Effect of substituting saturated with monounsaturated fatty acids on serum visfatin levels and insulin resistance in overweight women: A randomized cross-over clinical trial

Objective: This study aimed to determine the effects of a monounsaturated fatty acids (MUFA)-rich diet on serum visfatin, interleukin-6 and insulin levels among overweight women. Design: In this randomized cross-over clinical trial, 17 premenopausal overweight women were included. Participants were randomly assigned to consume either a hypocaloric, saturated fatty acids (SFA)-rich diet (16% SFA and 8% MUFA) or a hypocaloric, MUFA-rich diet (16% MUFA and 8% SFA) for 12 weeks crossing over after a 2-week washout period. Percentages of energy from other macronutrients were similar between the two diets. Biochemical and anthropometric assessments were done at the first and at the end of each period. Statistical analyses were done using paired t-test. In all statistical analysis, p < 0.05 was considered as significant. Results: The participant's mean body mass index was 27.6 kg/m(2). Mean percentages of MUFA intake were 13% during MUFA-rich diet and 7% during SFA-rich diet. The corresponding values for SFA intake were 8.5% and 14%, respectively. We failed to find any significant differences between two intervention diets in terms of their effect on the serum levels of IL-6, visfatin and insulin. However, serum visfatin and IL-6 levels increased during the SFA-rich diet (0.4 +/- 0.4 ng/ml and 0.19 +/- 0.3 pg/ml, respectively) and decreased during the MUFA-rich diet (-0.7 +/- 0.5 ng/ml and -0.17 +/- 0.3 pg/ml, respectively). In spite of a slight reduction in both periods, changes in serum insulin levels did not reach significant levels comparing the two periods. Conclusions: Our findings did not support any significant effect of a MUFA-rich intake on serum IL-6 and insulin levels as compared with a SFA-rich diet; however, it has the potential to favourably affect serum visfatin levels.