Found this article interesting due to it's implications for black folks in northern hemisphere countries.
"Vitamin D deficiency increases a person's risk for catching COVID-19 by 77% compared to those with sufficient levels of the nutrient, a study published Thursday by JAMA Network Open found.
Since African-Americans living in northern climes tend to have vit D deficiency, this will partially explain the relatively high mortality of black folks in both the US and UK.
"There are some dietary sources of vitamin D, including fatty fishes such as salmon, eggs, mushrooms and fortified foods, including most milk and dairy products, but it is not easy to get the levels one would get from supplements from these dietary sources alone," Meltzer said.
"Regular exposure to sunlight can [also] raise vitamin D levels," he said.
Actually, sunlight derived Vit D is the best Vit D (actually a hormone) and should be your primary go to. The side reason is that being outdoors is conducive to exercise which would address the other issues such as obesity.