Mahmoudabadi Mohammad Mehdi Shakouri, Rahbar Ali Reza
Department of Nutrition, School of Health, Mazandaran University of Medical Sciences, Mazandaran, Iran.
Department of Nutrition, The Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, I.R. Iran.
Oman Med J. 2014 Jan;29(1):39-45. doi: 10.5001/omj.2014.09.
The aim of this study is to investigate the effect of eicosapentaenoic acid combined with vitamin C in comparison with the pure form of eicosapentaenoic acid on the serum concentration of malondialdehyde, erythrocyte activity of superoxide dismutase, glutathione peroxidase, and the serum level of total antioxidant capacity in patients with type 2 diabetes.
Eighty one male diabetic patients, aged 33-63 years, were randomly assigned to one of 4 groups. The subjects consumed 500 mg/d pure eicosapentaenoic acid, 200 mg/d vitamin C, 500 mg eicosapentaenoic acid and 200 mg/d vitamin C or placebo depending on their groups. In fasting blood samples, superoxide dismutase and glutathione peroxidase activities were determined via the enzymatic method (Randox kit) and the serum total antioxidant capacity, malondialdehyde and vitamin C concentrations were estimated by colorimetric methods.
Administration of pure eicosapentaenoic acid in diabetic patients increased superoxide dismutase by 4%, glutathione peroxidase 53%, total antioxidant capacity 36% and decreased malondialdehyde significantly by 25%. Prescription of eicosapentaenoic acid combined with vitamin C demonstrated a significant increment for superoxide dismutase activity by 3% and for glutathione peroxidase activity by 52% during the study, but no significant change was seen for total antioxidant capacity and malondialdehyde, respectively. There was a significant decrease in FBS and HbA1c following prescription of eicosapentaenoic acid with/without vitamin C along the study, although these changes were not significant between the study groups.
It is concluded that prescription of eicosapentaenoic acid in the pure form reduces oxidative stress in type 2 diabetic patients; albeit, it does not alleviate hyperglycemia. Combination of vitamin C and eicosapentaenoic acid does not improve antioxidant property of eicosapentaenoic acid.
本研究旨在比较二十碳五烯酸（EPA）联合维生素C与单纯EPA对2型糖尿病患者血清丙二醛浓度、红细胞超氧化物歧化酶（SOD）活性、谷胱甘肽过氧化物酶（GSH-Px）活性以及血清总抗氧化能力的影响。
81名年龄在33至63岁之间的男性糖尿病患者被随机分为4组之一。根据分组情况，受试者分别每日服用500毫克纯EPA、200毫克维生素C、500毫克EPA加200毫克维生素C或安慰剂。空腹血样中，通过酶法（兰多克斯试剂盒）测定SOD和GSH-Px活性，采用比色法估算血清总抗氧化能力、丙二醛和维生素C浓度。
糖尿病患者服用纯EPA后，SOD增加4%，GSH-Px增加53%，总抗氧化能力增加36%，丙二醛显著降低25%。在研究期间，EPA联合维生素C的处方显示SOD活性显著增加3%，GSH-Px活性增加52%，但总抗氧化能力和丙二醛分别未见显著变化。在整个研究过程中，服用EPA加或不加维生素C后空腹血糖（FBS）和糖化血红蛋白（HbA1c）均有显著下降，尽管这些变化在研究组之间不显著。
得出结论，单纯形式的EPA处方可降低2型糖尿病患者的氧化应激；尽管如此，它并不能缓解高血糖。维生素C和EPA联合使用并不能改善EPA的抗氧化性能。
