We conducted a randomized controlled trial of the effects of dietary supple
ments on anemia, weight and height in 136 anemic school children from a low
socioeconomic background in Bagamoyo District schools in Tanzania. The aim
of the current study was to investigate the impact of dietary supplements
on anemia and anthropometric indices of anemic school children. The supplem
ents were vitamin A alone, iron and vitamin A, iron alone or placebo, admin
istered in a double-blinded design for 3 mo. All supplements were provided
with local corn meals. Hemoglobin concentration, body weight and height wer
e measured at baseline and at follow-up after supplementation. Vitamin A su
pplementation increased the mean hemoglobin concentration by 13.5 g/L compa
red with 3.5 g/L for placebo (P < 0.0001, 95% confidence interval (CI) 6.19
-13.57), the mean body weight by 0.6 kg compared with 0.2 kg for placebo (P
< 0.0001, 95% CI 0.19-0.65) and the mean height by 0.4 cm compared with 0.
1 cm for placebo (P = 0.0009, 95% CI 0.08-0.42). However, the group of chil
dren who received combined vitamin A and iron supplementation had the great
est improvements in all indicators compared with placebo (18.5 g/L, P < 0.0
001, 95% CI 14.81-22.23; 0.7 kg, P < 0.0001, 95% CI 0.43-0.88 and 0.4 cm, P
< 0.0001, 95% CI 0.22-0.56 for hemoglobin, weight and height, respectively
). It is likely that vitamin A supplementation may have a useful role in co
mbating the problems of vitamin A deficiency and anemia, as well as in impr
oving children's growth, in developing countries.