Health benefits and risks of plant proteins.
Plant proteins have a reduced content of essential amino acids in comparison to animal proteins. A significant reduction of limiting amino acids (methionine, lysine, tryptophan) means lower protein synthesis. In subjects with predominant or exclusive consumption of plant food a higher incidence of hypoproteinemia due to significant reduction of methionine and lysine intakes was observed. On the other hand, lower intake of these amino acids provides a preventive effect against cardiovascular disease via cholesterol regulation by an inhibited hepatic phospholipid metabolism. Vegetarians have a significantly higher intake of non-essential amino acids arginine and pyruvigenic amino acids glycine, alanine, serine. When plant protein is high in non-essential amino acids, down-regulation of insulin and up-regulation of glucagon is a logical consequence. The action of glucagon in the liver is mediated by stimulation of adenyl cyclase that raises cyclic-AMP (adenosine-3,5-monophosphate) concentrations. Cyclic-AMP down-regulates the synthesis of a number of enzymes required for de novo lipogenesis and cholesterol synthesis, up-regulates key gluconeogenic enzymes and the LDL receptors and decreases the IGF-1 activity (insulin-like growth factor). Cyclic-AMP thus provides a reduction of atherosclerosis risk factors as well as a retardation of cancer development. A sufficient consumption of plant proteins has the protective effects against chronic degenerative diseases (Tab. 2, Ref. 26).
Krajcovicova-Kudlackova
M
M
Research Base of The Slovak Medical University, Institute of Preventive and Clinical Medicine, Bratislava, Slovakia. marica.kudlackova@szu.sk
Babinska
K
K
Valachovicova
M
M
D000601:Amino Acids, Essential / Q000008:administration & dosage; D002318:Cardiovascular Diseases / Q000517:prevention & control; D014676:Diet, Vegetarian / Q000009:adverse effects; D004044:Dietary Proteins / Q000008:administration & dosage*; D010940:Plant Proteins / Q000008:administration & dosage*; D014674:Plant Proteins, Dietary
D000601:Amino Acids, Essential; D004044:Dietary Proteins; D010940:Plant Proteins; D014674:Plant Proteins, Dietary