Nestlé Research Center, Lausanne, Switzerland.
Amino Acids. 2012 Jul;43(1):57-65. doi: 10.1007/s00726-012-1245-7. Epub 2012 Feb 23.
Interest into the effects of carnosine on cellular metabolism is rapidly expanding. The first study to demonstrate in humans that chronic β-alanine (BA) supplementation (3-6 g BA/day for ~4 weeks) can result in significantly augmented muscle carnosine concentrations (>50%) was only recently published. BA supplementation is potentially poised for application beyond the niche exercise and performance-enhancement field and into other more clinical populations. When examining all BA supplementation studies that directly measure muscle carnosine (n=8), there is a significant linear correlation between total grams of BA consumed (of daily intake ranges of 1.6-6.4 g BA/day) versus both the relative and absolute increases in muscle carnosine. Supporting this, a recent dose-response study demonstrated a large linear dependency (R2=0.921) based on the total grams of BA consumed over 8 weeks. The pre-supplementation baseline carnosine or individual subjects' body weight (from 65 to 90 kg) does not appear to impact on subsequent carnosine synthesis from BA consumption. Once muscle carnosine is augmented, the washout is very slow (2%/week). Recently, a slow-release BA tablet supplement has been developed showing a smaller peak plasma BA concentration and delayed time to peak, with no difference in the area under the curve compared to pure BA in solution. Further, this slow-release profile resulted in a reduced urinary BA loss and improved retention, while at the same time, eliciting minimal paraesthesia symptoms. However, our complete understanding of optimizing in vivo delivery and dosing of BA is still in its infancy. Thus, this review will clarify our current knowledge of BA supplementation to augment muscle carnosine as well as highlight future research questions on the regulatory points of control for muscle carnosine synthesis.
人们对肌肽影响细胞代谢的作用的研究兴趣正在迅速扩大。最近才发表了第一项在人类中证明慢性β-丙氨酸（BA）补充剂（每天约 3-6 克 BA，持续约 4 周）可使肌肉肌肽浓度显著增加（>50%）的研究。BA 补充剂有可能不仅应用于运动和性能增强领域的利基市场，还应用于其他更具临床意义的人群。在研究了所有直接测量肌肉肌肽的 BA 补充剂研究（n=8）时，发现消耗的 BA 总量（每日摄入量范围为 1.6-6.4 克 BA/天）与肌肉肌肽的相对和绝对增加之间存在显著的线性相关性。支持这一点，最近的一项剂量反应研究表明，基于 8 周内消耗的 BA 总量，存在很大的线性依赖性（R2=0.921）。补充前肌肽的基线水平或个体的体重（65-90 公斤）似乎不会影响随后由 BA 消耗引起的肌肽合成。一旦肌肉肌肽增加，清除速度非常缓慢（~2%/周）。最近，一种 BA 缓释片补充剂已被开发出来，其血浆 BA 浓度峰值较小，达到峰值的时间延迟，与溶液中的纯 BA 相比，曲线下面积没有差异。此外，这种缓释特征导致 BA 排泄损失减少，保留时间延长，同时最小化了感觉异常症状。然而，我们对优化 BA 的体内传递和给药的全面理解仍处于起步阶段。因此，本文综述将阐明我们目前对 BA 补充以增加肌肉肌肽的认识，并强调关于肌肉肌肽合成控制的调节点的未来研究问题。
