If you have been lucky enough to avoid the COVID-19 virus thus far, you have likely spent more than a year sheltering-in-place, wearing face masks in public, fervently washing your hands, and sanitizing surfaces. But have you been practicing proper nutritional virus protection measures? Data on the role vitamin D has played in protecting infected individuals against life-threatening symptoms is still pouring in, but the implications are clear. Vitamin D deficiency is an epidemic in the US, and vitamin D deficiency is a common thread amongst those who have suffered serious and fatal cases of COVID-19. 

The evidence supporting vitamin D supplementation is so strong, in fact, that Congress just stepped in to publicize it and potentially create policy around it. U.S. Rep Glenn Grothman (R-WI) has introduced a House resolution (HR 116) that calls on the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) to update existing guidance and to encourage increased vitamin D intake during the COVID-19 pandemic, especially for the elderly and immunocompromised [1].

“As much of the public continues to wait for access to available vaccines,” said Rep. Grothman, “it’s critical that the House of Representatives is united in finding additional ways to limit the negative effects of the virus and provide the public with more information about how effective vitamin D can be in preventing serious COVID-19 symptoms [1].” With news emerging on variants that may defy the protection of vaccines, reaching adequate levels of vitamin D could be a saving grace for many individuals. 

Ok, but what is the evidence?

The resolution states that more than 40% of Americans are vitamin D deficient, but that number is closer to 80% among Black and Latinx populations [1]. Similarly, COVID-19 is disproportionately hospitalizing and killing Black and Latinx people. Again, elderly and immunocompromised people (of any race) are more likely to be both vitamin D deficient and suffer more severely from COVID-19 [1]. 

Vitamin D deficiency can result in obesity, diabetes, hypertension, depression, fibromyalgia, chronic fatigue syndrome, osteoporosis, and neurodegenerative diseases including Alzheimer’s disease [2]. Vitamin D deficiency plays a role in causing seventeen varieties of different cancers as well as heart disease, stroke, autoimmune diseases, birth defects, and periodontal disease [2]. These are the “co-morbidities” that lead to worse COVID-19 outcomes. It is estimated that around 100 million Americans have one or more of these high-risk conditions [1].

Vitamin D is a powerful vitamin. Aside from its most famous role in bone health, it has been shown to play roles in modulation of the immune system, increasing neuromuscular function, improving mood, protecting the brain against toxic chemicals, and potentially reducing pain [2].

In terms of the mechanism, as in, how vitamin D limits the severity of COVID-19 symptoms, there are a few hypotheses. Obviously, the most general is that proper vitamin D sufficiency prevents the co-morbidities described above. A second is that, as an immune modulator, vitamin D supports a healthy response to viral infection [3]. For example, overactivation of specific immune responses has been documented in cases of severe COVID [3]. Vitamin D appears to aid in the modulation of these same, specific responses [3].  

Why is there a race disparity in vitamin D deficiency?

The race disparity in deficiency likely relates to both physiology and societal inequities for these cultural groups. First, the melanin that makes skin appear darker in color is terrific for protecting against sunburn. But, by blocking the absorption of UV rays, dark skin also requires more time in the sun than lighter skin to make the same amount of vitamin D [2]. The general rule-of-thumb to produce adequate vitamin D is 15-20 minutes of direct sun exposure per day, with at least 40% of skin exposed (no sunscreen) [2]. The more melanin you express, the longer you will need in the sun for skin to make adequate vitamin D. 

Spending time in the sun is somewhat of a luxury in this day and age. Plus, people from Black and Latinx populations are disproportionately incarcerated, working “essential” jobs, and working long hours to make up for wage inequality. When you take in the whole, big picture, it makes sense that the odds are stacked against these populations for both vitamin D sufficiency and viral exposure. This issue needs to be addressed publicly. 

There are a few dietary sources of vitamin D (egg yolks, beef liver, fatty fish, or fortified dairy products). However, these food items are not common enough or rich enough in vitamin D to meet the needs of the average American.

What if I am vitamin D deficient?

This is where vitamin D education and supplementation come in. 

Once you know how important vitamin D is to both general health and COVID-19 resiliency, a simple blood test can help a medical professional analyze your vitamin D levels. Only you know whether you can fit more sunshine into your day and whether you are willing to risk the dangers of sun exposure without sunscreen. From there, you can decide upon a healthy daily dosage of supplemental vitamin D-3 (the same kind made by your skin in the sun). Metabolic Maintenance® offers vitamin D-3 (cholecalciferol) in a range of dosing options as a standalone supplement or as an ingredient in several multivitamin/mineral formulas.

Of course, supplements are an additional expense. Potentially, in the wake of new policy, the government may choose to intervene and provide supplements to those who cannot otherwise afford it. Public health agencies across the U.K. are already distributing vitamin D supplements to 2.5 million at-risk people, including those in long-term care facilities and those with pre-existing comorbidities such as obesity, diabetes, and cardiovascular disease [1].


  1. Runestad, Todd. “Congress lauds vitamin D for COVID-19”. Natural Products Insider. Feb 25, 2021. https://www.naturalproductsinsider.com/ingredients/congress-lauds-vitamin-d-covid-19?utm_source=Bibblio&utm_campaign=Related
  2. Naeem, Zahid. “Vitamin d deficiency-an ignored epidemic.” International journal of health sciences 4.1 (2010): V.
  3. Martineau, Adrian R., and Nita G. Forouhi. “Vitamin D for COVID-19: a case to answer?.” The Lancet Diabetes & Endocrinology 8.9 (2020): 735-736.