Vitamin D Newsletter


How Much, What Kind, Where to Get It

Angie from California writes:

Dr. Cannell: I'm confused about how much vitamin D I should take. The government says one thing but I'm reading in the newspapers and magazines that I should take much more. What kind of vitamin D should I take, what's the right amount, and where should I get it?

Dr. Cannell writes:

Great question! The only vitamin D you should take is cholecalciferol. No one knows for sure how much you should take but the easy answer is 2,000 units a day. The government says 2,000 units a day is safe to take on your own, without being under a doctor's care, and without getting blood tests. Two thousand units a day will do a lot of good. However, it may not be enough for some African Americans, the obese, the aged, and for people suffering from sunlight deprivation. The safest thing to do is to get a vitamin D level, or 25-hydroxyvitamin D, two or three times a year and take enough to maintain your level around 50 ng/mL (125 nM/L) year-round. Remember your highest natural level will be in the early fall and your lowest level in the early spring.

If you take more than 2,000 units a day, you should have blood levels done periodically. To my knowledge, no one has ever given 5,000 units of cholecalciferol a day for three or four years to see what happens to blood levels. We think it will be okay but still are not completely sure. I take 5,000 units in the winter, 2,000 units in the early spring and late fall, and none in the late spring, summer, and early fall when I enjoy the sun. I maintain my levels around 50 ng/mL.

Vitamin D comes in potencies such as 1,000, 5,000, or even 50,000 IU. The 50,000 IU capsule can definitely cause vitamin D toxicity if taken for many months, is meant for health care providers, and should only be taken on your own if you know what you are doing. Most health food stores sell 1,000 unit capsules of plain cholecalciferol.

Page last edited: 07 November 2010