RESUMO
OBJECTIVES: Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d(-1) on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2). METHODS: In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion. RESULTS: In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P < 0.05), although there was no effect (P>0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise. CONCLUSION: 28 d of beta-alanine supplementation at 6.4 g d(-1) appeared not to influence brain homocarnosine/carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists.
Assuntos
Encéfalo/metabolismo , Carnosina/metabolismo , Cognição/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , beta-Alanina/farmacologia , Adulto , Atletas/psicologia , Encéfalo/efeitos dos fármacos , Carnosina/análogos & derivados , Suplementos Nutricionais , Exercício Físico , Feminino , Humanos , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismoRESUMO
The effects of ß-alanine supplementation on high-intensity cycling performance and capacity have been evaluated, although the effects on longer duration cycling performance are unclear. Nineteen UK category 1 male cyclists completed four 20 km cycling time trials, two before and two after supplementation with either 6.4 gâ¢d-1 ß-alanine (n = 10; BA) or a matched placebo (n = 9; P). Performance time for the 20 km time trial and 1 km split times were recorded. There was no significant effect of ß-alanine supplementation on 20 km time trial performance (BA-pre 1943 ± 129 s; BA-post 1950 ± 147 s; P-pre 1989 ± 106 s; P-post 1986 ± 115 s) or on the performance of each 1 km split. The effect of ß-alanine on 20 km time trial performance was deemed unclear as determined by magnitude based inferences. Supplementation with 6.4 gâ¢d-1 of ß-alanine for 4 weeks did not affect 20 km cycling time trial performance in well trained male cyclists