Serum Zinc-Alpha-2 Glycoprotein and Zinc Levels and Their Relationship with Insulin Resistance and Biochemical Parameters in Overweight and Obese Children.

The biological role of zinc-alpha 2-glycoprotein (ZAG) has been associated with lipid mobilization, although this is not entirely clear. The study's aim was to examine the serum levels of ZAG and zinc (Zn) and the Zn/ZAG in a population of children with overweight (OW) and obesity (OB), and their relationship with biochemical parameters. Our study was a cross-sectional analysis of a group of Mexican children aged 6-10 (n = 72). We analyzed anthropometric data and biochemical parameters, including fasting plasma glucose (FPG), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides (TG), total cholesterol (TC), insulin, and homeostatic model assessment insulin resistance (HOMA-IR). ZAG protein levels were measured using enzyme-linked immunosorbent assay (ELISA), and serum zinc (Zn) levels were quantified using inductively coupled plasma mass spectrometry (ICP-MS). The Zn values indicate a statistically significant difference between normal weight (NW) and OW/OB children with Zn concentrations were 91 µg/dL for NW and 66 µg/dL for OW/OB children. ZAG values did not show significant differences between NW and OW/OB, and values were 2.1 mg/dL and 2.3 mg/dL, respectively. The Zn/ZAG ratio was lower in the OW/OB compared to the NW (p = 0.05). Correlations were found between FPG and Zn (p = 0.004) in NW boys, and ZAG (p = 0.046) in OW/OB boys, as well as a negative correlation between insulin and Zn in NW children of both sexes. HOMA-IR shows correlations between Zn (p = 0.008) in OW/OB boys, and ZAG (p = 0.010) in the OW/OB girls. Additionally, correlations were observed between LDLc, TG, and BMIz with Zn and ZAG in the boys. In the same way, we also found that girls with OW/OB had a Zn/ZAG ratio of - 2.32 (p = 0.043) compared to NW boys. In conclusion, our findings highlight the significant roles of Zn and ZAG in glucose and lipid metabolism. Furthermore, Zn/ZAG ratio may provide insights into nutritional deficiencies, adiposity, and metabolic health. However, further studies are necessary to validate our results.