Nov 30, 2010
A report today from the influential Institute of Medicine sets the first formal recommendations for daily intakes of calcium and vitamin D for bone health, and suggests that most people are getting what they need.
The recommended amounts are higher than guidelines set 13 years ago that were simply estimates, but the vitamin D recommendations immediately drew criticism from some experts who said they are still far too low.
According to the report, children and adults younger than 71 need no more than 600 international units (IUs) of vitamin D a day and should consume 700 to 1,300 milligrams of calcium a day, depending on their age.
The committee was surprised to see that most Americans are meeting their needs for both of the nutrients, except for adolescent girls who may not be getting enough calcium and some elderly people who don't get enough of either, says Catharine Ross, professor of nutrition at Pennsylvania State University and chairwoman of the panel that prepared the report. The Institute of Medicine (IOM) is set up by Congress to advise on a variety of health issues.
Among the reasons for sufficient intakes: food fortification and more supplement use. Many foods, such as milk and yogurt products, are rich in calcium and fortified with vitamin D. Fatty fish such as salmon, mackerel and tuna also have a lot of vitamin D.
Sunlight triggers the production of vitamin D in skin and contributes to people's levels.
Robert Heaney, a professor of medicine at Creighton University in Omaha who has studied vitamin D's health benefits, says the overall daily value of 600 IUs of vitamin D a day "is way too low." He says people should consider taking up to 4,000 IUs a day.
"For me, it's a no-brainer. There is a large body of evidence for benefit at intakes above the IOM recommendations. There is no risk, and very little cost, so why not take a chance of a benefit if there's any possibility?"
The committee, made up of nutrition scientists, set the upper limit for vitamin D at 4,000 IUs a day for those who are ages 9 and older. This is considered the safe boundary and is not the amount people should strive for, the panel cautions. Excessive vitamin D can damage the kidneys and heart, and too much calcium from supplements has been linked to kidney stones, the report says.
Vitamin D has been a hot topic in recent years because research has linked lower levels of the nutrient to certain cancers, diabetes, and bone and immune system problems.
The panel concluded that more scientific research is needed to investigate the potential health benefits of larger amounts of vitamin D.
"We looked at that evidence, and it's conflicting," Ross says. "Some studies show potential benefit, but others show no benefit, and some studies show the opposite, even harm."
Steven Clinton, a committee member and a professor in the division of medical oncology at Ohio State University, says part of the uncertainty over the nutrient comes from the blood tests that are used to measure it. "There are no national guidelines for how vitamin D should be measured and what levels are appropriate," he says.
Clinton recommends that national standards be developed.
By Nanci Hellmich, USA TODAY