A new study from Trinity College in Dublin suggests an association between vitamin D levels and mortality from COVID-19. Vitamin D is produced in the skin from UVB sunlight exposure and is transported to the liver and then the kidney where it is changed into an active hormone. This form of the vitamin increases calcium transport from food in the gut and keeps the skeleton strong. But vitamin D also supports the immune system and a number of recent studies confirm it has an important role in combating viral infections.
In this recent study the authors showed that people from sunny countries, such as Spain and Northern Italy, had lower concentrations of vitamin D and higher rates of vitamin D deficiency. These countries also experienced the highest infection and death rates from COVID-19 in Europe. People in countries further north – Norway, Finland and Sweden – typically had higher vitamin D levels despite less UVB sunlight exposure. In these countries, supplementation with vitamin D and fortification of foods is more common. These Nordic countries have also experienced lower rates of COVID-19 infection and deaths.
The authors suggest that optimizing vitamin D levels may help to reduce serious COVID-19 complications. Even though, currently, there are no randomized controlled studies to prove that vitamin D positively affects COVID-19 outcomes, there is strong circumstantial evidence between the levels of the vitamin and the severity of the virus, including death. Many in the US do not have optimum levels of vitamin D. The current daily recommendation is 600 IUs daily for everyone aged 1 year and older and 800 IUs for adults 70 plus.
