Effect of supplementary vitamins and iron on malaria indices in rural Gambian children

Abstract The effect of a combined supplement of iron, thiamine, riboflavin and vitamin C on malarial incidence in 5 to 14-year-old children was tested in a malnourished rural community in a region of The Gambia noted for high prevalence of malaria during the rainy season. 190 children, divided into 2 matched groups, received either the supplement or a matching placebo for 3 months. No significant difference in malarial incidence was observed between the 2 groups, despite a major improvement in biochemical indices of nutrient status in the supplemented group, especially for riboflavin and vitamin C. Severity of episodes was also similar between groups, but in subjects who developed parasitaemias there was a trend towards higher parasite counts in those receiving the active supplement. Nutritional interventions in malarious areas may have adverse effects on malaria, and the increase in parasitaemia was compatible with the hypothesis that a small but significant reduction in defences had occurred. However, the absence of increases in the incidence of proven malaria cases and their severity must also be taken into account, in order to make a balanced assessment of the possible increase in risk. Further investigations are needed to measure the risk in benefit rates, and to consider the effects of individual nutrients in isolation.