The role of diet in moderating the relationship between symptoms of depression and brain amyloid load

BACKGROUND: Healthy lifestyle factors, including diet, may affect brain amyloid beta (Aβ) load. This study examines dietary patterns as moderators of the relationships among symptoms of depression, anxiety, and brain Aβ load. METHOD: A cross-sectional study of cognitively unimpaired older adults (n = 524) from the Australian Imaging, Biomarkers, and Lifestyle study assessed dietary patterns, depressive and anxiety symptoms, and brain Aβ load. Moderation and simple slope analyses were conducted. RESULTS: The Dietary Approaches to Stop Hypertension (DASH) diet moderated the relationship between depressive and anxiety symptoms and brain Aβ load. Higher symptoms were associated with greater Aβ load in individuals with lower DASH adherence. This effect was also observed for anxiety symptoms in apolipoprotein E ε4 carriers. The Mediterranean and Western diets did not moderate these relationships. CONCLUSION: The DASH diet adherence may mitigate the impact of depressive and anxiety symptoms on brain Aβ load, supporting genotype-specific dietary interventions in mental and brain health. Highlights: The Dietary Approaches to Stop Hypertension (DASH) diet moderates the links among depression, anxiety, and brain amyloid load. Higher symptoms were linked to greater amyloid load in those with low DASH adherence. This effect was observed for anxiety symptoms in apolipoprotein E ε4 allele carriers. Mediterranean and Western diets did not moderate these relationships. Findings support genotype-specific dietary interventions for brain and mental health.