Mental health benefits of almond intake: novel insights from the ZOE PREDICT 3 cohort

Dietary factors, particularly nut consumption, play an important role in health outcomes. Nuts, including almonds, have been studied for their cardiovascular benefits due to their nutrient density, favourable lipid profiles, and antioxidant content (1) . Their high content of unsaturated fats, fibre, vitamin E, riboflavin, and magnesium may also exert neuroprotective effects and support mood regulation. Despite evidence linking overall nut consumption to cognitive and mood outcomes(2-3), research examining the impact of nuts on mental health—and almonds specifically—remains limited. Therefore, this study aims to examine associations between almond intake and a range of mental health outcomes in the ZOE PREDICT 3 cohort. We conducted a cross-sectional analysis of 163,015 UK and US participants with complete dietary, mental health, and covariate data from the ZOE PREDICT 3 cohort (ClinicalTrials.gov identifier: NCT04735835). Almond intake was assessed via food frequency questionnaire and analysed both as a continuous variable (g/day) and as categorical groups (none; tertiles 1–3 defined separately for the UK and US sub-cohorts). Mental health outcomes included a composite measure of overall mental health, broader subcategories of psychiatric/psychological and neurological/neurodegenerative conditions, 17 specific DSM-5 diagnostic categories, and a composite comorbidity measure. Associations were evaluated using Firth logistic regression to address rare outcomes and separation issues, adjusting for demographic, lifestyle, clinical and dietary covariates. Trend analyses were performed using median intake per category. All models were corrected for multiple comparisons using false discovery rate (FDR) adjustment. In fully adjusted models, higher almond intake, when modelled continuously (g/day, including non-consumers), was associated with lower odds of neurological/neurodegenerative conditions (n=5,721; OR=0.94; 95% CI:0.91–0.97; FDR p < 0.001), but showed no association with psychiatric outcomes (n=25,025; OR=0.998; 95% CI:0.99–1.01; FDR p=0.68). However, categorical analyses indicated a small but consistent dose–response trend, with higher almond intake associated with slightly lower odds of psychiatric conditions per category increase relative to non-consumers (OR=0.995; 95% CI:0.991–0.999; p=0.009). Subtype analyses showed that higher almond intake was associated with lower odds of anxiety disorders (n=7,360; OR=0.94; 95% CI:0.91–0.97; FDR p < 0.001) and somatic symptom disorders (n=462; OR=0.97; 95% CI:0.95–0.99; FDR p=0.03). Associations with depressive disorders (n=11,696; OR=0.98; 95% CI:0.96–0.997; unadjusted p=0.03; FDR p=0.16) and obsessive–compulsive disorders (n=590; OR=0.91; 95% CI:0.83–0.998; unadjusted p=0.045; FDR p=0.19) were nominally significant but did not survive FDR correction. No associations were observed for other mental health subtypes. These findings suggest that almond intake is associated with a reduced likelihood of anxiety-related conditions and support the inclusion of almonds as part of a healthy diet. As this study is cross-sectional, causal inference is not possible. Ongoing work will investigate underlying mechanisms, including gut–microbiome pathways, while future longitudinal studies are needed to establish causality.