How Much Is Enough?
The answer to the question, ‘How much vitamin D do I need?’ depends on who you are and who you ask. Age, skin type, where you live, and the season of the year all affect vitamin D levels. Federal guidelines say adults should get between 200 and 600 international units (IU) of vitamin D each day, with recommended levels increasing with age.
Vitamin D researcher Michael F. Holick, MD, PhD, believes the optimal daily dosage for preventing disease is closer to 1,000 IU. Holick heads the Vitamin D Research Lab at Boston University and is the author of the book The UV Advantage.
Holick tells WebMD that he takes a 1,000-IU vitamin D supplement each day.
“It is not easy to get the vitamin D you need from foods unless you make a special effort,” he says. “A glass of milk or vitamin D-fortified orange juice has only about 100 IU of vitamin D, and a serving of salmon has only about 500 IU.”
Holick says most people can get more than enough vitamin D in the spring, summer, and fall by engaging in what he calls “sensible sun exposure” -- no more than five to 10 minutes of direct sun to unprotected legs and arms two or three times a week.
“We are not talking about burning in the sun,” he says. “No one is saying that is good for you.”