Dietary cyanide from insufficiently processed cassava and growth retardation in children in the Democratic Republic of Congo (formerly Zaire).

Dietary cyanide exposure from cyanogenic glucosides in insufficiently processed cassava has been advanced as a contributing factor in child growth retardation. Whether cyanide exposure aggravates children's growth retardation was studied by comparing two populations of children from the northern and the southern zones of the Bandundu region, Democratic Republic of Congo (former Zaire), using dietary interviews, anthropometry and urine analyses. Both populations consumed cassava as their staple diet, but whereas in the north the cassava was well processed, in the south it was inadequately processed. The mean urinary thiocyanate was much higher in the south, whereas mean urinary sulphate excretion was equally low in the two areas. However, the mean urinary SCN/SO4 molar ratio was higher in the south (0.20), indicating that 10-20% of sulphur amino-acids were used for cyanide detoxication. No significant differences were found between the two populations in weight-for-height and weight-for-age indices but the height-for-age index was significantly lower in children from the south, indicating more severe growth retardation in children exposed to dietary cyanide. Because of the preferential use of sulphur amino-acids for cyanide detoxification in the human body, dietary cyanide exposure from cassava may be a factor aggravating growth retardation in Bandundu.