Stage-Dependent Cognitive Effects of a Multinutrient Intervention in Alzheimer's Disease: A Stage-Stratified Meta-Analysis

= 41.8%). For biomarker-confirmed prodromal AD, the 24-month primary neuropsychological test battery (NTB) 5-item composite endpoint showed a small, nonsignificant effect (SMD = 0.16; 95% CI, -0.08 to 0.41; original trial p = 0.166). The primary NTB memory endpoint in mild, drug-naive AD showed a small effect (SMD = 0.21; 95% CI, -0.06 to 0.49; original longitudinal-model p = 0.023), whereas the primary Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog) endpoint in treated mild-to-moderate AD showed no benefit (SMD = -0.06; 95% CI, -0.25 to 0.13; p = 0.513). At 36 months, the LipiDiDiet extension reported significant differences in the NTB 5-item composite, clinical dementia rating - sum of boxes (CDR-SB), memory, and brain-volume outcomes. The intervention was well tolerated. The evidence is compatible with a potential early-stage signal, but the small evidence base, lack of replication across stages, and manufacturer sponsorship warrant cautious interpretation.