Influence of oral beta-alanine and L-histidine supplementation on the carnosine content of the gluteus medius.

This study investigates whether the amount of carnosine (a naturally occurring amino acid) in a horse’s muscle fibers can be influenced by increasing the availability of beta-alanine (a non-essential amino acid) through supplementation. The findings highlight that prolonged beta-alanine supplementation increased its absorption and led to a significant growth of carnosine concentrations in the muscles. This suggests that in vivo carnosine synthesis depends considerably on beta-alanine, and increased muscle carnosine concentrations can enhance the muscle’s acid buffering capacity.

Supplementation and Data Collection

• The research involved six Thoroughbred horses whose diets were supplemented thrice a day with beta-alanine and L-histidine for 30 days. These supplements were selected as they are precursors to carnosine.
• Muscle tissue samples from the gluteus medius (a major muscle in horses) were collected both before and after the supplementation period for examination.
• Moreover, blood samples collected at various key points during the study helped determine the amounts of beta-alanine, histidine, and carnosine present in the plasma. The total amounts of these substances absorbed over a specified time were measured using an area under the curve (AUC) calculation.
• The carnosine levels in the different types of muscle fibers (types I, IIA, and IIB) were also evaluated.

Findings and Conclusion

• There was an observable adaptive response to sustained beta-alanine supplementation, which led to a significant rise in beta-alanine AUC, signifying increased absorption.
• However, the histidine AUC did not reflect a consistent rise during the supplementation period.
• Carnosine content in Type IIA and IIB muscle fibers increased considerably. Specifically, in Type IIA fibers, concentration increases were significant in two of the six horses, and in Type IIB, five out of the six horses showed significant increases.
• In conclusion, the changes in muscle carnosine concentration were determined to be influenced to a considerable extent by beta-alanine bioavailability. This was based on the significant correlation identified between individual increases in muscle carnosine concentration and changes in beta-alanine AUC.
• In addition to highlighting the importance of beta-alanine in carnosine synthesis, the research also pointed to the potential advantage of greater carnosine concentration: an enhanced capability for muscle tissue to buffer hydrogen ions (H+). Increased buffering capability might help to delay the onset of muscle fatigue during periods of intense exercise.