zarrin77
Member
Abstract:
Although many studies have shown that amino acid ingestion acutely stimulates protein anabolism, only few studies have investigated whether
long-term supplementation promotes changes in body composition. We therefore tested the hypothesis that l-leucine (LEU) and l-phenylalanine
(PHE) supplementation might have a positive impact on the body composition of rats submitted to intermittent periods of food restriction and
refeeding (weight cycling or WC). The WC protocol comprised three cycles, each consisting of 1 week of 50% food restriction followed by
2 weeks of ad libitum ingestion. The groups submitted to WC ingested the control diet (WC-CON) or the diet supplemented with LEU + PHE
(WC-AA). A pair-fed group receiving the control diet (PF-CON) was used as a reference for the effects of WC. Although food intake was the
same in all groups, higher body weight and energy efficiency were observed in the WC-AA group compared to the PF-CON and WC-CON groups
although not significantly in relation to the latter. These results were the consequence of a significant increase of lean body mass and body protein
content in the WC-AA group compared to the PF-CON and WC-CON groups. The WC-CON and WC-AA groups presented 36.1% and 18.9%
more body fat, respectively, than the PF-CON group but this difference was not significant. Neither fasting insulin nor glucose concentration nor
postprandial insulin secretion was significantly affected by the supplemented diet. In conclusion, supplementation with LEU + PHE improved the
body composition profile of rats submitted to WC, mainly by increasing lean body mass and body protein content.
Study attached
Although many studies have shown that amino acid ingestion acutely stimulates protein anabolism, only few studies have investigated whether
long-term supplementation promotes changes in body composition. We therefore tested the hypothesis that l-leucine (LEU) and l-phenylalanine
(PHE) supplementation might have a positive impact on the body composition of rats submitted to intermittent periods of food restriction and
refeeding (weight cycling or WC). The WC protocol comprised three cycles, each consisting of 1 week of 50% food restriction followed by
2 weeks of ad libitum ingestion. The groups submitted to WC ingested the control diet (WC-CON) or the diet supplemented with LEU + PHE
(WC-AA). A pair-fed group receiving the control diet (PF-CON) was used as a reference for the effects of WC. Although food intake was the
same in all groups, higher body weight and energy efficiency were observed in the WC-AA group compared to the PF-CON and WC-CON groups
although not significantly in relation to the latter. These results were the consequence of a significant increase of lean body mass and body protein
content in the WC-AA group compared to the PF-CON and WC-CON groups. The WC-CON and WC-AA groups presented 36.1% and 18.9%
more body fat, respectively, than the PF-CON group but this difference was not significant. Neither fasting insulin nor glucose concentration nor
postprandial insulin secretion was significantly affected by the supplemented diet. In conclusion, supplementation with LEU + PHE improved the
body composition profile of rats submitted to WC, mainly by increasing lean body mass and body protein content.
Study attached
