Academic journal article Iranian Journal of Public Health

Effects of Omega-3 Fatty Acids Supplement on Antioxidant Enzymes Activity in Type 2 Diabetic Patients

Academic journal article Iranian Journal of Public Health

Effects of Omega-3 Fatty Acids Supplement on Antioxidant Enzymes Activity in Type 2 Diabetic Patients

Article excerpt


Chronic diseases account for two-third of deaths in the world (1). The major chronic diseases are cardiovascular diseases, cancer, chronic respiratory disease, and diabetes (2). Diabetes mellitus is known as one of the major causes of death (3), and could lead to cardiovascular diseases and cancer (4). Estimations suggest that 285 million people were affected with diabetes in 2010 which will increase to 439 million in 2030 (5).

Diabetes is associated with increased oxidative damage mainly due to hyperglycemia (3), which could be the main contributors to cardiovascular diseases, cancer and diabetes itself (4). Antioxidant defense includes enzymatic and nonenzymatic path ways. There are quite a number of non-enzymatic antioxidants, namely vitamins (A), ascorbic acid, tocopherol, enzyme cofactors (Q10), nitrogen compounds (uric acid), and peptides (glutathione) (6). Common enzymatic strategies are super oxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (7). Oxidative enzymes activity is changed in diabetes, which could be a target for antioxidant therapy (8).

Long chain omega-3 fatty acids may reduce mortality in diabetic patient's trough reduction of blood triglycerides, platelet aggregability and improving endothelial functions (9). As omega-3 PUFAs decrease blood triglyceride and fatty acids (10, 11), increasing some oxidant cleavage pathways, they maybe act as antioxidants (12). Whether omega-3 PUFAs can reduce the oxidative damage is not clearly understood; moreover, some studies believe that they will increase prooxidative conditions (13).

This research project studied the effect of omega-3 supplementation on antioxidant enzymes including SOD, GPx, GR, catalase, and total antioxidant capacity (TAC) in erythrocytes of diabetic patients.

Materials and Methods

A randomized, placebo controlled, double blind clinical trial was performed on 90 type2 diabetic patients. Subjects were members of the Iranian Diabetic Association diagnosed as diabetic by the Association's physician. The inclusion criteria were not taking omega-3 or other nutritional supplements; not taking insulin; absence of renal, hepatic, and cardiovascular diseases or cancer. Data on anthropometric measurements and 24-hour recalls was taken by a nutritionist before and after treatment. A questionnaire was designed to obtain demographic information and medical and therapeutic regimen history, and fulfilled by face-toface interview at baseline and at the end of the study. Fasting blood samples (after 12-14 hours of overnight fasting) were taken before and after the intervention between 8 and 10 a.m. before taking any hypoglycemic drugs.

Based on the results of previous studies on omega-3 supplementation on diabetic patients, a dosage of 2714 mg per day was prescribed for two mo (14). It was provided in the form of three capsules, one with every meal. Capsules were made in PBL company, US and totally provided 2714mg (EPA=1548 mg, DHA=828 mg and 338 mg of other omega=3 fatty acids) per day. Placebo was provided especially for our study by Zakaria Company, Iran. It contained 2100 mg sunflower oil (12% SFA, 65% linoleic acid, 23% MUFA), which is the main oil used in the study population (15). Twenty-four-hour dietary recall data were analyzed by Food Processor ver.2 software. The subjects were asked periodically if they were following study protocols and if there were any changes in food habits, physical activity or therapeutic regimen. Changes would result in exclusion from the study, but no changes were reported.

Biochemical analysis

Red blood cells were separated by centrifugation at 3000 rpm for 10 min and washed with 9 g/l NaCl solution for three times. The hemolysates were stored at -70 °C for testing for enzymes. Catalase activity was measured by Abei method (16). Glutathione peroxidase was determined by paglia method (17) and glutathione reductase by the method of Goldberg (18). …

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