Vitamin D, the Sunshine Supplement, Has Shadowy Money Behind It - The New York Times
Enthusiasm for vitamin D among medical experts has dimmed in recent years, as rigorous clinical trials have failed to confirm the benefits suggested by early, preliminary studies. A string of trials has found no evidence that vitamin D reduces the risk of cancer, heart disease or falls in the elderly. And most scientists say there isn’t enough evidence to know if vitamin D can prevent chronic diseases that aren’t related to bones.
Although the amount of vitamin D in a typical daily supplement is generally considered safe, it is possible to take too much. In 2015, an article in the American Journal of Medicine linked blood levels as low as 50 nanograms per milliliter with an increased risk of death. That’s within the level considered healthy by the Endocrine Society, which defined vitamin D “sufficiency” as between 30 and 100 nanograms, Rosen said.