RESUMO
The iron bioavailability from three typical diets consumed by socioeconomic stratum IV (SES IV--working class) of the Venezuelan population was determined by the extrinsic label method. Although the iron content of the SES IV diets was about the same (250 mumol/d) as that of upper (SES I-III) and lower (SES V) socioeconomic strata diets, iron-replete subjects absorbed 43 and 61% more iron from the SES I-III diets than from the SES IV and V diets, respectively, and absorption from the main meal of the SES I-III diets was 100% greater. However, iron deficient subjects absorbed about the same amount of iron (45 mumol/d) from the SES IV diets as from the SES I-III diets. The SES I-III diets contained more iron absorption enhancers (ascorbic acid and meat protein) and less of the inhibitor phytate, than the SES IV and V diets. Iron absorption from the meals of four diets consumed at different times during the day was also measured. There was no significant difference in the percentage iron absorption from the same meals eaten in the morning after an overnight fast, and when eaten at the customary time of day.
Assuntos
Dieta , Ferro/farmacocinética , Fenômenos Fisiológicos da Nutrição , Classe Social , Absorção , Adulto , Ácido Ascórbico/administração & dosagem , Disponibilidade Biológica , Criança , Dieta/normas , Proteínas Alimentares/administração & dosagem , Feminino , Humanos , Ferro/administração & dosagem , Deficiências de Ferro , Masculino , Valor Nutritivo , Ácido Fítico/administração & dosagem , VenezuelaRESUMO
The possibility of improving the dietary value of precooked maize flour through fortification with 11% coarse defatted maize germ was investigated. The results of tests in humans presented here show that the total iron absorption from the fortified preparation is similar to that from the precooked maize alone, but with the advantage of being richer in several nutrients: protein (25%), zinc (61%), potassium (47%) and magnesium (112%), as well as fiber (34%). Fortification lowers (by 20%) rather than raises the cost of the flour, and may be an important contribution to the diet of those populations where maize bread is a major component of the diet.
Assuntos
Farinha , Alimentos Fortificados , Ferro/farmacocinética , Zea mays , Absorção , Adulto , Culinária , Fibras na Dieta , Feminino , Farinha/análise , Humanos , Ferro/sangue , MasculinoRESUMO
The iron status of 3228 subjects from the nutrition survey Proyecto Venezuela was studied. The sample included children from 1 to 16 y of age grouped by age and sex. Values for three indicators of iron status were compared: hemoglobin concentration, serum ferritin concentration, and percentage saturation of serum transferrin. In all groups there was a strong overlap in the hemoglobin concentration distribution curves for non-iron-deficient and iron-deficient subjects classified as such according to the other two indexes. The prevalence of iron deficiency ranged from 35% in 1-3 y olds to 10% in adolescent males, the values being almost identical in the nonanemic group compared with the total population. In the different groups, 80-97% of the subjects with abnormal values of at least one of these two indexes were not anemic. The difficulties involved in establishing a state of iron deficiency according to these indexes are discussed.
Assuntos
Anemia Hipocrômica/sangue , Deficiências de Ferro , Adolescente , Fatores Etários , Anemia Hipocrômica/epidemiologia , Criança , Pré-Escolar , Feminino , Ferritinas/sangue , Hemoglobinas/análise , Humanos , Lactente , Masculino , Prevalência , Fatores Sexuais , Transferrina/análise , Venezuela/epidemiologiaRESUMO
Proteins, some minerals and vitamins, play important roles in erythropoiesis and the survival of the red blood cell. This article deals specifically with the physiological requirements and recommended intakes of iron, folate and vitamin B12. A comparison of the physiologic iron requirements according to age and sex, and the amount of iron which is actually absorbed from the diets consumed by the lower socioeconomic strata of the Venezuelan population; indicates that these diets do not satisfy the requirements at all ages. Such disparity is most marked in children below three years of age, in adolescents and in women during their reproductive age. Failure to do so leads to varying degrees of iron deficiency. This low bioavailability of the Venezuelan diet is also observed in other Latin American diets consumed by the same low socioeconomic strata, which explains the high prevalence of iron-deficiency anemia in the vulnerable groups. The low intake of fruits and vegetables by the lower socioeconomic strata of the Latin American population prevents these sectors from consuming an adequate intake of folate, failing to fulfill the daily recommended intake (3.3 - 3.6 micrograms/kg body weight). This situation is aggravated in pregnant and lactating women who require an additional intake of 300 micrograms and 100 micrograms, respectively. Prevalence of folate deficiency in the first stage may be in the order of 30% in some regions. In the second stage of deficiency, characterized by megaloblastic changes in the bone marrow and an erythrocyte folate concentration of less than 50 micrograms/lt, it could be as high as 40% in pregnant women. Nutritional vitamin B12 deficiency does not constitute a health problem in Latin America. Various surveys in the lower socioeconomic strata have reported normal or higher than normal serum B12 concentrations, compared to well-nourished populations.
Assuntos
Anemia/etiologia , Eritropoese , Necessidades Nutricionais , Adolescente , Adulto , Anemia/epidemiologia , Disponibilidade Biológica , Criança , Pré-Escolar , Cobre/deficiência , Estudos Transversais , Dieta , Feminino , Deficiência de Ácido Fólico/epidemiologia , Deficiência de Ácido Fólico/etiologia , Humanos , Lactente , Recém-Nascido , Ferro/farmacocinética , Deficiências de Ferro , Masculino , Distúrbios Nutricionais/complicações , Gravidez , Venezuela/epidemiologia , Deficiência de Vitamina A/complicações , Deficiência de Vitamina B 12/complicações , Deficiência de Vitamina B 12/epidemiologiaRESUMO
Median daily iron absorption was determined in iron-replete males and females between 2 and 19 years of age from the upper and lower socioeconomic strata of the Venezuelan population. A comparison was made with iron absorption of well-nourished children, on the basis of hematological and anthropometric reference values from the U.S. The median absorption level, which was calculated from the increase in total body iron due to growth and the daily losses through exfoliation and menstruation, was also used to estimate the requirements of 95% of the population. When the requirements were expressed in terms of body weight, no significant difference in iron absorption was observed between the three Venezuelan and one U.S. groups, ranging from about 30 to 38 micrograms/kg/day in both sexes between 4 and 16 years of age. However, when the requirements were expressed without division by the weight factor, the requirements of the better nourished groups were somewhat higher than those of the Venezuelan lower socioeconomic population with, in addition, a threefold variation over the 5 to 16 year age range. These findings suggest that the total iron requirements of children at a certain age may be most adequately expressed in terms of the optimal body weight for that age.
Assuntos
Fenômenos Fisiológicos da Nutrição Infantil , Ferro/administração & dosagem , Adolescente , Estatura , Peso Corporal , Criança , Feminino , Humanos , Absorção Intestinal , Ferro/fisiologia , Masculino , Necessidades Nutricionais , Fatores Socioeconômicos , Estados Unidos , VenezuelaRESUMO
Hematologic studies carried out in inhabitants of the State of Carabobo revealed that 19% of the subjects studied presented iron deficiency, this being more prominent in women and in children. Iron deficiency anemia was absent in men, while in the other groups its frequency, as registered, was from 5 to 13%. Tests for iron absorption from foods which form the average diet of the population in the Carabobo State, and the diet consumed by adults from the low socioeconomic strata in the States of Carabobo and Yaracuy, demonstrated that in normal subjects, bioavailability is lower than physiological requirements of men, women and children. In the iron-deficient subjects, its bioavailability can cover physiological needs. It is estimated that an important proportion of the population strata consuming such diets, suffer from iron nutritional deficiency, especially women during the reproductive age, and children.
Assuntos
Anemia Hipocrômica/epidemiologia , Ferro/sangue , Adolescente , Adulto , Disponibilidade Biológica , Criança , Dieta , Volume de Eritrócitos , Feminino , Ferritinas/sangue , Deficiência de Ácido Fólico/epidemiologia , Hematócrito , Hemoglobinas/análise , Humanos , Ferro/farmacocinética , Masculino , Estudos de Amostragem , Fatores Socioeconômicos , Transferrina/análise , VenezuelaRESUMO
Cysteine significantly increases, about 2-fold, the absorption from nonheme iron present in vegetable foods, hemosiderin, and of a ferric salt, when this amino acid is administered during the ingestion of foods. No enhancing effect was obtained when the amino acid was mixed with the food before the final cooking. A slight but significant enhancement of heme iron absorption was observed when a large dose of cysteine was administered during the ingestion of hemoglobin. This amino acid mimics the enhancing effect from proteins present in animal foods such as beef, lamb, pork, fish, chicken, and liver. It could be possible that proteins and cysteine share the same mechanism by which they induce an increase of iron absorption.
Assuntos
Cisteína/farmacologia , Ferro/metabolismo , Verduras , Absorção , Cloretos , Proteínas Alimentares/farmacologia , Fabaceae , Feminino , Compostos Férricos/metabolismo , Compostos Ferrosos/metabolismo , Alimentos Fortificados , Hemoglobinas/metabolismo , Hemossiderina/metabolismo , Humanos , Masculino , Plantas Medicinais , Venezuela , Zea maysRESUMO
The data presented confirm the advantages of sugar as a vehicle for iron fortification over other vehicles used in the past. The absorption comparison between ferric and ferrous salts added to sugar demonstrated that Fe(III)-EDTA Complex and ferrous sulfate exhibited the highest absorption, while ferric ammonium citrate was poorly absorbed. It was also found that Fe(III)-EDTA reacts slowly with the tannin contained in tea; the color of the tea changes slightly in the first 2 hr after the addition of the fortified sugar. Iron absorption of sugar fortified with ferrous sulfate was tested in seven beverages. The mean absorption ratio from fortified sugar given with beverages to reference dose of iron ascorbate ranged between 0.42 and 0.70, that is, more than 4 times the absorption from fortified sugar when it is administered with a meal containing one or more vegetals. An absorption of between 0.25 and 0.80 mg of iron/soft drink sugar fortified with 3 mg of iron as ferrous sulfate can be expected in subjects with various degrees of iron deficiency. Thus, two soft drinks per day between meals would be enough to meet the iron requirement in more than 95% of menstruating women, even though the daily iron absorption from the diet is about 0.8 to 1.0 mg.
Assuntos
Alimentos Fortificados , Ferro , Sacarose , Absorção , Adulto , Bebidas Gaseificadas , Dieta , Carboidratos da Dieta , Compostos Férricos , Compostos Ferrosos , Alimentos Fortificados/normas , Hemoglobinas/metabolismo , Humanos , Ferro/metabolismo , Relação Estrutura-Atividade , Chá , Transferrina/metabolismo , Verduras , VenezuelaRESUMO
Iron absorption from hemosiderin and ferritin biosynthetically labeled with radioactive iron has been studied in 61 subjects. The geometrical mean iron absorption from hemosiderin in both normal and iron deficient subjects was 3.4%. Its mean absorption ranged from 1.9% in normal subjects to 4.7% in subjects with moderate iron deficiency and 7.3% in subjects with marked iron deficiency. The iron absorption from hemosiderin was markedly increased when it was administered with ascorbic acid or liver. The absorption of iron from hemosiderin when hemosiderin and wheat were consumed in a meal, was lower than the absorption from wheat. Iron from liver ferritin and liver hemosiderin were less absorbed in this study than that previously reported for liver hemoglobin. The studies presented here support the possibility that ferritin and hemosiderin form an iron pool different from the non-heme pool formed by vegetal iron, egg iron and ferric and ferrous salts.
Assuntos
Anemia Hipocrômica/metabolismo , Ferritinas/metabolismo , Hemossiderina/metabolismo , Ferro/metabolismo , Absorção , Animais , Ácido Ascórbico/farmacologia , Feminino , Hemoglobinas/metabolismo , Humanos , Radioisótopos de Ferro , Marcação por Isótopo , Fígado/metabolismo , Masculino , Coelhos , Transferrina/metabolismo , Triticum , VenezuelaRESUMO
Sugar as a vehicle for iron fortification presents several advantages over the other vehicles used in the last three decades. In vitro studies demonstrated that ferrous sulfate added to sugar in proportion of 1 mg to 1 g, respectively, is maintained in the ferrous form for a period of at least 1 year and does not induce adverse changes in the vehicle. Sugar, by itself, carries practically no inhibitors for the absorption of iron. Iron absorption from fortified sugar mixed with vegetals is the same as that of native vegetal iron. The absorption from fortified sugar is increased more than 50% over that observed from native vegetal when it is administered as a drink during the ingestion of a meal. A further increase in absorption was found when fortified sugar was administered with beverages. The mean absorption ratio of fortified sugar given with orange juice, Coca-Cola, and Pepsi-Cola to a reference dose of iron ascorbate was between 0.45 and 0.66, which is more than 3 times the absorption of this iron fortification mixed with vegetals. The mean absorption ratio from coffee was 0.30, and from coffee with milk, 0.15. These data indicate that the fortification of sugar with iron could be a better procedure for the prevention of iron deficiency than the iron fortification of bread and wheat products, from which iron is poorly absorbed. It could be used in developing countries where beverages are highly consumed by the low socioeconomic class. This program could be extended to all sugar consumption or be restricted to soft drinks.