People need zinc for everything from taste acuity to fighting infections, but taking high doses on a regular basis with the hope of shortening the duration of the common cold could be hazardous to your health.

That's because zinc competes with copper for absorption sites in the small intestine. Too much zinc could lead to too little copper, a mineral that plays a big role in enzyme function, the production ofhemoglobin, the formation and health of connective tissues, and the maintenance of nerves, among other things.

Also note that zinc and copper aren't the only minerals that have common pathways which can cause an imbalance when one arrives in large doses. Nutrient interdependencies are real and a big reason dietitians are rarely found in line at the supplement counter. Food is definitely the safer way to go.

However, if you are a vegetarian or simply don't consume many meat-based foods, you might be wise to look for zinc from supplements. But be sure to choose one that has no more than 15 milligrams of zinc unless you are pregnant, nursing a child, or are advised otherwise by your physician. Pregnant and nursing women are advised to take special prenatal vitamin and mineral supplements, which contain extra zinc and other important nutrients.