Report: A bit more vitamin D is good, but don't go overboard

WASHINGTON (AP) — Got milk? You may need a couple cups more than today's food labels say to get enough vitamin D for strong bones. But don't go overboard: Long-awaited new dietary guidelines say there's no proof that megadoses prevent cancer or other ailments - sure to frustrate backers of the so-called sunshine vitamin.

The decision by the prestigious Institute of Medicine, the health arm of the National Academy of Sciences, could put some brakes on the nation's vitamin D craze, warning that super-high levels could be risky.

"More is not necessarily better," cautioned Dr. Joann Manson of Harvard Medical School, who co-authored the Institute of Medicine's report released today.

Most people in the U.S. and Canada — from age 1 to age 70 — need to consume no more than 600 international units of vitamin D a day to maintain health, the report found. People in their 70s and older need as much as 800 IUs. The report set those levels as the "recommended dietary allowance" for vitamin D.