Progress in prevention of toxico-nutritional neurodegenerations

Grass pea (Lathyrus sativus) is a survival food during drought in Ethiopia and the Indian Subcontinent, producing the cheapest dietary protein and saving thousands of lives. It also is a mixed blessing as the cause of the crippling neurolathyrism after prolonged over-consumption. Cassava (Manihot esculenta) is a protein-poor root crop that is the staple food for over half a billion people in Africa, South America and Southeast Asia, and the cheapest source of dietary carbohydrates. Over-consumption of cassava roots in a monotonous diet can cause konzo, with clinical symptoms indistinguishable from neurolathyrism. The prominent features of both diseases are sudden onset of symmetric spastic paraparesis of the calf muscles and scissor gate. The common feature of grass pea seed and cassava roots is the low content of the essential sulphur containing amino acids methionine and cysteine. The focus of breeding has been the reduction of the neuro-excitatory amino acid b-ODAP (b-N-oxalyl-L-a,b-diaminopropionic acid) in grass pea and the reduction of the cyanogenic glucosides in cassava. Developing varieties with higher content in methionine and cysteine and a better balanced diet may be more relevant in improving nutrition without jeopardizing the tolerance for biotic and abiotic stress of these crops.