Vitamin D is commonly known as the “sunshine vitamin.” That’s because your skin makes vitamin D when it is exposed to sunlight (1Trusted Source). Getting enough vitamin D is important for optimal health. It helps maintain strong and healthy bones, aids your immune system and may help protect against many harmful conditions (2Trusted Source, 3Trusted Source). Despite its importance, roughly 42% of people in the US have a vitamin D deficiency. This number rises to a staggering 82.1% of black people and 69.2% of Hispanic people (4Trusted Source). There are several other groups of people that have higher vitamin D needs because of their age, where they live and certain medical conditions. Vitamin D dose International units or micrograms 1,000 micrograms (mcg) in a milligram (mg) 1,000 milligrams (mg) in a gram (g) 1,000 grams in a kilogram (Kg) 1 kg is 2.2 pounds IU mcg 400 10mcg 800 20mcg 1,000 25mcg 2,000 50mcg 4,000 100mcg

Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Vitamin D is essential for several reasons, including maintaining healthy bones and teeth. It may also protect against a range of diseases and conditions, such as type 1 diabetes. Despite its name, vitamin D is not a vitamin, but a prohormone, or precursor of a hormone. Vitamins are nutrients that the body cannot create, and so a person must consume them in the diet. However, the body can produce vitamin D.