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WASHINGTON (Reuters) - Most people in the United States and Canada get plenty of vitamin D and calcium, and may damage their health by taking too many supplements, experts advised on Tuesday.
Contrary to popular wisdom, many Americans and Canadians get plenty of calcium and vitamin D and most do not need extra supplements to keep their bones strong, the Institute of Medicine committee said.
"National surveys in both the United States and Canada indicate that most people receive enough calcium, with the exception of girls ages 9-18, who often do not take in enough calcium," the report reads.
"In contrast, post-menopausal women taking supplements may be getting too much calcium, thereby increasing their risk for kidney stones."
Many foods in North America are fortified with vitamin D and calcium, from milk to breakfast cereal and orange juice.
The Nutrition Business Journal estimates that sales of calcium supplements rose 5 percent from 2008 to 2009, with sales of $1.2 billion, while the vitamin D supplement market grew by 82 percent in a year, to $430 million.
The committee, led by nutritionist Catharine Ross of Pennsylvania State University, spent years examining medical evidence.
Even assuming that people were getting little or no vitamin D from the sun, they found most North Americans got enough.
"We are aware of reports and media attention to the idea that Americans and Canadians might have widespread Vitamin D deficiency," Ross told a news conference. "We found that, really, this widespread problem didn't seem to exist."
Calcium is needed to build and keep bones strong and a few studies have linked low levels of vitamin D to a range of diseases, from cancer to multiple sclerosis. The report found there was not enough evidence to make firm conclusions about anything but bones, though.
"We have seen in the last couple of years a dramatic increase in assays of vitamin D in routine medical care. This is, to a great degree, unnecessary," said Dr. Steven Clinton, a cancer expert at Ohio State University. "It probably should not be a part of routine medical care."
Ross said the team took a conservative approach in writing the report, available here
Committee members noted that beta-carotene supplements in fact raised the risk of lung cancer in smokers, vitamin E and selenium showed mixed results and hormone replacement therapy, widely believed to reduce the risk of heart disease, raised the risk of stroke and breast cancer.
North Americans need on average 400 International Units (IUs) of vitamin D per day, the committee decided. Those 71 and older may require as much as 800 IUs a day.
The committee set these requirements for calcium:
* Children aged 1 to 3 need 500 milligrams of calcium a day.
* Children aged 4 to 8 need 800 milligrams daily.
* Adolescents need more -- 1,300 milligrams a day.
* Women aged 19 to 50 and men up to 71 require on average 800 milligrams daily.
* Women over 50 and men over 71 need 1,000 mg.
More than 4,000 IUs of vitamin D and 2,000 milligrams of calcium a day can damage kidneys and other tissue, the committee found.
Editing by Paul Simao