Naturally occurring toxic factors in plants and animals used as food.

Toxic components of natural foodstuffs are discussed, with special reference to lathyrogens, pressor amines, azoxyglycosides, and labile sulfur compounds. The osteolathyrogen, gamma-glutamyl-beta-aminopropionitrile, in sweet pea (Lathyrus odoratus) seeds induces skeletal deformities and aortic rupture, probably by interfering with normal maturation of collagen fibres. Neurolathyrism in man may be caused by beta-N-oxalyl-L-alpha,beta-diaminopropionic acid, a neurotoxin recently identified in Lathyrus sativus seeds. Histamine, tyramine, noradrenaline, serotonin and other pressor amines occur in fruits and fermented foods such as bananas, pineapples, cheese and wine. Consumption of such foods by patients taking monoamine oxidase-inhibiting drugs (e.g. tranylcypromine) may produce serious hypertensive crises. Cycad nuts, widely used as human food in tropical and subtropical areas, contain a potent carcinogen, methyl azoxymethanol, which is more or less removed prior to use by leaching in water. Consumption of plants of the onion, cabbage and cress families introduces into the body such toxic chemicals as benzyl cyanide, goitrin and thiocyanates. The lachrymatory substance in onions is propenyl sulfenic acid.