The United States Preventive Services Task Force, an influential group that recently recommended against routine P.S.A. tests to detect prostate cancer, issued a draft statement on Tuesday recommending that healthy postmenopausal women should not take low doses of calcium or vitamin D supplements to prevent fractures.
The group, an independent panel of experts in prevention and primary care appointed by the federal Department of Health and Human Services, also considered use of the supplements by healthy premenopausal women and men. For those groups, it said, there was insufficient evidence to recommend taking vitamin D with or without calcium to prevent fractures.
The supplements also have been studied to see if they prevent cancer. But, the group said, there is insufficient evidence to say they do or do not. The cancer studies included ones testing the supplements to prevent all cancers as well as ones asking about colorectal cancer, prostate cancer and breast cancer.
Their analysis of the effects of the supplements included 137 studies, including randomized controlled trials, the gold standard for clinical evidence.
The low doses that the group referred to, at least for the postmenopausal women, were a typical level of 400 international units or less of vitamin D a day and 1,000 milligrams or less of calcium.
At that dose, said Dr. Kirsten Bibbins-Domingo, a member of the task force who is an associate professor of medicine at the University of California in San Francisco, "there is sufficient evidence to say they do not prevent fractures."
"When you take a vitamin supplement or any therapy for an extended period of time, you have to ask, 'What is the evidence that it works and what is the evidence of harms?' " Dr. Bibbins-Domingo said.
"It is clear that lower doses of calcium and vitamin D do not prevent fractures, and there is a small but measurable risk of kidney stones," she said. So with no evidence of benefit, there is no reason to risk harm.
Dr. Ethel Siris, who directs Columbia University's osteoporosis center, said she and other osteoporosis experts already knew the supplements did not prevent fractures.
"That's why when a patient with osteoporosis says, 'I will just take calcium and vitamin D,' we say, 'That's not enough,' " Dr. Siris said.
But Dr. Bibbins-Domingo said the task force recommendations did not apply to people with osteoporosis.
For most people, she said, there is no need for these supplements and good reason for many not to take them.
"Vitamin D and calcium are part of a healthy diet," Dr. Bibbins-Domingo said. "Most people can achieve sufficient doses with a healthy diet."
SOTT
SIGNS
OF THE
TIMES
OF THE
TIMES
Welcome to Sott.net
The World for People who Think
Yet another study, using too-low doses, determins that vitamin D is ineffective. This contradicts the IOMs study, released last autumn, which recommended 600IU for bone health and was itself faulted by the vitamin D researchers. Here's Robert P Heaney on the IOM study:
"Beyond these errors and inconsistencies, though, serious as they are, lies a much deeper flaw in the approach taken by the panel, exemplified by a quote from one of the panel members to the New York Times at the time of release of the report.11 The statement was simply that the “onus” (ie, burden of proof) fell on anyone who claimed benefits for intakes higher than the panel's current recommendations. This is an approach that is correct for drugs, which are foreign chemicals and which do carry an appropriately heavy requirement for proof. For drugs, the position of privilege is given to the placebo. And in the current IOM report, the privilege is given to a serum 25(OH)D level that is effectively the status quo. We judge that this is exactly backward for nutrients. The privilege instead must be given to the intake that prevailed during the evolution of human physiology, the intake to which, presumably, that physiology is fine-tuned. So far as can be judged from numerous studies documenting the magnitude of the effect of sun exposure,12, 13 the primitive intake would have been at least 4000 IU/day and probably two to three times that level, with corresponding serum 25(OH)D levels ranging from 40 to 80 ng/mL. The fact that primitive levels would have been higher than current IOM recommendations does not, of course, prove their necessity today. But such intakes should be given the presumption of correctness, and the burden of proof must be placed on those who propose that lower intakes (and lower serum levels) are without risk of preventable dysfunction or disease. The IOM, in its report, has utterly failed to recognize or meet that standard."
Calcium should never be taken as a supplement:
Calcium Supplements Linked to Significantly Increased Heart Attack Risk, Study Suggests
[Link]