I used to have terrible leg cramps - they would literally make jumpt out of bed. Then after a physical in which she checked my vit D and found it to be extremely low - my doc put me on prescription-strength vit D supplements. And I was thrilled that it seemed to really help my leg cramps. Eventually they pretty much stopped, and I didn't have another one til I went off the prescription-strength vit D and started taking the over-the-counter strength supplements (went from 50 mg a week to 1 mg a day). I bumped the levels up signifigantly and haven't had one in nearly a year. There may be other nutritional factors as well, but that one changed seemed to make a big difference for me.