Effect of beta-alanine supplementation on muscle carnosine concentrations and exercise performance

Abstract

High-intensity exercise results in reduced substrate levels and accumulation of metabolites in the skeletal muscle. The accumulation of these metabolites (e.g. ADP, Pi and H(+)) can have deleterious effects on skeletal muscle function and force generation, thus contributing to fatigue. Clearly this is a challenge to sport and exercise performance and, as such, any intervention capable of reducing the negative impact of these metabolites would be of use. Carnosine (beta-alanyl-L-histidine) is a cytoplasmic dipeptide found in high concentrations in the skeletal muscle of both vertebrates and non-vertebrates and is formed by bonding histidine and beta-alanine in a reaction catalysed by carnosine synthase. Due to the pKa of its imidazole ring (6.83) and its location within skeletal muscle, carnosine has a key role to play in intracellular pH buffering over the physiological pH range, although other physiological roles for carnosine have also been suggested. The concentration of histidine in muscle and plasma is high relative to its K (m) with muscle carnosine synthase, whereas beta-alanine exists in low concentration in muscle and has a higher K (m) with muscle carnosine synthase, which indicates that it is the availability of beta-alanine that is limiting to the synthesis of carnosine in skeletal muscle. Thus, the elevation of muscle carnosine concentrations through the dietary intake of carnosine, or chemically related dipeptides that release beta-alanine on absorption, or supplementation with beta-alanine directly could provide a method of increasing intracellular buffering capacity during exercise, which could provide a means of increasing high-intensity exercise capacity and performance. This paper reviews the available evidence relating to the effects of beta-alanine supplementation on muscle carnosine synthesis and the subsequent effects on exercise performance. In addition, the effects of training, with or without beta-alanine supplementation, on muscle carnosine concentrations are also reviewed.

Effect of β-alanine supplementation on 20 km cycling time trial performance

“…However, the strength of the currently available evidence to support the e ects of carnosine on calcium handling is limited 2,9 , with only one study 3 being conducted on human muscle bres. If calcium handling were the main mechanism for an e ect of elevated muscle carnosine on exercise performance, signi cant e ects of β-alanine supplementation would be expected across a wider range of exercise performance tests than have currently been shown 2,9 . Whilst the present study was not designed to examine the mechanisms related to increased exercise performance as a result of elevated muscle carnosine levels, the lack of an e ect of β-alanine would be consistent with the lack of an e ect of carnosine on calcium handling.…”

“…Several reviews have concluded that there are signi cant e ects of β-alanine supplementation on high-intensity exercise performance [9][10] . In particular, several studies have focussed on the effects of β-alanine supplementation on high intensity cycling capacity and have shown significant increases following supplementation [11][12][13] .…”

“…Whilst there is general consensus in the literature for a bene cial e ect of β-alanine supplementation on high intensity exercise performance [9][10][16][17] fewer studies have examined the e ects on longer duration exercise performance. However, a recent study examined the e ects of β-alanine supplementation on cycling performance in a time trial lasting ~ 1 hr 18 .…”

Carnosine and cancer: a perspective

“…This effect has been intensively investigated in muscle [for a review see (Sale et al 2010)]. Of course, synthesis of carnosine from b-alanine will be restricted to tissues expressing carnosine synthase [L-histidine:beta-alanine ligase (ADPforming) (6.3.2.11), formerly also designated 'carnosine synthetase'].…”

β–alanine: performance effects, usage and side effects

“…Training: acute Suzuki et al [78] showed an extremely large (+113%) increase in M-Carn in the vastus lateralis muscle of six untrained males after eight weeks of high intensity sprint [59], there was a small but non-significant increase (11%) in M-Carn in the soleus muscle in the group that consumed a β-alanine rich diet but in the group that consumed a vegetarian diet the change M-Carn was a small non-significant decrease (9%). An increase in a β-alanine rich diet may be one explanation for the findings of Suzuki et al [78] or that there was an error in the measurement of M-Carn in the muscle samples [18].…”