Cholewa Jason M, Guimarães-Ferreira Lucas, Zanchi Nelo Eidy
Department of Kinesiology Recreation and Sport Studies, Coastal Carolina University, Conway, SC, USA,
Amino Acids. 2014 Aug;46(8):1785-93. doi: 10.1007/s00726-014-1748-5. Epub 2014 Apr 24.
Betaine is a methyl derivative of glycine first isolated from sugar beets. Betaine consumed from food sources and through dietary supplements presents similar bioavailability and is metabolized to di-methylglycine and sarcosine in the liver. The ergogenic and clinical effects of betaine have been investigated with doses ranging from 500 to 9,000 mg/day. Some studies using animal models and human subjects suggest that betaine supplementation could promote adiposity reductions and/or lean mass gains. Moreover, previous investigations report positive effects of betaine on sports performance in both endurance- and resistance-type exercise, despite some conflicting results. The mechanisms underlying these effects are poorly understood, but could involve the stimulation of lipolysis and inhibition of lipogenesis via gene expression and subsequent activity of lipolytic-/lipogenic-related proteins, stimulation of autocrine/endocrine IGF-1 release and insulin receptor signaling pathways, stimulation of growth hormone secretion, increased creatine synthesis, increases in protein synthesis via intracellular hyper-hydration, as well as exerting psychological effects such as attenuating sensations of fatigue. However, the exact mechanisms behind betaine action and the long-term effects of supplementation on humans remain to be elucidated. This review aims to describe evidence for the use of betaine as an ergogenic and esthetic aid, and discuss the potential mechanisms underlying these effects.
甜菜碱是甘氨酸的甲基衍生物，最初从甜菜中分离出来。从食物来源和通过膳食补充剂摄入的甜菜碱具有相似的生物利用度，并在肝脏中代谢为二甲基甘氨酸和肌氨酸。人们已经对甜菜碱剂量范围为500至9000毫克/天的促力和临床效果进行了研究。一些使用动物模型和人体受试者的研究表明，补充甜菜碱可以促进脂肪减少和/或瘦体重增加。此外，尽管有一些相互矛盾的结果，但先前的研究报告了甜菜碱对耐力型和阻力型运动的运动表现有积极影响。这些作用背后的机制尚不清楚，但可能涉及通过基因表达以及脂解/脂肪生成相关蛋白的后续活性刺激脂肪分解和抑制脂肪生成，刺激自分泌/内分泌胰岛素样生长因子-1释放和胰岛素受体信号通路，刺激生长激素分泌，增加肌酸合成，通过细胞内过度水合增加蛋白质合成，以及产生心理作用，如减轻疲劳感。然而，甜菜碱作用的确切机制以及补充剂对人体的长期影响仍有待阐明。本综述旨在描述使用甜菜碱作为促力和美容辅助剂的证据，并讨论这些作用背后的潜在机制。
