Associations of diet quality and daily free sugar intake with depressive and anxiety symptoms among Chinese adolescents

Background: Assessing diet quality has been challenging, and the associations of diet quality and daily free sugar intake with depressive and/or anxiety symptoms have shown inconsistency.

Methods: A total of 1749 students aged 12-16 years were recruited using stratified random cluster sampling across three cities in China. The overall Global Dietary Recommendations (GDR) score, a novel indicator of diet quality, was constructed using the low-burden Diet Quality Questionnaire. Free sugar intake, including from beverages and foods, was measured using the Food Frequency Questionnaire. Daily free sugar intake was divided into low, medium, and high categories based on the latest version of the dietary guidelines for Chinese residents. Binomial and multinominal logistic regression analyses were used to examine the associations of the overall GDR score and daily free sugar intake categories or different sources of free sugar intake with depressive and/or anxiety symptoms.

Results: The overall GDR score was negatively associated with depressive symptoms (adjusted odds ratio[aOR] = 0.92, 95%CI: 0.87-0.98) and anxiety symptoms (0.95, 0.90-0.99), particularly with comorbid depression and anxiety (0.90, 0.84-0.97). Conversely, daily free sugar intake was positively associated with symptoms of depression and/or anxiety, the multiple aOR for symptoms depression or anxiety were significantly increased with higher daily free sugar intake (all P_trend < 0.05). Both free sugar from beverages and from foods were positively associated with depressive and/or anxiety symptoms. These associations were consistent between males and females.

Limitations: Cross-sectional design and self-reported symptoms.

Conclusions: Diet quality was negatively associated with symptoms of depression or anxiety, especially with comorbid symptoms among adolescents. Daily free sugar intake, regardless of its sources, was positively associated with symptoms of depression and/or anxiety.