The association of plasma glutamate with food addiction in individuals with major depressive disorder.

BACKGROUND

Food addiction (FA) is more prevalent in individuals with major depressive disorder (MDD) and may contribute to the increased risk of obesity in MDD. Peripheral glutamate, an amino acid found in the blood and tissues, has been linked to mental health symptoms, substance use and obesity. It is implicated in problematic eating however its relationship to FA has been underexpored. This study investigated associations between glutamate and FA in individuals with and without MDD.

METHODS

Sixty-one individuals with MDD and sixty controls were recruited and sub-categorised based on criteria of the Yale Food Addiction Scale 2.0 (YFAS). At a clinic visit, participants underwent a diagnostic interview, anthropometric assessments (e.g., BMI, blood pressure, waist circumference), blood sampling, and completed psychological questionnaires. Plasma glutamate was analysed via ELISA kits. ANOVAs and correlations assessed between-group differences and variable relationships.

RESULTS

FA was present in 41 % of MDD participants compared to 3 % of controls. Individuals with MDD had higher plasma glutamate than controls. Glutamate levels positively correlated with FA severity, emotional and external eating, stress, and depressive symptoms. Subgroup analyses showed those with both MDD and FA had the highest glutamate levels, compared to other groups.

CONCLUSION

This study provides novel evidence that FA symptoms are associated with elevated peripheral glutamate, reinforcing emerging links between glutamate, disordered eating, and depression. These findings underscore the need for further research into glutamatergic mechanisms underlying comorbid MDD and FA to inform more targeted and effective treatment approaches.