Objective: To observe the effects of high level Zn intake on zinc (Zn) copper (Cu), lipids metabolism and antioxidation function in man so as to provide scientific basis for Zn supplementation.
Methods: 40 rural healthy men were chosen and tablets of 50 mg Zn (as 0.2 g of zinc glucose) per day was taken by them for eight weeks. All subjects were checked up for five times: at week 0, 2, 4, 8 during the period of Zn supplementation and at week 12 and their serum, RBC, hair, and 24h-urine were collected for assays at the same time.
Results: (1) Zn contents in serum, RBC and hair increased significantly after 2 to 4 weeks supplementation and decreased at 4 weeks after stopping supplementation, but they were still higher than those before supplementation. Zn contents in 24h-urine increased significantly after supplementation and decreased at 4 weeks after stopping supplementation to the same level as before supplementation. (2) Cu contents in serum, RBC and hair increased significantly after 4 weeks supplementation and decreased at 4 weeks after stopping supplementation. Cu contents in 24h-urine did not change significantly during experiment. (3) RBC superoxide dismutase (SOD) activities were decreased persistently after 2 weeks supplementation and were not recovered at 4 weeks after stopping supplementation. RBC glutathione peroxidase (GPX) activities increased significantly after 4 weeks supplementation. The content of lipid peroxide (LPO) increased significantly after 2 weeks supplementation. (4) Total cholesterol (TC), triglyceride (TG), Low density lipoprotein cholesterol (LDL-C) and apolipoprotein B100 (ApoB100) increased significantly, high density lipoprotein cholesterol (HLD-C) and apolipoprotein A1 (ApoA1) decreased after supplementation.
Conclusion: When healthy men received 50 mg Zn supplement per day, it might interfere Zn, Cu and lipids metabolism and inhibit antioxidation process.