In recent years, research has associated low blood levels of the vitamin with higher risks of everything from heart disease, diabetes, and cancer to mood disorders and dementia. The findings have not gone unnoticed. Vitamin D supplements and screening tests have flowed in reputation.
Vitamin D has several important functions. Perhaps the most vital are regulating the absorption of calcium and phosphorus, and simplifying normal immune system function. Getting a sufficient amount of vitamin D is important for normal growth and development of bones and teeth, as well as improved resistance against certain diseases.
However, researchers analyzing hundreds of studies say vitamin D enhancements won’t protect healthy, middle-aged adults from osteoporosis. And even worse, they say the supplements may increase the risk of death from other diseases. But make sure you aren’t deficient in vitamin D before you stop taking the supplement.
While there is strong support for vitamin D's role in bone health, the evidence that it prevents other health conditions is not yet conclusive. Research on vitamin D and calcium supplementation has been mixed and, especially when it comes to randomized clinical trials, has been generally disappointing to date. A recent study found that those taking a vitamin D supplement did not lower rates of heart attack, stroke, or cancer. However, among people who later developed cancer, those who took vitamin D supplements for at least two years had a 25% lower chance of dying from their cancer compared with those who received a placebo.
So, it is very important that you take these supplements only if you have a deficiency.