NEW YORK - Older women shouldn't take vitamin D and calcium supplements to prevent broken bones, and there's not enough evidence to say whether it would help anyone else either, says a U.S. government-backed panel.

Based on two reviews of past research, the U.S. Preventive Services Task Force waded into the debate over the two vitamins that are thought to strengthen bones to prevent against breaks.

"Calcium and vitamin D are important in general health and bone health. For this recommendation, we review data on whether supplements of vitamin D and calcium can prevent fractures in addition to dietary intake," said Dr. Jessica Herzstein, a member of the Task Force.

Approximately 1.5 million Americans suffer from breaks that are tied to brittle bones each year. And about half of all women over 50 years old will end up with a break that's linked to the bone-weakening disease osteoporosis.

That's a major concern, according to the Task Force, because broken bones are linked to chronic pain, disability and increased risk of sickness and early death.

Based on the reviews, the panel found there were no benefits but some risk for post-menopausal women taking low-dose vitamin D and calcium supplements - below 400 international units and 1,000 milligrams, respectively.

Specifically, taking low-dose supplements didn't change the older women's risk for broken bones, but was tied to a small increase in the risk of kidney stones.

They also found that there is not enough evidence to suggest higher doses of the vitamins would be effective or safer in older women, or that taking any dose of the supplements would help men or younger women.

For men and younger women, "We're not saying don't take it, we're just saying we don't know enough right now," said Herzstein, who is in charge of employee health at Air Products in Allentown, Pennsylvania.

She added that these recommendations do not apply to people who already have a diagnosis of osteoporosis, a history of fractures or are living in an assisted-living community.

Herzstein said it's important for people to talk with their doctors about the supplements.

Cara Welch, senior vice president of scientific and regulatory affairs for the Natural Product Association in Washington, D.C., told Reuters Health she agreed that people should talk to their doctors, but said the group disagrees with the new recommendation.

"We believe this recommendation is out of step with current research, and it really should not affect consumers who are trying to supplement their calcium and vitamin D intake with supplements," Welch said.

According to the most recent data from a national survey of Americans, 56 percent of women over 60 years old take vitamin D supplements, and 60 percent take calcium supplements.

The two vitamins are often sold together and are relatively inexpensive.

The Task Force already recommends women older than 65 years old be screened for the bone-weakening disease osteoporosis, and younger women who have a higher risk of broken bones.

The panel also recommends senior citizens with a history of falls and vitamin D deficiency take supplements to help strengthen muscles and help with balance.

Vitamin D has also been researched as a preventive measure against dementia, heart disease and cancer, but with mixed results. Herzstein said the panel will soon be issuing recommendations about the vitamin for some of those diseases.

Marion Nestle, a nutrition researcher from New York University who coauthored a commentary published alongside the recommendations in the Annals of Internal Medicine, said that good studies on vitamin D are hard to do, and any end to the debate over whether to take supplements or not is a long way off.

"These studies are so difficult to do and to interpret that scientific consensus seems impossible to achieve, especially in situations where entire organizations are devoted to convincing people to take high-dose vitamin D," she wrote in an email to Reuters Health.

Older people who take vitamin D supplements along with calcium may live longer than others, according to a new review of previous studies.

The researchers looked at data regarding the vitamin D intake  of more than 70,000 adults in their 60s and 70s. They found that people who took vitamin D, along with calcium supplements, were 9 percent less likely to die over a three-year period, compared with people who took neither supplement.

However, they found that taking vitamin D alone had no effect on mortality rates.

For every 151 people who took with daily vitamin D and calcium for three years, one life would be spared, according to the researchers' calculations.

The finding comes on the heels of several studies with conflicting results about the health benefits of vitamin D, including its possible effects on longevity. The new review is the largest of its kind, and included eight randomized controlled trials, said study leader Lars Rejnmark, of Aarhus University Hospital in Denmark. Such trials are considered the strongest type of scientific evidence.

The study confirms researchers' suspicions  that vitamin D may increase longevity, said Dr. Philippe Autier of the International Prevention Research Institute, who was not involved in the review.

Study participants were generally older people with health conditions, and possibly had inadequate nutrition. Therefore, it’s “not guaranteed that anyone in good health  who takes these vitamins would increase life expectancy,” Autier said.

In the review, the researchers found that 5.5 percent of the 35,412 people who didn't take vitamin D or calcium died during the study period, whereas 5.3 percent of the 35,116 people who took vitamin D died. 

Taking vitamin D, with or without calcium, had a significant effect on mortality rates only after three years; mortality rates were not significantly different among those taking the vitamin after one or two years, according to the study.

Vitamin D and calcium are important throughout life, because of their role in bone health, Rejnmark said. But he recommends people start paying particular attention to their intake "around menopause for women, and around the age of 50 for men."

While the review was based on studies of people who took supplements, Rejnmark said he does not believe the benefits would be any different for people who get the nutrients through food.

Autier noted that the greatest source of vitamin D is what the skin makes naturally when it is exposed to sunlight. People with darker skin tones, who are less able to produce vitamin D  in response to sunlight, should consider supplements as a viable option, he said.

A total of 87 percent of the studies' participants were female, but Rejnmark said this had no bearing on the results, and vitamin D and calcium are equally beneficial to both sexes in terms of preserving longevity.

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