In Endocrine Today, June 2014, an editorial by Dr. Nelson Watts sheds light on the issue with studies that claim there is no benefit to the use of vitamin D supplements in preventing fractures, as proclaimed in the U.S. Preventive Services Task Force two years ago. The same task force also claimed there is no benefit to calcium supplementation, and Dr. Watts has comments on that also. Dr. Watts points out that the primary reason for the lack of evidence of benefit with vitamin D supplementation is that the studies reviewed are flawed, and many participants may already have been vitamin D adequate thereby the studies did not look at the sub-population of those who are truly vitamin D deficient. This makes perfect sense, in that why would I expect to see fracture risk reduction in a study population if the majority of participants are not deficient in this “threshold-nutrient”. We already know that elderly who are measured to be deficient in vitamin D are more prone to falling, and bringing up the vitamin D level reduces the risk of falling. But giving vitamin D to a population who are not deficient will not show a reduction in falls and fractures.
He goes on to talk about calcium, which is poorly absorbed, and absorption varies among people as he refers to the “fractional calcium absorption” ranging from 10% in one person to 30% in another. So does this mean I can take calcium and not have enough absorbed and get a false sense of security that I am protected by taking a supplement? Dr. Watts sheds insight on some of the studies proclaiming lack of benefit from either calcium or vitamin D supplementation. I know I will be looking closer at my calcium and vitamin D intake after reading his editorial. Here’s the link: http://www.healio.com/endocrinology/bone-mineral-metabolism/news/print/endocrine-today/%7Bdb51495d-5c09-432d-a2ed-73a72e7b73dd%7D/vitamin-d-continues-to-be-scrutinized-poorly-understood