Silvia Maria Franciscato Cozzolino

Nutritional status of selenium in Alzheimer's disease patients

Studies have shown that various antioxidants are decreased in different age-related degenerative diseases and thus, oxidative stress would have a central role in the pathogenesis of many disorders that involve neuronal degeneration, including Alzheimers disease (AD). The present study aimed to assess the nutritional status of Se in AD patients and to compare with control subjects with normal cognitive function. The case-control study was carried out on a group of elderly with AD (n 28) and compared with a control group (n 29), both aged between 60 and 89 years. Se intake was evaluated by using a 3-d dietary food record. Se was evaluated in plasma, erythrocytes and nails by using the method of hydride generation atomic absorption spectroscopy. Deficient Se intake was largely observed in the AD group. AD patients showed significantly lower Se levels in plasma, erythrocytes and nails (32.59 microg/l, 43.74 microg/l and 0.302 microg/g) when compared with the control group (50.99 microg/l, 79.16 microg/l and 0.400 microg/g). The results allowed us to suggest that AD has an important relation with Se deficiency.

Effect of zinc supplementation on serum leptin levels and insulin resistance of obese women

Leptin is thought to be a lipostatic signal that contributes to body weight regulation. Zinc might play an important role in appetite regulation and its administration stimulates leptin production. However, there are few reports in the literature on its role on leptin levels in the obese population. The present work asseses the effect of zinc supplementation on serum leptin levels in insulin resistance (IR). A prospective double-blind, randomized, clinical, placebo-controlled study was conducted. Fifty-six normal glucose-tolerant obese women (age: 25–45 yr, body mass index [BMI]=36.2 ±2.3 kg/m2) were randomized for treatment with 30 mg zinc daily for 4 wk. Baseline values of both groups were similar for age, BMI, caloric intake, insulin concentration, insulin resistance, and zinc concentration in diet, plasma, urine, and erythrocytes. Insulin and leptin were measured by radioimmunoassay and IR was estimated by the homeostasis model assessment (HOMA). The determinations of zinc in plasma, erythrocytes, and 24-h urine were performed by using atomic absorption spectrophotometry. After 4 wk, BMI, fasting glucose, and zinc concentration in plasma and erythrocyte did not change in either group, although zinc concentration in the urine increased from 385.9±259.3 to 470.2±241.2±μg/24 h in the group with zinc supplementation (p<0.05). Insulin did not change in the placebo group, whereas there was a significant decrease of this hormone in the supplemented group. HOMA also decreased from 5.8±2.6 to 4.3±1.7 (p<0.05) in the zinc-supplemented group but did not change in the placebo group. Leptin did not change in the placebo group. In the zinc group, leptin was 23.6±12.3 μg/L and did not change. More human data from a unique population of obese individuals with documented insulin resistance would be useful in guiding future studies on zinc supplementation (with higher doses or longer intervals) or different measures.

Importância do zinco na nutrição humana

Recent clinical and experimental findings have reinforced the importance of zinc in human nutrition. Zinc plays a key role in the function of several enzymes like alcohol dehydrogenase, copper-zinc superoxide dismutase, carbonic anhydrase, alkaline phosphatase, ribonucleic acid polymerase and enzymes in the central nervous system. Zinc also participates in cell division, genetic expression, physiological processes like growth and development, genetic transcription, as well as programmed cell death, acting in the stabilization of biomembrane structures and cellular components. Furthermore, zinc affects the immune function and cognitive development. Effects of its deficiency include hypogonadism, oxidative damage, and alterations in the immune system, hypogeusia, neuropsychological impairment and dermatitis. In view of the abundant research on this mineral, this study had the objective of divulging more recent literature supporting the concept that zinc is essential in human nutrition.

Zinc nutritional status and its relationships with hyperinsulinemia in obese children and adolescents

A perturbation of zinc metabolism has been noted in subjects with obesity. The present work intends to investigate whether the zinc nutritional status is associated with hyperinsulinemia in obesity. A study was carried out in a group of obese children and adolescents (n=23) and compared to a control group (n=21), both between 7 and 14 yr of age. Software analyzed diet information from 3-d food records. Body composition was evaluated by body mass index (BMI), bioelectrical impedance, and skinfold measurements. Zinc nutritional status was evaluated by Zn determination in plasma, erythrocyte, and 24-h urine, by atomic absorption spectrophotometry (λ=213.9 nm). Insulin was measured by radioimmunoassay (Linco Res). Diets consumed by both groups had marginal concentrations of zinc. Zinc concentrations in plasma and erythrocytes were significantly lower in the obese group. Urinary zinc excretion and serum insulin were significantly higher in the same group, although the insulinemia and the parameters of zinc nutritional status were not significantly correlated. As a result, considering that zinc is part of the synthesis and secretion of this hormone, an assessment is necessary of the possible participation of the oligoelement in the mechanisms of insulin resistance, commonly present in obese patients.

Zinc nutritional status in obese children and adolescents.

Studies in animals and humans have corroborated that zinc (Zn) metabolism is altered in obesity. The present work intends to evaluate the Zn nutritional status in obese children and adolescents by the determination of some biochemical parameters and analyses of the diets. The investigation was carried out in a group of obese children and adolescents (n=23) and compared to a control group (n=21), both between 7 and 14 yr of age. A software analyzed diet information from 3-d food records. Body composition was evaluated by body mass index, bioelectrical impedance, and skinfold measurements. Zinc nutritional status was evaluated by Zn determination in plasma, erythrocyte, and 24-h urine, by atomic absorption spectrophotometry (γ=213.9 nm). Diets consumed by both groups had marginal concentrations of zinc. Zinc concentrations in plasma and erythrocytes were significantly lower in the obese group. Urinary zinc excretion was significantly higher in the same group. The results allowed one to conclude that zinc nutritional status in obese individuals is altered.

Biodisponibilidade de minerais

A importância da determinacao da biodisponibilidade de minerais em dietas esta centralizada no estabelecimento das recomendacoes de ingestao destes elementos em funcao das necessidades dos individuos. Assim, os estudos de biodisponibilidade de nutrientes devem ser especificos para cada pais, tendo em vista a grande diversidade de dietas e de individuos. Nesta abordagem, procurou-se discutir as metodologias disponiveis para avaliacao da biodisponibilidade de minerais e os fatores que podem interferir nesta medida, visando motivar jovens pesquisadores a se interessarem por esta area de pesquisa que promete grandes descobertas.

Zinc Nutritional Status of Morbidly Obese Patients Before and After Roux-en-Y Gastric Bypass: A Preliminary Report

Background: Previous researchers have found that the nutritional zinc status in obese and diabetic subjects is altered: low zinc concentrations in plasma and erythrocytes with high urinary zinc excretion were observed. This study assessed the influence of the Roux-en-Y gastric bypass (RYGBP) on the plasma, erythrocyte and urinary zinc concentrations before the beginning of the mineral supplementation. Methods: 24 morbidly obese patients were studied before and 2 months after RYGBP (the period in which the patients were still not ingesting mineral supplements). Fast blood sample, 24-hour urine, and 3-day food records were collected in the pre- and postoperative phases. Zinc concentration in the samples was analyzed by flame atomic absorption spectrophotometry, and dietary analysis of the food records were performed using the software Virtual Nutri with the inclusion of zinc concentration in the database for regional foods. Results: Pre- and postoperative results were respectively: plasma 68.0 and 66.3 μg/dL; erythrocytes 36.6 and 43.8 μg/g Hb; urine 884.7 μg/24h and 385.9 μg/24h; and zinc intake 10.5 and 6.7 mg/day. Conclusion: These results suggest that RYGBP changed mainly the zinc erythrocyte and urinary concentrations. As expected, the zinc intake was lower in the postoperative phase, which in the medium and long term, could cause problems for the patients.

Associations between glutathione peroxidase-1 Pro198Leu polymorphism, selenium status, and DNA damage levels in obese women after consumption of Brazil nuts

OBJECTIVE Alterations in selenium (Se) status may result in suboptimal amounts of selenoproteins, which have been associated with increased oxidative stress levels. The Pro198Leu polymorphism at the glutathione peroxidase-1 (GPx1) gene is supposed to be functional. The response of Se status, GPx activity, and levels of DNA damage to a Se supplementation trial between the genotypes related to that polymorphism was investigated. METHODS A randomized trial was conducted with 37 morbidly obese women. Participants consumed one Brazil nut, which provided approximately 290 μg of Se a day, for 8 wk. Blood Se concentrations, erythrocyte GPx activity, and DNA damage levels were measured at baseline and at 8 wk. The results were compared by genotypes. RESULTS The genotype frequencies were 0.487, 0.378, and 0.135 for Pro/Pro (the wild-type genotype), Pro/Leu, and Leu/Leu, respectively. At baseline, 100% of the subjects were Se deficient, and after the supplementation, there was an improvement in plasma Se (P < 0.001 for Pro/Pro and Pro/Leu, P < 0.05 for Leu/Leu), erythrocyte Se (P = 0.00 for Pro/Pro and Pro/Leu, P < 0.05 for Leu/Leu), and GPx activity (P = 0.00 for Pro/Pro, P < 0.00001 for Pro/Leu, P < 0.001 for Leu/Leu). In addition, the Pro/Pro group showed a decrease in DNA damage after Brazil nut consumption compared with baseline (P < 0.005), and those levels were higher in Leu/Leu subjects compared with those with the wild-type genotype (P < 0.05). CONCLUSION Consumption of one unit of Brazil nuts daily effectively increases Se status and increases GPx activity in obese women, regardless of GPx1 Pro198Leu polymorphism. However, the evaluated biomarkers showed distinct results in response to the supplementation when the polymorphism was considered.

Brazilian nut consumption improves selenium status and glutathione peroxidase activity and reduces atherogenic risk in obese women

Studies have shown that there are inverse relationships between nut consumption and the reduction of cardiovascular risk. This study tested the hypothesis that daily consumption of Brazilian nuts would have a positive effect upon selenium (Se) status, erythrocyte glutathione peroxidase activity, lipid profile, and atherogenic risk in severely obese women. Thirty-seven severely obese women each consumed 1 Brazilian nut a day (290 μg of Se a day) for 8 weeks. Blood Se concentrations, total erythrocyte glutathione peroxidase activity, lipid profile, and Castelli I and II indexes were evaluated before and after the nuts consumption. All the patients were Se deficient at baseline; this deficiency was remedied by the consumption of the Brazilian nut (P < .0001). The intake of Brazilian nuts promoted a significant increase in high-density lipoprotein cholesterol concentrations (P < .00001), which then resulted in a significant improvement of the Castelli I (P < .0002) and II (P < .0004) indexes. This study shows that obese people who implement daily consumption of Brazilian nuts can improve both Se status and lipid profile, especially high-density lipoprotein cholesterol levels, thereby reducing cardiovascular risks.

COMPOSIÇÃO CENTESIMAL E DE MINERAIS DE MARISCOS CRUS E COZIDOS DA CIDADE DE NATAL/RN

The aim of this study was to analyse the centesimal composition as well as zinc, copper and iron contents of the five species from raw and cooked shellfishes: shrimp (Penaeus brasiliensis), crab (Ucides cordatus), lobster (Panulirus argus), oyster (Crassostrea rhizophorae) and mussel (Anomalocardia brasiliana). The edible samples were collected in the fish market of the Natal city. Shellfishes were considered an expressive source of the proteins and minerals, while quantities of lipids and calories were low. After the cooking process protein and ash concentration increased in most of shellfishes. Zinc analysis showed variable concentration in the species. Oyster was the food with the highest zinc values. Mussel was considered the best source of iron and copper but around 50% of the copper detected was lost after decoction. This behavior was not observed in crab samples. These results can contribute to food composition table and evaluation of the Brazilian diets.