Erythrocyte Antioxidant Enzymes in Overweight Thai

The specific activities of antioxidant enzymes, [eg superoxide dismutases (SOD), glutathione peroxidase (GPX) and catalase (CAT)], anthropometric measurements, including waist/hip ratio of 48 male and 167 female overweight persons (body mass index (BMI) ≥25.0 kg/m) compared with a 26 male and 80 female control group (BMI = 18.5-24.9 kg/m) of Thai volunteers who attended the Out-patient Department, General Practice Section, Rajvithi Hospital, Bangkok, for a physical check-up during March-October, 1998, were investigated. There was a slightly significant difference between the median age of the sexes. The medians of height, weight, and waist/hip ratio in males were significantly higher than those in female overweight and obese subjects. The median of arm circumference (AC), mid arm muscle circumference (MAMC) in males was significantly higher than those in female overweight and obese subjects (p < 0.05). The prevalences of hypertension based on systolic and diastolic blood pressure of ≥160/ ≥95 mmHg, were 8.3% and 37.5% for males and 5.4% and 18.6% for females, respectively. There was no significant difference between the median of antioxidant enzymes (SOD, GPX and CAT) between the sexes. No significant differences in the antioxidant enzymes in male overweight/obese persons and normal controls were presented, whereas antioxidant enzymes in female overweight/obese persons were statistically lower than in control females (p < 0.05). A significantly higher SOD, GPX, and CAT status was observed in normal subjects compared with overweight/obese subjects (p < 0.01). A higher prevalence of SOD ≤ 2,866 U/gHb, GPX (≤ 15.96 U/gHb in females was found, compared with males. A high percentage of lower catalase (CAT≤ 19.2x10 IU/gHb) was found in both sexes (64.5% in males and 64.5% in females). In obese subjects (BMI ≥ 30.0 kg/m), there were significantly positive relationships between systolic and diastolic blood pressure, systolic blood pressure and waist/hip ratio, and SOD could be related to weight, BMI as well as GPX and CAT, whereas the opposite result was observed for age and SOD. Correspondence: Dr Rungsunn Tungtrongchitr, Department of Tropical Nutrition and Food Science, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok 10400, Thailand. Tel/Fax: (662) 2485748 SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH Vol 31 No. 2 June 2000 326 been done to understand all the factors contributing to these high levels. There is extensive documentation of populations in Thailand, Brazil, Cuba and Vietnam, with high energy and fat intakes and above average levels of obesity among adults (Mo-suwan et al, 1993; INCLEN Multi-center Collaborative Group, 1994). The reasons for overweight are genetic (data from studies of twins), overeating, smoking cessation, alcohol consumption, lack of exercise, change in lifestyle, energy intake and energy expenditure (consider resting metabolic expenditure), environmental factors, salt/potassium retention, major depression/anxiety/other psychological or medical illness, medications, during and after pregnancy, cultural (perception of obesity), and socioeconomic factors. In Thailand, the transition from the rural to the urban environment affects health in various aspects, such as changes in eating habits, drinking of alcohol and smoking (Osuntokun, 1985; Hamburg, 1987; Epstein, 1989). Diseases related to obesity, such as hypertension and diabetes mellitus, have increased in rural Thai people (Chaisiri et al, 1997). Physical signs of obesity (overweight) are hypertension (increase blood pressure), coronary heart disease, predisposition to diabetes, hyperlipidemia (increased cholesterol level), metabolic abnormalities, increased risk of gallbladder disease, gout, some types of cancer, and development of osteoarthritis of the weight bearing joints. In the relationship between weight and blood pressure, being overweight is a significant risk factor for the development of hypertension. The prevalence of hypertension is greatly increased by the fact that more than half of all adults (prevalence varies by study) are overweight. Although the association between higher body fat and blood pressure has been recognized for years, recent studies discovered a 50% to 30% higher incidence of hypertension among adults who consider themselves overweight, compared with those classified as being of normal weight. Similar findings are related from studies involving children and young adults, in which the correlation coefficient between weight and blood pressure has been observed to be as high as 0.4. Two proposed mechanisms underlying this correlation are the stimulation of sodium retention and increased catecholamine release, which are results of increased sodium sensitivity and hyperinsulinemia. Age, gender and race are modifiers/confounders of obesity. It has been recently suggested that oxidative stress induced by reactive oxygen species (ROS) are capable of reacting with unsaturated lipids and of initiating chain reactions of lipid peroxidation in the membrane, leading to their oxidation, and followed by (1) a decrease in the half life of bio-molecules, (2) a loss of protein functions; enzymes, receptors, membrane phospholipids, (3) the appearance of toxic products: oxidized LDL, MDA, (4) the formation of MDA-proteins and MDA-DNA adducts. However, cells are protected against oxidative damage by the body’s defense system. The first of these involves enzymes that directly metabolize ROS superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT)]. Among these enzymes, SOD plays a central role in the metabolism of ROS by directly dismuting the superoxide anion radical in hydrogen peroxide, which is scavenged by CAT and GPX. The latter enzyme requires the presence of reduced glutathione (GSH) to be effective (Fridovich, 1985). The other defense system includes molecules that interact directly with free radicals to neutralize them (eg ascorbic acid, α-tocopherol, retinol and glutathione). The aim of this study was to determine trends in overweight and obesity according to BMI in relation to antioxidant enzymes and blood pressure in healthy overweight and obese Thais compared with normal subjects. This would both establish baseline values for these parameters and allow us to investigate the change in antioxidant enzymes in obese persons. MATERIALS AND METHODS