Anti‐obesity effects of amino acid in high‐fat diet induced obese mice

Abstract

Anti‐obesity effects of dietary supplemented amino acid have been reported. Dietary supplementation of glutamine, alanine, or leucine decreases high‐fat diet induced obesity in C57BL/6J mice. It was reported that histidine supplementation suppressed food intake and fat accumulation in Wistar rats. And it was shown that dietary arginine supplementation reduced fat mass in Zucker diabetic fatty rats. However there is no information about the anti‐obesity effects of other amino acids than above mentioned. Therefore, we conducted this series of experiments to compare the anti‐obesity effects of 20 kinds of proteinogenic amino acids. Male C57BL/6J mice were fed a high‐fat diet supplemented with either one of 20 proteinogenic amino acids (1‐6 %) for 4 to 8 weeks. Body weight, food intake, epididymal fat weight, and plasma triglyceride concentration were measured. Results showed that supplementation with any one of cystine (3%), histidine (5%), leucine (3%), lysine HCl (3%), threonine (3%), and tryptophan (3%) suppressed body weight gain and visceral fat deposition. Reduction of food intake was observed in cystine and histidine group but not in leucine, lysine, threonine, and tryptophan group. Plasma triglyceride concentration reduced only in lysine group. In conclusion, dietary supplementation of any one of leucine, lysine, threonine, and tryptophan prevents high‐fat diet induced obesity without reduction in food intake, which suggests increased energy expenditure. Among these amino acids, lysine is the most potent amino acid to reduce adiposity, since it decreases diet induced obesity as well as hyperlipidemia.

Threonine, but Not Lysine and Methionine, Reduces Fat Accumulation by Regulating Lipid Metabolism in Obese Mice

“…Our result is also contradictory to a previous study in which body weight control and reduced serum triacylglycerol were observed for Lys addition . It was noteworthy that the mice of the previous study were fed with HFD for 23 weeks and then switched to regular chow or fed with HFD in conjunction with AAs simultaneously for 4 to 8 weeks, while the mice of this study were fed with HFD for 12 weeks and then continued with HFD. Moreover, the supplementary method was also different.…”

“…The current study showed a mark reduction in body weights of mice after 10 weeks of feeding of Thr. A Pearson correlation coefficient (a measure of the linear association of two variables) between body weight and WAT by Thr supplementation was 0.90, suggesting the dominated contribution of adipose tissue loss in the reduction of body weight. , Along with the reduced body weight and WAT weight, the serum lipid profiles were already improved by Thr supplementation, which further prove the efficacy of Thr in the regulation of lipid metabolism. However, Lys or Met failed to decrease body weight and WAT weight although a trend was observed for Lys treatment.…”

“…More importantly, the family of functional AAs was further expanded despite that other AAs such as branched-chain amino acids and arginine have been widely studied. The supplemented dose varied from 1.5 to 2.5 to 3.7%. − This study employed 3% dosage, which was parallel to that in a previous study where the obesity was prevented by Lys or Thr supplementation …”

“…Besides this, it was reported that lysine addition for 4 weeks markedly reduced serum triacylglycerol and hepatic lipid droplet accumulation of the mice under a high-fat diet (HFD) feeding for 23 weeks . In another study, body weight gain and visceral fat deposition were suppressed after Thr or Lys supplementation accompanied by an HFD for 4 to 8 weeks . Met in conjunction with HFD for 4 weeks, however, induced adverse effects in relation to serum lipid parameters .…”

“…17 In another study, body weight gain and visceral fat deposition were suppressed after Thr or Lys supplementation accompanied by an HFD for 4 to 8 weeks. 18 Met in conjunction with HFD for 4 weeks, however, induced adverse effects in relation to serum lipid parameters. 19 The three AAs have not been studied for decreasing fat deposition under an identical model.…”