Évaluation de l’intérêt nutritionnel d’isolats de protéines de colza chez le rat et l’Homme : application à la prévention du syndrome métabolique

Abstract

Plant protein have long been opposed to animal protein because some plant protein present a relative mismatch between their amino acid pattern and human requirements for the renewal of body protein. Nevertheless, beyond its theoretical relevance to match the metabolic demand for protein metabolism, the amino acid pattern of dietary protein may also be of importance in the nutritional prevention of certain metabolic diseases. Of major public health concern is the metabolic syndrome, a cluster of risk factors associating obesity, insulin resistance, endothelial dysfunction, and low-grade inflammation. Two amino acids may be of importance in the pathophysiology of the metabolic syndrome: cysteine, the glutathione precursor, and arginine, the nitric oxide precursor. In this context, rapeseed protein, which is rich in cysteine and a good source of arginine, is an attractive candidate for studying the potential of dietary protein to prevent insulin resistance and related metabolic/ physiological abnormalities in the setting of the metabolic syndrome. After having presented a study demonstrating the high postprandial nitrogen utilization of rapeseed protein in humans, this review report two studies from our group showing that 1) rapeseed protein prevents the onset of insulin resistance induced by a diet rich in saturated fatty acids and sucrose in rats; 2) rapeseed protein alleviates the postprandial vascular endothelial dysfunction and oxidative stress coming after a meal rich in saturated fatty acids and sucrose. The beneficial preventive effects can be accounted for, at least to some extent, by the high cysteine and arginine content of the rapeseed protein. Studies are urgently needed to assess the beneficial effect of this emerging protein source in humans.