Vitamin D deficiency could lead a person more susceptible to infection. In a retrospective study of 489 patients at the University of Chicago, untreated Vitamin D deficiencies were 77% more likely to test positive for COVID-19 than those who likely had sufficient Vitamin D levels. In a pilot study in Spain, A Vitamin D analog reduces the incidence of ICU admissions for COVID-19.
Vitamin D is inexpensive, as yet the deficiency rate in the USA is estimated at 70% of the general population, especially in people of color. It is actually a hormone that controls over 1000 genes. It is synthesized by the skin after UVB irradiation. With the use of sun-block, one has to get sufficient dose of Vitamin D with oral supplement. Increase in age is associated with decrease in Vitamin D production, and increase in body fat will render less Vitamin D availability in the blood stream. Latitude also affects the amount of UVB reaching the skin for Vitamin D production.
The sweet spot of Vitamin D level is between 30 to 80ng/ml of serum. This can be checked with simple blood test. Vitamin D supplement up to 4000 IU per day should be adjusted according to the blood test result.
Besides the commonly known benefit in Calcium Metabolism, Vitamin D is needed for Serotonin production. It regulates social behaviour, emotion, aggresion, anxiety, perception, cognition, memory and appetite. Other modalities that stimulate Serotonin include Omega 3 fatty acid ( EPA and DHA ).
Vitamin D deficiency accelerates aging, with telomere length is an aging bio-marker. Vitamin D extends telomere length, decreases DNA damage and inflammation. Other modalities that extend telomere length include meditation, exercise, and proper sleep.
There are possible rationale in COVID-19 for Vitamin D with activation of Vitamin D receptor ( VDR ) signalling pathway. These include lowering Acute Respiratory Distress Syndrome and cytokine storm ; modulating neutrophil activity, maintaining the integrity of pulmonary epithelial barrier, and tapering down the increase coagulability.