Calcium, Vitamin D Assumptions Shaken

The latest news about calcium and vitamin D may not look so encouraging, but most experts say the take-home message is the same: Keep taking your pills.

The biggest study ever to examine the value of the supplements suggests they convey only limited protection against broken bones. They failed to protect against most fractures in the mostly low-risk women, but seemed to offer some benefit against hip breaks among women over 60 and those who took the pills most faithfully.

"Equally as disappointing," points out The Early Show medical correspondent Dr. Emily Senay, "there was no colorectal cancer prevention (found). And there was a lot of hope hung on there."

Senay added, "This is not the final word (on bone health benefits or protection against colorectal cancer). A lot more analysis will go on, and, certainly, a lot more discussion. I don't want people to get too confused or upset about these findings. There's going to be more to come."

The outcome could affect an enormous number of people, since an estimated 10 million Americans have break-prone bones thanks to osteoporosis. One of two women will suffer such a fracture in her lifetime.

Doctors, who have long taken the value of these supplements almost as an article of faith, tried to put the findings as positively as possible.

"We still do believe ... that maintaining an adequate calcium intake will lay the foundation for bone health," said lead author Dr. Rebecca Jackson at Ohio State University.

But some disappointment seeped out at the margins. The study is "not as ringing an endorsement of calcium as one might like," said one of the researchers, Dr. Norman Lasser at New Jersey Medical School.

The study's findings were published Thursday in The New England Journal of Medicine. They were a long-awaited offshoot of the big national study of diet and hormone therapy known as the Women's Health Initiative.For women older than 50, federal guidelines recommend 1,200 milligrams of bone-building calcium and 400-600 international units of vitamin D daily from diet and, if needed, supplements.

"The official recommendations are not changing," Senay stressed. "Women who are at especially high risk for osteoporosis need to speak to their doctors not only about vitamin D and calcium supplementation, but also possibly other medications that can help them maintain bone mass or improve bone mass.

"Examine your diet. If you are short on the official recommendations for calcium and vitamin D or calcium, possibly then consider supplementation, again, speaking to your physician. If you are taking it for colorectal cancer prevention, I think the news there is not so good."

The seven-year study of 36,282 women ages 50 to 79 gave half the participants 1,000 milligrams of calcium and 400 units of vitamin D, while the other half took dummy pills.

However, many were also taking their own supplements before the research began, and they were allowed to keep doing so, whether they were assigned to the test group or the comparison group. These extra supplements may have helped the women stay healthy but ironically diluted the findings, since any benefit is harder to show against a backdrop of fewer fractures. Also, women in the study were taking hormone pills, likely further cutting the number of fractures.

The study showed better hip bone density in the group given supplements, but they ranked no better statistically in avoiding fractures of all kinds.

However, some benefit seemed apparent. Women over age 60 reduced their chances of hip fracture by 21 percent with the supplements. And those who took their supplements most regularly lowered their risk by 29 percent.

"There's probably a small benefit," said Dr. Joel Finkelstein, of Massachusetts General Hospital, who wrote an editorial to accompany the study. "It's a good start, but women at higher risk need to know it's not enough."

Many experts downplayed the meaning of the negative finding. Dr. Bess Dawson-Hughes, a Tufts University vitamin expert who helped shape the dietary guidelines, said they should remain unchanged for now.

"You put people who don't need it together with people who aren't taking it, and you find nothing — and that really isn't all that surprising," she said.