Effects of a moderate iron overload and its interaction with yacon flour, and/or phytate, in the diet on liver antioxidant enzymes and hepatocyte apoptosis in rats.

The effect of moderate Fe overload in the diet and its interaction with phytate, and/or yacon flour (YF), recognized as an inhibitor, and facilitator, of Fe absorption, respectively, was evaluated in healthy rats. For this purpose the following parameters were analyzed: (1) apparent iron (Fe), copper (Cu) and zinc (Zn) absorption; (2) blood Fe; (3) blood lipids (cholesterol, tryacylglicerol); (4) blood AST and ALT; (5) liver histology (histopathology, hemosiderin depots, apoptosis index; (6) liver fatty acid incorporation; (7) liver antioxidant enzyme activity. Moderate Fe overload may cause change in some liver markers (hemosiderin depots, apoptosis index and GPx) and blood lipids (total cholesterol and VLDL) and the interaction with yacon flour, and phytate, in the Fe overloaded diets may exert a protective effect on these alterations.

Dietary iron overload: short- and long-term effects on cecal morphometry in growing rats.

In animal models, Fe overload is associated with organ oxidative stress and tissue injury. In this context, luminal Fe may affect the mucosal barrier and function or generate a pathological milieu in the intestine that triggers epithelial cell stress. Here, we hypothesized that increased liver Fe levels resulting from dietary Fe overload may be associated with architectural changes in the cecal mucosa. Weanling male Wistar rats (n=7-10/group) were fed diets (modified from AIN-93G) containing adequate or supplemental Fe (approximately 10 times the recommended levels) for 4 and 12 wk. At euthanasia, the blood Hb was determined, and Fe analyses were performed in stool and liver samples using atomic absorption spectrophotometry. Cecal tissue was collected for histological and morphometric analysis. No significant differences were observed in the blood Hb or Hb Fe pool between groups in either period. Iron overload led to a higher fecal Fe excretion, whereas the liver Fe was increased only after 12 wk when compared with controls. After 4 wk, the consumption of Fe-overloaded diets resulted in changes in the mucosal architecture of the cecum, which were intensified after 12 wk. At this time, these changes were significantly correlated with the hepatic Fe content. These findings suggest that changes in the cecal mucosa may have occurred as a result of oxidative stress caused by excessive amounts of Fe in the intestinal lumen. The consequences of these effects on the intestinal absorption and its implications for liver Fe homeostasis should be considered in future studies.

Changes in bone mass, biomechanical properties, and microarchitecture of calcium- and iron-deficient rats fed diets supplemented with inulin-type fructans.

Feeding mineral-deficient diets enhances absorptive efficiency as an attempt of the body to compensate for the lack of an essential nutrient. Under certain circumstances, it does not succeed; and nutritional deficiency is produced. Our hypothesis was that inulin-type fructans (ITF), which are known to affect mineral absorption, could increase Ca and Fe bioavailability in Ca- and Fe-deficient rats. Male Wistar rats (n = 48, 4 weeks old) were assigned to 1 of 8 groups derived from 2 x 2 x 2 factorial design with 2 levels of added Fe (0 and 35 mg/kg), Ca (0 and 5 g/kg), and ITF (0 and 100 g/kg) for 33 days. The Fe status (hemoglobin, serum Fe, total Fe-binding capacity, transferrin saturation, liver minerals) was evaluated. Tibia minerals (Ca, Mg, and Zn), bone strength, and histomorphometry were determined. In nondeficient rats, ITF supplementation did not affect Fe status or organ minerals, with the exception of tibia Mg. Moreover, ITF improved bone resilience and led to a reduction in eroded surface per body surface and number of osteoclasts per area. In Ca-deficient rats, ITF increased liver (Fe and Zn) and tibia (Zn) mineral levels but impaired tibia Mg, yield load, and resilience. In conclusion, ITF worsened the tibia Mg levels and elastic properties when supplemented in Ca-deficient diets. In contrast, although bone Ca was not affected in nondeficient rats under the present experimental conditions, bone quality improved, as demonstrated by a moderate reduction in femur osteoclast resorption and significant increases in tibia Mg content and elasticity.

Effects of dietary lipid composition and inulin-type fructans on mineral bioavailability in growing rats.

OBJECTIVE: This study reports the effects of feeding with a combination of inulin-type fructans (ITF) and fish oil (FO) on mineral absorption and bioavailability as part of a semipurified diet offered to rats. METHODS: Male Wistar rats (n = 24) were fed a 15% lipid diet (soybean oil [SO] or a 1:0.3 fish:soybean oil mixture [FSO]) and diets containing the same sources of lipids supplemented with 10% ITF (Raftilose Synergy 1) ad libitum for 15 d. Feces and urine were collected for mineral analyses during the last 5 d of the test period. Fatty acid composition was determined in liver and cecal mucosa homogenates. Liver and bone mineral analyses were performed by atomic absorption spectrophotometry. Bone biomechanical analyses were evaluated by a 3-point bending test. RESULTS: Compared with the controls, ITF-fed rats had enlarged ceca and a significant decrease in cecal content pH (P < 0.001). The apparent mineral absorption was improved in these rats, and this effect was enhanced by dietary combination with FO for all minerals except for magnesium. Addition of ITF to the diet resulted in higher bone mineral content (calcium and zinc) and bone strength, but increased bone mineral content was only statistically significant in FO-fed animals. A decrease in liver iron stores (P = 0.015) was observed in rats fed FO, considering that ITF consumption returned to levels comparable to the SO control group. CONCLUSION: These findings confirm the positive influence of ITF on mineral bioavailability, which was potentiated by addition of FO to the diet.

Sobrecarga moderada de ferro em ratos: interação com frutanos e/ou fitato no metabolismo hepático e ósseo / Moderate iron overload in rats: interaction with fructans and/or phytate in hepatic and bone metabolism

O excesso de Fe no organismo gera espécies reativas de oxigênio (ERO) que são potencialmente tóxicas. Entretanto, a magnitude dos efeitos da exposição à moderada sobrecarga de Fe e da sua interação com facilitadores e/ou inibidores da absorção mineral não é conhecida. O objetivo deste trabalho foi avaliar esses efeitos e a sua interação com fruta nos e/ou fitato (facilitadores e inibidores da absorção de Fe, respectivamente) nos índices séricos do estado nutricional em Fe, no perfil dos lipídeos séricos e em parâmetros do metabolismo hepático e ósseo. Para o experimento foram utilizados 34 ratos machos Wistar, pesando inicialmente 49,3 ± 3,9g, alojados individualmente em gaiolas de aço semimetabólicas por 92 dias. Uma dieta AIN-93G (Dieta 1: Grupo Controle) e quatro dietas AIN93G modificadas foram usadas para o estudo, com as seguintes características: Dieta 2: sobrecarga moderada de ferro com 550mgFe/kg de ração (Grupo SBC); Dieta 3: sobrecarga moderada de ferro + 18% de farinha de yacon (Grupo SBC+FY); Dieta 4: sobrecarga moderada de ferro + 0,6% de fitato (Grupo SBC+FIT); Dieta 5: sobrecarga moderada de ferro + 18% de farinha de yacon + 0,6 % de fitato (Grupo SBC+FY+FIT). Os resultados demonstraram que a moderada sobrecarga de Fe ou a sua interação com farinha de yacon e/ou fitato não alterou os índices séricos do estado nutricional em Fe. Ocorreu aumento na atividade sérica da AST apenas no grupo SBC (p=0,055). Nos grupos SBC e SBC+FY houve diminuição na concentração do colesterol sérico (p=0,002) e, apenas no grupo SBC+FY+FIT, diminuição da concentração sérica do VLDL. No fígado, houve aumento significativo (p=0,002) da concentração de Fe não-heme nos grupos IO (+83%) e SBC+FIT (+117%) e, em todos os grupos SBC, na atividade da enzima GPx (p=0,000). A atividade da CAT foi menor (p=0,036) apenas para o grupo SBC+FY+FIT. Em todos os grupos SBC ocorreu significativo aumento nos depósitos de hemossiderina em torno das células de Kupffer (p=0,000). Houve aumento na apoptose em todos os grupos SBC, com os grupos SBC+FY e SBC+FY +FIT apresentando o maior número de corpúsculos apoptóticos/área (+405% e +342%, respectivamente) (p=0,000). Não houve alteração nos parâmetros relacionados ao metabolismo ósseo. No grupo SBC+FY houve significativo aumento na absorção aparente de Ca (p<0,05). Conclusões: A moderada sobrecarga de Fe não alterou os índices séricos do estado nutricional em Fe, mas resultou em alterações no tecido hepático e no perfil dos lipídeos séricos. Com exceção do perfil de lipídeos séricos, no qual apenas o fitato pareceu exercer efeito protetor, nos demais parâmetros avaliados a interação com farinha de yacon rica em fruta nos e/ou fitato reverteu parcial ou totalmente as alterações induzidas pela moderada sobrecarga de Fe

Excess Fe in the organism generates potentially toxic reactive oxygen species (ROS). However, the magnitude of the effects of a moderate Fe overload and its interaction with factors which inhibit or facilitate mineral absorption is not known. The aim of the present work was to evaluate such effects and their interaction with fructans and/or phytate (compounds which facilitate and inhibit Fe absorption, respectively) on serum iron status indices, on the profile of serum lipids and on hepatic and bone metabolism parameters. In the experiment, thirty-four male Wistar rats initially weighing 49,3 ± 3,9g were used. The rats were housed in individual stainless-steel wire-mesh cages for 92 days. An AIN-93G diet (Diet 1: Control Group) and four modified AIN-93G diets were used in the study. The modified diets presented the following formulations: Diet 2: moderate Fe overload with 550mgFe/kg diet (IO Group); Diet 3: moderate Fe overload + 18% yacon flour (IO-YF Group); Diet 4: moderate Fe verload + 0.6% phytate (IO-Phy Group); Diet 5: moderate Fe overload + 18% yacon flour + 0.6% phytate (IO-YF-Phy Group). The results demonstrated that a moderate Fe overload or its interaction with yacon flour and/or phytate did not alter the serum iron status indices. An increase in the serum AST activity was observed only in the IO group (p=0,055). In the IO and IO-YF groups, there was a reduction in the serum cholesterol concentration (p=0,002) and a reduction in the serum VLDL concentration was observed only in the IO-YF-Phy group. In the liver, there was a significant increase (p=0,002) in non-heme Fe concentration in the IO (+83%) and IO-Phy (+117%) groups. Also, GPx activity was significantly increased (p=0,000) in all IO groups. CAT activity was lower (p=0,036) only in the IO-YF-Phy group. A significant increase in hemosiderin deposition around Kupffer cells was observed in all IO groups (p=0,000). Apoptosis was increased in all IO groups, whereas the IO-YF and IO-YF-Phy groups showed the largest number of apoptotic bodies/area (+405% and +342%, respectively) (p=0,000). There was no alteration in the parameters related to bone metabolism. In the IO-YF group, there was a significant increase in Ca apparent absorption (p<0,05).Conclusions: The moderate Fe overload did not alter the serum iron status índices, but led to alterations in the hepatic tissue and in the profile of serum lipids. Except for the profile of serum lipids where only phytate seemed to have a protective effect, in the other evaluated parameters the interaction with yacon flour rich in fructans and/or phytate partially or totally reversed the alterations induced by the moderate Fe overload

Avaliação por métodos in vitro e in vivo da biodisponibilidade de sulfato ferroso microencapsulado / In vitro and in vivo evaluation of iron bioavailability from microencapsulated ferrous sulfate

OBJETIVO: Avaliar, por métodos in vitro e in vivo, a biodisponibilidade de uma nova forma de sulfato ferroso microencapsulado (genericamente denominado Ferlim), desenvolvido para a fortificação de alimentos, comparando-a com a de ferro eletrolítico (Fe0). MÉTODOS: A avaliação da dialisabilidade in vitro utilizou como matriz leite em pó reconstituído. A avaliação in vivo, utilizando o método de recuperação de hemoglobina em leitões anêmicos, teve duração de 13 dias e os animais (n=23) foram agrupados de acordo com o produto do peso (kg) x hemoglobina (g/dL). Como controle foi utilizado FeSO4.7H2O. RESULTADOS: As porcentagens médias de ferro dialisado foram 2,2 (desvio-padrão=0,1) por cento, 3,4 (desvio-padrão=0,1) por cento e 3,6 (desvio-padrão=0,0) por cento para FeSO4.7H2O, Ferlim e Fe0, respectivamente (p<0,05). A absorção de ferro foi de 16,0 (desvio-padrão=3,1) por cento para o grupo controle, de 15,1 (desvio-padrão=3,8) por cento para o grupo Ferlim e de 12,8 (desvio-padrão=4,3) por cento para o grupo Fe0, não sendo significantemente diferentes (p>0,05). As porcentagens de absorção do valor biológico relativo do FeSO4.7H2O foram de 94,2 (desvio-padrão=23,8) por cento para o grupo Ferlim e de 79,7 (desvio-padrão=26,6) por cento para o grupo Fe0, sem diferenças significantes (p>0,05). Em valores numéricos (p>0,05), o grupo Fe0 apresentou menor média de absorção ( por cento) valor biológico relativo de concentração de ferro total, de ferro heme e não-heme no fígado. CONCLUSÃO: A microencapsulação do sulfato ferroso com alginato mantém sua biodisponibilidade, caracterizando-se como boa alternativa para a fortificação de misturas sólidas.

OBJECTIVE: To evaluate, by in vitro and in vivo methods, the bioavailability of a new microencapsulated ferrous sulfate (Ferlim) developed for food fortification, and compare it with electrolytic iron (Fe0). METHODS: In vitro dialyzability assessment used reconstituted milk powder as matrix. In vivo assessment using the hemoglobin regeneration method in anemic piglets lasted for 13 days and the animals (n=23) were grouped according to the product of weight (kg) x hemoglobin (g/dL). FeSO4.7H2O was used as control. RESULTS: The percentages of dialyzed iron were 2.2 (standard deviation=0.1) percent, 3.4 (standard deviation=0.1) percent and 3.6 (standard deviation=0.0) percent for FeSO4.7H2O, Ferlim and Fe0 respectively (p<0.05). Iron absorption was 16.0 (standard deviation=3.1) percent for the control group, 15.1 (standard deviation=3.8) percent for the Ferlim group and 12.8 (standard deviation=4.3) percent for the Fe0 group; the differences were not significant (p>0.05). The absorption percentages of the relative biological value of FeSO4.7H2O were 94.2 (standard deviation=23.8) percent for the Ferlim group and 79.7 (standard deviation=26.6) percent for the Fe0 group; the differences were not significant (p>0.05). In numerical values (p>0.05), the Fe0 group presented the lowest mean relative biological value absorption ( percent) and concentration of total iron, heme iron and non-heme iron in the liver. CONCLUSION: Microencapsulation of ferrous sulfate with alginate retains its bioavailability therefore it is a good alternative for the fortification of solid mixtures.