Zinc is the second most common trace mineral in our bodies and affects all organs and cells. It is a micronutrient needed for metabolism, our sense of taste and smell and especially key during times of rapid growth, such as pregnancy, infancy, childhood, and puberty. Zinc deficiency is associated with impaired growth, slower wound healing and increased susceptibility to infections like the common cold.

“It’s very clear: If you are zinc deficient, your immune system will not function as well,” said Dr. David Hafler, professor of neurology and immunobiology at Yale School of Medicine.

Zinc’s importance wasn’t always so clear. In the 1960s, a hematologist named Dr. Ananda S. Prasad suspected that low levels of zinc hampered growth in humans. But when it came time for him to test his hypothesis by administering zinc to his growth-stunted patients in Egypt, he couldn’t find it anywhere. So he had capsules made