scholarly journals Dietary Iron

2021 ◽  
Author(s):  
Kouser Firdose ◽  
Noor Firdose
Keyword(s):  
Iron Absorption ◽  
Inositol Phosphate ◽  
Iron Bioavailability ◽  
Animal Origin ◽  
Dietary Iron ◽  
Physiologic Mechanism ◽  
Prevalence Of Obesity ◽  
Iron Iron ◽  
Haem Iron ◽  
Iron Excretion

Iron metabolism differs from the metabolism of other metals in that there is no physiologic mechanism for iron excretion, it is unusual; approximately 90% of daily iron needs are obtained from an endogenous source, the breakdown of circulating RBCs. Additionally humans derive iron from their everyday diet, predominantly from plant foods and the rest from foods of animal origin. Iron is found in food as either haem or non-haem iron. Iron bioavailability has been estimated to be in the range of 14–18% for mixed diets and 5–12% for vegetarian diets in subjects with no iron stores. Iron absorption in humans is dependent on physiological requirements, but may be restricted by the quantity and availability of iron in the diet. Bioavailability of food iron is strongly influenced by enhancers and inhibitors in the diet. Iron absorption can vary from 1 to 40%. A range of iron bioavailability factors that depend on the consumption of meat, fruit, vegetables, processed foods, iron-fortified foods, and the prevalence of obesity. The methods of food preparation and processing influence the bioavailability of iron. Cooking, fermentation, or germination can, by thermal or enzymatic action, reduce the phytic acid and the hexa- and penta-inositol phosphate content. Thus improving bioavailability of non-haem iron. This chapter will elaborate the dietary iron sources and means of enhancing bioavailability.

scholarly journals Dietary Iron Bioavailability: A Simple Model That Can Be Used to Derive Country-Specific Values for Adult Men and Women

2019 ◽  
Vol 41 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Susan Fairweather-Tait ◽  
Cornelia Speich ◽  
Comlan Evariste S. Mitchikpè ◽  
Jack R. Dainty
Keyword(s):  
Iron Absorption ◽  
Iron Status ◽  
Iron Bioavailability ◽  
Whole Body ◽  
Dietary Iron ◽  
Iron Intake ◽  
Middle Income ◽  
Iron Losses ◽  
Using Data ◽  
The 1960S

Background: Reference intakes for iron are derived from physiological requirements, with an assumed value for dietary iron absorption. A new approach to estimate iron bioavailability, calculated from iron intake, status, and requirements was used to set European dietary reference values, but the values obtained cannot be used for low- and middle-income countries where diets are very different. Objective: We aimed to test the feasibility of using the model developed from United Kingdom and Irish data to derive a value for dietary iron bioavailability in an African country, using data collected from women of child-bearing age in Benin. We also compared the effect of using estimates of iron losses made in the 1960s with more recent data for whole body iron losses. Methods: Dietary iron intake and serum ferritin (SF), together with physiological requirements of iron, were entered into the predictive model to estimate percentage iron absorption from the diet at different levels of iron status. Results: The results obtained from the 2 different methods for calculating physiological iron requirements were similar, except at low SF concentrations. At a SF value of 30 µg/L predicted iron absorption from the African maize-based diet was 6%, compared with 18% from a Western diet, and it remained low until the SF fell below 25 µg/L. Conclusions: We used the model to estimate percentage dietary iron absorption in 30 Beninese women. The predicted values agreed with results from earlier single meal isotope studies; therefore, we conclude that the model has potential for estimating dietary iron bioavailability in men and nonpregnant women consuming different diets in other countries.

Dietary and Physiological Factors That Affect the Absorption and Bioavailability of Iron

2005 ◽  
Vol 75 (6) ◽  
pp. 375-384 ◽  
Author(s):  
Janet R. Hunt
Keyword(s):  
Iron Deficiency ◽  
Molecular Mechanisms ◽  
Iron Absorption ◽  
Iron Status ◽  
Work Capacity ◽  
Iron Bioavailability ◽  
Human Studies ◽  
Dietary Iron ◽  
Iron Availability ◽  
Blood Indices

Iron deficiency, a global health problem, impairs reproductive performance, cognitive development, and work capacity. One proposed strategy to address this problem is the improvement of dietary iron bioavailability. Knowledge of the molecular mechanisms of iron absorption is growing rapidly, with identification of mucosal iron transport and regulatory proteins. Both body iron status and dietary characteristics substantially influence iron absorption, with minimal interaction between these two factors. Iron availability can be regarded mainly as a characteristic of the diet, but comparisons between human studies of iron availability for absorption require normalization for the iron status of the subjects. The dietary characteristics that enhance or inhibit iron absorption from foods have been sensitively and quantitatively determined in human studies employing iron isotopes. People with low iron status can substantially increase their iron absorption from diets with moderate to high availability. But while iron supplementation and fortification trials can effectively increase blood indices of iron status, improvements in dietary availability alone have had minimal influence on such indices within several weeks or months. Plentiful, varied diets are the ultimate resolution to iron deficiency. Without these, more modest food-based approaches to human iron deficiency likely will need to be augmented by dietary iron fortification.

Co‐products of beef processing enhance non‐haem iron absorption in an in vitro digestion/caco‐2 cell model

2018 ◽  
Vol 54 (4) ◽  
pp. 1256-1264 ◽  
Author(s):  
Elisabeth A. A. O'Flaherty ◽  
Paraskevi Tsermoula ◽  
Eileen E. O'Neill ◽  
Nora M. O'Brien
Keyword(s):  
Iron Absorption ◽  
Cell Model ◽  
In Vitro Digestion ◽  
Beef Processing ◽  
Haem Iron

scholarly journals An intensified training schedule in recreational male runners is associated with increases in erythropoiesis and inflammation and a net reduction in plasma hepcidin

2018 ◽  
Vol 108 (6) ◽  
pp. 1324-1333 ◽  
Author(s):  
Diego Moretti ◽  
Samuel Mettler ◽  
Christophe Zeder ◽  
Carsten Lundby ◽  
Anneke Geurts-Moetspot ◽  
...  
Keyword(s):  
Exercise Training ◽  
Iron Absorption ◽  
Iron Status ◽  
Geometric Mean ◽  
Iron Bioavailability ◽  
Oral Iron ◽  
Low Grade ◽  
Hemoglobin Mass ◽  
Low Grade Inflammation ◽  
Iron Utilization

ABSTRACT Background Iron status is a determinant of physical performance, but training may induce both low-grade inflammation and erythropoiesis, exerting opposing influences on hepcidin and iron metabolism. To our knowledge, the combined effects on iron absorption and utilization during training have not been examined directly in humans. Objective We hypothesized that 3 wk of exercise training in recreational male runners would decrease oral iron bioavailability by increasing inflammation and hepcidin concentrations. Design In a prospective intervention, nonanemic, iron-sufficient men (n = 10) completed a 34-d study consisting of a 16-d control phase and a 22-d exercise-training phase of 8 km running every second day. We measured oral iron absorption and erythroid iron utilization using oral 57Fe and intravenous 58Fe tracers administered before and during training. We measured hemoglobin mass (mHb) and total red blood cell volume (RCV) by carbon monoxide rebreathing. Iron status, interleukin-6 (IL-6), plasma hepcidin (PHep), erythropoietin (EPO), and erythroferrone were measured before, during, and after training. Results Exercise training induced inflammation, as indicated by an increased mean ± SD IL-6 (0.87 ± 1.1 to 5.17 ± 2.2 pg/mL; P < 0.01), while also enhancing erythropoiesis, as indicated by an increase in mean EPO (0.66 ± 0.42 to 2.06 ± 1.6 IU/L), mHb (10.5 ± 1.6 to 10.8 ± 1.8 g/kg body weight), and mean RCV (30.7 ± 4.3 to 32.7 ± 4.6 mL/kg) (all P < 0.05). Training tended to increase geometric mean iron absorption by 24% (P = 0.083), consistent with a decreased mean ± SD PHep (7.25 ± 2.14 to 5.17 ± 2.24 nM; P < 0.05). The increase in mHb and erythroid iron utilization were associated with the decrease in PHep (P < 0.05). Compartmental modeling indicated that iron for the increase in mHb was obtained predominantly (>80%) from stores mobilization rather than from increased dietary absorption. Conclusions In iron-sufficient men, mild intensification of exercise intensity increases both inflammation and erythropoiesis. The net effect is to decrease hepcidin concentrations and to tend to increase oral iron absorption. This trial was registered at clinicaltrials.gov as NCT01730521.

The Precision of in vitro Methods and Algorithms for Predicting the Bioavailability of Dietary Iron

2005 ◽  
Vol 75 (6) ◽  
pp. 436-445 ◽  
Author(s):  
Sean Lynch
Keyword(s):  
Iron Absorption ◽  
Heme Iron ◽  
Iron Bioavailability ◽  
Cell Uptake ◽  
In Vitro Tests ◽  
Cellular Iron ◽  
Non Heme Iron ◽  
Human Volunteers ◽  
Dialyzable Iron

Three factors determine how much iron will be absorbed from a meal. They are the physiological mechanisms that regulate uptake by and transfer through the enterocytes in the upper small intestine, the quantity of iron in the meal, and its availability to the cellular iron transporters. Established methods exist for predicting the effect of physiological regulation and for measuring or estimating meal iron content. Three approaches to estimating bioavailability have been advocated. Two are in vitro screening procedures: measurement of dialyzable iron and Caco-2 cell uptake, both carried out after in vitro simulated gastric and pancreatic digestion. The third is the use of algorithms based on the predicted effects of specific meal components on absorption derived from isotopic studies in human volunteers. The in vitro procedures have been very useful for identifying and characterizing factors that affect non-heme iron absorption, but direct comparisons between absorption predicted from the in vitro tests and measurements in human volunteers have only been made in a limited number of published studies. The available data indicate that dialysis and Caco-2 cell uptake are useful for ranking meals and single food items in terms of predicted iron bioavailability, but may not reflect the magnitudes of the effects of factors that influence absorption accurately. Algorithms based on estimates of the amounts of heme iron and of enhancers and inhibitors of non-heme iron absorption in foods make it possible to classify meals or diets as being of high, medium, or low bioavailability. The precision with which meal iron bioavailability can be predicted in a population, for which a specific algorithm has been developed, is improved by measuring the content of the most important enhancers and inhibitors. However, the accuracy of such predictions appears to be much lower when the algorithm is applied to meals eaten by different populations.

scholarly journals Comparative Evaluation of Intestinal Absorption and Functional Value of Iron Dietary Supplements and Drug with Different Delivery Systems

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5989
Author(s):  
Paolo Pastore ◽  
Marco Roverso ◽  
Erik Tedesco ◽  
Marta Micheletto ◽  
Etienne Mantovan ◽  
...  
Keyword(s):  
Side Effects ◽  
Dietary Supplements ◽  
Iron Absorption ◽  
Therapeutic Targets ◽  
Iron Bioavailability ◽  
The Other ◽  
Time Dependent ◽  
Nutritional Deficiencies ◽  
Deficiency Anemia ◽  
Iron Supplements

Iron is a fundament micronutrient, whose homeostasis is strictly regulated. Iron deficiency anemia is among the most widespread nutritional deficiencies and its therapy, based on dietary supplement and drugs, may lead to severe side effects. With the aim of improving iron bioavailability while reducing iron oral therapy side effects, novel dietary supplements based on innovative technologies—microencapsulation, liposomes, sucrosomes—have been produced and marketed. In the present work, six iron dietary supplements for different therapeutic targets were compared in terms of bioaccessibility, bioavailability, and safety by using an integrated in vitro approach. For general-purpose iron supplements, ME + VitC (microencapsulated) showed a fast, burst intestinal iron absorption kinetic, which maintained iron bioavailability and ferritin expression constant over time. SS + VitC (sucrosomes), on the other side, showed a slower, time-dependent iron absorption and ferritin expression trend. ME + Folate (microencapsulated) showed a behavior similar to that of ME + VitC, albeit with a lower bioavailability. Among pediatric iron supplements, a time-dependent bioavailability increase was observed for LS (liposome), while PIC (polydextrose-iron complex) bioavailability is severely limited by its poor bioaccessibility. Finally, except for SS + VitC, no adverse effects on intestinal mucosa vitality and barrier integrity were observed. Considering obtained results and the different therapeutic targets, microencapsulation-based formulations are endowed with better performance compared to the other formulations. Furthermore, performances of microencapsulated products were obtained with a lower iron daily dose, limiting the potential onset of side effects.

scholarly journals Intestinal Mucosal Mechanisms Controlling Iron Absorption

Blood ◽  
1963 ◽  
Vol 22 (4) ◽  
pp. 406-415 ◽  
Author(s):  
MARCEL E. CONRAD ◽  
WILLIAM H. CROSBY ◽  
Betty Merrill
Keyword(s):  
Iron Deficiency ◽  
Epithelial Cells ◽  
Iron Absorption ◽  
The Body ◽  
Iron Store ◽  
Dietary Iron ◽  
Receptor System ◽  
Excess Iron ◽  
Metabolic Requirement ◽  
Iron Receptor

Abstract Radioautographic studies provide evidence to support a concept of the mechanism whereby the small intestine controls absorption of iron. Three different states of the body’s iron stores have been considered in this regard: iron excess, iron deficiency and normal iron repletion. As the columnar epithelial cells of the duodenal villi are formed they incorporate a portion of intrinsic iron from the body’s iron store, the amount depending upon the body’s requirement for new iron. It is predicated that with iron excess the iron-receptor mechanism in these cells is saturated with intrinsic iron; this then prevents the cell from accepting dietary iron. In the normal state of iron repletion the receptor mechanism remains partly unsaturated, allowing small amounts of dietary iron to enter the cell. Part of this proceeds into the body to satisfy any metabolic requirement for iron. Part is retained in the mucosal epithelial cells to complete the saturation of the iron-receptor mechanism. This bound iron is subsequently lost when the epithelial cells are sloughed at the end of their life cycle. In iron deficiency it is postulated that the receptor system is inactive or diminished so that entry of dietary iron into the body is relatively uninhibited.

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