Beginning in July, the average recommended daily intake for vitamin D listed on food nutrition labels will double, from 400 to 800 International Units (IUs) daily. This increase is mainly based on newer scientific evidence which was used to develop the 2020-2025 Dietary Guidelines for Americans.
That evidence links vitamin D with a wide range of health benefits. The “sunshine vitamin” may protect people against a variety of serious problems, including osteoporosis, heart disease, depression and insomnia, along with some cancers.
Multiple studies have connected low vitamin D levels with poor muscle strength as well, particularly in older people. Vitamin D deficiency among pregnant women has even been linked to lower IQ scores in their children.
Most recently, research has shown that having adequate blood levels of vitamin D may be protective against COVID-19; in fact, one study published this March found that around 80% of a group of people hospitalized with serious cases of the virus were found to have vitamin D deficiency in common.
While estimates vary regarding how many Americans are currently deficient in vitamin D – and those estimates also differ by age group, skin color and other variables – most researchers agree that at least 35% of the U.S. population fails to meet the vitamin D sufficiency standard of 30 nanograms per milliliter (ng/ml).
Because most foods don’t naturally contain significant amounts of vitamin D (fatty fish like salmon and tuna are exceptions), fortified foods provide most of the vitamin D in American diets. Almost all of the U.S. milk supply is vitamin D-fortified, along with many breakfast cereals and some brands of orange juice, yogurt and other products.
The sun, of course, is a primary source of vitamin D for most people – and summer is naturally a prime time to take in more by going outside on sunny days. However, spending too much time in the sun poses its own health risks, chief among them being skin cancers including melanoma. Because the SPF ingredients in sunscreen also block vitamin D absorption, though, some doctors now recommend exposing your skin to direct sunlight for up to 20 minutes a day before applying sunscreen.