|Roussel, Anne Marie|
Submitted to: Journal of American College of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2003
Publication Date: 5/7/2003
Citation: Roussel, A., Kerkeni, A., Zouari, N., Majoub, S., Matheau, J., Anderson, R.A. 2003. Antioxidant effects of zinc supplementation in tunisian people with type 2 diabetes mellitus. Journal of American College of Nutrition. 22:316-321 (2003) Interpretive Summary: Diabetes and elevated levels of blood sugars are accompanied by increased generation of harmful factors called free radicals that damage cells. The lack of control of blood sugar leading to glucose intolerance and ultimately diabetes is one of the leading causes of poor health. The incidence of diabetes is expected to double in the next two to three decades. This study demonstrated that improved intake of the dietary nutrient, zinc, decreased the levels of the damaging free radicals. Tunisian people with type 2 diabetes were supplemented with zinc and improvements were observed in the the levels of free radicals and also in factors that are involved in the distruction of these substances. This work is of potential benefit to the millions of people worldwide who have elevated levels of blood sugar.
Technical Abstract: Study was designed to determine the effects of zinc (Zn) supplementation on oxidative stress in people with type 2 diabetes mellitus (type 2 DM). Tunisian adult subjects with HbA1C > 7.5% were supplemented for 6 months with 30 mg/d of Zn as Zn gluconate or placebo. The effects of supplementation on plasma zinc (Zn), copper (Cu), urinary Zn, plasma thiobarbituric acid reactive substances (TBARS), Cu-Zn superoxide dismutase (SOD) in red blood cells, blood lipids and lipoproteins, HbA1C and fasting glucose were measured at the beginning of the study and after 3 and 6 months. At the beginning of the study, more than 30% of the subjects exhibited plasma Zn values less than the normal minimum of 10.7 mol/L, whereas levels of plasma Cu and antioxidant RBC Cu-Zn SOD enzyme activity were in the normal ranges. Oxidative stress, monitored by plasma TBARS, was increased in people with diabetes compared with healthy Tunisian subjects (3.32 ± 0.05 mol/L vs 2.08 ± 0.04 mol/L) and an inverse correlation was found between Zn plasma levels and plasma TBARS. After 3 and 6 months of Zn supplementation, all of the patients exhibited plasma Zn values greater than 10.7 mol/L. There was a decrease of plasma TBARS in Zn supplemented group after 6 months (15 %) with no significant changes in the placebo group. Supplementation did not alter significantly HbA1C nor glucose homeostasis. These data demonstrate the potential beneficial antioxidant effects of Zn supplementation in people with type 2 DM. These results are particularly important in light of the deleterious consequences of oxidative stress in people with diabetes.