Background and Objectives: Brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1) have a wide range of biological activities that are influenced by childhood obesity. Therefore the purpose of this study was to examine the effects of 8 weeks of vitamin C intake and regular aerobic exercise on serum BDNF and IGF-1 levels in obese girls.

Materials & Methods:  In this quasi-experimental research, 28 obese girls were selected and randomly divided into four equal groups as follows: control, exercise, vitamin C, and combined. Aerobic exercise was carried out at 50% to 70% maximal heart rate and 3 sessions per week for 8 weeks. The vitamin C and combined groups consumed 500mg vitamin C tablets 3 times per week. Fasting blood samples were collected before and 48 hours after the last interventions. Serum BDNF and IGF-1 levels were measured by ELISA and enzyme immunoassay methods, respectively.

Results:  For the vitamin C, exercise and combined intervention groups, the levels of BDNF after 8 weeks were increased and the IGF-1 levels were reduced. Furthermore, all the three interventions were associated with significantly greater percent changes in the BDNF and IGF-1 levels than in the control group, but the effect of combined intervention on IGF-1 percent changes was only greater in comparison to the other interventions (p<0.05).

Conclusion: The favorable effects of the independent and combined interventions of aerobic exercise and vitamin C intake may be partly mediated by the impact of these interventions in regulation of the growth factors‘(BDNF and IGF-1) levels. But the combined intervention could further reduce IGF-1 levels in comparison to other interventions.

Key words: Aerobic exercise, Brain-derived neurotrophic factor, Insulin-like growth factor-1, Vitamin C