Nearly two billion people in the developing world are deficient in <answer>zinc</answer>. In children it causes an increase in infection and diarrhea, contributing to the death of about 800,000 children worldwide per year. The World Health Organization advocates <answer>zinc</answer> supplementation for severe malnutrition and diarrhea. Zinc supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth. However, <answer>zinc</answer> supplements should not be administered alone, because many in the developing world have several deficiencies, and <answer>zinc</answer> interacts with other micronutrients.
What are two billion people in the world deficient in?
zinc