My dad drinks a lot of milk each day. I’m not sure if it’s because he likes it or whether he’s focusing on the nutritional benefits of vitamin D. But a new report from the Institute of Medicine states that while vitamin D is great for maintaining bone strength (which Dad needs since he’s in his mid-80s), high doses don’t prevent cancer, heart disease, diabetes, influenza, autism, or multiple sclerosis, according to a NPR story by Richard Knox.

So how much vitamin D and calcium should you take each day? “Over the last 10 years, the public has heard conflicting messages about other benefits of these nutrients – especially vitamin D – and also about how much calcium and vitamin D they need to be healthy,” the Institute report’s authors wrote. To clarify what you need, the Institute of Medicine analyzed current data on health outcomes associated with vitamin D and calcium.

The Institute now recommends that children and most adults take 600 international units of vitamin D a day while adults over 70 need 800. While that’s more than the previous recommendations of 200 units a day for young adults and 400 for people over 50, it is much less than the daily doses of 1,000 to 4,000 units that advocates often suggest, according to a story by NPR’s Richard Knox.

In addition, the panel reviewed calcium intake, which works with vitamin D for healthy bone development and maintenance. According to the NPR report, the panel recommended the following:

• Children, age 1-3, need 700 milligrams of calcium daily.
• Children, age 4-8, need 1,000 milligrams daily.
• Adolescents need no more than 1,300 milligrams daily.
• Adults up to age 50 need 1,000 milligrams daily.
• Women, age 51 and older, need 1,200 milligrams daily.
• Men, age 70 and older, need 1,200 milligrams daily.

Interestingly, the Institute’s panel did not find a high level of vitamin D deficiency among U.S. citizens. The new report recommends that people’s blood levels of vitamin D should be about 20 nanograms per milliliter of blood, which is less than the 30-40 nanograms suggested by proponents and which would have meant that more than half of Americans could be considered deficient for this vitamin.

“The Institute of Medicine experts worry that taking vitamin D in large doses over a long period might harm some people,” Knox reported. “The evidence is inconclusive, but the panel points to studies hinting at higher levels of pancreatic and esophageal cancer. Panelists say there’s reason to worry about excess deposits of calcium in arteries from too much vitamin D.” A New York Times story on this study also reports that evidence suggests that high levels of vitamin D can increase the risk for bone fractures and the overall death rate. “While those studies are not conclusive, any risk looms large when there is no demonstrable benefit,” New York Times report Gina Kolata wrote.

According to the National Institutes of Health Office of Dietary Supplements, vitamin D is found naturally in a few foods. Fatty fish, such as salmon, tuna, and mackerel, is the best source. In addition, beef liver, cheese, egg yolks, and mushrooms have small amounts. Almost all milk in the United States is fortified with 400 IU of vitamin D per quart. Vitamin D also is added to some breakfast cereals and brands of orange juice, yogurt, margarine, and soy beverages.