Comparative Cyanide Levels in Cassava Varieties from Rural Sierra Leone Communities

Background Cassava (Manihot esculenta Crantz) is a major staple crop in sub-Saharan Africa, valued for its carbohydrate-rich roots and nutrient-dense leaves. Despite its nutritional benefits, cassava contains cyanogenic glycosides primarily linamarin and lotaustralin which release toxic hydrogen cyanide (HCN) upon enzymatic hydrolysis. Chronic exposure to cyanide from poorly processed cassava can result in severe health disorders, including tropical ataxic neuropathy, goiter, and in extreme cases, death.  Aim This study aimed to determine and compare the cyanide content in sweet and bitter varieties of cassava leaves and roots collected from Gloucester village (Western Rural Area) and Fonkoya village (Magbema Chiefdom, Kambia District) in Sierra Leone.  Methods A quantitative analytical approach was employed using acid hydrolysis followed by alkaline titration to assess HCN content. Samples were authenticated by the Department of Botany, Fourah Bay College, and processed using standard procedures. Cyanide levels were calculated based on silver nitrate titration, using the conversion factor: 1 cm3 of 0.020 M AgNO3 = 1.08 mg HCN.  Results Bitter cassava samples exhibited significantly higher cyanide concentrations than sweet varieties across both locations. Gloucester samples showed greater HCN levels than those from Fonkoya. The highest cyanide content was recorded in bitter cassava leaves from Gloucester (13.39 mg/kg), while the lowest was found in sweet cassava roots from Fonkoya (4.48 mg/kg). Overall, leaves had higher cyanide levels than roots.  Conclusion This study highlights a critical public health concern regarding cyanide exposure from cassava consumption in Sierra Leone. The findings emphasize the need for public education on proper processing methods, promotion of low-cyanide cassava varieties, and regulatory monitoring. Addressing these gaps is essential for reducing cyanide toxicity risk and ensuring the safety of cassava as a dietary staple.