Cassava, konzo, and neurotoxicity.

Cassava (Manihot esculenta) forms part of the staple diet for more than 600 million people across the world, particularly those that live in poverty and remote areas where food security is poor.1 The plant grows in poor soil and is relatively drought resistant; the tubers are rich in carbohydrates and the leaves contain some protein. Cassava contains cyanogenic glucosides (linamarin and lotaustralin) that are released as hydrogen cyanide, which are thought to protect the plants from insects and other animals. For human consumption, the plants need to be detoxified, usually by soaking, drying in the sun, boiling, fermentation, or grating with roasting.2 These processes allow the cyanogenic glucosides to be released, but depend upon traditional practices, time taken, and the availability of water. Neurotoxicity is associated with incompletely detoxified cassava, although the exact mechanisms by which these compounds cause neurological damage is unclear. The toxicity of cyanide is reduced by its transformation to thiocyanate or cyanate, which requires sulphur donors, often limited in malnutrition.