Based on epidemiology data, as to the higher incidence of risk to complications related to Covid-19 exposure in African Americans, science has been exploring a number of possible reasons.
New research – Does the High Prevalence of Vitamin D deficiency in African Americans Contribute to Health Disparities – which appeared in the online, peer-reviewed journal Nutrients in February of 2021 – says there is a higher prevalence of Vitamin D deficiency in many African Americans – the result of people of African descent having brown-black melanin skin pigment, versus Angelo-Celtics, who have a yellow-to-reddish melanin.
That means African Americans are particularly at risk for vitamin D deficiency (less than 20 ng/mL in the blood) at high latitudes, where vitamin D synthesis depends on exposure to solar UVB radiation. At high latitudes, the UVB radiation dose is lower – causing a lower Vitamin D production, which starts in the skin.
The researchers from the University of California, Berkley, Sunlight, Nutrition and Health Research Center in San Francisco, Harvard T.H. Chan School of Public Health, and Brigham and Women’s Hospital – both in Boston, comment that, “vitamin D deficiency can be corrected rapidly and inexpensively.”
Vitamin D, a seco-hormone, which is a critical component of skeletal integrity, also regulates the activity of many thousand protein-encoding human genes.
Vitamin D’s conversion from 25(OH)D2 to 1,25(OH)D3 is a multi-step process in the body. The process begins, when “vitamin D3 is synthesized in human skin by the UVB-dependent conversion of 7-dehydrocholesterol to vitamin D3. Vitamin D3 is then converted to 25(OH)D3, a precursor of the crucial vitamin D steroid hormone, 1,25-dihydroxyvitamin D3, or calcitriol, in a reaction requiring magnesium.”
Evidence points to the fact that higher serum 25(OH)D levels can reduce the risk or severity of acute respiratory tract infections, possibly including COVID-19 – with Vitamin D’s positive impact on innate and acquired immunity.
The researchers cite evidence, which says the, “incidence and mortality of COVID have been far higher in African Americans than in European Americans; after adjustment for age, African Americans are 4.5 times more likely to die from COVID-19 than European Americans.
As for Vitamin D’s effect on reducing Covid-19 patients from advancing into intensive care units, “in a non-randomized intervention study conducted in Spain among hospitalized patients hospitalized for COVID-19, high doses of vitamin D (as 25(OH) D3) were administered in combination with standard care; only 1/50 required admission to the intensive care unit compared to 13/26 comparable control patients.”
Vitamin D is mainly found in fish and fortified foods, such as milk, and sun exposure (if possible), which is why vitamin D supplementation, based on laboratory studies, is required to meet Institute of Medicine’s (IOM) level of at least 20ng/mL.
However, “levels between 20 and 30 ng/mL have also been associated with lower risks of colorectal cancer, total mortality, dementia, multiple sclerosis, and bone mineral density.”
Yet, according to the Nutrient’s investigators, “three-quarters of African Americans not already taking supplements have levels that do not ensure adequacy even by the IOM definition (20 ng/mL), and 96% have levels below 30 ng/mL. Notably, for African Americans living in Boston, 4000 IU/day was required to achieve serum levels of 30 ng/mL.”
The researchers concluded by stating, “while further research is needed to identify the optimal strategy for vitamin D supplementation and fortification, no reason exists to delay addressing vitamin D deficiency among populations with high prevalence of deficiency, such as African Americans. The potential benefits promise to be large, and much evidence indicates that the risks of supplementation up to 4000 IU per day vitamin D are minimal.”