Here’s another example of how too much of a good thing can be harmful. A commentary in a respectable journal warns about health risks associated with  excessively high doses of calcium and vitamin D supplements.  This increases some individuals’ risk of developing dangerously high levels of calcium in the blood, which could cause high blood pressure and even kidney failure.

Postmenopausal women, pregnant women, transplant recipients, patients with bulimia, and individuals who are on dialysis have the highest risks due to various physiological reasons.

Calcium supplements taken at recommended levels can be beneficial, but it is important to limit daily calcium in pill form to no more than 1200-1500 mg. For added insurance, the authors  recommend those taking calcium and/or vitamin D supplements to have their blood calcium levels checked annually.