Fruit Intake and Alzheimer's Disease: Results from Mendelian Randomization

Alzheimer's disease (AD) is the leading cause of dementia in old age, recognized as a global health priority. To explore causal effects of fresh fruit intake and dried fruit intake on AD liability, this study utilized GWAS from the UK Biobank and FinnGen to conduct Mendelian randomization (MR) analysis, and used inverse variance weighted (IVW), MR-Egger, and weighted median approaches for MR estimates, and visual inspections judged result stability. Results suggested little evidence of a potential causal relationship between fresh fruit intake and AD (OR=0.97, 95%CI=0.50-1.91, P=0.939), while significant, robust causality was indicated between dried fruit intake and AD (OR=4.09, 95%CI=2.07-8.10, P<0.001). Stability evaluations showed no heterogeneity or pleiotropy affecting interpretability and credibility of primary analyses. In conclusion, we strengthened evidence for positive causality from dried fruit intake to AD liability, with causality from fresh fruit intake on AD risk was not demonstrated.