Protein, amino acids and obesity treatment

Abstract

Dietary proteins have been used for years to treat obesity. Body weight loss is beneficial when it concerns fat mass, but loss of fat free massespecially muscle might be detrimental. This occurs because protein breakdown predominates over synthesis, thus administering anabolic dietary compounds like proteins might counter fat free mass loss while allowing for fat mass loss. Indeed, varying the quantity of proteins will decrease muscle anabolic response and increase hyperphagia in rodents fed a low protein diet; but it will favor lean mass maintenance and promote satiety, in certain age groups of humans fed a high protein diet. Beyond protein quantity, protein source is an important metabolic regulator: whey protein and plant based diets exercize favorable effects on the risk of developing obesity, body composition, metabolic parameters or fat free mass preservation of obese patients. Specific amino-acids like branched chain amino acids (BCAA), methionine, tryptophan and its metabolites, and glutamate can also positively influence parameters and complications of obesity especially in rodent models, with less studies translating this in humans. Tuning the quality and quantity of proteins or even specific amino-acids can thus be seen as a potential therapeutic intervention on the body composition, metabolic syndrome parameters and appetite regulation of obese patients. Since these effects vary across age groups and much of the data comes from murine models, long-term prospective studies modulating proteins and amino acids in the human diet are needed.

Weight Loss Strategies and the Risk of Skeletal Muscle Mass Loss

“…The idea that higher intakes of protein (absolute or proportional) may be an optimum dietary weight management strategy has found support in the scientific literature over a number of years. However, the focus of attention has tended to be directed towards the ability of dietary protein to suppress hunger and promote satiety [ 60 , 61 ], its effect on energy intake, resting metabolic rate, and thermogenesis [ 62 ], and endocrine and gut hormone responses [ 63 ]. Alongside these important areas of weight management, the role of dietary protein in the preservation of FFM and SMM under conditions of negative energy balance induced by an energy restricted diet has also been explored in some detail.…”

The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

“…Discovered by Sir F.G. Hopkins in 1901 in milk casein hydrolysate, Trp was found to be an essential amino acid in experiments with mouse diet. Over the years, interest in Trp and its nutritional role in the mammalian diet has received enormous attention, much of which can be found in recent reviews [ 1 , 2 , 3 , 4 , 5 , 6 ]. Here, I have taken a complimentary approach, critically analyzing the major roles of Trp in cellular functions and in intermediary metabolism, such as translation, protein structure, adduct formation, the generation of important regulators, and most recently, RNA virus regulation.…”

GEO data mining and TCGA analysis reveal altered branched chain amino acid metabolism in pancreatic cancer patients

“…Muscle is another important place where BCAAs are produced or deposited [ 25 , 26 ]. To unveil the BCAA metabolism in muscle of pancreatic cancer patients, GSE130563 dataset was additionally applied to do further investigation.…”

“…On the other hand, in skeletal muscle, MYC plays a pivotal role but the only identified differentially expressed BCAA transporter, SLC7A5, shows merely subtle change. BCAA is substantial to the maintenance of muscle mass [ 26 , 29 ]. During cancer-induced cachexia, muscle proteins would degrade and release BCAAs into peripheral blood [ 29 ].…”