To assess changes in the Fe and vitamin A status of the population of Nangweshi refugee camp associated with the introduction of maize meal fortification.

Pre- and post-intervention study using a longitudinal cohort.

Nangweshi refugee camp, Zambia.

Two hundred and twelve adolescents (10–19 years), 157 children (6–59 months) and 118 women (20–49 years) were selected at random by household survey in July 2003 and followed up after 12 months.

Maize grain was milled and fortified in two custom-designed mills installed at a central location in the camp and a daily ration of 400 g per person was distributed twice monthly to households as part of the routine food aid ration. During the intervention period mean Hb increased in children (0·87 g/dl; P < 0·001) and adolescents (0·24 g/dl; P = 0·043) but did not increase in women. Anaemia decreased in children by 23·4 % (P < 0·001) but there was no significant change in adolescents or women. Serum transferrin receptor (log10-transformed) decreased by −0·082 μg/ml (P = 0·036) indicating an improvement in the Fe status of adolescents but there was no significant decrease in the prevalence of deficiency (−8·5 %; P = 0·079). In adolescents, serum retinol increased by 0·16 μmol/l (P < 0·001) and vitamin A deficiency decreased by 26·1 % (P < 0·001).

The introduction of fortified maize meal led to a decrease in anaemia in children and a decrease in vitamin A deficiency in adolescents. Centralised, camp-level milling and fortification of maize meal is a feasible and pertinent intervention in food aid operations.