Reading medical news, one might conclude based on recent headlines that supplementing Vitamin D could be beneficial to your health in a not-insignificant way, and that a lack of the essential substance could pose a grave risk to you.
And while its necessity is not disputed, doctors say that data supporting Vitamin D’s role in combating everything from heart disease to eyesight may be somewhat lacking. JoAnn Manson, MD, of Brigham and Women’s Hospital in Boston is a principal investigator on a Vitamin D-related study, and she told MedPageToday that some of the benefits of the vitamin may be overstated due to the nature of earlier studies measuring its impact:
“Many of the randomized trials people have heard about were trials designed to look at the effect of vitamin D on fractures and falls,” she said, with other effects as secondary outcomes.
It’s in the nature of statistics, she pointed out, that if researchers look at enough outcomes, some will be significant just on the basis of chance… The vast mass of the evidence for any kind of nonskeletal benefit is observational, and therefore suspect until confirmed by a properly designed, randomized trial, Manson said.
Referring to the old scientific adage that “correlation does not prove causation,” Manson noted that “confounding factors” such as obesity, poor nutrition, or lack of exercise could be contributing to misleading data and stressed that confounding factors cannot be underscored in any such study. MedPageToday also noted similar enthusiasm surrounding hot supplements of their time Beta Carotene and Selenium before randomized trials “demolished observational evidence many times in the past.”
Have you been diagnosed with a Vitamin D deficiency? Have you attempted to up your intake?