NPA, CRN Respond to Negative Vitamin D Study
October 16, 2013
WASHINGTON—A new study in The Lancet questions vitamin D supplementation's effectiveness in fracture prevention, deeming supplementation "inappropriate" in community-dwelling residents without vitamin D deficiency risk factors.
The meta-analysis by University of Auckland researchers identified 23 studies assessing the effects of vitamin D on bone mineral density (BMD) (The Lancet. doi:10.1016/S0140-6736(13)61647-5). BMD was measured at one to five sites in each study, for a total of 70 tests. Researchers found six instances of significant benefit and two of significant detriment, concluding, "Continuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate."
However, industry organizations the Natural Products Association (NPA) and the Council for Responsible Nutrition (CRN) called the study into question, pointing out one major flaw: the meta-analysis only looked at vitamin D, rather than a combination of vitamin D and calcium. As a result, the study misleads consumers by only looking at half of the equation, said Cara Welch, Ph.D., senior vice president of scientific and regulatory affairs, NPA.
“It’s common knowledge that the beneficial effect of vitamin D in osteoporosis prevention occurs when the supplementation is vitamin D plus calcium," Welch said. "The beneficial effect of vitamin D and calcium is due to the fact they work in tandem, and examining the outcomes of just vitamin D caused the researchers to start with a weak premise. In fact, the Food and Drug Administration has an approved health claim for vitamin D and calcium regarding osteoporosis."
Duffy MacKay, N.D., vice president, scientific and regulatory affairs, CRN, noted the study may inappropriately discourage both healthy and at-risk populations from taking vitamin D.
" For populations that are most vulnerable to vitamin D deficiencies and insufficiencies—especially older adults—getting vitamin D from food alone is particularly challenging, and so supplementation may be warranted," he said. "We have concerns that the author’s broad-based advice will do nothing but cause potentially dire consequences if people, particularly those at-risk for fracture, fail to obtain the recommended daily intake of vitamin D."
The Institute of Medicine recommends dietary intake for adults of 600-800 IU of vitamin D and 1000-1300 mg of calcium daily. In addition, the 2010 Dietary Guidelines for Americans identified calcium and vitamin D supplementation as useful in postmenopausal women with low nutrient levels to reduce the risk of osteoporosis.