Mothers or caretakers of children participating in the study received the same information and instructions provided regularly to all beneficiaries of the milk distribution program at the MDC. They were instructed how to reconstitute the milk powder and were encouraged to feed the selected children 400 mL, preferably at two separate times during the day (200 mL in the morning and 200 mL in the afternoon). Milk was bought and collected by each family on a weekly or bimonthly basis at the MDC. The portion of 400 mL of rehydrated fortified milk (FM) contained 5.28 mg of iron as ferrous gluconate, 48 mg of sodium ascorbate, 5.28 mg of zinc as zinc oxide and 36.2 mg of folic acid. The non-fortified milk (NFM) contained per 400 mL: 0.16 mg of iron, 1.6 mg of zinc and 6.8 mg of vitamin C. The micronutrient premix,purchased from DSM Nutritional Products (Herleen, The Nederland) was added to the powdered milk in the plant by the manufacturer (LICONSA, SA,Queretaro, Mexico) and 220 g units of the products were packed in metallic foil sachets.