Histidine-containing dipeptide supplementation improves delayed recall: a systematic review and meta-analysis

Abstract Context Histidine-containing dipeptides (carnosine, anserine, beta-alanine and others) are found in human muscle tissue and other organs like the brain. Data in rodents and humans indicate that administration of exogenous carnosine improved cognitive performance. However, RCTs results vary. Objectives To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) of histidine-containing dipeptide (HCD) supplementation on cognitive performance in humans to assess its utility as a cognitive stabiliser. Data Sources OVID Medline, Medline, EBM Reviews, Embase, and Cumulative Index to Nursing and Allied Health Literature databases from 1/1/1965 to 1/6/2022 for all RCT of HCDs were searched. Data Extraction 2653 abstracts were screened, identifying 94 full-text articles which were assessed for eligibility. Ten articles reporting the use of HCD supplementation were meta-analysed. Data Analysis The random effects model has been applied using the DerSimonian-Laird method. HCD treatment significantly increased performance on Wechsler Memory Scale (WMS) −2 Delayed recall (Weighted mean difference (WMD) (95% CI (CI)) = 1.5 (0.6, 2.5), P