Vitamin D has an interesting story lately with recent good evidence found that it does not prevent fractures including osteoporotic fractures in adults. But in several aspects, it has always been an interesting story. When it was first discovered and subsequently given its name (because A,B and C were already taken), it was recognized as the cure for the bone disease called rickets. This disease would cause malformed soft bones with the most recognizable feature being bowing of the legs because of the weight of the body pressing down on soft bones. The recognition that sunlight or foods with vitamin D would prevent rickets was compelling for people living in areas where there was not much sunlight coupled with diets that did not have a lot of vitamin D like Scotland (lots of clouds and diet rich in oats, which does not have vitamin D).
Traditionally, vitamin D has been linked with healthy bones. Vitamin D is important for bones because it regulates the absorption of calcium in the diet and helps move calcium into and out of bones, the latter when blood calcium levels drop.
The fact that Vitamin D facilitates the production of calcium for bone growth, is the reason why giving vitamin D to people who have low blood levels of vitamin D with osteoporosis seemed reasonable. Hence, giving people who are predisposed to fractures Vitamin D presumably would lead to more calcium being absorbed, thus making stronger bones. However, in a recent study published in the New England Journal of Medicine by Dr. LeBoff showed that there was no difference in number of fractures between people given Vitamin D and people that did not get vitamin D. Included in the groups were people who had low vitamin D levels. So, vitamin D supplements did not prevent fractures which if you have osteoporosis or at risk for it, you take it to prevent fractures. If you have osteoporosis or at risk and you are taking vitamin D, we are not suggesting that you discontinue taking it, always consult with your primary care provider before making any changes, but we thought this study was illuminating . It is also interesting to note that excess doses of vitamin D can cause problems due to excessive calcium levels leading to kidney stones, confusion, vomiting and muscle weakness—more information for your consideration.
That leads to the question of what else is vitamin D associated with? It turns out it is associated with a diverse number of conditions and diseases. Other studies have noted that low vitamin D levels are associated with certain cancers such as breast cancers, tuberculosis, autoimmune diseases, influenza, cardiovascular disease, and even higher risk of severe disease from COVID -19. Low levels of vitamin D have also been associated with macular degeneration in adults, an eye condition that affects vision. Additionally, adults with type 2 diabetes have better control of blood sugars when vitamin D deficiency is corrected.
All things considered it is good to check your vitamin D to make certain that it is in the normal range. So, for adults who do not have an obvious medical condition that would lead to low vitamin D (e.g., kidney dialysis) check to see if your vitamin D level is low and if so, to take a vitamin D supplement which usually would be 1000-2000IU of vitamin D3 daily to get the level back into a normal range . Recheck the level after taking the supplement for 6 weeks to make sure the level is corrected.