To examine consumption rates and serum ferritin (SF) concentrations (as a marker of safety) among schoolchildren (3–6 years) provided with daily and weekly micronutrients.

Micronutrients were provided for one school term (13 weeks) to a kindergarten in northern China as single-dose SprinklesTM sachets containing 30 mg of iron as encapsulated ferrous fumarate, 5 mg zinc gluconate, 50 mg vitamin C, 300 μg vitamin A, 7.5 μg vitamin D3 and 150 μg folic acid. Sixteen classrooms were randomly assigned to: (1) daily supplements for 5 days a week (daily group); (2) weekly supplements (weekly group); or (3) no supplements (control group). Consumption of sachets was monitored for each child and SF concentrations were measured at the end of study. Random effects general linear models and graphs were used to compare the groups.

A total of 415 children from 16 classrooms entered the study. At the end of the study, mean consumption rates per child were 86% (daily group; standard deviation (SD) 12%) and 87% (weekly group; SD 16%). Median SF concentrations were 71 μg l−1 (range 27–292 μg l−1; daily group), 55 μg l−1 (range 11–299 μg l−1; weekly group) and 54 μg l−1 (range 7–327 μg l−1; control group); the overall difference was not significant (P = 0.06). However, the daily group was significantly different from the control (P = 0.02); daily and weekly groups had higher SF at lower percentiles and similar SF at higher percentiles compared with the control group.

The high consumption rates and appropriate SF concentrations in the supplemented groups suggest that a short-term school programme with Sprinkles is an efficient and safe way to provide micronutrients (including iron).