A new study published in the journal Scientific Reports, from the Nature group, found that dietary supplementation with vitamin D acted as a preventive and mitigating agent for those who caught Covid. Those who took the vitamin had a reduction from 28 to 28 % in the risk of becoming infected. Among those who became infected, the risk of death in the following month was reduced by 33% if the supplement was in the D3 version (of animal origin) instead of D2 (from plants). Two months of prior supplementation, however, are required for levels in the body to rise. According to the researchers, if vitamin D had been recommended for the entire American population in 2020, 49 1,000 deaths would have been avoided in the United States.
The study took methodological precautions so that the effects of vitamin D were not confused with natural immunity due to previous infection and other cautious behaviors, such as the use of masks . The source of the data was a database of US military veterans: 220 1,000 took vitamin D3, 35 1,000 took D2 and 408 1,000 received no supplementation — they were the control group, for comparison.
The authors, led by Robert D. Gibbons, from the Department of Medicine at the University of Chicago, comment that their results corroborate a previous study from Andalusia, in southern Spain, which also observed a reduction of 35% in Covid-19 mortality with vitamin D supplementation. In the case of Spaniards, supplementation was prescribed 15 days before hospitalization and was on calcifediol instead of D3.
Vitamin D and skin color2020
The vitamin occurs in low amounts in food. Therefore, contact with sunlight is important for the production of more D3, from a cholesterol derivative in the skin. It is the beneficial role of ultraviolet rays. Three centuries ago, rickets was described, a bone problem that occurs due to vitamin deficiency. Psychological effects of the deficiency of the molecule are also known, such as depression.
Sunbathing is so important that it is the explanation for the appearance of fair skin in humans. Originally with dark skin, when occupying regions closer to the North Pole, humans suffered from a lack of vitamin D, in the face of a lower incidence of sunlight. Among the offspring, therefore, children with lighter skin (which block UV rays less) naturally produced more vitamin D and were healthier, having more chances of surviving in the region and leaving offspring. With the passing of generations and the repetition of this process, white skin appeared at least twice in humans: in Europe and in northern Asia. In low latitudes, close to the equator, it is the opposite: the incidence of UV rays is high, and lighter people do not have an advantage, as they have an increased risk of skin cancer, caused by the same sun rays.
As darker skins have more difficulty producing vitamin D naturally, predictably, the study of American veterans found that blacks benefited even more from vitamin D supplementation than whites. The reduction in the risk of infection in blacks was
%, while in whites it was 220 %. Higher blood levels of the vitamin were also associated with greater risk reductions. Among patients who had low levels of vitamin D and were prescribed supplementation with a maximum daily dose of 116 1,000 IU , the reduction in the risks of catching Covid was the greatest recorded by the study: 49%.
The authors suggest that their results be tested by studies in which people are randomly assigned to each treatment or non-treatment group, which would add rigor. “Physicians could consider regularly prescribing vitamin D3 to patients with deficient levels to protect them against infection with Covid-19 and related mortality”, they comment in the article. “A dose of 50 a thousand IU” daily, they conclude, “may be especially beneficial”.