritional supplements should not be considered substitutes for a good diet, because no supplements contain all the benefits provided by healthy foods. Source—Harvard School of Public Health