The purpose of the study is to see if giving vitamin and mineral supplements helps to protect infants and children from diarrhea, which vitamins and minerals help to improve a child's weight and growth, and if the same results occur in infants and children with HIV. HIV is the virus that causes AIDS. Study participants will include 516 infants aged 4-6 months. Participants will include: (1) HIV-infected children, (2) HIV-uninfected children with HIV-infected mothers, and (3) HIV-uninfected children with HIV-uninfected mothers. Subjects will have an equal chance of receiving one of three different vitamin and/or mineral supplements during the study. Study procedures will include up to 7 blood samples and stool samples every 3 months and body composition every 6 months. Participants will be involved in the study for up to 18 months.