Selenium intake reduces serum C3, an early marker of metabolic syndrome manifestations, in healthy young adults

Objectives: To evaluate the associations between serum complement factor 3 (C3) and several anthropometrical, biochemical and lifestyle features in healthy young adults, emphasizing on the putative effect of selenium intake on C3 concentrations. Methods: This study enrolled 100 healthy young adults aged 18-34 years. Anthropometric and blood pressure measurements and lifestyle features were analyzed. Fasting blood samples were collected for the measurement of glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerols and C3 concentrations. Nail samples were collected for the analysis of selenium concentrations. Results: Values of BMI (P = 0.034), sum of skinfold thicknesses (STs) (P = 0.021), body fat mass (BFM) (P = 0.023), percentage of overweight subjects (P = 0.007), serum triacylglycerols (P = 0.012) and nail selenium (P = 0.001) were significantly different between subjects above and below the median of serum C3 concentrations. The following correlations with serum C3 were identified tricipital ST (P = 0.033), sum of STs (P = 0.012), BMI (P = 0.008), BFM (P = 0.018), waist-to-height ratio (P = 0.016), serum glucose (P = 0.045), serum triacylglycerols (P = 0.001) and nail selenium (P = 0.006). Circulating C3 showed a positive association with several adiposity markers such as BMI (P = 0.001), waist circumference (P = 0.006), waist-to-height ratio (P = 0.002), BFM (P = 0.025), as well as serum glucose (P = 0.027) and triacylglycerols (P < 0.001), whereas nail selenium was a statistically significant negative predictor of C3 concentrations (P = 0.018). Conclusions: C3 seems to be related with selenium status and several anthropometrical and biochemical measurements linked to metabolic syndrome in apparently healthy young adults. These findings suggest a possible role for selenium intake in the modulation of C3, whose assessment may be an early marker of metabolic syndrome manifestations. European Journal of Clinical Nutrition (2009) 63, 858-864; doi:10.1038/ejcn.2008.48; published online 5 November 2008