Is vitamin D really a cure-all, and how should we get our fix?
The rationale is quite simple. The body needs sunlight to produce the vitamin. Without adequate sunlight there will be a deficiency and need of a substitute. The supplements aren’t magic, its the removal of systemic health effects caused by deficiency. I rather find that the studies deal with how severe these effects are and the systemic nature makes it hard to pin point. However, I don’t even understand why this has been contested for such a long time.