Dietary sugar intake and risk of depression: findings from the TwinsUK cohort.

BACKGROUND: High intakes of sugars have been linked to depression, but few studies have accounted for both sugar and fat subtypes, which is important because many high-sugar foods also contain substantial fat. This study examined the association between dietary sugar intake and depression risk while accounting for multiple fat subtypes. METHODS: Using data from the UK TwinsUK cohort (cross-sectional analyses: n = 3029 in 2002 and n = 3452 in 2017; longitudinal analysis: n = 1485) associations between sugar intake and depression risk were examined at two time points and longitudinally. Depression was assessed using the Hospital Anxiety and Depression Scale (HADS) in 2002 and 2017, and dietary intake was estimated using a validated 120-item food frequency questionnaire at corresponding periods. Cross-sectional analyses used binary logistic regression to model HADS-defined depression cases, and longitudinal analyses used linear regression to examine change in HADS outcomes. Models were adjusted for total sugars and sugar subtypes, fat subtypes, age, body mass index, sex, Index of Multiple Deprivation and alcohol intake. RESULTS: Higher total sugar intake was associated with greater odds of HADS-defined depression in 2002 (odds ratio (OR) 1.34 per 100 g, 95% confidence interval (CI) 1.07 to 1.68) and 2017 (OR 1.41 per 100 g, 95% CI 1.21 to 1.65). In longitudinal analyses, increasing sugar intake was associated with higher HADS scores over follow-up (b 0.63, 95% CI 0.10 to 0.99). CONCLUSIONS: Higher sugar intake was associated with higher depressive symptom scores, independent of fat subtypes, and may reflect broader dietary patterns including higher consumption of ultra-processed foods. Further randomised controlled trials are needed to determine whether reducing dietary sugar intake can improve depressive symptoms.