A randomized-controlled, double-blind study of the impact of selenium supplementation on thyroid autoimmunity and inflammation with focus on the GPx1 genotypes.

PURPOSE: To analyze the impact of selenium supplementation on serum antiTPO levels and thyroid echogenicity in patients with CAT, evaluating the response in subgroups with different GPx1 genotypes. METHODS: CAT patients (n = 55) with positive antiTPO were randomized to selenomethionine (SeMet) 200 µg daily (n = 28) or placebo (n = 27) for 3 months. Assessments included GPx1 genotyping at baseline and serum levels of plasma selenium, erythrocyte GPx1 activity, antiTPO and thyroid echogenicity at baseline, and 3 and 6 months. RESULTS: In the SeMet group, the increase in plasma levels of selenium and erythrocyte GPx1 activity was similar among patients with different GPx1 genotypes. In the overall cohort, patients randomized to SeMet showed a 5 % decrease in antiTPO levels at 3 months (p = non-significant) and 20 % at 6 months (p < 0.001 versus 3 months). In contrast, patients in the placebo group did not show significant changes in antiTPO levels at any time point. Subgroup analysis showed that patients with different GPx1 genotypes presented comparable responses in antiTPO levels and echogenicity index to SeMet. CONCLUSIONS: Selenium supplementation decreased serum antiTPO levels in CAT patients, with similar response among patients with different GPx1 genotypes.

Zinc absorption in Brazilian subjects fed a healthy meal.

BACKGROUND: The high amounts of phytic acid present in diets from developing countries are considered as important inhibitors of zinc (Zn) absorption. The present study aimed to assess the fractional absorption of Zn from a meal containing common Brazilian foods using the stable isotope technique. METHODS: Twelve men, aged 19-42 years, were fed a healthy experimental diet comprising lettuce, tomato, French fries, steak with onions, rice, beans, papaya, orange, pineapple, and passion fruit juice. Each subject received one intravenous dose of enriched (70) Zn, and the lunch was extrinsically labelled with enriched (67) Zn. Urinary (67) Zn and (70) Zn enrichments were assessed by inductively coupled plasma mass spectrometry. RESULTS: The labelled meal phytate : Zn molar ratio was very divergent with respect to chemically determined and calculated data. Subjects presented a normal Zn nutritional status before and after the study. The mean Zn absorption from the labelled meal was 30% (range 11-47%). CONCLUSIONS: According to the World Health Organization parameters, the results denote a moderate/high Zn bioavailability in the evaluated meal, with a variability in the absorption percentage that is similar to other studies. The data show that a typical Brazilian meal, with an adequate energy amount and a balanced macronutrient distribution, presents a Zn bioavailability in accordance with the worldwide recommended standard.

A follow-up study of the chronic kidney disease patients treated with Brazil nut: focus on inflammation and oxidative stress.

Brazil nut is the richest known food source of selenium. The supplementation with Brazil nut during 3 months was effective in reducing oxidative stress and inflammation in hemodialysis (HD) patients. However, there are no available data on the antioxidant effect after that supplementation. The objective of this work was to determine if the beneficial effects of one Brazil nut supplementation per day during 3 months for the HD patients could be sustained after 12 months. Twenty-nine HD patients (58.6 % men, 51.0 ± 3.3 years) from RenalCor Clinic, Rio de Janeiro, Brazil, were followed up 12 months after the supplementation study had finished. The plasma levels of antioxidant substances as selenium, glutathione peroxidase (GPx), 8-isoprostane, 8-hydroxy-2-deoxyguanosine (8-OHdG) and cytokines (tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6)) were determined before, after 3 months of supplementation and after 12 months. After 3-months supplementation, cytokines, 8-OHdG and 8-isoprostane plasma levels have decreased and the activity of GPx and selenium plasma levels have increased significantly. Additionally, after 12 months, the values of 8-isoprostane, 8-OHdG and cytokines increased and the activity of GPx and selenium plasma levels decreased significantly. The levels of oxidative stress and inflammation biomarkers after 12 months increased compared to the basal levels. Consequently, it is necessary to motivate patients to adopt different dietary intake patterns.

Determination of various nutrients and toxic elements in different Brazilian regional diets by neutron activation analysis.

The concentration of 19 elements (As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se and Zn) was evaluated in some diets taken from different regions of Brazil by Instrumental and Radiochemical Neutron Activation Analysis. Several populations with different socio-economic living conditions and inhabiting in different regions of Brazil were studied in order to estimate and to detect the variability of the mineral and toxic element content among Brazilian populational groups. The data obtained showed a significant difference between the contents of these elements in the diets from the regions studied. The general conclusions from the data obtained in this study were: 1) regarding the daily amounts of essential elements (Ca, Cl, Co, Fe, Mn, Na, K, Fe, Se and Zn), the Santa Catarina 2 diet showed the closest values when compared to the recommended values of RDA (Recommended Dietary Allowance) and/or WHO (World Health Organization). The Santa Catarina 1(low income groups) showed the lowest when compared to the same values. 2) The intake of toxic elements (As, Br, Cd, Hg, Sb) among the diets does not seem to be a major problem when compared to PTWI (Provisional Tolerable Weekly Intake, WHO), except for Hg intakes in regions near gold mining activities, like Manaus and Mato Grosso, where the values found were near the upper limit set by WHO.

[Effect of supplementation with peach palm as source of vitamin A: study with rats]. / Efeito da suplementação com pupunha como fonte de vitamina A em dieta: estudo em ratos.

The effect of supplementation with peach palm (Bactris gasipaes H.B.K.), as an alternative source of vit. A, in the regional diet of Manaus, AM, Brazil, in which the pulp was cooked and transformed into flour, was studied. The biological trial involved rats which were depleted in zinc and vitamin A, followed by repletion using the regional diet (RD), RD plus peach palm and RD plus vitamin A. The parameters used to determine the utilization of vitamin A were the vitamin A concentrations in the liver and plasma, and the growth of the animals. The diet was prepared according to the data of Shrimpton and Giugliano for families earning less than two legal minimum salaries. Adult post-partum rats were used, with six male pups each, which received a diet based on casein washed with 1% EDTA, without the addition of zinc or vitamin A for a period of 25 days, for the purpose of obtaining newly-weaned animals which were deficient in Zn and Vit.A. A control group received a diet also based on casein washed with 1% EDTA, but with all the nutrients in the quantities suggested by the Committee on Laboratory Animal Diets. The repletion period of the newly-weaned rats was of 30 days and the experimental design was entirely randomized with four groups of eight rats each. The diet supplementation followed the recommendations of the Committee on Laboratory Animal Diets. At the end of the experiment, it was observed that rats which consumed the diet based on the regional diet of Manaus supplemented with either peach palm or vitamin A showed a significantly greater concentration of vitamin A in the liver, 43.3 +/- 6.5 micrograms/g, 42.0 +/- 4.3 micrograms/g, respectively in relation to the regional diet, 5.5 +/- 1.1 micrograms/g (p < 0.05). The amount of zinc present in the regional diet, 10.7 mg per day, was bioavailable as determined by the concentration of zinc in the femurs. The results suggest that the regional diet of Manaus needs to be supplemented with vitamin A to maintain the hepatic reserves, and that such supplementation can be accomplished with peach palm, an abundant local commodity.

[Iron supplementation effects on zinc bioavailability in a regional diet of northeastern Brazil]. / Efeito da suplementação com ferro na biodisponibilidade de zinco em uma dieta regional do nordeste do Brasil.

The effects of supplementation with iron on the zinc bioavailability of the regional diet of northeastern Brazil (RDN), were investigated. One assay with Wistar rats, feed on RDN and control diets was carried out. The RDN diets contained 16 mg Zn/kg and levels of 35 mg, 70 mg and 140 mg Fe/kg, respectively. The control diets were prepared according to the standards of the Committee on Laboratory Animal Diets, with levels of protein, iron and zinc identical to those of RDN diets. Index of apparent absorption and zinc retained in the femur of the animals were the parameters utilized to measure zinc bioavailability. The results demonstrated that the supplementation with iron decreased the zinc bioavailability, and the effects were seen to affect diet quality and the Fe:Zn ratio. This fact must be taken into consideration in practices such as the fortying of foodstuffs and the administration of vitamin-mineral supplements to populations with nutritional deficiencies.

[Nutritional analysis and complementation of a food basket derived from consumption]. / Análise nutricional e complementação alimentar de cesta básica derivada do consumo.

INTRODUCTION: The DISEASE & PROCON Basket (DPB) is a list of basic foodstuffs, drawn up on the basis of a Standard of Living and Work Research project in S. Paulo city, Brazil. Seeing that it has been used as a standard for price variations, it is desirable that such an economic instrument as this, should also represent a truly healthy standard of nutrition. Thus, this study seeks to verify the adequacy of the food products in the DPB in relation to the nutritional needs of a typical reference family in S. Paulo city. It also proposes some techniques for dietary complementation. METHODOLOGY: A demographic census, undertaken in 1991 has been used to establish the reference family, as well as 2/3rds of RDA as corresponding to its nutritional needs, and the food composition tables of McCance & Widdowson to analyse the nutrient content of the DPB. Dietary complementation were undertaken by three different methods: Ad Hoc (direct suggestions), Linear Programming (computer software was utilized to minimize costs), and Hybrid (a combination of the first two). RESULTS: Food items in the DPB showed insufficient values for vitamins A, C, B2 and B6, and for minerals Ca, Mg, Fe, Zn, I and Se; besides, a relatively high fat content was found. The Hybrid Method of food complementation seems to present the best results, associating low cost and local dietary habits. DISCUSSION: A relation between the dietary deficiencies of the DPB and the nutritional transition in the developing countries may be infered. The epidemiological risks associated with these changes in eating patterns should not be incorporated into a reliable economic instrument.

Interaction of zinc and vitamin A in rats receiving a regional diet of Manaus, Amazonas, Brazil. Effect of supplementation with vitamin A, zinc and zinc and vitamin A.

The interaction of zinc and vitamin A in rats receiving a regional diet of Manaus, supplemented with vitamin A, zinc and zinc and vitamin A was studied. The regional diet was elaborated according to data of Shrimpton and Giugliano (6), for families receiving less than two minimum salaries. The biological test to study the interaction was based on the depletion of zinc and vitamin A in rats in the period of lactation, and a period of repletion where supplements of zinc (0.82 mg%) and vitamin A (94.2 micrograms %) were given, either separately or together, according to the recommendations of the Committee on Laboratory Animal Diets (7). From the results, it was concluded that there was an interaction of these nutrients in terms of mobilization of hepatic vitamin A. Although the regional diet of Manaus did not meet the zinc RDA, the amount present was enough to utilize the available vitamin A. Although the amount of zinc present in the diet, as determined by parameters of bioavilability, such as growth, concentration in organs and zinc-dependent enzymes, was adequately used by the animals, probably due to promoting factors in the diet. The Manaus regional diet needs to be supplemented with vitamin A in order to maintain the hepatic reserves, and with zinc, to maintain the normal levels of vitamin A in plasma.

[Interaction of vitamin A and zinc in lactating rats. Experimental deficiency model]. / Interação de zinco e vitamina A em ratos na lactação. Modelo de deficiência experimental.

An experimental deficiency model of vitamin A and zinc in lactating rats was developed. The experimental design consisted in a depletion period of 4 weeks immediately after birth where test group animal received a casein based feed, deficient in zinc and vitamin A, and a control feed according to the recommendations of the Committee on Laboratory Animal Diets. Female Rathus norvergicus, var albinus (Rodentia, Mammalia) with 6 young males each were used. These came from the Biotério of the Faculdade de Ciências, Farmacêuticas of USP. At the end of the depletion period it was found that the weight of the males control group (109.1 g +/- 3.9 g) was significantly greater than that of the test group (40.8 g +/- 6.7 g). The same was true for the concentration of zinc in the femurs of these animals, in the control group the concentration was significantly greater (115.7 micrograms/g +/- 5.4 micrograms/g) than in the test group (35.5 micrograms/g +/- 3.3 micrograms). The concentration of vitamin A in the plasma of the control group (31.5 micrograms/dL +/- 2.5 micrograms/dL) also was significantly greater than the test group animals (8.9 micrograms/dL +/- 3.4 micrograms/dL). The concentration of hepatic vitamin A was similar for both groups. We can conclude that there was interaction of zinc and vitamin A, by liver and depletion in zinc. Although the plasmatic concentration of vitamin A indicates a depletion, this cannot be considered as total because of the hepatic reserves.

[Zinc bioavailability in the regional diet of São Paulo]. / Biodisponibilidade de zinco em dieta regional de São Paulo.

Zinc bioavailability in the diet of the population of São Paulo area, with income lower than two minimum salaries, was studied in Wistar rats, recently weaned, with an average weight of 47.0 g. Three groups formed the experimental protocol: for 60 days. The experimental groups was fed ad libitum with a diet based on the diet of São Paulo (DRSP), control 1-"pair feeding" and control 2, ad libitum, with a diet of casein supplemented with methionine (CA). The diets contained 11% protein and 11 mg of zinc per kg of diet. To investigate zinc bioavailability, the apparent zinc absorption index and zinc content in the carcass, were used. Zinc bioavailability in the DRSP diet is low in comparison to the control diet CA. A significantly positive correlation between zinc intake and zinc level in the carcass, was observed.

[Utilization of different iron concentrations on pregnant adolescents also supplemented with zinc and folate]. / Utilização de diferentes concentrações de ferro por adolescentes grávidas também suplementadas com zinco e ácido fólico.

The pregnant teenager is considered at nutritional risk specially due to the fact that most of them still growing and developing. Therefore the demands of pregnancy compete with those of growth causing an extra need for her and the fetus (1). Iron, zinc and folate are essential nutrients that are frequently low on the teenagers diet. Besides that there is not much specific information available about these nutrient recommendations and their interaction among each other. The data available is limited and demands more investigation. This study was conducted at a Public Maternity Hospital located at Teresina, Piauf, Brazil. The main objective of this study was to investigate the effect of different concentrations of iron supplementation (80 and 120 mg of ferrous sulfate) together with folate (250 micrograms) and zinc (5 mg) on the hemoglobin concentration and iron stores (plasma ferritin) of pregnant adolescents. The supplementation was done from the 16th to 20th weeks of gestation until delivery. The data founded proved that either 80 mg or 120 mg of iron supplements had similar effect on the improvement of hemoglobin concentration although results showed no statistical significance.

Analysis of plasma and erythrocyte zinc levels in premenopausal women with breast cancer.

INTRODUCTION: Zinc deficiency has been associated with damage and oxidative changes in DNA that may increase an individual's risk of cancer. Furthermore, zinc metabolism may be affected in cancer patients, leading to alterations in its distribution that would favor carcinogenesis. Plasma and erythrocyte zinc levels in women with breast cancer were evaluated in this cross-sectional, controlled study. MATERIAL AND METHODS: Fifty-five premenopausal women of 25 to 49 years of age with and without breast cancer were divided into two groups: Group A, composed of women without breast cancer (controls, n = 26) and Group B, composed of women with breast cancer (cases, n = 29). Plasma and erythrocyte zinc levels were measured by flame atomic absorption spectrophotometry at γ = 213.9 nm. Diet was assessed using the 3-day diet recall method and analyzed using the NutWin software program, version 1.5. Student's t-test was used to compare means and significance was established at p = 0.05. RESULTS: Mean plasma zinc levels were 69.69 ± 9.00 g/dL in the breast cancer patients and 65.93 ± 12.44 g/dL in the controls (p = 0.201). Mean erythrocyte zinc level was 41.86 ± 8.28 µgZn/gHb in the cases and 47.93 ± 7.00 µgZn/gHb in the controls (p < 0.05). In both groups, dietary zinc levels were above the estimated average requirement. CONCLUSIONS: The present results suggest that zinc levels are lower in the erythrocyte compartment of pre-menopausal women with breast cancer.

Effect of Brazil nut supplementation on the blood levels of selenium and glutathione peroxidase in hemodialysis patients.

OBJECTIVE: In patients who have undergone hemodialysis, large amounts of reactive oxygen species (ROS) are produced and, at higher concentrations, ROS are thought to be involved in the pathogenesis of cardiovascular disease. It has been proposed that selenium (Se) may exert an antiatherogenic influence by reducing oxidative stress. The richest known food source of selenium is the Brazil nut (Bertholletia excelsa, family Lecythidaceae), found in the Amazon region. We evaluated the effect of Brazil nut supplementation on blood levels of Se and glutathione peroxidase (GSH-Px) activity in patients on hemodialysis. METHODS: A total of 81 patients on hemodialysis (52.0±15.2 y old, average time on dialysis 82.3±91.4 mo, body mass index 24.9±4.4 kg/m(2)) from the RenalCor and RenalVida Clinics in Rio de Janeiro, Brazil, were studied. All patients received one nut (around 5 g, averaging 58.1 µg Se/g) a day for 3 mo. The Se concentrations in the nuts and in plasma and erythrocytes were determined by atomic absorption spectrophotometry with hydride generation (Hitachi, Z-500). GSH-Px levels were measured using Randox commercial kits. RESULTS: Plasma Se (18.8±17.4 µg/L) and erythrocyte (72.4±37.9 µg/L) levels were below the normal range before nut supplementation. After supplementation, the plasma level increased to 104.0±65.0 µg/L and erythrocytes to 244.1±119.5 µg/L (P<0.0001). The activity of GSH-Px also increased after supplementation, from 46.6±14.9 to 55.9±23.6 U/g of hemoglobin (P<0.0001). Before supplementation, 11% of patients had GSH-Px activity below the normal range (27.5-73.6 U/g of hemoglobin). After supplementation, all patients showed GSH-Px activity within the normal range. CONCLUSION: The data revealed that the investigated patients presented Se deficiency and that the consumption of only one Brazil nut a day (5 g) during 3 mo was effective to increase the Se concentration and GSH-Px activity in these patients, thus improving their antioxidant status.

Estimate of toxic element intake in diets of pre-school children and elderly collected by duplicate portion sampling.

A study was carried out with a group of pre-school children staying at the central nursery of the University of São Paulo and with a group of elderly living in private institutions in São Paulo, Brazil, with the aim of evaluating the contents of toxic elements present in the diets of these groups. For sampling, the duplicate portion technique was used, which consisted of collecting all the foods and beverages consumed during three consecutive days. A radiochemical separation procedure was developed and applied to the determination of As, Cd, Sb, W, Th and U, by means of retention of these elements in the resin Chelex 100 and inorganic exchanger tin dioxide in an appropriate medium. The elements analysed presented levels of ingestion below the maximum levels recommended by the World Health Organization (WHO), and thus can be considered as not presenting any health hazard to the individuals studied in the present work.

Tolerable dietary lipid content that does not alter insulin secretion.

Lipids, either as membrane components or as fuel, are important nutrients that can affect insulin secretion. The aim of this study was to establish the maximum tolerable amount of fat present in the diet, which does not induce significant alteration in the process of insulin secretion. For that, just-weaned male albino rats (70-90 g body weight) were fed during 6 weeks with diets for growing rodents containing 7% fat (A Group) as recommended by the American Institute of Nutrition-AIN. Two other groups in which the fat content of the diet was increased to reach 10% (B Group) or 13% (C Group) were also included. Insulin release, 86Rb+ and 45Ca2+ Fractional Outflow Rate (FOR) during the process of glucose-induced insulin secretion was determined in perfused islets isolated from these animals. No statistical differences in these parameters were detected between A and B rats. However, in the C group, a lower 86Rb+ FOR was found during the whole experiment and a poor insulin secretory response to glucose stimulus was observed. These results led us to postulate that the maximal limiting amount of total lipids present in the diet that does not impair the process of glucose-induced insulin secretion is 10%. These findings authorize future studies on the interference of different dietary lipid sources, in a content 43% more elevated than that recommended (10% against 7%), on the mechanisms of insulin secretion.

Biodisponibilidade de zinco em dieta regional de Säo Paulo / Zinc bioavailability in the regional diet of Säo Paulo

A biodisponibilidade de zinco em dieta regional de Säo Paulo, da populaçäo com renda menor que 2(dois) salários mínimos, foi estudada em ratos alinos Wistar, recém-desmamados, com peso ao redor de 47.0g. Foram formados três grupos de animais, um experimental, que recebeu raçäo à base da dieta regional de Säo Paulo (DRSP), ad libitum, e os outros dois contrôles, que receberam raçäo à base de caseína suplementada com metionina (CA), "pair feeding" e ad libitum, por um período de 60 dias. As raçöes continham 11% de proteína e 11 mg de zinco/Kg. Para se avaliar a biodisponibilidade de zinco utilizou-se o Indice de absorçäo aparente de zinco e o nível de zinco na carcaça (AU). Observou-se que a biodisponibilidade de zinco da raçäo DRSP é baixa quando comparada com a raçäo contrôle CA. Houve uma correlaçäo positiva significativa entre a quantidade absorvida de zinco e o nível de zinco na carcaça