Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil.
Nutrition. 2012 Feb;28(2):182-9. doi: 10.1016/j.nut.2011.04.004. Epub 2011 Aug 26.
Aging is characterized by alterations in body composition such as an increase in body fat and decreases in muscle mass (sarcopenia) and bone density (osteopenia). Leucine supplementation has been shown to acutely stimulate protein synthesis and to decrease body fat. However, the long-term effect of consistent leucine supplementation is not well defined. This study investigated the effect of leucine supplementation during aging.
Six-month-old rats were divided into three groups: an adult group (n = 10) euthanized at 6 mo of age, a leucine group (n = 16) that received a diet supplemented with 4% leucine for 40 wk, and a control group (n = 19) that received the control diet for 40 wk. The following parameters were evaluated: body weight, food intake, chemical carcass composition, indicators of acquired chronic diseases, and indicators of protein nutritional status.
Body weight and fat were lower in the leucine group after 40 wk of supplementation compared with the control group but still higher than in the adult group. The lipid and glycemic profiles were equally altered in the control and leucine groups because of aging. In addition, leucine supplementation did not affect the changes in protein status parameters associated with aging, such as decreases in body and muscle protein and total serum protein.
The results indicate that leucine supplementation attenuates body fat gain during aging but does not affect risk indicators of acquired chronic diseases. Furthermore, supplemented animals did not show signs of a prevention of the decrease in lean mass associated with aging.
衰老的特征是身体成分的改变，如体脂肪增加、肌肉质量（肌少症）和骨密度（骨质疏松症）减少。亮氨酸补充已被证明能急性刺激蛋白质合成，并减少体脂肪。然而，持续亮氨酸补充的长期效果尚不清楚。本研究调查了亮氨酸补充在衰老过程中的作用。
6 月龄大鼠分为三组：成年组（n=10），6 月龄时安乐死；亮氨酸组（n=16），接受添加 4%亮氨酸的饮食 40 周；对照组（n=19），接受对照饮食 40 周。评估以下参数：体重、食物摄入量、化学体成分、获得性慢性疾病指标和蛋白质营养状况指标。
亮氨酸组在补充 40 周后体重和体脂肪均低于对照组，但仍高于成年组。由于衰老，对照组和亮氨酸组的血脂和血糖谱均发生改变。此外，亮氨酸补充并未影响与衰老相关的蛋白质状况参数的变化，如体蛋白和肌肉蛋白以及总血清蛋白的减少。
结果表明，亮氨酸补充可减轻衰老过程中的体脂肪增加，但不影响获得性慢性疾病的风险指标。此外，补充动物未显示出预防与衰老相关的瘦体重减少的迹象。
