Recent reports out of the U.K. indicate low Vitamin D levels and obesity may be important reasons people get sicker from Covid-19. Early deaths among health care providers in England disproportionally hit doctors of Indian origin who have darker pigmented skin and lower Vitamin D levels. In the U.S, an incredible 80% of African Americans have Vitamin D deficiency, which might account for a portion of the increased mortality from Covid 19 among this demographic. But why would this be?
Low Levels of Vitamin D, Increased Risk of Covid-19
The notion that low levels of Vitamin D might cause an increased risk from Covid is more than plausible. Vitamin D is an important cofactor in biochemical processes within the body that tamp down the storm of cytokines that occur with viral infection. Death from Covid 19 most often occurs because the body’s own immune system surges out of control, causing worsening of fluid in the lungs and damage to multiple organs. Without the Vitamin D-dependent mechanisms to slow this surge, the immune system acts like a runaway train.
Darker skin pigment means less Vitamin D conversion from natural sunlight. Researchers hypothesize that the increased risks being seen from Covid-19 around the world among darker pigmented individuals may stem from lower Vitamin D levels due to this sunlight-pigment interaction. For lighter-skinned individuals, ten to twenty minutes of sunlight around mid-day is sufficient to have normal Vitamin D levels in most cases. For many darker-pigmented skin individuals, it often requires taking supplements of 2,000 to 5,000 IU or more daily to reach normal levels. Bottom line, it is a simple blood test to check your level and the Vitamin D supplements are available everywhere, so it should not be overly difficult to maintain this level in the normal range.
The Impact of Obesity on Vitamin D
Worse still, obesity, another risk factor for Covid mortality, also leads to low Vitamin D. As Vranic writes, “The association between Vitamin D deficiency and obesity as well as with obesity-related diseases has been confirmed by numerous studies, but the presence of a causal relationship is still unclear. There are many possible explanations regarding the inverse relationship between increased adiposity, particularly abdominal obesity, and low plasma VD concentrations.”
Large studies looking at Vitamin D and other potentially important variables in the battle against Covid 19 will be reporting their findings in the months to come. But there appears to be enough evidence from epidemiology studies and biochemical mechanism to warrant all of us to maintain a healthy Vitamin D level during this pandemic.
- Vranić L, Mikolašević I, Milić S. Vitamin D Deficiency: Consequence or Cause of Obesity?. Medicina (Kaunas). 2019;55(9):541. Published 2019 Aug 28. doi:10.3390/medicina55090541
- Biesalski HK. Vitamin D deficiency and co-morbidities in COVID-19 patients – A fatal relationship?. Nfs Journal. 2020;20:10-21. doi:10.1016/j.nfs.2020.06.001