Major Depressive Disorder, Inflammation, and Nutrition: A Tricky Pattern?

Major depressive disorder (MDD) is a psychiatric disease associated with inflammation. The Western diet (WD) is a high-fat, high-sugar diet also associated with inflammation. We aimed to show whether the diet of MDD patients was a WD and could act as a risk factor in this context. We conducted a transversal study of MDD patients and controls (CTRLs) without comorbidities. We performed blood analyses including C-reactive protein (CRP), a diet anamnesis, and an advanced glycation end-product assessment. We found that 34.37% of MDD patients had a CRP level above 3 to 10 mg/L, which remained higher than CTRLs after adjustments (sex, BMI, age, smoking status). The MDD patients had an excess of sugar and saturated and trans fatty acids; a deficiency in n-3 polyunsaturated fatty acid, monounsaturated acid, dietary fibers, and antioxidants; a high glycemic load; and aggravating nutritional factors when compared to the CTRLs. We found correlations between nutritional factors and CRP in univariate/multivariate analysis models. Thus, MDD patients showed an elevated CRP level and a WD pattern that could contribute to sustaining an inflammatory state. Further studies are required to confirm this, but the results highlighted the importance of nutrition in the context of MDD.