Carnosine supplementation improves cognitive outcomes in younger participants of the NEAT trial

Some prior studies suggested that supplementation with carnosine or β-alanine can improve cognitive abilities and neurodegenerative disorders in certain elderly or at-risk populations. However, the efficacy of carnosine in improving cognitive performance in a healthy, adult population has not been assessed. We examined this as a post-hoc secondary outcome in the placebo-controlled, randomized Nucleophilic Defense Against PM Toxicity (NEAT) clinical trial (NCT03314987). Participants in this trial were instructed to take either cornstarch (placebo) or carnosine capsules (2g daily) for up to 12wk. Cognitive ability was assessed using the Cognition test battery, which consists of ten individual tests known to engage specific brain systems and covering a range of cognitive domains. Speed, accuracy, and efficiency were obtained for the whole battery as well as for each of the ten individual tests. Participant testing occurred at baseline, prior to randomization, after approximately 6wk of supplementation (Follow-up-1), and after approximately 12wk of supplementation (Follow-up-2). Of the 299 participants who were randomized, we obtained useable measures for 242 participants at Follow-up-1 and 231 ​at Follow-up-2. Age-based stratification (23-35 years, 36-50 years, 51-65 years), showed statistically significant improvements in overall speed and efficiency in the youngest age group stratum at both follow-up visits. This same group also demonstrated significant improvements in seven speed or accuracy scores of the individual tests. The other age groups demonstrated few or no significant improvements. Thus, in a study population largely devoid of susceptibility factors or pre-existing conditions, carnosine supplementation selectively improved high-level cognitive performance in young individuals.