Effect of a weight loss program on IGF-1 levels and symptoms of anxiety and depression in individuals with obesity

Abstract

Introduction: Exercise induces the secretion of molecules known as exerkines. These molecules include IGF-1, a hepatokine that plays a very important role in obesity, has neuroprotective effects and can ameliorate depression-like behaviors in animal models. Although IGF-1 may have a positive effect in preventing depression and improving brain function, its role in obesity and depression is complex. Therefore, it is important to investigate how its levels are modulated under an exercise and diet program in individuals with these three conditions simultaneously. Objective: To quantify serum IGF-1 levels in individuals with obesity and symptoms of anxiety and/or depression before and after a 3-month weight loss program (WLP). Methods: After signing an informed consent form (INR 114/24), blood samples were taken from 36 participants with diagnosed obesity (BMI ≥ 30 kg/m²). Body composition was analyzed using bioelectrical impedance (InBody) and the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) were performed. Based on the cut-off points of the BDI (≥10) and the BAI (≥6), two study groups were formed: a control group with obesity without symptoms of anxiety and/or depression before and after the intervention (n=19) and (n=19); and a group with symptoms of depression and anxiety before (Spre) (n=17) and without symptoms after the WLP (Spost) (n=15). Serum IGF-1 levels were quantified before and after the WLP by ELISA. Statistical analysis included the Kolmogorov-Smirnov test for normality and unpaired Student's t-test, with a p-value of <0.05 considered significant. Results: After the WLP, anthropometric parameters such as BMI and % body fat (BF) showed a significant decrease (p＜0.001), as did serum IGF-1 levels between groups. In this regard, the Cpost group showed a significant decrease in IGF-1 compared to Cpre (p=0.006). The Spost group, which showed improvement in symptoms of depression and/or anxiety, also showed a significant decrease in IGF-1 compared to Spre (p=0.010) and had similar levels to the Cpost group. Conclusion: The 3-month WLP resulted in an improvement in body composition (decrease in BMI, FM and maintenance of FM), which may have contributed to the decrease in serum IGF-1 levels and consequently to the improvement in anxiety and depression symptoms in the obese subjects.