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Vitamin D, a fat soluble vitamin essential for maintaining adequate serum calcium and phosphate concentrations that enable normal mineralization of bone, is also involved with immune function and supporting the muscle and nervous system. Emerging scientific evidence also suggests vitamin D status may influence certain types of cancers, neurologic disease, infectious disease, autoimmune disease, and cardiovascular disease. Over the last several months, numerous studies have indicated a possible link between Vitamin D deficiency in adults and infection by the novel coronavirus (SARS-CoV-2).

Since the introduction of the Australian “Slip, slop, slap” campaign in the 70s, Vitamin D deficiency has impacted significant proportions of all age groups worldwide. One in three Australians is considered Vitamin D deficient, while 42 percent of Americans are considered Vitamin D deficient. In the US, the highest rate is seen in blacks (82.1 percent), followed by Hispanics (69.2 percent).1 A paper published in PLOS One Medical Journal titled, “New Approach to Develop Optimized Sunscreens that Enable Cutaneous Vitamin D Formation with Minimal Erythema Risk,” found that an SPF 50 when properly applied, screened out up to 99 percent of UV light, including the UVB light we use to make vitamin D.2 One billion people world-wide lack vitamin D.3

Consequently, oral Vitamin D is one of the most commonly purchased supplements in the US. More than 200,000 people search for it online monthly. Annual US consumer spending on non-dietary vitamin D supplementation has risen from $248 million in 2008 to more than $1 billion today. Two decades ago, fewer than one percent of adults in the US took vitamin D supplements. But less than 15 years later, nearly one in five adults takes viatmin D every day. Forty-six percent of supplement users aged 55+ take vitamin D. According to the 2015-2020 US Dietary Guidelines, vitamin D is listed as an under-consumed nutrient of public health.

The American Academy of Dermatology recommends that an adequate amount of vitamin D should be obtained from a healthy diet that includes foods naturally rich in vitamin D, foods/beverages fortified with vitamin D, and/or vitamin D supplements. Vitamin D should not be obtained from unprotected exposure to UV radiation.

Research shows that we get 90 percent of the vitamin D we need from the sun. While it’s difficult to meet all vitamin D needs from food, eating healthy vitamin D-containing foods doesn’t come with the potential health risks of too much sun exposure. Although only a small portion of vitamin D is obtained from diet, Table 1 lists some of the best sources of vitamin D, according to the Office of Dietary Supplements.4

The “right” amount of vitamin D is up for debate and not unanimously agreed upon by health professionals and organizations. The AAD and Institute of National Academy of Sciences Institute of Medicine (IOM) recommend individuals age one to 70 years acquire 600 IU a day and recommend 800 IU/day for older ages. Researchers at UC San Diego and Creighton University have challenged the intake of vitamin D recommended by the IOM, stating that the Recommended Dietary Allowance underestimates the need by a factor of 10.

Vitamin D and COVID-19

More recently, there has been some discussion about coronavirus and vitamin D levels. In a cohort study of 489 patients who had a vitamin D level measured in the year before COVID-19 testing, the relative risk of testing positive for COVID-19 was 1.77 times greater for patients with likely deficient vitamin D status compared with patients with likely sufficient status, a difference that was statistically significant.5

Additionally, another a large, population-based study published inThe FEBS Journal revealed that low plasma vitamin D levels emerged as an independent risk factor for Coronavirus infection and hospitalization.

A study published from Northwestern University patient data across 10 countries demonstrated a correlation between low vitamin D levels and hyperactive immune systems, concluding that Vitamin D strengthens innate immunity and prevents overactive immune responses. The finding could explain several mysteries, including why children are less likely to die from COVID-19. Their study stated that patients with severe deficiency are twice as likely to experience major complications. The researchers noted that patients from countries with high COVID-19 mortality rates, such as Italy, Spain and the UK, had lower levels of vitamin D compared to patients in countries that were not as severely affected.

A study by Mendy, et al looked at medical data and analyzed it to identify potential risk factors associated with COVID-19 hospitalization and severity. The study showed that Vitamin D deficiency significantly increased the risk of hospitalization due to COVID-19 (77 percent increased risk), COVID-19 disease severity (95 percent increased risk), and the need for intensive care unit admission due to COVID-19 (155 percent increased risk).

A recent study published in the Irish Medical Journal (IMJ) titled “Optimisation of Vitamin D Status for Enhanced Immuno-protection Against COVID-19” supports research that vitamin D deficiency is associated with increased risk of acute viral respiratory infection and community acquired pneumonia, including COVID-19. The study also found that “Correction of vitamin D deficiency is thought to suppress CD26, a putative adhesion molecule for COVID-19 host cell invasion. We therefore recommend that all (Ireland residents) older adults, hospital inpatients, nursing home residents and other vulnerable groups be urgently supplemented with Vitamin D to enhance their resistance to COVID-19, and that this advice be quickly extended to the general adult population.”

Vitamin D and SUNSCREENS

There has been a lot of conflicting information in the science community in terms of dosing and its actual health benefits. One thing for sure is we have patients that are concerned about their vitamin D levels and their use of sunscreen.

Sunscreens have slowly advanced over the last few decades. The first sunscreen was invented by chemist Franz Greiter in 1938. In 1962, we had the start of SPF protection. and the introduction of water resistant sunscreens was in 1977. In 1980, Coppertone developed the first UVA/UVB Broad Spectrum sunscreen.

All conventional broad-spectrum SPF products are designed to screen out as much of the ultraviolet radiation (UVR) as possible to prevent sunburn, skin aging, and DNA damage. Broad Spectrum SPF protection protects across both UVA & UVB light. UVA light is the light we receive year-round from the sun and is far more damaging to our skin and to our DNA and consequently puts us at greater risk of melanoma. Although also damaging in large quantities, UVB light is a far shorter light and only reaches our skin in the hotter months between 10am and 3pm. It doesn’t penetrate through clouds, smog, glass, or clothing, and part of the UVB light is responsible for our bodies producing up to 90 percent of the vitamin D we need.

There is a new innovation in the sunscreen arena. A sunscreen has been specifically designed and formulated to prevent sunburn or sun damage while allowing the passage of sufficient UVB light (specifically between 290nm-300nm) that our bodies use to naturally produce vitamin D. In 2016, a study was performed to test the Solar D Derma Tech - Vitamin D Promoting SPF Technology (SPF30) that is used by the US brand Summer Ready, against four other leading brands ranging from SPF 30 to 50. The study was performed using the protocols prescribed by the FDA to determine SPF values, and conducted by Bioscreen Testing Services, Inc. USA. 

All sunscreens were smeared on clear silica plates, and UVB light from a lamp was shone through them and the percentages of light that passed through the plates was measured. The percentages of UVB light at a wavelength of between 290-300nm (Vitamin D Producing range) is shown in the chart. As is clearly outlined, there is a significant difference in the percentage of UVB light that is transmitted between all the sample sunscreens.

The study also examined how this UVB exposure would impact the bodie’s ability to permit vitamin D production. This vitamin D production study was an original in vitro experiment conducted in the laboratories of Dermatest, Pty Ltd of Sydney, Australia. Based on the results of this study, we can calculate that exposing a middle-aged person with healthy Caucasian skin to One MED dose of summer mid-day sunlight would result in the skin producing vitamin D using all of the sunscreens we sampled. However, the range of results differ significantly across the sunscreens tested.

As can be clearly seen by these studies, it is possible to formulate sunscreen to allow far greater amounts of the UVB light we use to make vitamin D compared to existing formulations. This study also shows that this light equates to a far greater chance of vitamin D production without risking any sunburn or sun damage by complying with SPF industry standards.


Vitamin D has long been recognized as essential for health, including for regulation of immune response. Accumulating data suggests that vitamin D insufficiency may represent a risk for more severe disease among those infected with SARS-CoV-2. The global problem of vitamin D deficiency may be a sequelae of increased sunscreen use and UV avoidance. Advancements in sunscreen formulation allow dermatologists have a new tool in their arsenal to help encourage their patients to not worry about their vitamin D when using sunscreens.

1. Forrest KY, Stuhldreher WL. Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res. 2011 Jan;31(1):48-54. doi: 10.1016/j.nutres.2010.12.001. PMID: 21310306

2. Kockott D, Herzog B et al. New Approach to Develop Optimized Sunscreens that Enable Cutaneous Vitamin D Formation with Minimal Erythema Risk. PLoS One 2016 Jan 29;11(1):e0145509.

3. P Lips. Worldwide status of vitamin D nutrition. J Steroid Biochem Mol Biol. 2010 Jul;121(1-2):297-300.

4. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central

5. David O. Meltzer, MD, PhD1; Thomas J. Best, PhD2; Hui Zhang, PhD2; et al Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results JAMA Netw Open. 2020;3(9):e2019722.

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