RESUMO
Food fortification has been shown to be an effective strategy to overcome iron malnutrition. When a new iron compound is developed for this purpose, it must be evaluated from a nutritional and technological point of view before adding it into foods. In this way, we have evaluated ferrous gluconate stabilized by glycine as a new iron source to be used in wheat flour fortification. We performed biological studies in rats as well as sensory perceptions by human subjects in wheat flour fortified with this iron source. The productions of pentane as a rancidity indicator as well as the change of the sensorial properties of the biscuits made with stabilized ferrous gluconate-fortified wheat flour were negligible. Iron absorption in water from this iron source was similar to the reference standard ferrous sulfate. Nevertheless, because of the phytic acid content, iron absorption from fortified wheat flour decrease 40% for both iron sources. The addition of zinc from different sources did not modify iron absorption from ferrous sulfate and stabilized ferrous gluconate in water and wheat flour. The iron absorption mechanism as well as the biodistribution studies demonstrate that the biological behavior of this iron source does not differ significantly from the reference standard. These results demonstrate that the iron source under study has adequate properties to be used in wheat flour fortification. Nevertheless, more research is needed before considering this iron source for its massive use in food fortification.
Assuntos
Compostos Férricos/farmacologia , Alimentos Fortificados , Radioisótopos de Ferro/metabolismo , Triticum/metabolismo , Animais , Disponibilidade Biológica , Cromatografia , Feminino , Compostos Férricos/química , Farinha , Gluconatos/química , Glicina/química , Ferro/metabolismo , Ferro da Dieta , Masculino , Pentanos/química , Percepção , Ácido Fítico/química , Ratos , Ratos Wistar , Padrões de Referência , Paladar , Fatores de Tempo , Sulfato de Zinco/químicaRESUMO
Zinc deficiency remains a serious health problem worldwide affecting developed as well as developing countries. Despite the evidence proving that zinc deprivation during the periods of rapid growth negatively affects the cognitive brain as well as sexual development, there are few complete studies carried out in children. The present article proposes a revision of the evidence gathered until now on the relationship existing between zinc deficiency and intellectual and sexual development during the stages of childhood, preadolescence, and adolescence.
Assuntos
Desenvolvimento Humano/fisiologia , Desenvolvimento Sexual/fisiologia , Zinco/deficiência , Animais , Sistema Nervoso Central/metabolismo , Cognição/fisiologia , Humanos , Desnutrição/fisiopatologia , Zinco/metabolismoRESUMO
Iron is an essential micronutrient involved in multiple biochemical and physiological process. In this review we discuss the most relevant aspect of its metabolism in order to reach a better comprehension of the relevant roll that this micronutrient plays in human health.
Assuntos
Humanos , Ferro/metabolismo , Micronutrientes/metabolismo , Absorção , Ferro/farmacocinética , Micronutrientes/farmacocinéticaRESUMO
Diabetes mellitus is a group of metabolic disorders, the incidence of which varies widely throughout the world. The treatment of diabetes mellitus includes insulin, oral antidiabetic agents, and dietary regimens. Although the emphasis is on macronutrients intakes, there is strong evidence that there is an abnormal metabolism of several micronutrients in diabetic individuals. Zinc is one of the essential micronutrients of which status and metabolism is altered in this condition. This work is a short review about the close relation among zinc, glucose metabolism, and insulin physiology, as well as about the few experimental data about zinc absorption and zinc supplementation in diabetes mellitus patients.
Assuntos
Diabetes Mellitus/sangue , Diabetes Mellitus/tratamento farmacológico , Zinco/farmacologia , Complicações do Diabetes , Suplementos Nutricionais , Radicais Livres , Glucose/metabolismo , Humanos , Insulina/metabolismoRESUMO
Microencapsulated ferrous sulfate with soy lecithin (SFE-171) has been used as an iron source for the fortification of milk and dairy products. With the purpose to extend the use of this agent to other kind of foods or even to pharmaceutical preparations for oral administration, the SFE-171 was turned into a fluid powder (SFE-171-P) by means of vacuum drying. The iron bioavailability (BioFe) of SFE-171-P was evaluated in this work by means of the prophylactic-preventive method in rats, using ferrous sulfate as reference standard. Both iron sources were separately added to a basal diet of low iron content in a concentration of 10 mg iron/kg diet. Two groups of 10 weaned rats 25 days old received the fortified diets during 28 days, while a third group of the same size received the basal diet without iron additions. The weights and haemoglobin concentrations (HbC) of every animal were determined before and after the treatment, thus allowing the calculation of the mass of iron incorporated into haemoglobin (HbFe) during this period. The BioFe of the iron sources were obtained as the percentage ratio between the HbFe and the mass of iron consumed by each animal. The results were also given as Relative Biological Value (RBV), which relates the BioFe of the studied source with that of the reference standard. The liver iron concentration (LIC) of each animal was determined at the end of the experiment in order to evaLuate the influence of the studied iron sources on the liver iron stores. SFE-171-P presented BioFe, RBV and LIC values of (47 +/- 7)%, 109% and (46.6 +/- 3.4) mg/kg respectively, while the corresponding values for the reference standard were of (43 +/- 7)%, 100% and (45.0 +/- 4.7) mg/kg. These results show that the drying process used to produce the SFE-171-P does not affect its bioavailability, which is also adequate for the potential use of this product in food fortification or with pharmaceutical purposes.
Assuntos
Compostos Ferrosos/farmacocinética , Ferro/farmacocinética , Fosfatidilcolinas/farmacocinética , Animais , Química Clínica/métodos , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Composição de Medicamentos , Feminino , Hemoglobinas/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
The bioavailability of iron from a new commercial source containing ferric gluconate stabilized with glycine sold under the trade name Bioferrico was studied in this work by means of the prophylactic-preventive test in rats. NaFeEDTA was also studied by the same methodology for comparative purposes and ferrous sulfate was used as the reference standard. The test was conducted for 4 wk with male weaned rats, which were randomized into four groups of at least eight animals each. A control group received a basal diet of low-iron content, whereas the other groups received the same diet with iron added at a dose of 20 mg/kg as FeSO4.7H2O, NaFeEDTA, and Bioferrico, respectively. Individual hemoglobin concentrations (HbC) and weights were determined at the beginning and at the end of the study and food intake was daily registered. The iron bioavailability (BioFe) of each source was calculated as the ratio between the amount of iron incorporated into hemoglobin during the treatment (HbFe) and the total iron intake per animal (ToFeIn). A relative biological value (RBV) was obtained for each iron source under study as the ratio between the BioFe of the tested compound and that of the reference standard. The RBVs were 98% and 86% for Bioferrico and NaFeEDTA, respectively. Bioferrico showed a high bioavailability and behaved inertly in relation to the sensorial properties of the fortified food when it was added to flour. These qualities emphasize Bioferrico as a promising source for iron fortification.
Assuntos
Compostos Férricos/farmacologia , Gluconatos/farmacologia , Ferro/farmacocinética , Animais , Peso Corporal , Ácido Edético/farmacologia , Glicina/farmacologia , Hemoglobinas/biossíntese , Deficiências de Ferro , Masculino , RatosRESUMO
The essentiality of zinc for humans was first documented by Prasad in the 1960s. The main clinical manifestations associated with zinc deficiency are growth retardation, hypogonadism, diarrhea, and increased susceptibility to infectious diseases. Thus, in the past 25 yr, there was an increased interest of researchers in studying the role of zinc in human immunity. Although mechanistic research has been carried out using animal models, there are several studies in humans with similar results. This work is an attempt to review the information available in this field to understand the important role that zinc plays in the normal development and function of the immune system.
Assuntos
Sistema Imunitário/fisiologia , Estado Nutricional , Zinco/metabolismo , Idoso , Animais , Criança , Humanos , Timo/metabolismo , Timo/fisiologiaRESUMO
Food fortification with a proper zinc compound is an economic and effective strategy to prevent zinc deficiency. BioZn-AAS, a zinc gluconate stabilized with glycine, was compared with zinc sulfate (reference standard), zinc hydroxide, and zinc gluconate, all of them labeled with (65)Zn. This preclinical study was performed on Sprague-Dawley rats of both sexes, and the administered dose was 85 microg/kg of zinc. Bioavailability studies showed that absorption of BioZn-AAS was not statistically different than absorption from other sources in female rats (25.65% +/- 2.20% for BioZn-AAS, 28.24% +/- 4. 60% for ZnSO(4), 24.91% +/- 4.02% for Zn[OH](2), and 25.51% +/- 2. 70% for Zn-gluconate). In the case of the male rats, absorption of BioZn-AAS (27.97% +/- 4.20%) was higher (P<0.05) than that from the other compounds (23.15% +/- 2.90% for ZnSO(4), 22.62% +/- 3.90% for Zn[OH](2), and 22.30% +/- 3.90% for Zn-gluconate). Biodistribution studies demonstrated that the zinc from BioZn-AAS followed the same metabolic pathway as zinc from the other sources. Toxicity studies were performed with 50 female and 50 male rats. The value of oral lethal dose 50 (LD(50)) was 2000 mg/kg for female rats and 1900 mg/kg for male rats. Therefore, we conclude that BioZn-AAS has adequate properties to be considered a proper zinc compound for food fortification or dietary supplementation.
Assuntos
Especificidade de Órgãos , Compostos de Zinco/farmacocinética , Compostos de Zinco/toxicidade , Absorção , Animais , Disponibilidade Biológica , Feminino , Gluconatos/farmacocinética , Hidróxidos/farmacocinética , Dose Letal Mediana , Masculino , Ratos , Ratos Sprague-Dawley , Sulfato de Zinco/farmacocinéticaRESUMO
Radio-iron tests are frequently used to measure the bioavailability of different iron sources for food fortification. As the labeling procedures must be done under laboratory conditions, complementary studies should be carried out to evaluate the bioavailability of iron sources produced on an industrial scale. The iron bioavailability of SFE-171 (ferrous sulfate microencapsulated with phospholipids) was studied in previous reports using the compounds labeled with 59Fe and 55Fe; the results showed an iron bioavailability similar to that of ferrous sulfate. In the present work, the iron bioavailability of industrial SFE-171 was studied by the prophylactic-preventive method in rats using ferrous sulfate as the reference standard. Elemental iron powder was also studied by the same method for comparative purposes. The liver iron concentration of each animal was determined at the end of the experiment in order to evaluate the influence of each iron source on the liver iron stores. Relative biological values of 98 and 34% were found for SFE-171 and elemental iron powder, respectively, while the corresponding relative liver iron concentrations were 104 and 45%. The results provided by the prophylactic-preventive method show that the iron bioavailability of industrial SFE-171 is similar to that of ferrous sulfate; these results are also in agreement to those obtained with the radioactive compounds. We can conclude that the SFE-171 obtained by industrial procedures for massive use in iron food fortification has the same bioavailability as that of the SFE-171 produced and labeled under laboratory conditions.
Assuntos
Compostos Ferrosos/farmacocinética , Absorção Intestinal , Ferro/metabolismo , Animais , Disponibilidade Biológica , Composição de Medicamentos , Compostos Ferrosos/administração & dosagem , Alimentos Fortificados , Ferro/administração & dosagem , Fígado/química , Fígado/metabolismo , Masculino , Fosfolipídeos , Ratos , Ratos Sprague-Dawley , Padrões de ReferênciaRESUMO
Among the many examples of neuroendocrine-immune system interactions the relationship between the thyroid axis and the immune function has yet to be clearly established. Here we studied the influence of thyroid hormones on the course of an alloimmune response. Murine T(3) and T(4) levels were found to be increased a few days after the immunization of mice with allogeneic lymphoid cells. Besides in vivo treatment with T(4) was shown to increase alloantibody titers during the early stages of alloimmunization and to enforce lymphoid proliferation in vitro in a mixed lymphocyte reaction. Conversely, lowering thyroid hormone seric levels by propylthiouracil treatment, negatively modulates the humoral and cellular alloimmune responses. The evidence here points to the existence of a bidirectional communication between both systems. The possibility that the antigenic challenge would increase the thyroid gland activity thus leading to a positive modulatory action upon the immune response is also discussed.