Leucine, as an essential amino acid and activator of mTOR (mammalian target of rapamycin), promotes protein synthesis and suppresses protein catabolism. However, the effect of leucine associated with exercise on weight loss and improvement on cholesterol metabolism remains unclear, and whether leucine has beneficial effects as a long-term dietary supplement has not been examined.
PURPOSE: To evaluate the effect of leucine associated with exercise on weight loss and metabolism of cholesterol in rats previously submitted to a high-fat diet.
METHODS: Initially fifteen Sprague-Dawley rats were to fed with high-fat diet for 15 weeks. Subsequently, they were distributed in two groups, exercise group (EG) (n = 8) and exercise + leucine (GEL) (n = 7). Both groups rats were submitted to a swimming exercise for 60 minutes per day for 6 weeks, and GEL rats recieved supplementation with 5% of leucine. After 21 weeks the animals were sacrificed and samples for analysis were collected. Test t was done for statistical analysis with p<0.05.
RESULTS: There was a significant variation in body weight of GEL compared with GE (-32.50 ± 37.05 vs. 30.87 ± 7.82 respectively; p<0.03), equivalent to -6.15% vs. 1.73%. In addition, GEL compared with the GE showed a significant increase in HDL-c (43.46 ± 5.81 vs 32.34 ± 12.27 respectively; p<0.04). The values of triglycerides (TG), total cholesterol and ratio of triglycerides to HDL-cholesterol (TG/HDL-c) showed no significant difference, 88.19 ± 20.03 (GEL) vs. 98.42 ± 33.12 (GE), p>0.490; 69.89 ± 17.30 (GEL) vs. 60.04 ± 12.06 (GE), p>0.218; 2.06 ± 0.40 (GEL) vs 2.64 ± 0.60 (GE), p>0.060; respectively.
CONCLUSIONS: The results of this study suggest that exercise when combined with supplementation with leucine favors the loss of body weight and increases the fraction of HDL-C in rats previously submitted to a high-fat diet via multiple mechanisms.
Supported by FAPESP, 07/59291-3 and 07/51964-9.