Evaluation of the effect of caloric restriction on serum BDNF in overweight and obese subjects: preliminary evidences.

Unlabelled: Brain-derived neurotrophic factor (BDNF) has emerged as a new element related with insulin resistance and obesity.

Objective: To evaluate the effect of a 3-month reduced-calorie diet (RCD) on serum BDNF concentrations in overweight and obese subjects.

Subjects: Seventeen healthy overweight and obese subjects of both sexes (24 - 48 years, BMI 34.6 +/- 1.1 kg/m2).

Methods: Anthropometry, oral glucose tolerance test (OGTT), lipid levels, and serum BDNF were measured at baseline and at the end of the third month. Reduced-calorie diet was defined as a 25% reduction in energy intake composed of: 55% carbohydrates, 20% proteins, and 25% fat (less than 10% saturated fat and over 10% nonsaturated fat). Refined sugar was not allowed.

Results: There was a significant decrease in BMI, waist circumference, body fat percentage, fasting glucose, post-OGTT glucose levels, area under the curve of glucose, and HOMA2-IR after 3 months of RCD. Serum BDNF showed a significant increase (3.97 +/- 0.87 to 6.75 +/- 1.62 ng/ml, P = 0.02). Final serum BDNF correlated negatively with weight (r = -0.51, P = 0.03), and basal post-OGTT insulin correlated positively with final serum BDNF (r = 0.48, P = 0.04).

Conclusions: Serum BDNF increases in insulin-resistant overweight and obese subjects after three months on a RCD. This observation could indicate that BDNF may be modulated in humans through diet composition.