What the new vitamin D advice means

A recent vitamin D report from the Institute of Medicine forced a lot of people to reconsider the essential nutrient. Here's a look at what the expert panel said, and why it reached its controversial conclusions.

How much vitamin D did the experts say is necessary?

For most children, teens and adults, a daily dose of 400 international units (IUs) of the vitamin is sufficient, and 600 IUs are recommended. Seniors older than 70 should ideally receive 800 IUs of vitamin D a day, the panel determined. For babies younger than 1, the panel considered 400 IUs of vitamin D enough.

Those levels are somewhat higher than the ones set in 1997, the last time a government panel examined vitamin D intake. But they are far below what many doctors and supplement advocates had been urging.

Why weren't they higher?

The idea that people could benefit from daily doses as high as 2,000 IUs is based on the belief that vitamin D can reduce the risk of many chronic diseases, including type 2 diabetes, cardiovascular disease, metabolic disturbances, depression and certain cancers.

A slew of recent studies have linked low levels of vitamin D to an increased incidence of these health problems. But the expert panel concluded that the studies were not convincing — many, in fact, showed no such connection — so it based its recommendations only on the amount of vitamin D needed to maintain bone health and prevent fractures.

Does that mean I should give up my vitamin D supplements?

Maintaining a healthy level of vitamin D through diet alone has become much easier since manufacturers began fortifying foods with the nutrient. Fortified foods — including virtually all milk, many brands of orange juice, and some cheeses, yogurts, margarines and breakfast cereals — are now some of the richest dietary sources of vitamin D. High levels exist naturally in fatty fish such as tuna, salmon and mackerel, and it's also present in egg yolks and beef liver.

But there are a lot of people who may still need to add a vitamin D pill to their daily diet. For instance, people who follow a vegan diet need to look hard for supplemental sources of vitamin D, as do those with milk allergies, lactose intolerance, and people who rarely eat fish.

"We didn't actually say in the report that supplementation is verboten," said Dr. Glenville Jones, an endocrinologist at the University of Queensland in Canada who was on the expert panel.

So I should keep on buying foods fortified with vitamin D?