Toxic constituents of plant foodstuffs By Irvin E. Liener, Department of Biochemistry, University of Minnesota, St. Paul, Minnesota, USA Unlike chemical additives, naturally occurring toxic substances in plants pose a unique challenge since they cannot be eliminated by legislation. This paper discusses toxic or antinutritional factors in plants that are valuable sources of protein for human diets or animal feeds. It focuses on methods to eliminate or inactivate these substances to ensure safe dietary protein sources. Proteins that inhibit trypsin, an enzyme involved in protein digestion, are common in legumes. Soybean trypsin inhibitor contributes to poor nutritional value of unheated soybeans and is reduced by heat treatment. The mechanism of its effect is unclear but may relate to pancreatic hypertrophy. Phytohaemagglutinin in legumes causes red blood cell agglutination and severe growth issues in rats. It acts on the intestinal mucosa, impairing absorption. Human lathyrism is linked to Lathyrus sativus, with β-N-oxalyl-L-α,β-diaminopropionic acid being a possible cause. Certain cruciferous oilseeds contain thioglycosides that release goitrogenic compounds. Heat treatment can reduce their goitrogenicity. Cyanide-containing glycosides are found in lima beans, sorghum, and others. Thermal inactivation of enzymes can detoxify these plants. Favism, a hemolytic anemia, is linked to Vicia faba. Vicine may be the causative agent in susceptible individuals. Natural substances can interfere with mineral and vitamin utilization. For example, soybean protein affects zinc, manganese, copper, and iron availability. Raw kidney beans increase vitamin E requirements in chicks. Linseed meal contains a pyridoxine antagonist. Naturally occurring toxicants in human nutrition are not well understood. However, prolonged consumption of one food may reveal hidden toxic effects. As protein shortages increase, people may consume less varied diets, increasing the risk of toxic effects. Selecting plant varieties with reduced toxic components can help prevent this. ## REFERENCE Liener, I. E. (1966). Adv. Chem. Ser. 57, 178.Toxic constituents of plant foodstuffs By Irvin E. Liener, Department of Biochemistry, University of Minnesota, St. Paul, Minnesota, USA Unlike chemical additives, naturally occurring toxic substances in plants pose a unique challenge since they cannot be eliminated by legislation. This paper discusses toxic or antinutritional factors in plants that are valuable sources of protein for human diets or animal feeds. It focuses on methods to eliminate or inactivate these substances to ensure safe dietary protein sources. Proteins that inhibit trypsin, an enzyme involved in protein digestion, are common in legumes. Soybean trypsin inhibitor contributes to poor nutritional value of unheated soybeans and is reduced by heat treatment. The mechanism of its effect is unclear but may relate to pancreatic hypertrophy. Phytohaemagglutinin in legumes causes red blood cell agglutination and severe growth issues in rats. It acts on the intestinal mucosa, impairing absorption. Human lathyrism is linked to Lathyrus sativus, with β-N-oxalyl-L-α,β-diaminopropionic acid being a possible cause. Certain cruciferous oilseeds contain thioglycosides that release goitrogenic compounds. Heat treatment can reduce their goitrogenicity. Cyanide-containing glycosides are found in lima beans, sorghum, and others. Thermal inactivation of enzymes can detoxify these plants. Favism, a hemolytic anemia, is linked to Vicia faba. Vicine may be the causative agent in susceptible individuals. Natural substances can interfere with mineral and vitamin utilization. For example, soybean protein affects zinc, manganese, copper, and iron availability. Raw kidney beans increase vitamin E requirements in chicks. Linseed meal contains a pyridoxine antagonist. Naturally occurring toxicants in human nutrition are not well understood. However, prolonged consumption of one food may reveal hidden toxic effects. As protein shortages increase, people may consume less varied diets, increasing the risk of toxic effects. Selecting plant varieties with reduced toxic components can help prevent this. ## REFERENCE Liener, I. E. (1966). Adv. Chem. Ser. 57, 178.