—Gina Romano, Ithaca, New York One major concern is a vitamin D deficiency. Vitamin D is called the “sunshine vitamin” because it’s made when the skin is exposed to sunlight and is naturally present in only a small number of foods. The vitamin is important for strong bones and muscles, regulation of blood pressure, reduction of inflammation and more. It even aids your immune system, which may help fight COVID-19. Foods fortified with vitamin D can help.