Some studies, like the AREDS2 study proving benefit for macular degeneration are definitive. Others, not so much. On July 27, 2022, The New York Times breathlessly declared that Vitamin D was ineffective. And their title was both strong and negative: Study Finds Another Condition That Vitamin D Pills Do Not Help.
The newspaper was trying to be the first to report a new study out published in the New England Journal of Medicine that concluded taking Vitamin D does not help reduce the odds of getting a fracture. The study, run through the National Institutes of Health was good, but not perfect. It randomized nearly 25,000 people to receive 2,000 IU daily of Vitamin D or placebo, following them for five years.
But I read the detailed 11 pages of the study and there are several weaknesses. Pre-treatment Vitamin D levels averaged 30 ng/ml, while patients receiving Vitamin D, even after 5 years, averaged 40 ng/ml. So the increase in blood levels likely wasn't enough to move the needle. The study wasn't focused on those with low Vitamin D levels. In fact, the preponderance of recruited patients had normal levels to start. Only 2% of study participants suffered "major osteoporotic fractures," which is a small number to attempt to see differences. Although a difference in fracture rate wasn't seen, the study did discover improvements in bone density for those taking the supplement. But most importantly, the study didn't focus on those with low Vitamin D levels. In fact, this quote from the study demonstrates the authors' underlying concern, "It would not have been feasible or ethical to study the effects of vitamin D as compared with placebo on incident fractures in a population preselected for vitamin D deficiency."