Effect of theanine, γ-glutamylethylamide, on bodyweight and fat accumulation in mice

To clarify the details of the anti-obesity effect of theanine, γ-glutamylethylamide, female ICR mice were fed diets containing theanine at the concentrations of 0.01, 0.02, 0.04, 0.08 and 0.16% for 16 weeks. Bodyweight and food intake in the mice were measured every 4 weeks, and several organs and intraperitoneal adipose tissues (IPAT) were weighed after the feeding. In addition, lipid levels in the serum and liver were analyzed. As a result, the bodyweight increase and weight of IPAT were significantly reduced in mice fed 0.04% theanine compared with controls, but not in mice fed other diets. The levels of triglycerides (TG) and non-esterified fatty acids in the serum and TG level in the liver in mice fed the 0.04% theanine diet were remarkably decreased. These results indicated that bodyweight increase and fat accumulation were suppressed by a limited concentration of 0.04% theanine in mice.