LCT and Mental deterioration: Second, 24-h dietary recalls present inherent constraints: (1) recall bias, particularly in older adults with cognitive decline; (2) inadequate capture of daily/weekly dietary variations, potentially underestimating long-term microbiome impacts on gut microbiota and frailty risk (54, 55); and (3) discrepancies between reported intake and actual microbial nutrient exposure (e.g., lactase activity differences).