Most clinicians are familiar with the concept that when a little is good, more is often better, but a lot is still reliably toxic. This results in the mindset of there being little chance of doing harm with supplementing a “little,” especially when the supplements involved are well-known and relatively popular supplements, widely regarded as being beneficial without question. In the case of calcium, iron, and copper the downside of minimal supplementation could not be more clear-cut. All three of these agents are essential for health, especially inside the cells. Nevertheless, once a relatively low daily intake of these nutrients is exceeded only minimally, toxicity rapidly ensues, with the highest intakes resulting in the greatest toxicity.  Read more.