Vitamin D deficiency can lead to poor health outcomes. The deficiency has been associated with a large number of disorders such as metabolic syndrome and cancers, as well as autoimmune, psychiatric and neurodegenerative diseases.  Many of these conditions correlate to higher rates and more severe cases of COVID-19. There is also a robust correlation to underlying metabolic health conditions such as obesity, high blood sugar and high blood pressure (of which all three are elements of metabolic syndrome), but there is growing evidence from labs and research around the globe that correlates vitamin D with severe COVID-19 outcomes.

Adequate serum vitamin D is apparently an important part of innate and adaptive immune function. While vitamin D insufficiency is an individual health problem, it is also a problem for our body politic. Vitamin D insufficiency causes undue strain on our healthcare system and on the economy during a pandemic. Public health policy might be well served by prioritizing adequate vitamin D levels in the population. This could improve health outcomes, reduce illness from infectious disease and reduce the overall effects of poor health in our society.

The epidemic of vitamin D deficiency in America is a compounding factor that wreaks havoc on our health and healthcare bureaucracy. A recent study in Boston found two-thirds of healthy young adults were vitamin D deficient by the end of winter, and around 60 percent of nursing home residents are deficient. Early in the pandemic, several population studies—including one in Israel and one in Chicago — linked low levels of vitamin D to poor health outcomes and heightened susceptibility for COVID-19.

While the exact nature of the causative role vitamin D deficiency plays in many of these conditions remains unclear, vitamin D supplementation can be a central strategy for the government to minimize the effects of the pandemic.

Vitamin D does not operate like most vitamin supplements. It is a fat soluble vitamin that is scarcely found in food. Produced in the skin from UVB sun exposure, it is transported to the liver and then to the kidney where it changes into a hormone. This hormone is responsible for increasing calcium transport from food into the gut and ensuring that calcium is adequate. However, like all hormones, it also has other functions, such as supporting immune pathways in the body.

The consequences of having very low vitamin D are dire, and high vitamin D levels have been proven to cause problems with digestion, although these levels are difficult to reach. It remains that around 35 percent of adults in the United States are vitamin D deficient, with much higher percentages in those at greatest risk from COVID-19. The best way to know the ideal dose is to monitor blood levels, but there are people who are highly likely to be deficient in vitamin D. These people should have vitamin D available to them as a part of combating the effect that COVID-19 has on our society.

In a 2017 study on the financial viability of vitamin D supplementation in a nursing home, researchers found that the provision of systematic vitamin D supplementation to nursing home residents would provide substantial net economic benefit to society. They also found that assessing vitamin D status before starting supplementation was not necessary for the patients that were particularly at risk for vitamin D deficiency.

There has not yet been placebo-controlled research, in which one group takes vitamin D and another does not, in regards to COVID-19. So, there is no clear evidence for causation. However, our government has been working to find a solution and a vaccine, and we have completely changed our lives to minimize the effect that COVID-19 has on our economy and health for the long term.

Ensuring that vitamin D is easily accessible could manifest in several ways, including an increase in accessible testing and distribution channels. Letting government and institutional subsidies support ways to easily obtain vitamin D blood tests and supplements is also a simple and cost-effective preventative measure that is likely to lower the impact from COVID-19, especially as we head into winter.