Whole blood cyanide levels of mainly dietary origin in a human population sample in Port Harcourt, Nigeria.

Whole blood cyanide levels in a human population sample of volunteers known to each gari-based meals at least once a day were determined. The most widely eaten cassava product in the area of research is gari. The mean blood cyanide obtained for healthy normal volunteers was 0.294 +/- 0.09 mumol/L while the value for sicklers was 0.398 +/- 0.008 mumol/L, indicating the possibility of reduced rate of metabolism and excretion of cyanide by sicklers as compared to non-sicklers. Investigation of post-absorption distribution indicated that whole blood cyanide increased by 0.014 mumol/L, 3-4 hours after a gari-based meal in normal volunteers. A decrease of 0.012 mumol/L occurred after a whole-rice meal. The increase in plasma cyanide 2-3 hours after a gari-based meal was about 25% more than the increase in erythrocyte cyanide suggesting a significant contribution of plasma cyanide to whole blood cyanide levels. 0.013-0.015 mg cyanide per kg of gari was determined for samples of this staple food in the locality of research.