Methods currently used to determine iron bioavailability have disadvantages for both the subjects and researchers involved. One safe and simple method that needs further evaluation, the serum iron absorption method, involves an initial blood drawing, dosage s of iron, and blood drawings taken at intervals thereafter. Generally, the rise in serum iron or area under the curve is used to determine iron uptake. Two experiments were conducted using the serum iron absorption method in an effort to improve the utility of this method for the measurement of iron bioavailability. With this effort in mind, an equation adjusting for dose of iron (0.5-8 mg) and blood volume was used to estimate serum iron absorption and allow for adequate comparisons of other iron absorption data obtained with this method and others. One very significant result was that low serum ferritin was found to be a predictor of high serum estimated iron absorption (SEIA). Similarly, low serum ferritin levels were also highly correlated to iron absorption when radioiron methods were used. In Experiment I, college-aged women (n=11) with low serum ferritin levels (average 11 ng/ml) participated in four serum iron trials in which four iron sources were used as iron dosages. Ferrous sulfate in orange juice (2.2 mg iron), ground beef (0.62 mg iron), cereal (6.6 mg iron), and ground beef and cereal together (3.6 mg iron) were used. Comparisons were made between the results obtained using this serum iron absorption data and other radioiron absorption data for similar iron sources, and the results were quite similar to iron absorption levels reported in the literature. In Experiment I, the ferrous sulfate (40%) and ground beef treatments (46%) had the highest serum estimated iron absorption (SEIA) and the cereal/ground beef (5%) and cereal treatments (3%) had significantly less. Experiment II involved 28 college-aged women who participated in four serum iron absorption trials. For these four trials the iron dose was the same (2 mg iron as ferrous sulfate in orange juice). However, pre-trial supplements containing either (1) 30 mg iron, 60 mg ascorbic acid, (2) 30 mg iron, no ascorbic acid, (3) no iron, 60 mg ascorbic acid, or (4) a placebo were given (one per day) on each of the three days prior to the weekly serum iron absorption trials. During each pre-trial supplementation period, three daily diet records were kept by subjects to determine if the previous intake of nutrients (from food or pre-trial supplements) influenced the outcome of the serum iron absorption trial. Pre-trial supplementation of 30 mg iron, no ascorbic acid caused a significantly lower SEIA. Dietary nutrients did not cause a significant effect on SEIA. Mean SEIA following combined iron supplements was lower (p=0.081) 16% vs. 23% following non-iron containing supplements. For this experiment, the SEIA was higher in subjects with low serum ferritin (20 ng/ml).

Dietary calcium has been classified as one of the minerals frequently limiting in the American diet (FAO, 1962) . Bone demineralization has been observed as a result of calcium deficient diets (Salomon et al., 1972), partial gastrectomies (Eddy, 1971) and inadequate hormonal balance (Albright et al., 1948). Although bone demineralization, or osteoporosis, has been attributed to many factors, the interrelationship of gastric acidity and the utilization of dietary calcium may be a key to the etiology of osteoporosis. Eighty weanling male albino rats were divided into eight groups. All animals had their stomachs exposed through a mid-line incision. Control rats were sham-operated while the treatment animals had their stomachs X-irradiated to destroy the secretory cells. Four diets were prepared containing calcium carbonate, calcium chloride, tri-calcium phosphate or calcium gluconate as calcium sources. For a three-week experimental period, ten control and ten X-irradiated rats were fed each diet. In vitro data suggests that the solubility of each calcium salt, except calcium gluconate, increased in an acid media. Saturated viii ix solutions of calcium carbonate and tri-calcium phosphate had low quantities of calcium ion in solution in neutral pH's, but as the acidity was changed from pH 4 to pH 3 the calcium ion concentration increased as much as eight times. This demonstrates that the presence of acid with insoluble forms of calcium salts will generally increase calcium ion concentration in solution. All X-irradiated animals had an average fasting gastric pH of over 6, while the control rats averaged pH 2.5. The calcium absorption data demonstrates that X-irradiated rats fed diets containing soluble calcium salts (calcium chloride, 18.5 percent and calcium gluconate, 25.13 percent) had increased absorption values over those fed diets containing calcium salts of low solubility (calcium carbonate, 12.94 percent and tri-calcium phosphate, -7.06 percent). Femur strength and bone calcium data reflected similar evidence. Both femur strength and bone calcium of the X-irradiated rats fed the less soluble forms of calcium salt were significantly lower than the controls, while X-irradiated rats fed the more soluble forms of calcium had femur strength and bone calcium similar to the controls. Achlorhydric, or X-irradiated, animals were observed to have decreased iron stores in comparison with the control rats. Hemoglobin levels, liver iron and iron absorption were all significantly reduced in the x-irradiated animals. From the results of these experiments, it is apparent that gastric acidity and the solubility of the dietary calcium source play an important role in the utilization of calcium.

A considerable amount of research has shown that a severe dietary deficiency of protein or vitamins will markedly depress antibody synthesis. Very little work has been done with the effect of mineral deficiencies on antibody production, and no evidence has been presented showing the relationship of the effects of small changes in nutrient intake to the sensitivity of the antibody response to small degrees of malnutrition and the relationship of dietary iron, calcium and vitamin D to the production of antibodies. In two experiments, it was shown that as the level of iron in the diet is decreased, the production of antibodies is decreased proportionally. In the first iron experiment, 42, weanling male rats were given 7 levels of iron ranging from 20 to 5 mg Fe/kg diet. Antibody titer after immunization with tetanus toxoid was decreased proportionally from 88 to 17. In a second iron experiment, 10 raths were given either 10 or 0 mg Fe/kg diet and their titers to tetanus toxoid were 340 and 19 respectively. In another two experiments, it was found that the level of dietary calcium makes little or no significant difference on antibody production, when fed either with or without vitamin D. In the first calcium experiment, 20 rats were given either 6.3, 4.4. or 3.2 gm Ca/kg diet and their antibody titers after tetanus toxoid immunization ranged from 88 to 55. in the final calcium study, 50 rats were divided into ten groups and given five different levels of dietary calcium ranging from 6.3 to 1.3 gm Ca/kg diet. Half of each dietary group was given adequate vitamin D and vitamin D was withheld from the other half. In this experiment, antibody titers to tetanus toxoid ranged from 90 to 110. From the results of these experiments, it is apparent that dietary iron plays an important role in the synthesis of antibodies and thus in the maintainance of resistance against infectious disease. It is also evident that the antibody response is sensitive to different degrees of malnutrition, with antibody production being decreased proportionally to the severity of the dietary deficiency.

No description available.

Student Number : 9902006N - MSc(Med) Dissertation - School of Medicine - Faculty of Health Sciences / Hepatocellular carcinoma (HCC) is the most common primary malignant tumour of the liver. Aflatoxin B1 (AFB1) is a potent hepatocarcinogen, and dietary iron overload has been shown to contribute to HCC development in black africans. Both are well studied hepatotoxins. The aim of this study was to use a Wistar rat model over a 12 month period to investigate synergy and the extent thereof between AFB1 ingestion and dietary iron overload. 25ug/day of AFB1, reconstituted in DMSO, was administered by gavaging the animals, over a period of 10 days with a 2 day interval in between. The chow diet was supplemented with 0.75% (w/w) ferrocene iron. Experimental subjects were divided into 4 groups. Group 1 was fed the normal chow diet. Group 2 was fed 0.75% (w/w) ferrocene iron alone. Group 3 was gavaged 250μg AFB1 alone. Group 4 was fed the 0.75% (w/w) ferrocene iron and gavaged 250μg AFB1. A number of assays were conducted to investigate synergy. Colorimetric assays were used to measure serum iron, total-iron binding capacity, ALT, AST, GGT, nitrite production, lipid peroxidation and hydroxyproline concentrations. ELISA’s were used to determine ferritin, 8-isoprostane and 8-hydroxyguanosine concentrations. Nontransferrin bound iron was measured using an HPLC method. A chemiluminescent assay was used to measure superoxide anion production. Cytokines were measured using a suspension array system. Mutagenicity was assessed using the Ames mutagenicity assay using salmonella typhimirium strains TA97, TA98, TA100 and TA102. Iron profiling indicated that iron overloading occurred with the ingestion of the ferrocene diet. Biomarkers of oxidative stress, as illustrated by the measurement of 8-hydroxyguanosine and lipid peroxidation, showed additive synergistic effects between the two carcinogens. The anti-inflammatory interleukin-10 was shown to be markedly elevated with the co-administration of the two carcinogens, indicating the elevated inflammatory processes. Additive synergistic effects were noted in terms of the liver disease marker ALT. The salmonella typhimirium strain TA102 used in the Ames mutagenicity test showed increased colony counts with respect to the coadministration of carcinogens (P<0.05), although no synergistic effect was noted. In a few of the presented parameters, the AFB1 group was not significantly different to the control group, although significant differences between the Fe group and the Fe + AFB1 groups were noted. The implication of which is that the presence of AFB1 is increasing the activity of Fe as a carcinogen, thereby acting as a co-carcinogen. Examples of such parameters illustrating this are presented in the results section including serum ALT, serum nitrite, liver and serum lipid peroxidation, liver and serum 8-hydroxyguanosine, some of the mutagenicity assays, and interleukin-10. The conclusion of this study suggests that AFB1 acts as a co-carcinogen in the presence of iron overloading, implying that a synergistic relationship between these two toxins exists.

Introdução: A deficiência de ferro decorre, principalmente, da quantidade insuficiente de ferro na dieta para atender às necessidades nutricionais do indivíduo. Seu estágio mais grave, a anemia ferropriva, é reconhecida como um problema epidemiológico da maior relevância, sendo as crianças em idade pré-escolar, especialmente os lactentes, o grupo mais vulnerável à desnutrição. Objetivo: Identificar a prática alimentar e estimar sua capacidade de atender à recomendação e à necessidade de ferro das crianças de 6 a 23 meses de idade atendidas pela Estratégia Saúde da Família no Maranhão. Métodos: Estudo transversal de base populacional realizado no estado do Maranhão. A partir dos dados de consumo referido (inquérito recordatório de 24h), foram identificadas as práticas alimentares e calculadas quantidades de ferro, vitamina C e de energia a partir dos quais se quantificou o ferro biodisponível utilizando a equação de Monsen e Balintfly. Estimaram-se, ainda, as densidades do ferro total e do ferro biodisponível, além da adequação às recomendações da OMS. Resultados: Do total de 401 crianças estudadas, 7 crianças permaneciam em aleitamento materno exclusivo e dentre aquelas em que foi referida a alimentação complementar, o leite materno esteve presente entre 53 por cento delas, mesmo com a introdução do leite de vaca. A quantidade média de energia foi 826 kcal; ferro total 5,4 mg; ferro biodisponível 0,31 mg; densidade de Ferro/1000kcal= 6,4 e densidade de Ferro biodisponível/1000kcal= 0,34. Em comparação às recomendações, a ingestão energética apresentou valores abaixo da recomendação para mais de 50 por cento da população de estudo, em todas as faixas etárias, já em relação ao ferro, a partir dos 15 meses pelo menos 60 por cento das crianças alcançam a recomendação. Conclusão: A prática alimentar não se mostrou adequada para atender à recomendação e à necessidade de ferro diária, o que pode ser explicado pelo baixo consumo de alimentos fontes de ferro, com boa biodisponibilidade do mineral e de alimentos estimuladores de sua absorção. / Introduction: Iron deficiency is mainly due to the insufficient amount of iron in the diet to meet the nutritional needs of the individual. Its most severe stage, iron deficiency anemia is recognized as an epidemiological problem of the greatest importance, being the children of preschool age, especially infants, the group most vulnerable to malnutrition. Objective: To identify eating habits and estimate their ability to meet the recommendation and the need of iron for children 6-23 months of age served by the Family Health Strategy in Maranhão. Methods: Sectional study population-based study conducted in the state of Maranhão. From the data of consumption above (R24h), dietary practices and calculated amounts of iron, vitamin C and energy were identified from which the bioavailable iron was quantified using the equation of Monsen and Balintfly. Were estimated, furthermore, the densities of total iron and bioavailable iron, as well as compliance with WHO recommendations. Results: Of the 401 children studied, seven children remained in exclusive breastfeeding and among those that was reported complementary feeding, breast milk was present among 53per cent of them, even with the introduction of cow\'s milk. The average amount of energy was 826 kcal; Total Iron 5.4 mg; bioavailable iron 0.31 mg; density of Iron / 1000 kcal = 6.4 and density of bioavailable iron / 1000 kcal = 0.34. Compared to the recommendations, energy intake showed values below the recommendation for more than 50per cent of the study population in all age groups, as compared to iron, from 15 months at least 60per cent of children reach the recommendation. Conclusion: A diet was not adequate to meet the recommendation and the need for daily iron, which can be explained by low consumption of iron-rich foods with good bioavailability of the mineral-stimulating food absorption.

Introdução: A deficiência de ferro decorre, principalmente, da quantidade insuficiente de ferro na dieta para atender às necessidades nutricionais do indivíduo. Seu estágio mais grave, a anemia ferropriva, é reconhecida como um problema epidemiológico da maior relevância, sendo as crianças em idade pré-escolar, especialmente os lactentes, o grupo mais vulnerável à desnutrição. Objetivo: Identificar a prática alimentar e estimar sua capacidade de atender à recomendação e à necessidade de ferro das crianças de 6 a 23 meses de idade atendidas pela Estratégia Saúde da Família no Maranhão. Métodos: Estudo transversal de base populacional realizado no estado do Maranhão. A partir dos dados de consumo referido (inquérito recordatório de 24h), foram identificadas as práticas alimentares e calculadas quantidades de ferro, vitamina C e de energia a partir dos quais se quantificou o ferro biodisponível utilizando a equação de Monsen e Balintfly. Estimaram-se, ainda, as densidades do ferro total e do ferro biodisponível, além da adequação às recomendações da OMS. Resultados: Do total de 401 crianças estudadas, 7 crianças permaneciam em aleitamento materno exclusivo e dentre aquelas em que foi referida a alimentação complementar, o leite materno esteve presente entre 53 por cento delas, mesmo com a introdução do leite de vaca. A quantidade média de energia foi 826 kcal; ferro total 5,4 mg; ferro biodisponível 0,31 mg; densidade de Ferro/1000kcal= 6,4 e densidade de Ferro biodisponível/1000kcal= 0,34. Em comparação às recomendações, a ingestão energética apresentou valores abaixo da recomendação para mais de 50 por cento da população de estudo, em todas as faixas etárias, já em relação ao ferro, a partir dos 15 meses pelo menos 60 por cento das crianças alcançam a recomendação. Conclusão: A prática alimentar não se mostrou adequada para atender à recomendação e à necessidade de ferro diária, o que pode ser explicado pelo baixo consumo de alimentos fontes de ferro, com boa biodisponibilidade do mineral e de alimentos estimuladores de sua absorção. / Introduction: Iron deficiency is mainly due to the insufficient amount of iron in the diet to meet the nutritional needs of the individual. Its most severe stage, iron deficiency anemia is recognized as an epidemiological problem of the greatest importance, being the children of preschool age, especially infants, the group most vulnerable to malnutrition. Objective: To identify eating habits and estimate their ability to meet the recommendation and the need of iron for children 6-23 months of age served by the Family Health Strategy in Maranhão. Methods: Sectional study population-based study conducted in the state of Maranhão. From the data of consumption above (R24h), dietary practices and calculated amounts of iron, vitamin C and energy were identified from which the bioavailable iron was quantified using the equation of Monsen and Balintfly. Were estimated, furthermore, the densities of total iron and bioavailable iron, as well as compliance with WHO recommendations. Results: Of the 401 children studied, seven children remained in exclusive breastfeeding and among those that was reported complementary feeding, breast milk was present among 53per cent of them, even with the introduction of cow\'s milk. The average amount of energy was 826 kcal; Total Iron 5.4 mg; bioavailable iron 0.31 mg; density of Iron / 1000 kcal = 6.4 and density of bioavailable iron / 1000 kcal = 0.34. Compared to the recommendations, energy intake showed values below the recommendation for more than 50per cent of the study population in all age groups, as compared to iron, from 15 months at least 60per cent of children reach the recommendation. Conclusion: A diet was not adequate to meet the recommendation and the need for daily iron, which can be explained by low consumption of iron-rich foods with good bioavailability of the mineral-stimulating food absorption.