Aflatoxin Metabolites in Relation to Protein-Energy Malnutrition in Zambia

Abstract

Findings in the Sudan show a possible association between aflatoxins and kwashiorkor, a category of Protein-Energy Malnutrition (PEM). Similarities in the geographical and seasonal prevalence of aflatoxins and kwashiorkor, as well as similarities in the metabolic derangements caused by aflatoxins and observed in kwashiorkor suggest that aflatoxins may play an etiological role in the pathogenesis of kwashiorkor. Studies in Zambia have shown that aflatoxin contamination occurs in commonly eaten foods, suggesting that the Zambian population is exposed to the toxin. The presence of urinary aflatoxins in patient with and without liver pathology at an incidence which reflects the level of contamination has also been reported. PEM is known to be endemic in Zambia witlva seasonal prevalence similar to that observed with aflatoxin contamination of food. A one-year survey was therefore undertaken to investigate the relationship between aflatoxins and the various categories of PEM. Metabolism of the aflatoxins was determined by analyzing urine and serum samples of PEM cases and appropriate controls from the University Teaching Hospital, Lusaka. As previous studies had shown a higher level of aflatoxin contamination in foods in the Eastern province, urine samples from PEM cases and appropriate controls were obtained from St. Francis1 Hospital, Katete, for comparison. The incidence of urinary aflatoxins in samples from Lusaka and Katete was 6.1 per cent, with a mean concentration of 0.365 ng/ml. Aflatoxin B, and aflatoxicol were detected. Aflatoxicol concentrations were highest in control and lowest in kwashiorkor samples, though aflatoxicol was detected slightly more frequently in the latter. Aflatoxin B, excretion was observed to follow a similar pattern. Comparing the incidences in Lusaka and Katete, a significant difference was not observed. In serum samples the incidence of aflatoxins was 2.8 per cent, with a mean concentration of 1.87 ng/ml. Aflatoxin B, and aflatoxicol were detected with aflatoxicol only being detected in one case of kwashiorkor. Total aflatoxin concentration was higher in kwashiorkor than controls while the incidence was similar in the two groups. The incidence of urinary aflatoxin in the rainy season (18.8 per cent) was greater than in the dry season (5 per cent), however, no significant difference was observed in the seasonal variation of aflatoxins in sera. Urinary aflatoxins were detected more often in males than in females but no significant difference occurred in the sera analyses. The results suggest that there may be certain unusual associations in the incidence, concentrations and type of aflatoxin detected between the different nutritional groups, in particular the role of aflatoxicol in kwashiorkor and the lower excretion levels observed. Possibly this indicates a decreased capacity to deal with aflatoxins. Whether this a cause or an effect of the kwashiorkor syndrome, is still not clear. These preliminary findings merit an extended study to examine more closely the relationship of aflatoxins and kwashiorkor in Zambian children.