The effects of a weight loss diet with or without prebiotic supplementation on anthropometric measures, metabolic and inflammatory status, gut permeability, endotoxemia and depression status in obese women suffering from major depressive disorder

Abstract

Background and Objectives: Major depressive disorder (MDD) is a common psychiatric disorder, closely associated with obesity and metabolic syndrome; inflammation is a linking element between MDD and obesity. Gut microbiota dysbiosis, observed in both MDD and obesity, leads to endotoxemia and inflammatory status, eventually exacerbating depressive symptoms. Manipulation of gut microbiota by prebiotics might help alleviate depression. The present study aimed to investigate the effects of a calorie-restricted diet combined with inulin supplementation on anthropometric measures, metabolic and inflammatory status, gut permeability, endotoxemia and depression status in obese women with MDD. Methods and Materials: In this double-blind placebo-controlled randomized clinical trial, 62 obese women with MDD were allocated to receive 10 g/day of either oligofructose-enriched inulin (OE-inulin) or placebo (maltodextrin) for eight weeks; all the patients also followed a 25% calorie-restricted diet. Anthropometric measures, dietary intakes, physical activity, resting metabolic rate (RMR), and blood pressure of the patients were assessed pre- and post-intervention. Depression and anxiety status of the participants were evaluated using Hamilton depression rating scale (HDRS), Beck depression inventory (BDI-II), World Health Organization- five well-being index (WHO-5), and Spielberger state-trait anxiety inventory form Y (STAI-Y). After 12 h overnight fasting, venous blood samples of the patients were taken at baseline and endpoint of the study to measure fasting serum levels of blood sugar (FBS), insulin, Homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile, zonulin, lipopolysaccharide (LPS), inflammatory biomarkers (Tumor necrosis factor-α; TNF-α, Interleukin-10; IL-10, and high sensitivity C-reactive protein; hs-CRP), and brain-derived neurotrophic factor (BDNF). Results: Forty-five patients completed the trial (prebiotic group (n)=22; placebo group (n)=23). Energy and macronutrients intakes decreased significantly in both study groups by the end of study (P<0.001). Physical activity of the patients did not change significantly in neither of the groups, throughout the study. A significant decrease was observed in both groups in terms of body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), systolic blood pressure, and HDRS scores, compared to baseline; however, the between-group differences in the mean changes of all these parameters were non-significant post-intervention. Total cholesterol (TC) significantly decreased only in the prebiotic arm, while the within-group changes were non-significant for the other components of lipid profile, FBS, insulin, HOMA-IR, LPS, zonulin, inflammatory biomarkers, and BDNF in both prebiotic and placebo groups; no significant between-group differences were found for these parameters by the study endpoint, either. Stratified by the median weight loss of the whole study sample, those who lost ≥1.9 kg of their body weight, showed significantly improved HDRS score (P=0.013) and TC (P=0.013), compared to women with <1.9 kg weight reduction, irrespective of the supplement they took. Conclusion: Prebiotic supplementation (10 g/day) for eight weeks had no significant beneficial effects compared to placebo, on anthropometric measures, metabolic parameters, and serum biomarkers of gut permeability, endotoxemia, inflammation, or BDNF among obese women with MDD. Greater weight loss led to significant improvement in depression status and TC, though. These findings indicate that obese depressed women might more likely benefit from dietary interventions than nutritional supplements. Further investigations with longer durations, other types or higher dosages of prebiotics, and including a control group receiving only the prebiotic supplement and general dietary recommendations (but not a calorie-restricted diet), are warranted to more vividly elucidate the probable beneficial effects of calorie restriction and prebiotic supplementation on depressive symptoms.