Experts say as many as 2 billion people around the world have diets deficient in zinc, and studies are raising concerns about the health implications this holds for infectious disease, immune function, DNA damage and cancer.
Zinc deficiency is quite common in the developing world. Even in the United States, about 12 percent of the population is probably at risk for zinc deficiency, and perhaps as many as 40 percent of the elderly. Many or most people have never been tested for zinc status, but existing tests are so poor it might not make much difference if they had been.
Source: Science Daily September 17, 2009