Enhance Iron Absorption Research Articles

19 A-Lactalbumin and Casein-Glycomacropeptide Have No Effect on Iron Absorption From Low-Iron Formula in Healthy Term Infants

Background and aims: Iron absorption from infant formula is low. α-Lactalbumin and casein-glycomacropeptide are thought to enhance mineral absorption. We evaluated the effects of α-lactalbumin and casein-glycomacropeptide on iron absorption from low-iron infant formula in healthy term non-iron-deficient infants. Methods: In a double-blind randomized controlled trial, 32 infants were assigned to receive one of three low-iron (4mg iron/L) formulas from 6 weeks to 12 6 months of age. The formulas contained the same protein amount (13.1g/L) but different concentrations of α-lactalbumin and casein-glycomacropeptide: (1) standard formula (11% α-lactalbumin/14% casein-glycomacropeptide; n=10), (2) α-lactalbuminenriched formula (25% α-lactalbumin/15% casein-glycomacropeptide; n=11), and (3) α-lactalbumin-enriched/casein-glycomacropeptide-reduced formula (25% α-lactalbumin/10% casein-glycomacropeptide; n=11). Ten exclusively breastfed infants were recruited as a reference. At 5.5 months of age, infants were given 58 Fe with one of their feeds. Blood samples were collected 14 days later for fractional iron absorption and serum ferritin determination. Results: Mean (±SD) iron absorption was 10.3±7.0% from standard formula, 8.6±3.8% from α-lactalbumin-enriched formula, and 9.2±6.5% from α-lactalbumin-enriched/casein-glycomacropeptide-reduced formula, with no difference among the three formula groups (P=0.92). Iron absorption from all three formulas was 9.4±5.8% compared to 12.9±6.5% from breastmilk (P=0.73). In the formulafed infants, but not the breastfed infants (P=0.51), iron absorption was negatively correlated with serum ferritin (P=0.01), and was higher (P=0.01) in infants with serum ferritin < 12μg/L (16.4±12.4%) compared to those with serum ferritin ≥12μg/L (8.6±4.4%). Conclusions: α-Lactalbumin and casein-glycomacropeptide do not affect iron absorption from low-iron formula in healthy term infants. Low serum ferritin concentrations enhance iron absorption from infant formula.

Molecular basis of iron-loading disorders

Iron-loading disorders (haemochromatosis) represent an important class of human diseases. Primary iron loading results from inherited disturbances in the mechanisms regulating intestinal iron absorption, such that excess iron is taken up from the diet. Body iron load can also be increased by repeated blood transfusions (secondary iron loading), usually as part of the treatment for various haematological disorders. In these syndromes, an element of enhanced iron absorption is also often involved. The central regulator of body iron trafficking is the liver-derived peptide hepcidin. Hepcidin limits iron entry into the plasma from macrophages, intestinal enterocytes and other cells by binding to the sole iron-export protein ferroportin, and facilitating its removal from the plasma membrane. Mutations in hepcidin or its upstream regulators (HFE, TFR2, HFE2 and BMP6) lead to reduced or absent hepcidin expression and a concomitant increase in iron absorption. Mutations in ferroportin that prevent hepcidin binding produce a similar result. Increased ineffective erythropoiesis, which often characterises erythrocyte disorders, also leads to reduced hepcidin expression and increased absorption. Recent advances in our understanding of hepcidin and body iron homeostasis provide the potential for a range of new diagnostic and therapeutic tools for haemochromatosis and related conditions.

Orange But Not Apple Juice Enhances Ferrous Fumarate Absorption in Small Children

Ferrous fumarate is a common, inexpensive iron form increasingly used instead of ferrous sulfate as a food iron supplement. However, few data exist as to whether juices enhance iron absorption from ferrous fumarate. We studied 21 children, ages 4.0 to 7.9 years using a randomized crossover design. Subjects consumed a small meal including a muffin containing 4 mg Fe as ferrous fumarate and either apple (no ascorbic acid) or orange juice (25 mg ascorbic acid). They were separately given a reference dose of Fe (ferrous sulfate) with ascorbic acid. Iron absorption increased from 5.5% +/- 0.7% to 8.2% +/- 1.2%, P < 0.001 from the muffins given with orange juice compared with muffins given with apple juice. The absorption of ferrous fumarate given with orange juice and enhancement of absorption by the presence of juice were significantly positively related to height, weight, and age (P < 0.01 for each). Although iron absorption from ferrous fumarate given with apple juice was significantly inversely associated with the (log transformed) serum ferritin, the difference in absorption between juice types was not (P > 0.9). These data demonstrate an overall benefit to iron absorption from ferrous fumarate provided with orange juice. The effect was age related such that in children older than 6 years of age, there was a nearly 2-fold increase in iron absorption from ferrous fumarate given with orange juice.

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Alternative pathways for absorption of iron from foods

Iron is known to be absorbed from foods in two major forms, heme iron and non-heme iron. Iron status as well as dietary factors known to affect iron absorption has limited effect on heme iron absorption, whereas inhibitors and enhancers of iron absorption have pronounced effects on non-heme iron absorption. The enterocyte transporter for non-heme iron, DMT1, is strongly up-regulated during iron deficiency and down-regulated during iron overload. A transporter for heme iron, HCP1, was recently characterized and is present on the apical membrane of enterocytes. Two other pathways for iron absorption have been discovered and may serve to facilitate uptake of iron from two unique iron-binding proteins, lactoferrin and ferritin. Lactoferrin is an iron-binding protein in human milk and known to survive proteolytic digestion. It mediates iron uptake in breast-fed infants through endocytosis via a specific lactoferrin receptor (LfR). Recently, lactoferrin has become popular as a food additive and may enhance iron status in several age groups. Ferritin is present in meat, but also in plants. The ferritin content of plants can be enhanced by conventional breeding or genetic engineering, and thereby increase iron intake of populations consuming plant-based diets. Ferritin is a bioavailable source of iron, as shown in recent human studies. Ferritin can be taken up by intestinal cells via endocytosis, suggesting a receptor-mediated mechanism.

Influence of garlic or its main active component diallyl disulfide on iron bioavailability and toxicity

Garlic is regularly consumed and is known to have diverse biologic activities, particularly due to its antioxidant properties. In this study, we hypothesized that crude garlic can prevent iron-mediated oxidative stress in a rat model of nutritional iron overload, and we used an in vitro model to confirm the results. For the in vivo studies, rats received a basal diet supplemented with or without carbonyl iron (3%) and were fed distilled water or garlic solution (1g/kg body weight) by gavage for 3 weeks. The presence of both garlic and iron led to a 2-fold increase in plasma iron and a 50% increase in liver iron as compared with iron alone. However, garlic did not offer any protection against iron-induced oxidative stress. Duodenal divalent metal transporter-1 mRNA expression was fully repressed by iron and by the combined treatments but was also reduced by garlic alone. To confirm these data, we tested the effect of diallyl disulfide, one of the active components in garlic, in vitro on polarized Caco-2 cells. A 24-hour treatment decreased iron uptake at the apical side of Caco-2 cells but increased the percentage of iron transfer at the basolateral side. This probably resulted from a modest induction of ferroportin mRNA and protein expression. These results suggest that garlic, when given in the presence of iron, enhances iron absorption by increasing ferroportin expression. The presence of garlic in the diet at the dose studied does not seem to protect against iron-mediated oxidative stress.

The effect of gold kiwifruit consumed with an iron fortified breakfast cereal meal on iron status in women with low iron stores: A 16 week randomised controlled intervention study

BackgroundDietary treatment is often recommended as the first line of treatment for women with mild iron deficiency. Although it is well established that ascorbic acid enhances iron absorption, it is less clear whether the consumption of ascorbic acid rich foods (such as kiwifruit) with meals fortified with iron improves iron status. The aim of this study is to investigate whether the consumption of ZESPRI® GOLD kiwifruit (a fruit high in ascorbic acid and carotenoids) with an iron fortified breakfast cereal meal increases iron status in women with low iron stores.Methods/DesignEighty nine healthy women aged 18-44 years with low iron stores (serum ferritin (SF) ≤ 25 μg/L, haemoglobin (Hb) ≥ 115 g/L) living in Auckland, New Zealand were randomised to receive an iron fortified breakfast cereal (16 mg iron per serve) and either two ZESPRI® GOLD kiwifruit or a banana (low ascorbic acid and carotenoid content) to eat at breakfast time every day for 16 weeks. Iron status (SF, Hb, C-reactive protein (CRP) and soluble transferrin receptor (sTfR)), ascorbic acid and carotenoid status were measured at baseline and after 16 weeks. Anthropometric measures, dietary intake, physical activity and blood loss were measured before and after the 16 week intervention.DiscussionThis randomised controlled intervention study will be the first study to investigate the effect of a dietary based intervention of an iron fortified breakfast cereal meal combined with an ascorbic acid and carotenoid rich fruit on improving iron status in women with low iron stores.Trial registrationACTRN12608000360314

Difructose Anhydride III Enhances Bioavailability of Water-Insoluble Iron in Anemic Vietnamese Women

Difructose anhydride III (DFAIII) is an indigestible disaccharide and has been shown to enhance iron absorption in animal studies; however, the effect has not been investigated in anemic subjects. We investigated the efficacy of co-administration of DFAIII with water-insoluble iron in the treatment of iron deficiency anemia in Vietnamese women. One hundred sixty-eight moderately anemic women (80 g/L<hemoglobin (Hb)<120 g/L) participated in a double-blinded, placebo-controlled study with daily supplementation of iron for 6 mo. The volunteers were randomly assigned into four groups, i.e., Group A: received 15 mg Fe as ferric pyrophosphate; Group B: received 15 mg Fe as ferric pyrophosphate and 1.25 g DFAIII; Group C: received 15 mg Fe as ferrous sulfate; Group D: received a placebo. Hb and iron status were measured at baseline and after 2, 4 and 6 mo of intervention. The ratio of transferrin receptor to ferritin was used to estimate stored and functional body iron (BI). One hundred sixteen (69.0%) women completed the trial. After 6 mo, mean (+/-SE) Hb concentration was higher in Group A (121.6+/-1.7 g/L), Group B (126.4+/-1.5 g/L) and Group C (126.8+/-1.6 g/L) compared to Group D (107.0+/-1.7 g/L, p<0.0001). Mean change in BI was twofold greater in Group B (5.0+/-0.5 mg/kg) than that in Group A (2.5+/-0.6 mg/kg, p=0.008). The percentage of anemia was significantly reduced in Group B (18.8%) compared to Group D (95.8%, p<0.0001) and Group A (39.1%, p=0.033). Co-administration of DFAIII enhances Hb concentration and iron stores more than single administration of water-insoluble iron in anemic Vietnamese women.

Difructose anhydride III promotes iron absorption in the rat large intestine

Objectives We examined the intestinal segment responsible for and the mechanisms involved in the non-digestible disaccharide difructose anhydride III (DFAIII)-mediated enhancement of iron absorption. Methods Net iron and calcium absorption (percentage) were observed in male Sprague-Dawley rats fed an AIN93G-based diet with or without DFAIII (30 g/kg of diet) for 2 wk after cecectomy or laparotomy (experiment 1). The absorption rates of calcium and iron from ligated jejunal loops (experiment 2) or ligated cecal sacs (experiment 3) in anesthetized rats fed a control or DFA diet were observed with or without the addition of DFAIII to the instilled mucosal fluid. Levels of the major iron transporter divalent metal transporter-1 (DMT-1) mRNA per 28S rRNA were evaluated by real-time polymerase chain reaction in the intestinal mucosa. Results Net absorption (percentage) of iron and calcium was higher in the DFA group than in the DFA-free group in laparotomized rats. The enhancement of iron absorption was almost and calcium absorption was partly abolished by cecectomy. The absorption rate of calcium, but not of iron, from the jejunal loops was increased by the addition of DFAIII (100 mmol/L). Iron absorption was clearly higher in the ligated cecal sacs of the DFAIII-fed group than in the DFA-free group with or without the mucosal addition of DFAIII. DMT-1 mRNA level per 28S rRNA was maintained in the cecal mucosa through large increases in cecal size due to DFAIII feeding. Conclusion The DFAIII-induced increases in iron absorption are the result of increased cecal iron absorptive capacity through expansion of the cecal mucosa maintaining DMT-1 mRNA expression.

Comparing Soluble Ferric Pyrophosphate to Common Iron Salts and Chelates as Sources of Bioavailable Iron in a Caco-2 Cell Culture Model

Iron bioavailability from supplements and fortificants varies depending upon the form of the iron and the presence or absence of iron absorption enhancers and inhibitors. Our objectives were to compare the effects of pH and selected enhancers and inhibitors and food matrices on the bioavailability of iron in soluble ferric pyrophosphate (SFP) to other iron fortificants using a Caco-2 cell culture model with or without the combination of in vitro digestion. Ferritin formation was the highest in cells treated with SFP compared to those treated with other iron compounds or chelates. Exposure to pH 2 followed by adjustment to pH 7 markedly decreased FeSO(4) bioavailability but had a smaller effect on bioavailabilities from SFP and sodium iron(III) ethylenediaminetetraacetate (NaFeEDTA), suggesting that chelating agents minimize the effects of pH on iron bioavailability. Adding ascorbic acid (AA) and cysteine to SFP in a 20:1 molar ratio increased ferritin formation by 3- and 2-fold, respectively, whereas adding citrate had no significant effect on the bioavailability of SFP. Adding phytic acid (10:1) and tannic acid (1:1) to iron decreased iron bioavailability from SFP by 91 and 99%, respectively. The addition of zinc had a marked inhibitory effect on iron bioavailability. Calcium and magnesium also inhibited iron bioavailability but to a lesser extent. Incorporating SFP in rice greatly reduced iron bioavailability from SFP, but this effect can be partially reversed with the addition of AA. SFP and FeSO(4) were taken up similarly when added to nonfat dry milk. Our results suggest that dietary factors known to enhance and inhibit iron bioavailability from various iron sources affect iron bioavailability from SFP in similar directions. However, the magnitude of the effects of iron absorption inhibitors on SFP iron appears to be smaller than on iron salts, such as FeSO(4) and FeCl(3). This supports the hypothesis that SFP is a promising iron source for food fortification and dietary supplements.

Optimization of a phytase-containing micronutrient powder with low amounts of highly bioavailable iron for in-home fortification of complementary foods

Background:In-home fortification of complementary foods with micronutrient powders containing low amounts of iron may be potentially safer than powders containing high amounts of iron. However, low iron doses have little nutritional effect, unless iron absorption is high.Objective: The objective was to maximize iron absorption from a low-iron micronutrient powder for in-home fortification by testing combinations of iron as NaFeEDTA, ascorbic acid, and a microbial phytase active at gut pH. In addition, a recently proposed enhancer of iron absorption, l-α-glycerophosphocholine (GPC), was tested.Design: In 6 separate iron-absorption studies using a crossover design, women (n = 101) consumed whole-maize porridge fortified with 3 mg stable isotope–labeled FeSO4 or NaFeEDTA with different combinations of enhancers added to the meals at the time of consumption. Incorporation of iron isotopes into erythrocytes 14 d later was measured.Results: The addition of phytase when iron was present as either NaFeEDTA or FeSO4, with or without ascorbic acid, significantly increased iron absorption. The combined addition of phytase, ascorbic acid, and NaFeEDTA resulted in an absorption of 7.4%, compared with an absorption of 1.5% from FeSO4 without enhancers in the same meal (P < 0.001). The addition of ascorbic acid did not significantly increase iron absorption from NaFeEDTA, and the addition of calcium did not significantly inhibit iron absorption from NaFeEDTA in the presence of ascorbic acid. The addition of l-α-glycerophosphocholine did not significantly increase iron absorption.Conclusion: Optimization of the micronutrient powder increased iron absorption from a highly inhibitory meal ≈5-fold. This approach may allow for effective, untargeted in-home fortification of complementary foods with low amounts of highly bioavailable iron.

Iron absorption from meat pate fortified with ferric pyrophosphate in iron-deficient women

Objective Preventing iron deficiency has been a main target of the World Health Organization since 1992. Difficulties to reach dietary recommended iron intakes and to enhance iron absorption should be overcome. We compared in iron-deficient women the bioavailability of iron of three meat pate products enriched with ferrous sulfate, ferric pyrophosphate encapsulated in liposomes, or ferric pyrophosphate encapsulated in liposomes plus a hemoglobin-based meat pigment. Methods Seventeen women with low iron stores (ferritin <30 μg/L) took part in a three-way, randomized, crossover, double-blind postprandial intervention. Test meals consisted of 80 g of the three different enriched meat pate products, which were spread on two slices of white bread. The pate composition was 13.5 g of protein/100 g, 30 g of fat/100 g (49% monounsaturated fatty acids, 35% saturated fatty acids, 16% polyunsaturated fatty acids), 1 g of carbohydrates/100 g, and 19 mg of total iron (including 15 mg of iron from the test fortificants). Blood samples were taken at baseline and each hour for 6 h after eating the meal and serum iron was determined. Results Serum iron concentration evolution during the postprandial study was similar with the three meals, and maximum concentrations were obtained between hours 2 and 4. The effect of type of fortificant was not significant. Conclusion Consumption of meat pate fortified with ferric pyrophosphate encapsulated in liposomes can be part of a dietary strategy for preventing iron deficiency in humans. The addition of larger amounts of a meat pigment rich in heme iron should be further studied.

Interactions between ethylenediaminetetraacetic acid (EDTA) and iron absorption pathways, in the Caco-2 model

EDTA is a well known enhancer of iron absorption; however, the precise way of absorption of iron ingested in presence of EDTA is not known; some data suggest it could use a passive, non regulated paracellular way. Iron (sulphate or gluconate) absorption by Caco-2 cells was assessed in presence of EDTA. EDTA did not change the apical uptake of iron; transport in the basal chamber increased by 98% for FeSO 4 and 95% for Fe gluconate. By contrast, intracellular storage decreased by 31% for FeSO 4 and 64% for Fe gluconate. In addition EDTA induced a significant increase of permeability of the cell monolayer assessed by a decrease of transepithelial electrical resistance: 314 ± 34 Ω cm −2 to 235 ± 57 Ω cm −2 for sulphate, 414 ± 33 Ω cm −2 to 223 ± 36 Ω cm −2 for gluconate; iron free control: 410 ± 10 Ω cm −2. Conclusions: these results suggest that in presence of EDTA iron absorption occurs mainly by the paracellular instead of the regulated cellular way, that could potentially enhance its toxicity.

Oily Fish Increases Iron Bioavailability of a Phytate Rich Meal in Young Iron Deficient Women

Background: Iron deficiency is a major health problem worldwide, and is associated with diets of low iron bioavailability. Non-heme iron absorption is modulated by dietary constituents, one of which is the so-called “meat factor”, present in meat, fish (oily and lean) and poultry, which is an important enhancer of iron absorption in humans. Food processing also affects iron bioavailability. Objective: To evaluate the effect of consuming sous vide cooked salmon fish on non-heme iron bioavailability from a bean meal, rich in phytate, in iron-deficient women. Design: Randomized crossover trial in 21 young women with low iron stores (ferritin < 30 μg/L). Two test meals were extrinsically labelled with stable isotopes of iron (Fe-57 or Fe-58). Iron bioavailability was measured as the incorporation of stable isotopes into erythrocytes 14 d after meals consumption. Results: The addition of fish to the bean meal significantly increased (p < 0.001) iron absorption. Serum ferritin concentration and iron absorption were inversely correlated for both the bean meal (R2 = 0.294, p = 0.011) and the fish and bean meal (R2 = 0.401, p = 0.002). Conclusion: Sous vide cooked salmon fish increases iron absorption from a high phytate bean meal in humans.

Peptides Isolated from in Vitro Digests of Milk Enhance Iron Uptake by Caco-2 Cells

Milk proteins, during digestion, produce a range of biologically active peptides. Among those are peptides that may enhance iron absorption. The objective of this project was to investigate the effect of isolated milk peptides on iron uptake. Cow's milk, 0% fat, was subjected to a modified in vitro digestion process. The milk digest was further fractionated by gel filtration. All eluted fractions as well as beta-casein synthetic peptides (a tripeptide and a hexapeptide) were subsequently tested for effects on iron uptake with Caco-2 cell monolayers. Fractions of milk digests obtained through Sephadex G-25 gel filtration had a significant enhancing effect on iron uptake in Caco-2 cells compared to nonfractionated milk digests. Two fractions (P = 0) and the hexapeptide (P < 0.0001) enhanced iron uptake by up to 3-fold, whereas others and the tripeptide had no effect. These results suggest that selected peptides produced during the in vitro digestion of milk may enhance iron absorption; however, it remains to be demonstrated whether this effect may be nutritionally significant.

An Overview of Methods for Assessment of Iron Bioavailability from Foods Nutritionally Enhanced Through Biotechnology

Iron deficiency and iron deficiency anemia continue to be significant public health problems worldwide. While supplementation and fortification have been viable means to improve iron nutriture of the population in developed countries, they may be less successful in developing regions for a number of reasons, including complexities in distribution and consumer compliance. Biofortification of staple crops, through conventional plant breeding strategies or modern methods of biotechnology, provides an alternative approach that may be more sustainable once initial investments have been made. Three types of biofortification strategies are being essayed, singly or in combination: increasing the total iron content of edible portions of the plant, decreasing the levels of inhibitors of iron absorption, and increasing the levels of factors that enhance iron absorption. Bioavailability is a key concept in iron nutrition, particularly for nonheme iron such as is found in these biofortified foods. An overview is presented of methods for evaluation of iron bioavailability from foods nutritionally enhanced through biotechnology.

A High School Soccer Player with Energy Deficiency

A High School Soccer Player with Energy Deficiency

Dialyzability of Minerals in Corn Masa Gruel (Atole) Fortified with Different Iron Compounds: Effects of Ascorbic Acid, Disodium EDTA, and Phytic Acid

Lime-treated corn gruel (atole) is a common weaning food in iron-deficient populations, especially in Mexico and Central America, and is a potential vehicle for fortification with iron. The objective of this study was to screen promising iron compounds for use in the fortification of atole, using in vitro enzymatic digestion-dialysis techniques, while also considering their response to known iron absorption enhancers and inhibitors. Atole, unaltered or preincubated with phytase, was fortified with iron (10 mg/L) from ferrous sulfate, ferrous bisglycinate, or ferrous fumarate, or with ferric chloride, ferric ammonium citrate, or ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA), and submitted to in vitro digestion. Dialysis of calcium, copper, iron, phosphorus, and zinc (analyzed by inductively coupled plasma atomic emission spectrometry) was measured when atole was fortified with iron compounds alone or together with ascorbic acid or disodium ethylenediaminetetraacetic acid (Na2EDTA). Iron dialyzability was higher with NaFeEDTA (p < .05) than with all other iron compounds, which did not differ among themselves in iron dialyzability. Addition of ascorbic acid had no significant effect on iron dialysis, whereas Na2EDTA enhanced iron dialyzability by 7 to 10 times in unaltered atole and 15 to 20 times in phytase-preincubated atole (p < .05). Addition of Na2EDTA always increased intrinsic zinc dialyzability, and most of the time this increase was significant. Phytase pretreatment generally increased mineral dialysis. Adding EDTA (either as NaFeEDTA or as Na2EDTA) to atole can increase the dialyzability of ferrous and ferric iron compounds and enhance the dialyzability of intrinsic zinc without any negative effects on calcium, phosphorus, or copper dialysis.

Nonheme Iron Absorption in Young Women Is Not Influenced by Purified Sulfated and Unsulfated Glycosaminoglycans

Meat is a well-known enhancer of iron absorption, yet the molecular entity mediating the effect remains obscure. Recently published data indicate that highly acidic sulfated glycosaminoglycans (GAG) from fish and chicken muscle are effective stimulants of iron uptake in Caco-2 cells. Two fully randomized stable isotope studies with crossover design were performed in a group of 16 apparently healthy young women to assess the effect of purified sulfated and unsulfated GAG on human iron absorption. Iron absorption was measured on the basis of erythrocyte incorporation of 57Fe or 58Fe 14 d after the administration of labeled semisynthetic meals (SSM) based on egg albumin, corn oil, maltodextrin, and water. The meals were consumed with or without added sodium hyaluronate (NaH, 300 mg) or chondroitin sulfate (CS, 360 mg) as representative unsulfated and sulfated GAG, respectively. The level of GAG added was 3 times (NaH) to about 10 times (CS), the amount expected to be present in 150 g beef muscle. Geometric mean iron absorption from SSM containing NaH (21.2%) or CS (19.4%) did not differ from that of SSM without GAG (19.5 and 20.3%, respectively). NaH and CS at those levels do not affect human nonheme iron absorption.

Matrix effects of lupine ( Lupinus luteus L.) and rapeseed ( Brassica napus L.) products on in vitro non-haem iron availability from pork meat

Limited iron bioavailability is regarded as one of the most confounding factors responsible for low iron absorption and utilisation. In the gastrointestinal lumen of humans and monogastric animals, iron absorption is highly affected by dietary components that decrease or enhance iron availability. This study aims at investigating the matrix effects of lupine and rapeseed products on in vitro non-haem iron availability when included in meat-based diets. In vitro iron availability is measured as Fe(II) dialysability obtained by a method combining in vitro protein digestion and dialysis (IVPD dialysis). Aliquots were collected following digestion with pepsin or pepsin/pancreatin and investigated for their effects on Fe(II) dialysability. Thus, the IVPD imitates the conditions in the duodenum and the proximal jejunum. The method confirms that the major effects on in vitro non-haem iron availability are achieved during duodenal conditions. The results showed a significant enhancing effect of pepsin-digested pork meat on Fe(II) dialysability and a pronounced effect of the plant components on Fe(II) dialysability from meat proteins. Lupine enhances Fe(II) dialysability after pepsin/pancreatin digestion in contrast to rapeseed. Moreover, lupine may constitute a valuable vegetable food component in enhancing iron availability and solubility more distally in the intestine than observed for other enhancers of iron absorption.