This study will determine whether supplements of the mineral zinc will improve mental health and school performance among schoolchildren in Guatemala.

Mental health problems are an important cause of dysfunction throughout the world, accounting for 8.1% of the Global Burden of Disease. The need for interventions that can prevent mental health conditions, particularly among children, cannot be overemphasized. This study will determine whether zinc supplementation improves the mental health and school performance among children in Guatemala.

Participants will be randomly assigned to receive daily supplements of either zinc or placebo for 6 months. Participants will be assessed at study entry and after the 6-month treatment. Participants and their parents and teachers will complete questionnaires about the participants' symptoms of depression and anxiety, concentration and activity levels, school performance, and any environmental stressors to which the participants may be exposed to.

Inclusion Criteria:

• Attend a public school in specific Guatemalan community and has thorough and up-to-date school records
• Currently in 2nd to 6th grade
• Parent or guardian willing to provide informed consent

Exclusion Criteria:

• Any illness that may affect participants' zinc levels
• Any chronic illness
• History of cancer