Selenium status and oxidative stress in obese: Influence of adiposity.

BACKGROUND: Selenium deficiency appears to limit antioxidant defense in obese individuals. This study evaluated the association between adiposity indices, selenium status, and oxidative stress in obese women. METHODS: This was a cross-sectional study involving 139 women who were divided into the following two groups: the case group (obese women, n = 63) and the control group (normal-weight women, n = 76). Plasma, erythrocyte, and urinary selenium levels were determined using inductively coupled plasma optical emission spectrometry. Body weight, height, waist circumference, hip circumference and neck circumference were measured. Body mass index, waist/height ratio, conicity index, body fat index, body adiposity index, body circularity index, and visceral adiposity index were calculated. Plasma levels of thiobarbituric acid reactive substances were determined. The erythrocyte glutathione peroxidase activity was determined using an automatic biochemical analyzer and Ransel kit. RESULTS: Obese women had selenium deficiency characterized by reduction in plasma and erythrocyte concentrations (P < .001). The urinary selenium excretion was higher in the case group compared to the control group (P < .001). Adiposity indices values and plasma concentrations of thiobarbituric acid reactive substances were significantly elevated in obese women (P < .001). There was a significant association between adiposity indices and selenium status (P < .001), and between erythrocyte selenium and erythrocyte glutathione peroxidase activity (P < .001). CONCLUSION: Obese women evaluated in the study have reduced plasma and erythrocyte concentrations of selenium and an increased urinary excretion of selenium. The correlation analysis reveals an association between intra-abdominal fat accumulation and selenium metabolism and oxidative stress.

Influence of cortisol on zinc metabolism in morbidly obese women.

INTRODUCTION: The accumulation of visceral fat affects the metabolism of hormones and some nutrients, but these mechanisms remain unclear. OBJECTIVE: To assess the influence of cortisol on the metabolism of zinc in morbidly obese women. METHOD: Cross-sectional, case-control study involving 80 women aged between 20 and 59 years. The participants were divided into two groups: experimental (morbidly obese, n = 40) and control (normal weight, n = 40). Zinc concentrations were determined by atomic absorption spectroscopy and serum and urinary cortisol by chemiluminescence method. RESULTS: Zinc intake was significantly different between groups. Mean plasma zinc was lower in obese compared to control group. Mean values for erythrocyte zinc were 44.52 ± 7.84 µg/gHb and 40.17 ± 6.71 µg/gHb for obese and control groups, respectively. Urinary excretion of this mineral was higher in obese compared to control subjects (p < 0.05). Mean values for plasma cortisol were 9.58 ± 4.86 µg/dL for obese and 9.89 ± 5.61 µg/dL for control groups. Mean values for urinary cortisol were 163.00 ± 100.35 µg/dL and 109.71 ± 34.88 µg/dL for obese and control groups, respectively (p > 0.05). The correlation analysis between cortisol and zinc was not significant (p > 0.05). CONCLUSIONS: Obese patients have hypozincemia and high erythrocyte zinc levels. The correlation between zinc parameters and cortisol concentration showed no influence of this hormone on zinc metabolism.

The effect of Roux-en-Y gastric bypass on zinc nutritional status.

BACKGROUND: Researchers have found that zinc nutritional status in obese and diabetic subjects is altered: low zinc concentrations in plasma and erythrocytes, with high urinary zinc excretion, were observed. This study evaluated the effect of Roux-en-Y gastric bypass (RYGBP) on plasma, erythrocyte and urinary zinc concentration. METHODS: 22 morbidly obese patients were studied before and 6 months after RYGBP. Fasting blood sample and 24-hour urine were collected in the pre- and postoperative phases. A software analyzed the diet information from 3-day food records after RYGBP. Zinc nutritional status was evaluated by determination of the concentration of this mineral in plasma and erythrocytes, and the urinary excretion of zinc / 24 hours by atomic absorption spectrophotometry. RESULTS: The diets consumed by the patients had adequate average concentrations of zinc. Zinc concentration in plasma, erythrocytes and urine were within the values of normality before RYGBP, with mean values of 93.25 +/- 19.34 microg/dL, 43.85 +/- 7.76 microg Zn/gHb and 583.05 +/- 359.30 microg Zn/24 hours, respectively. At 6 months after RYGBP, there was a change in these parameters to 69.82 +/- 10.95 microg/dL, 51.80 +/- 6.92 microg Zn/gHb, 535.29 +/- 216.40 microg Zn/24 hours in the concentration of plasma, erythrocyte and urinary zinc. CONCLUSION: These results suggest that RYGBP promoted, besides change in body composition, an alteration in the zinc plasma and erythrocytes concentrations which in the medium and long term, could cause problems for these patients.