Mehrnoosh Khodaeian1, Ozra Tabatabaei-Malazy2, Mostafa Qorbani3,4, Farshad Farzadfar4, Peyvand Amini5, Bagher Larijani1. 1. Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. 2. Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. 3. Department of Community Medicine, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran. 4. Non-Communicable Disease Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran university of Medical Sciences, Tehran, Iran. 5. Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA.
Abstract
BACKGROUND: Data regarding the effect of vitamin C (VC) and vitamin E (VE) supplementation on insulin resistance in type 2 diabetes mellitus (T2DM) are controversial. We aimed to systematically review the current data on this topic. MATERIALS AND METHODS: All randomized controlled trials (RCTs) conducted to assess the effect of VC and/or VE on insulin resistance in diabetes published in Google Scholar and PubMed web databases until January 2014 were included. Exclusion criteria were studies conducted in animal, type 1 DM, children or pregnant women. Main outcome measure was insulin resistance by homoeostasis model assessment (HOMA) index. According to degree of heterogeneity, fixed- or random-effect model was employed by stata software (11.0). RESULTS: We selected 14 RCTs involving 735 patients with T2DM. VE or mixture-mode supplementation did not have any significant effect on HOMA with a standardized mean difference (SMD): 0·017, 95% CI: -0·376 to 0·411 (P = 0·932); and SMD: -0·035, 95% CI: -0·634 to 0·025 (P = 0·070), respectively, by random-effect model. VC supplement alone did not improve insulin resistance with a SMD: -0·150, 95% CI: -0·494 to 0·194 (P = 0·391), by fixed-effect model. Meta-regression test demonstrated that HOMA index may have not been influenced by the year of publication, dosage or duration of treatment. CONCLUSIONS: The sole intake of VC, VE or their combination with other antioxidants could not improve insulin resistance in diabetes.
BACKGROUND: Data regarding the effect of vitamin C (VC) and vitamin E (VE) supplementation on insulin resistance in type 2 diabetes mellitus (T2DM) are controversial. We aimed to systematically review the current data on this topic. MATERIALS AND METHODS: All randomized controlled trials (RCTs) conducted to assess the effect of VC and/or VE on insulin resistance in diabetes published in Google Scholar and PubMed web databases until January 2014 were included. Exclusion criteria were studies conducted in animal, type 1 DM, children or pregnant women. Main outcome measure was insulin resistance by homoeostasis model assessment (HOMA) index. According to degree of heterogeneity, fixed- or random-effect model was employed by stata software (11.0). RESULTS: We selected 14 RCTs involving 735 patients with T2DM. VE or mixture-mode supplementation did not have any significant effect on HOMA with a standardized mean difference (SMD): 0·017, 95% CI: -0·376 to 0·411 (P = 0·932); and SMD: -0·035, 95% CI: -0·634 to 0·025 (P = 0·070), respectively, by random-effect model. VC supplement alone did not improve insulin resistance with a SMD: -0·150, 95% CI: -0·494 to 0·194 (P = 0·391), by fixed-effect model. Meta-regression test demonstrated that HOMA index may have not been influenced by the year of publication, dosage or duration of treatment. CONCLUSIONS: The sole intake of VC, VE or their combination with other antioxidants could not improve insulin resistance in diabetes.
Authors: Maria E Balbi; Fernanda S Tonin; Antonio M Mendes; Helena H Borba; Astrid Wiens; Fernando Fernandez-Llimos; Roberto Pontarolo Journal: Diabetol Metab Syndr Date: 2018-03-14 Impact factor: 3.320