The Association between Brain-Derived Neurotrophic Factor (BDNF) Protein Level and Body Mass Index

Background and Objectives: Obesity is a major health concern worldwide. Many studies emphasize the important role of brain-derived neurotrophic factor (BDNF) in regulating appetite and body weight. We aimed to investigate the association between BDNF protein serum levels and body mass index (BMI). Materials and Methods: We conducted a cross-sectional study among 108 healthy adult participants divided into six categories depending on their body mass index (BMI). The ages of the participants ranged between 21 to 45 years. The BDNF serum level was measured using the enzyme-linked immunosorbent assay (ELISA) technique. Results: A Kruskal–Wallis test showed a significant difference in BDNF between the different BMI categories, χ(2)(2) = 24.201, p < 0.001. Our data also showed that BDNF levels were significantly lower in people with obesity classes II and III than those of normal weight (p < 0.05). The Spearman rank correlation test was statistically significant with negative correlations between the BMI and BDNF (r) = −0.478, (p < 0.01). Moreover, we observed a negative dose-dependent relationship pattern between BMI categories and the levels of circulating BDNF protein. Conclusions: In this study, our data support the hypothesis that low serum levels of BDNF are associated with high BMI and obesity in Saudi adults.