RESUMO
OBJECTIVE: Combating iron deficiency in toddlers with iron-fortified food has proved difficult in countries with phytate-rich diets. For this purpose, a new haem iron preparation was developed. The study compared changes in iron status after administration of refried beans with beans fortified with a haem iron preparation or ferrous sulphate (FeSO4). DESIGN: In a masked, stratified-randomised intervention trial, children received five 156-g cans of refried black beans per week for 10 consecutive weeks. The beans-only (control), FeSO4 and haem iron groups were offered a cumulative dose of 155 mg, 1625 mg and 1700 mg of iron from the bean intervention, respectively. Haemoglobin (Hb) and ferritin concentrations were determined at baseline and after 5 and 10 weeks. Compliance was examined weekly. SETTING: A low-income community in Guatemala City. SUBJECTS: One hundred and ten children aged 12-36 months with initial Hb values between 100 and 115 g l(-1). RESULTS: The cumulative intake of beans was approximately 80% of that offered, signifying an additional approximately 1300 mg of either haem or inorganic iron in the corresponding treatment groups over 10 weeks. Hb concentrations increased by the order of 7.3-11.4 g l(-1) during the intervention, but without significant differences across treatments. Average ferritin concentrations were unaffected by treatment assignment. However, post hoc analysis by subgroups of initial high ferritin and initial low ferritin found the Hb increments after 10 weeks in the haem iron group (13.1+/-7.7 g l(-1)) to be significantly greater than the respective increases (6.8+/-11.2 and 6.4+/-8.5 g l(-1)) in the inorganic iron and beans-only groups. CONCLUSIONS: Canned refried beans are a candidate vehicle for fortificant iron. Given the improved colour and organoleptic properties imparted by haem iron added to refried beans, its additional potential for benefiting the iron status of consumers with iron deficiency may recommend it over FeSO4.
Assuntos
Anemia Ferropriva/dietoterapia , Alimentos Fortificados , Ferro da Dieta/uso terapêutico , Anemia Ferropriva/sangue , Pré-Escolar , Relação Dose-Resposta a Droga , Método Duplo-Cego , Fabaceae , Feminino , Ferritinas/análise , Compostos Ferrosos/administração & dosagem , Compostos Ferrosos/uso terapêutico , Guatemala/epidemiologia , Hemoglobinas/análise , Humanos , Lactente , Ferro da Dieta/administração & dosagem , Masculino , Cooperação do Paciente , Resultado do TratamentoRESUMO
Several observations suggest that iron is an essential factor in myelination and oligodendrocyte biology. However, the specific role of iron in these processes remains to be elucidated. This role could be as an essential cofactor in metabolic processes or as a transcriptional or translational regulator. In this study, we used animals models each with a unique defect in iron availability, storage, or transfer to test the hypothesis that disruptions in these mechanisms affect myelinogenesis and myelin composition. Disruption of iron availability either by limiting dietary iron or by altering iron storage capacity resulted in a decrease in myelin proteins and lipids but not the iron content of myelin. Among the integral myelin proteins, proteolipid protein was most consistently affected, suggesting that limiting iron to oligodendrocytes results not only in hypomyelination but also in a decrease in myelin compaction. Mice deficient in transferrin must receive transferrin injections beginning at birth to remain viable, and these mice had increases in all of the myelin components and in the iron content of the myelin. This finding indicates that the loss of endogenous iron mobility in oligodendrocytes could be overcome by application of exogenous transferrin. Overall, the results of this study demonstrate how myelin composition can be affected by loss of iron homeostasis and reveal specific chronic changes in myelin composition that may affect behavior and attempts to rescue myelin deficits.
Assuntos
Encéfalo/metabolismo , Ferro/metabolismo , Modelos Animais , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Animais , Transporte Biológico , Western Blotting/métodos , Química Encefálica , Dieta , Ácidos Graxos/metabolismo , Feminino , Ferritinas/genética , Ferritinas/metabolismo , Deficiências de Ferro , Masculino , Camundongos , Camundongos Mutantes Neurológicos , Camundongos Transgênicos , Proteínas da Mielina/metabolismo , Gravidez , Ratos , Ratos Sprague-Dawley , TransferrinaRESUMO
In Latin America, 10-30% of reproductive age females and upwards of 40-70% of pregnant women may be iron deficient. The true prevalence in young children and infants is often hard to determine because of problems in survey design, data collection, or sampling. There is little doubt, however, that iron deficiency anemia is a significant nutritional problem in many infants within the first 5 years of life. Numerous intervention studies have been performed across the world with varying success and it is clear that in nearly all situations it is a preventable disease with preventable consequences. One such consequence is the alteration in cognition that occurs in iron deficient individuals during the early parts of their life cycle and perhaps at later times as well. While iron deficiency was once presumed to exert most of its deleterious effects only if anemia was present, it is now clear that many organs show morphologic, physiologic, and biochemical changes before there is any drop in hemoglobin concentration. Iron deficiency is associated with alterations in many metabolic processes that may impact brain functioning; among them are mitochondria electron transport, neurotransmitter synthesis and degradation, protein synthesis, organogenesis, and others. It is necessary to separate the developmental aspects of iron deficiency and neural functioning from the aspects of iron deficiency that could occur at any time in life. A number of reviews have discussed the links between brain iron and neuropathology, brain iron, nutrition, and development, and iron status and cognition. New knowledge concerning the acquisition of iron by the brain in early life is being generated by numerous research groups. In the next decade a much clearer understanding of the role of brain iron on neural functioning will probably emerge.
Assuntos
Encéfalo/metabolismo , Deficiências de Ferro , Distúrbios do Metabolismo do Ferro/metabolismo , Doenças do Sistema Nervoso/metabolismo , Animais , Transtornos Cognitivos/etiologia , Humanos , Ferro/metabolismo , Distúrbios do Metabolismo do Ferro/complicações , Sistema Nervoso/fisiopatologia , Doenças do Sistema Nervoso/etiologiaRESUMO
PURPOSE: The purpose of this study was to compare the pregnancy outcome and the growth and development of infants of adolescent and older mothers in a Latin American setting in which young mothers received aggressive prenatal care, and in which breast feeding behavior of all women was strongly encouraged and recorded. Our hypothesis was that the generally higher rates of low birth weight and neonatal complications among infants of Chilean adolescents would be eliminated by an aggressive protocol of prenatal care. METHODS: Data on prenatal care, gestation, birth and infant growth and development were extracted retrospectively from the medical records of 200 low socioeconomic status para I patients, all of whom received care by the same hospital team. The sample included 50 women ages 14-16, 50 women 17-19, and 100 women 20-24.
Assuntos
Bem-Estar do Lactente , Idade Materna , Adolescente , Adulto , Peso ao Nascer , Aleitamento Materno , Chile , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez , Cuidado Pré-Natal , Estudos Retrospectivos , Fatores Socioeconômicos , Aumento de PesoRESUMO
The location and function of iron in the central nervous system are reviewed with particular emphasis on human biology. Iron is distributed to different cell types in the brain in a heterogeneous fashion through the action of transferrin, transferrin receptors, and the metabolic needs of those cells. The function of this iron and its storage is documented in states of growth and development as well as during pathological states associated with aging. The information relating this biology to current observations of attention deficits in iron-deficient humans is also reviewed.
Assuntos
Encéfalo/metabolismo , Ferro/fisiologia , Adulto , Envelhecimento/metabolismo , Doença de Alzheimer/metabolismo , Animais , Criança , Pré-Escolar , Ferritinas/fisiologia , Humanos , Lactente , Ferro/metabolismo , Esclerose Múltipla/metabolismo , Doença de Parkinson/metabolismo , Ratos , Receptores da Transferrina/fisiologia , Transferrina/fisiologiaAssuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Anemias Nutricionais/prevenção & controle , Ferro/deficiência , Bolívia , Bolívia/etiologia , Altitude , EtnicidadeRESUMO
Thirty-seven young adult male highland residents at 3,600-4,100 m in La Paz, Bolivia, performed short-duration cycle ergometry at 60, 80, and 100% of maximal voluntary O2 consumption (VO2max). Three groups of subjects representing the high-altitude population mean hemoglobin (Hb), the 10th percentile Hb, and below the 1st percentile were examined to test the hypothesis that the relationship of exercise performance to Hb concentration is similar to those relationships established at low altitude. Anemic individuals (n = 8) had 23% lower voluntary VO2max and 28% lower maximal work loads compared with controls (n = 17) or marginally anemic subjects (n = 12) although the relationship of VO2 to work load was similar. Anemic individuals maintained significantly higher arterial O2 partial pressures and Hb saturations during heavy exercise (90 +/- 0.5 vs. 85 +/- 0.6%) in conjunction with a greater heart rate up to maximal effort. A significantly decreased erythrocyte 2,3-diphosphoglycerate (2,3-DPG)-to-Hb molar ratio (0.70 +/- 0.04 vs. 1.12 +/- 0.06), suggestive of a left-shifted dissociation curve in anemics, is in contrast to the expected right-shifted curve. Moderate anemics were similar to controls. Anemic individuals did not differ in arterial lactate concentration from controls at absolute work loads; anemics had significantly lower arterial lactate concentrations at maximal effort than controls with no differences in the work load-to-lactate relationship. In conclusion, O2 transport during exercise at high altitude seems unaffected by the Hb concentrations as low as the 10th percentile of the population mean.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Altitude , Anemia Hipocrômica/fisiopatologia , Esforço Físico , Adulto , Anemia Hipocrômica/sangue , Bicarbonatos/sangue , Bolívia , Dióxido de Carbono/sangue , Ácidos Difosfoglicéricos/sangue , Teste de Esforço , Humanos , Lactatos/sangue , Masculino , Oxigênio/sangue , Consumo de OxigênioAssuntos
Altitude , Crescimento , Fenômenos Fisiológicos da Nutrição , Consumo de Oxigênio , Estatura , Peso Corporal , Bolívia , Cefalometria , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Dobras CutâneasRESUMO
The stress of chronic hypobaric hypoxia present at high altitudes induces a series of adaptive changes in the intermediate metabolism in erythrocytes of high-altitude natives. Aymaras of the high Andean Plateau are shown to have within erythrocytes: (a) increased activity of NADH2 (GAPDH) generating stages, (b) decreased activity of NADH2 (LDH) consuming steps, (c) significantly increased methaemoglobin content, and (d) a large increase in the level of reduced glutathione. These alterations occur also in persons of the same ethnic group residing at low altitude. There is, however, only a moderate elevation of classic haematological parameters (erythrocyte count, haemoglobin and haematocrit) in highland natives. The functional implications of these metabolite changes are discussed with respect to regulation of erythrocyte metabolism.