For many years older women have been advised by their physicians to take calcium and vitamin D pills to protect their bones as they age.
But according to the latest and the biggest research ever conducted to examine the value of that timeworn advice, calcium and vitamin D pills provide only limited protection. They failed to protect against most fractures in the mostly low-risk female patients.
At the same time, the supplements seemed to protect against hip breaks among women over 60 years of age and those taking the pills faithfully.
The research is “not as ringing an endorsement of calcium as one might like,” said one of the investigators, Dr. Norman Lasser at New Jersey Medical School.
But still, he and other experts are encouraging women to carry on taking the supplements anyway.
“We don’t want to send the message to people to throw away their calcium pills, which was my wife’s first reaction,” Lasser said.
“We still do believe … that maintaining an adequate calcium intake will lay the foundation for bone health,” said the lead author, Dr. Rebecca Jackson, at Ohio State University.
The findings of the study were published today in the New England Journal of Medicine. They are a long-awaited offshoot of a big national research of diet and hormone therapy known as the Women’s Health Initiative.
The result influences great number of people as about 10 million Americans have bones prone to breakage due to osteoporosis. 50% of women will suffer such a fracture during their lives. For women over 50 years of age, federal guidelines recommend 1,200 milligrams of bone-building calcium and 400-600 international units of vitamin D per day from diet and some supplements if necessary.
The seven-year research of 36,282 women ages 50 to 79 gave half of the participants 1,000mg of calcium and 400 units of vitamin D, while the other half took imitation of pills.
However, many women also were taking their own supplements before the study began and they were allowed to carry on doing so, whether they were assigned to the test group or the comparison group. These additional supplements may have helped them stay healthy but ironically diluted the results, as any benefit is harder to show against a backdrop of fewer fractures. What’s more, women in the research were taking hormone pills, which probably further cut the number of fractures.
The research demonstrated 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 obvious. Women over 60 years of age decreased their likelyhood of hip fracture by 21% with the supplements. Those taking their supplements most regularly reduced their risk by 29%.
“There’s probably a small benefit,” said Dr. Joel Finkelstein of Massachusetts General Hospital, who wrote an editorial to accompany the research. “It’s a good start, but women at higher risk need to know it’s not enough.”
The meaning of the negative finding was downplayed by many experts. 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.
Some scientists claimed that the effect would have been even clearer with higher doses of vitamin D, perhaps up to 1,000 units a day. The vitamin helps the body absorb calcium and promotes muscle health, reducing falls.
The research revealed a remarkable side effect with the diet supplements: a 17% increase in the risk of kidney stones. But several physicians downplayed that risk, saying hip fractures are typically worse than kidney stones.
According to doctors, the research indicates that women at higher risk of fracture, whose tests demonstrate lost bone density, likely require more than diet supplements. They may require osteoporosis medications.…