Objective: To investigate the efficacy of biscuits fortified with different doses of vitamin A on improving vitamin A deficiency (VAD), anaemia and physical growth of pre-school children.
Design: A randomised double-masked population-based field interventional trial with a positive control group.
Setting: Banan district of Chongqing, China.
Subjects: A total of 580 pre-school children aged 3-6 years were randomly recruited into four groups. Children in groups I and II were given biscuits fortified with vitamin A at 30 % of the recommended daily intake (RDA) and 100 % of the RDA once a day for 9 and 3 months, respectively. Children in group III received biscuits containing 20,000 IU of vitamin A once a week for 3 months. Initially, the children in group IV received a 200,000 IU vitamin A capsule just once. At the beginning and end of the study, blood samples were collected to measure Hb, serum retinol, retinol-binding protein and prealbumin, and weight and height were measured.
Results: All the fortification types significantly decreased the prevalence of VAD and anaemia in each group (P < 0.05). The effect of 9-month intervention on group I was the most efficient (P < 0.0045). After intervention, the Z-scores of height-for-age, weight-for-age and weight-for-height in all groups increased markedly compared with baseline (P < 0.05), but no significant difference was observed among the groups.
Conclusions: Data indicated that consuming vitamin A-fortified biscuits with daily 100 % RDA for 3 months has the same effect on the improvement of VAD, anaemia and physical growth as did the weekly 20,000 IU and single 200,000 IU administration in pre-school children.