Magnesium is an important part of more than 300 enzymes which regulate many body functions, including energy production and muscle contractions. It also helps maintain nerve and muscle cells and is a component of bones. Legumes, nuts, whole grains and green vegetables are good sources. Excess amounts from food are unlikely to cause harm unless kidney disease prevents magnesium from being excreted. Symptoms may resemble diabetes, including impaired glucose tolerance and nerve damage.
Copper helps make hemoglobin, which carries oxygen in the blood.
It's also a part of many body enzymes and helps all body cells produce energy. Rare, except from genetic problems or consuming too much zinc, which can hinder copper absorption. Cooking in copper pots also increases copper content of foods. Fluoride helps harden tooth enamel, protecting teeth from decay. It may also protect against osteoporosis by strengthening bones.