Gold, silver, and platinum get all the attention as the world's most precious metals. But they're more precious for the global economy than for human health. Instead, other metals and minerals (metals are one type of mineral) are more important for our health (see "What essential metals do for us"). Indeed, some of them are so important that we can't live without them. "Each one plays a role in hundreds of body functions. It may take just a very small quantity of a particular mineral, but having too much or too little can upset a delicate balance in the body," says Dr. Bruce Bistrian, chief of clinical nutrition at Beth Israel Deaconess Medical Center.