Plasma concentration of IL-6 and TNF-α and its relationship with zincemia in obese women

Objective: In obesity, the excessive adipose tissue increases the synthesis of inflammatory cytokines, which appear to alter the metabolism of minerals, such as zinc. However, the mechanisms involved remain unclear. This study investigated whether the concentrations of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in plasma can to influence biochemical parameters of zinc in obese women. Methods: Seventy-six pre-menopausal women, aged between 20 and 50 years, were divided into two groups: the case group, composed of obese women (n = 37) and the control group, composed of non-obese women (n = 39). Analysis of the plasmatic and erythrocytary zinc, and plasmatic cytokines were conducted by flame atomic absorption spectrophotometry and by ELISA, respectively. Results: The plasmatic zinc and concentrations of IL-6 in plasma did not show significant differences between obese women and controls (p>0.05). The erythrocytary zinc was 36.4 +/- 15.0 mu g/gHb in the case group, and 45.4 +/- 14.3 mu g/gHb (p = 0.025) in the control group. The concentrations of TNF-alpha in plasma were 42.0 +/- 11.9 pg/mL and 19.0 +/- 1.0 pg/mL in obese women and in controls, respectively (p<0.001). The plasmatic zinc had a significant negative correlation with the values of TNF alpha (r = -0.44, p = 0.015). Conclusion: Obese women presented lower concentrations of erythrocytary zinc than the control group. The study demonstrated a probable influence of the inflammatory process on metabolism of zinc in obese patients. (C) 2013 Elsevier Editora Ltda. All rights reserved.