Zinc
The daily recommended allowance for zinc—found in oysters, lean beef, and breakfast cereal—is 11 milligrams for males and 8 milligrams for females. There are claims that the mineral can prevent and treat symptoms of the common cold, but the evidence doesn’t hold up. A few studies suggest that cold symptoms are less severe and resolve sooner in zinc users, but others show no benefit. Plus, high doses can actually weaken the immune system, so you might want to stick with these ways to treat a cold instead.
Bottom line: Don’t take it except for occasional use of zinc lozenges or sprays for colds.
Too much of a good thing? When it comes to supplements, more is not always better.
