Caco-2 cell ferritin formation predicts nonradiolabeled food iron availability in an in vitro digestion/Caco-2 cell culture model

A multifaceted analysis: Unveiling the complexities of wheat genotypes, fortification, and processing on iron and zinc bioavailability in whole wheat flour and chapati

This study examines the complex interactions between wheat cultivar selection and fortification with NaFeEDTA and ascorbic acid (AA) on the bioavailability of iron (Fe) and zinc (Zn) in whole wheat flour (WWF) and chapati. Nineteen hexaploid wheat cultivars were rigorously assessed for their intrinsic Fe and Zn profiles, including total content (TC), solubility (S), and bio-accessibility (B), utilizing an in-vitro gastrointestinal model. Significant variations (P < 0.05) were observed among cultivars, with Fe content ranging from 32.8 mg.kg-1 to 42.8 mg.kg-1 and Zn content ranging from 34.5 mg.kg-1 to 43.8 mg.kg-1 in WWF. Fortification with NaFeEDTA (T3: 250 mg.kg-1) significantly increased total Fe TC in WWF by 85.0 %, Fe and Zn solubility by 51.2 % and 22.3 %, and bio-accessibility by 165.5 % and 84.2 %, respectively, compared to control. Conversely, AA fortification (T3: 250 mg.kg-1) elevated Fe and Zn solubility by 98.7 % and 62.1 %, and bio-accessibility by 282.2 % and 230.5 %, respectively, compared to control. Notably, cultivar-specific responses to both fortification strategies were also evident. When translated to chapati, both NaFeEDTA and AA fortification (T3) enhanced Fe and Zn bio-accessibility compared to unfortified chapati. The impact of fortification was cultivar-dependent, with certain cultivars showing greater efficacy in improving Fe and Zn bio-accessibility. Correlation analysis revealed intricate relationships among Fe and Zn bioavailability parameters, highlighting the importance of tailored fortification approaches. These findings have significant implications for optimizing fortification strategies to improve bioavailable Fe and Zn intake through wheat-based diets.

Advancements in Nano-Mandoor Bhasma: Unravelling the Particle Size-Ascorbic Acid Synergy for Enhanced Iron Bioavailability for Anemia Treatment

Mandoor Bhasma (MB) medicine, based on classical Indian Ayurveda, was size- and surface-modified to improve its therapeutic efficiency for treating iron-deficient anemia. Physical grinding reduced the size of MB to the nanoparticle (nano-MB) range without changing its chemical composition, as measured by particle size distribution. The surface of nano-MB was modified with ascorbic acid (nano-AA-MB) and confirmed using scanning electron microscopy and Fourier transformed infrared spectroscopy. Enhanced iron dissolution from the surface-modified nano-AA-MB under neutral-to-alkaline pH conditions, and in the intestinal region of the simulated gastrointestinal tract (GIT) digestion model was determined using inductively coupled plasma mass spectroscopy. GIT digestae of MB microparticles and nano-AA-MB were found to be biocompatible in human colon epithelial (Caco-2) cells, with the latter showing threefold higher iron uptake. Subsequently, a dose-dependent increase in cellular ferritin protein was observed in the nano-AA-MB digestae-treated Caco-2 cells, indicating the enhanced bioavailability and storage of dissolved iron. Overall, the study showed that reducing the size of centuries-old traditional Mandoor Bhasma medicine to nanoscale, and its surface-modification with ascorbic acid would help in enhancing its therapeutic abilities for treating iron-deficient anemia.

Uptake of iron from ferrous fumarate can be mediated by clathrin-dependent endocytosis in Hutu-80 cells

Iron uptake in the intestinal epithelium is associated with transport of ferrous iron via the DMT1 transporter (SLC11a2; NRAMP2). In later years, uptake of iron from complex sources, such as nanoparticles, has been found to be mediated through endocytosis. Here we propose that iron from the simple salt ferrous fumarate, a common iron supplement, can be absorbed by clathrin-mediated endocytosis. We used siRNA to silence DMT1 transporter expression, pharmacological inhibition of endocytosis, and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to show that iron uptake from ferrous fumarate can be mediated by both transport via DMT1 and by clathrin-dependent endocytosis in Hutu-80 cells. Iron uptake (ferritin L) from ferrous fumarate (0.5 mM, 24 h) in DMT1 silenced cells was significantly decreased (60% ± 11%) in comparison to iron controls while a 1-h dose of ferrous fumarate (0.5 mM) significantly decreased ferritin L formation in the presence of the clathrin inhibitor chlorpromazine (61% ± 10%, in post-confluent cells and 37% ± 9% in non-confluent cells). A pilot showed a similar trend for Ferritin (H) levels (confluent cells) and for total cellular iron load (non-confluent cells). ToF-SIMS analysis revealed diminished membrane-associated iron load in endocytosis-inhibited ferrous fumarate treated cells. The reported results support a clathrin-mediated endocytosis mechanism for uptake of iron from ferrous fumarate in addition to iron uptake by DMT1. More studies are needed to understand what determines which uptake mechanism are employed and to which extent.

Milk osteopontin has high iron-binding capacity and facilitates iron absorption in intestinal cells

Insufficient absorption of iron and the consequent development of iron deficiency have serious health consequences. Hence, identification and development of iron delivery systems that can increase the bioavailability and uptake of dietary iron are important. Osteopontin (OPN) is an acidic and highly phosphorylated integrin-binding protein found in milk where it exists as a full-length protein and as N-terminally derived fragments. Milk OPN can be taken up by enterocytes and transported across the intestinal barrier into the circulation. Milk OPN has previously been shown to bind calcium and magnesium. This study investigates milk OPN as a carrier of iron and its potential to increase iron absorption in intestinal cells. Full-length OPN and N-terminal fragments of OPN were shown to bind ∼30 and ∼10 mol of iron, respectively, and the phosphorylated residues were crucial for iron binding. Osteopontin retained iron bound after simulated gastrointestinal digestion. Immunodetection of digested OPN and OPN-Fe complexes showed that the OPN-Fe complexes were more resistant to pepsin digestion than OPN without bound iron. The cellular uptake of iron was investigated by measuring intracellular ferritin formation and mRNA expression of divalent metal transporter 1 in Caco-2 cells. Osteopontin increased the uptake of iron even in the presence of phytic acid, a dietary inhibitor of iron absorption. These data indicate that OPN can function as an iron carrier for use in alternative strategies for delivering iron in a bioavailable form for intestinal uptake.

Yellow bean (Phaseolus vulgaris L.) germplasm with less dietary fiber have shorter cooking times and more bioavailable iron

Some yellow-colored market classes of dry bean (Phaseolus vulgaris L.) are valued by consumers as an easy-to-digest, fast cooking alternative to darker colored red and black beans, which in comparison generally have longer cooking times and reduced iron bioavailability. There is evidence that the cooking time of yellow beans is linked to the dietary fiber content and may also contribute to nutrient digestibility and bioavailability. Therefore, 52 fast-, moderate-, and slow-cooking yellow beans with diverse iron bioavailability from five market classes (Amarillo, Canario, Green-yellow, Manteca, and Mayocoba) were selected for total dietary fiber (TDF) analysis. TDF was measured as insoluble (IDF) + soluble (SDF) + oligosaccharides (OLIGO) using method AOAC2011.25. Wide variations in the concentrations of IDF (16.0-23.1%), SDF (1.6-7.7%), OLIGO (1.5-3.4%), and TDF (20.6-31.3%) were detected among the yellow beans with various cooking times. Lower concentrations of IDF in yellow beans were associated with shorter cooking times and higher iron bioavailability. The larger sized Andean yellow beans had more SDF than Middle American. One Mayocoba breeding line from Puerto Rico, PR1146-124, had 42% less OLIGOs than average, and may be useful for breeding low-flatulence beans for consumer acceptability. Fast cooking yellow beans provide the same SDF and OLIGO concentrations as yellow beans with longer cooking times but have the added benefit of shorter cooking times (convenience) and provide more bioavailable iron after cooking.

Bioaccessibility and Caco-2 cell uptake of iron chlorophyllin using a biologically relevant digestion model

Iron deficiency remains a top nutrient deficiency worldwide. Iron chlorophyllin (IC), a compound structurally analogous to heme, utilizes the protoporphyrin ring of chlorophyll to bind iron. IC has previously been shown to deliver more iron to Caco-2 cells than FeSO4, the most common form prescribed for supplementation. However, previous test conditions used digestive conditions outside of those observed in humans. This study sought to assess IC bioaccessibility and Caco-2 cell uptake using physiologically relevant digestive solutions, pH, and incubation time, as compared to other iron sources (i.e., FeSO4, and hemoglobin (Hb)). Co-digestion with ascorbic acid (AA) and albumin was also investigated. Following gastric, duodenal, and jejunal digestion, IC-bound iron was less bioaccessible than iron delivered as FeSO4, and IC-bound iron was less bioaccessible than Hb-bound iron. IC-bound iron bioaccessibility was not affected by AA and was enhanced 2x when co-digested with a low dose of albumin. However, Caco-2 cell incubation with IC-containing digesta increased cell ferritin 2.5x more than FeSO4 alone, and less than Hb. IC with AA or with 400 mg albumin also increased cell ferritin more than IC alone, with the greatest increases observed following incubation of digesta containing IC + AA + 400 mg albumin. These results suggest IC can serve as an improved source of iron for supplementation as compared to FeSO4. These results also support further in vivo investigations of IC-based iron delivery in populations at risk of iron deficiency.

Coupling in vitro food digestion with in vitro epithelial absorption; recommendations for biocompatibility

As food transits the gastrointestinal tract, food structures are disrupted and nutrients are absorbed across the gut barrier. In the past decade, great efforts have focused on the creation of a consensus gastrointestinal digestion protocol (i.e., INFOGEST method) to mimic digestion in the upper gut. However, to better determine the fate of food components, it is also critical to mimic food absorption in vitro. This is usually performed by treating polarized epithelial cells (i.e., differentiated Caco-2 monolayers) with food digesta. This food digesta contains digestive enzymes and bile salts, and if following the INFOGEST protocol, at concentrations that although physiologically relevant are harmful to cells. The lack of a harmonized protocol on how to prepare the food digesta samples for downstream Caco-2 studies creates challenges in comparing inter laboratory results. This article aims to critically review the current detoxification practices, highlight potential routes and their limitations, and recommend common approaches to ensure food digesta is biocompatible with Caco-2 monolayers. Our ultimate aim is to agree a harmonized consensus protocol or framework for in vitro studies focused on the absorption of food components across the intestinal barrier.

Effect of fermentation on nutrient composition, antinutrients, and mineral bioaccessibility of finger millet based Injera: A traditional Ethiopian food

Finger millet, like other cereals, contains high amounts of antinutrients that bind minerals, making them unavailable for absorption. This study explores the effect of traditional fermentation on nutritional, antinutritional, and subsequent mineral bioaccessibility (specifically iron, zinc, and calcium) of finger millet based Injera. Samples of fermented dough and Injera prepared from light brown and white finger millet varieties were analyzed for nutritional composition, antinutritional content, and mineral bioaccessibility following standard procedures. With some exceptions, the proximate composition of fermented dough was significantly affected by fermentation time. Compared to unfermented flour, the phytate and condensed tannin content significantly (p < 0.05) decreased for fermented dough and Injera samples. A strong decline in phytate and condensed tannin content was observed in white finger millet Injera as fermentation time increased, compared to light brown finger millet based Injera. The mineral bioaccessibility of Injera prepared from finger millet and maize composite flour increased with fermentation time, leading to a significant increase in bioaccessible iron, zinc, and calcium, ranging from 15.4-40.0 %, 26.8-50.8 %, and 60.9-88.5 %, respectively. The results suggest that traditional fermentation can be an effective method to reduce phytate and condensed tannin content, simultaneously increasing the bioaccessibility of minerals in the preparation of finger millet based Injera.

Whole genome sequencing of the poly-γ-glutamic acid-producing novel Bacillus subtilis Tamang strain, isolated from spontaneously fermented kinema

Kinema, a traditional fermented soybean food from the Himalayas, is well-liked for its sticky texture and flavourful umami taste. Among 175 bacterial strains from spontaneously fermented kinema samples, Bacillus subtilis Tamang strain stood out for its high stickiness and viscosity. The strain's Poly-γ-glutamic acid (γ-PGA) contains various groups of glutamic acid and has a molecular weight of 660 kDa. It demonstrates the ability to solubilize iron, preserve ferritin in Caco-2 cells, and exhibit antibacterial properties. The genome of B. subtilis Tamang is devoid of plasmid elements but does feature nine insert elements. Noteworthy is the presence of unique secondary metabolites with potential antimicrobial effects, such as amyloliquecidin GF610, bogorol A, and thermoactinoamide A. A total of 132 carbohydrate-active enzymes (CAZy) were identified, hinting at possible prebiotic characteristics. The genome analysis revealed genes responsible for γ-PGA production via the capBCA complex. Furthermore, genes associated with fibrinolytic activity, taste enhancement, biopeptides, immunomodulators, and vitamins like B12 and K2 were found, along with probiotics and various health benefits. The genetic material for L-asparaginase production, known for its anti-cancer properties, was also detected, as well as CRISPR-Cas systems. The absence of virulence factors and antimicrobial resistance genes confirms the safety of consuming B. subtilis Tamang as a food-grade bacterium.

Genome-wide association and genomic prediction for iron and zinc concentration and iron bioavailability in a collection of yellow dry beans

Dry bean is a nutrient-dense food targeted in biofortification programs to increase seed iron and zinc levels. The underlying assumption of breeding for higher mineral content is that enhanced iron and zinc levels will deliver health benefits to the consumers of these biofortified foods. This study characterized a diversity panel of 275 genotypes comprising the Yellow Bean Collection (YBC) for seed Fe and Zn concentration, Fe bioavailability (FeBio), and seed yield across 2 years in two field locations. The genetic architecture of each trait was elucidated via genome-wide association studies (GWAS) and the efficacy of genomic prediction (GP) was assessed. Moreover, 82 yellow breeding lines were evaluated for seed Fe and Zn concentrations as well as seed yield, serving as a prediction set for GP models. Large phenotypic variability was identified in all traits evaluated, and variations of up to 2.8 and 13.7-fold were observed for Fe concentration and FeBio, respectively. Prediction accuracies in the YBC ranged from a low of 0.12 for Fe concentration, to a high of 0.72 for FeBio, and an accuracy improvement of 0.03 was observed when a QTN, identified through GWAS, was used as a fixed effect for FeBio. This study provides evidence of the lack of correlation between FeBio estimated in vitro and Fe concentration and highlights the potential of GP in accurately predicting FeBio in yellow beans, offering a cost-effective alternative to the traditional assessment of using Caco2 cell methodologies.

Iron deficiency anemia: a critical review on iron absorption, supplementation and its influence on gut microbiota

Iron deficiency anemia (IDA) caused by micronutrient iron deficiency has attracted global attention due to its adverse health effects. The regulation of iron uptake and metabolism is finely controlled by various transporters and hormones in the body. Dietary iron intake and regulation are essential in maintaining human health and iron requirements. The review aims to investigate literature concerning dietary iron intake and systemic regulation. Besides, recent IDA treatment and dietary iron supplementation are discussed. Considering the importance of the gut microbiome, the interaction between bacteria and micronutrient iron in the gut is also a focus of this review. The iron absorption efficiency varies considerably according to iron type and dietary factors. Iron fortification remains the cost-effective strategy, although challenges exist in developing suitable iron fortificants and food vehicles regarding bioavailability and acceptability. Iron deficiency may alter the microbiome structure and promote the growth of pathogenic bacteria in the gut, affecting immune balance and human health.

Content and Availability of Minerals in Plant-Based Burgers Compared with a Meat Burger

Increasing numbers of individuals follow plant-based diets. This has sparked interest in the nutritional evaluation of the meat substitute sector. Nutritional understanding of these products is vital as plant-based eating becomes more common. For example, animal products are rich sources of iron and zinc, and plant-based foods could be inadequate in these minerals. The main aim was to analyse the mineral composition and absorption from a range of plant-based meat-free burgers and compare them to a typical beef burger. Total and bioaccessible mineral contents of plant-based burgers and a beef burger were determined using microwave digestion and in vitro simulated gastrointestinal digestion, respectively. Mineral bioavailability was analysed by in vitro simulated gastrointestinal digestion of foods, followed by exposure of Caco-2 cells to the sample digests and assessment of mineral uptake. Mineral quantification for all samples was achieved using inductively coupled ICP-optical emission spectrometry (ICP-OES). The content of minerals varied significantly amongst the burgers. Significantly greater quantities of Fe and Zn were found in the beef burger compared to most meat substitutes. Bioaccessible Fe was significantly higher in the beef compared to most of the plant-based meat alternatives; however, bioavailable Fe of most plant-based burgers was comparable to beef (p > 0.05). Similarly, bioaccessible Zn was significantly (p < 0.001) higher from the beef burger. Moreover, beef was superior regarding bioavailable Zn (p ≤ 0.05-0.0001), with only the mycoprotein burger displaying comparable Zn bioavailability (p > 0.05). Beef is an excellent source of bioaccessible Fe and Zn compared to most plant-based substitutes; however, these plant-based substitutes were superior sources of Ca, Cu, Mg and Mn. The quantity of bioaccessible and absorbable Fe varies dramatically among the meat alternatives. Plant-based burgers have the potential to provide adequate quantities of iron and zinc to those consuming such burgers as part of a varied diet. Thus, guiding consumer choices will depend on the variety of the vegetable constituents and their iron nutritional quality in different burgers.

An In Vitro Small Intestine Model Incorporating a Food Matrix and Bacterial Mock Community for Intestinal Function Testing

Consumed food travels through the gastrointestinal tract to reach the small intestine, where it interacts with the microbiota, forming a complex relationship with the dietary components. Here we present a complex in vitro cell culture model of the small intestine that includes human cells, digestion, a simulated meal, and a microbiota represented by a bacterial community consisting of E. coli, L. rhamnosus, S. salivarius, B. bifidum, and E. faecalis. This model was used to determine the effects of food-grade titanium dioxide nanoparticles (TiO₂ NPs), a common food additive, on epithelial permeability, intestinal alkaline phosphatase activity, and nutrient transport across the epithelium. Physiologically relevant concentrations of TiO₂ had no effect on intestinal permeability but caused an increase in triglyceride transport as part of the food model, which was reversed in the presence of bacteria. Individual bacterial species had no effect on glucose transport, but the bacterial community increased glucose transport, suggesting a change in bacterial behavior when in a community. Bacterial entrapment within the mucus layer was reduced with TiO₂ exposure, which may be due to decreased mucus layer thickness. The combination of human cells, a synthetic meal, and a bacterial mock community provides an opportunity to understand the implications of nutritional changes on small intestinal function, including the microbiota.

Edible Halophytes with Functional Properties: In Vitro Protein Digestibility and Bioaccessibility and Intestinal Absorption of Minerals and Trace Elements from Australian Indigenous Halophytes

Halophytes are considered emerging functional foods as they are high in protein, minerals, and trace elements, although studies investigating halophyte digestibility, bioaccessibility, and intestinal absorption are limited. Therefore, this study investigated the in vitro protein digestibility, bioaccessibility and intestinal absorption of minerals and trace elements in saltbush and samphire, two important Australian indigenous halophytes. The total amino acid contents of samphire and saltbush were 42.5 and 87.3 mg/g DW, and even though saltbush had a higher total protein content overall, the in vitro digestibility of samphire protein was higher than the saltbush protein. The in vitro bioaccessibility of Mg, Fe, and Zn was higher in freeze-dried halophyte powder compared to the halophyte test food, suggesting that the food matrix has a significant impact on mineral and trace element bioaccessibility. However, the samphire test food digesta had the highest intestinal Fe absorption rate, whereas the saltbush digesta exhibited the lowest (37.7 vs. 8.9 ng/mL ferritin). The present study provides crucial data about the digestive "fate" of halophyte protein, minerals, and trace elements and increases the understanding of these underutilized indigenous edible plants as future functional foods.

A new evaluation system of iron bioavailability in seaweed

In marine ecosystems, the avid binding of iron (Fe) to organic ligands influences Fe bioavailability in seaweed. This study aimed to elucidate Fe's biological availability to seaweed and develop a simple and rapid bioassay method as a new evaluation system. Undaria pinnatifida was used as a model seaweed species and the actual seaweed samples were collected using the 0.5 m × 0.5 m quadrat from the Mashike Bay area of Hokkaido, Japan. Chlorophyll fluorescence measurements were utilized as an index to evaluate the biological -effectiveness of Fe and compared with the results of culture tests based on growth. The effect of Fe content on media, pre-culture, concentrations and types of chelating and reducing agents in clearing solutions, cleaning time, Fe removal effect, and resistance to seaweed were systematically optimized to obtain the maximum efficacy of the washing solution. A bioassay was developed to evaluate the Fe environment by combining chlorophyll fluorescence measurements. The findings suggest that the tolerance of seaweeds to the wash solution is strongly influenced by the concentrations of the chelating and reducing agents than their types. Washing with 0.02 M Ti-Citrate/EDTA solution for 80 s was the most effective in terms of maximum Fe removal with minimum cell damage. The application of pre-culture and chemical pre-treatment methods under Fe deficiency to the culture strain confirmed the maximum reproducibility in the culture test. Finally, the developed method was applied to actual seaweed samples and was found to be applicable to many seaweed species. However, the method was less robust for some seaweed species and depended on the seaweed growth stage.

Differential Effects of Iron Chelates vs. Iron Salts on Induction of Pro-Oncogenic Amphiregulin and Pro-Inflammatory COX-2 in Human Intestinal Adenocarcinoma Cell Lines

We previously showed that two iron compounds that are orally ingested by humans, namely ferric EDTA and ferric citrate, can induce an oncogenic growth factor (amphiregulin) in human intestinal epithelial adenocarcinoma cell lines. Here, we further screened these iron compounds, plus four other iron chelates and six iron salts (i.e., 12 oral iron compounds in total), for their effects on biomarkers of cancer and inflammation. Ferric pyrophosphate and ferric EDTA were the main inducers of amphiregulin and its receptor monomer, IGFr1. Moreover, at the maximum iron concentrations investigated (500 µM), the highest levels of amphiregulin were induced by the six iron chelates, while four of these also increased IGfr1. In addition, we observed that ferric pyrophosphate promoted signaling via the JAK/STAT pathway by up-regulating the cytokine receptor subunit IFN-γr1 and IL-6. For pro-inflammatory cyclooxygenase-2 (COX-2), ferric pyrophosphate but not ferric EDTA elevated intracellular levels. This, however, did not drive the other biomarkers based on COX-2 inhibition studies and was probably downstream of IL-6. We conclude that of all oral iron compounds, iron chelates may particularly elevate intracellular amphiregulin. Ferric pyrophosphate additionally induced COX-2, probably because of the high IL-6 induction that was observed with this compound.

Iron bioavailability of maize (Zea mays L.) after removing the germ fraction

Maize is a staple food for many communities with high levels of iron deficiency anemia. Enhancing the iron concentrations and iron bioavailability of maize with traditional breeding practices, especially after cooking and processing, could help alleviate iron deficiency in many of these regions. Previous studies on a small number of maize genotypes and maize flour products indicated that degermination (germ fraction removed with processing) could improve the iron bioavailability of maize. This study expanded upon this research by evaluating the iron bioavailability, mineral concentrations, and phytate concentrations of 52 diverse maize genotypes before (whole kernels) and after degermination. Whole and degerminated maize samples were cooked, dried, and milled to produce corn flour. Iron bioavailability was evaluated with an in vitro digestion Caco2 cell bioassay. In 30 of the maize genotypes, bioavailable iron increased when degerminated, thus indicating a higher fractional iron uptake because the iron concentrations decreased by more than 70% after the germ fraction was removed. The remaining 22 genotypes showed no change or a decrease in iron bioavailability after degermination. These results confirm previous research showing that the germ fraction is a strong inhibitory component for many maize varieties. Phytate concentrations in maize flours were greatly reduced with degermination. However, the relationship between phytate concentrations and the iron bioavailability of processed maize flour is complex, acting as either inhibitor or promoter of iron uptake depending on the color of the maize kernels and processing method used to produce flour. Other factors in the maize endosperm fractions are likely involved in the effects of degermination on iron bioavailability, such as vitreous or floury endosperm compositions and the polyphenol content of the bran. This study demonstrates that iron nutrition from maize can be enhanced by selecting genotypes where the inhibitory effect of the bran color and endosperm fraction are relatively low, especially after processing via degermination.

Absorption of iron from Tegillarca granosa using an in vitro simulated digestion and Caco-2/HepG2 co-culture system

BACKGROUND

Iron-deficiency anemia is one severe micronutrient malnutrition and has captured worldwide attention. This study evaluated the in vitro iron absorption of two iron-binding proteins (hemoglobin and ferritin) from Tegillarca granosa. In addition, the protein structure-iron absorption relationship and the regulatory effect of hepcidin on cellular iron absorption were explored.

RESULTS

Our findings revealed that both hemoglobin and ferritin extracted from T. granosa contained abundant iron-binding sites, as evidenced by stronger peaks in amide I and II regions compared with the two proteins from humans. Less β-sheet (27.67%) structures were found in hemoglobin compared with ferritin (36.40%), probably contributing to its greater digestibility and more release of available iron. This was confirmed by the results of Caco-2/HepG2 cell culture system that showed iron absorption of hemoglobin was 26.10-39.31% higher than that of ferritin with an iron content of 50-150 μmol L^-1 . This high iron absorption of hemoglobin (117.86-174.10 ng mg^-1 ) could also be due to more hepcidin produced by HepG2 cells, thereby preventing ferroportin-mediated iron efflux from Caco-2 cells. In addition, the possible risk of oxidative stress was evaluated in cells post-iron exposure. In comparison with ferrous sulfate, a common iron supplement, Caco-2 cells treated with the iron-binding proteins had a 9.50-25.73% lower level of intracellular reactive oxygen species, indicating the safety of hemoglobin and ferritin.

CONCLUSION

Collectively, the data of this research would be helpful for understanding the key features and potential of developing hemoglobin and ferritin from T. granosa as novel iron supplements. © 2022 Society of Chemical Industry.

A two-gene strategy increases iron and zinc concentrations in wheat flour, improving mineral bioaccessibility

Dietary deficiencies of iron and zinc cause human malnutrition that can be mitigated by biofortified staple crops. Conventional breeding approaches to increase grain mineral concentrations in wheat (Triticum aestivum L.) have had only limited success, and our understanding of the genetic and physiological barriers to altering this trait is incomplete. Here we demonstrate that a transgenic approach combining endosperm-specific expression of the wheat VACUOLAR IRON TRANSPORTER gene TaVIT2-D with constitutive expression of the rice (Oryza sativa) NICOTIANAMINE SYNTHASE gene OsNAS2 significantly increases the total concentration of zinc and relocates iron to white-flour fractions. In two distinct bread wheat cultivars, we show that the so called VIT-NAS construct led to a two-fold increase in zinc in wholemeal flour, to ∼50 µg g-1. Total iron was not significantly increased, but redistribution within the grain resulted in a three-fold increase in iron in highly pure, roller-milled white flour, to ∼25 µg g-1. Interestingly, expression of OsNAS2 partially restored iron translocation to the aleurone, which is iron depleted in grain overexpressing TaVIT2 alone. A greater than three-fold increase in the level of the natural plant metal chelator nicotianamine in the grain of VIT-NAS lines corresponded with improved iron and zinc bioaccessibility in white flour. The growth of VIT-NAS plants in the greenhouse was indistinguishable from untransformed controls. Our results provide insights into mineral translocation and distribution in wheat grain and demonstrate that the individual and combined effects of the two transgenes can enhance the nutritional quality of wheat beyond what is possible by conventional breeding.

Efficacy of Pneumatophorus japonicus meat as an iron fortificant in whole-wheat flour in preventing iron deficiency

Iron deficiency anemia (IDA) is a global health concern affecting one-third of the world's population, particularly those dominated by plant-based food. Fortifying staple foods with iron has been an effective strategy for preventing IDA. Pneumatophorus japonicus is an essential economic fish in China. Pneumatophorus japonicus dark meat is usually underutilized as a byproduct, though it contains bounteous nutrients, including heme iron (10.50 mg/100 g). This study aimed to investigate the iron bioavailability of P. japonicus dark meat and to evaluate its potential as an iron fortifier for whole-wheat flour, a typical staple food, using an in vitro digestion/Caco-2 cell culture system. Our results suggested the excellent iron bioavailability of P. japonicus dark meat in comparison with beef (a heme dietary iron reference), whole-wheat flour (a non-heme dietary iron reference), and FeSO₄ (a conventional iron supplement). The addition of P. japonicus dark meat notably enhanced iron solubility, bioavailability, and protein digestibility of whole-wheat flour. The flour-dark meat mixture yielded 1.96 times the iron bioavailability compared to beef per gram. The iron bioavailability was further improved by adding vitamin C, a commonly used dietary factor, at the Vc/iron mass ratio of 2:100-5:100. Our findings reveal the promise of P. japonicus dark meat as a significant source of bioavailable iron, providing a basis for developing fish byproducts as alternatives for iron supplementation. PRACTICAL APPLICATION: This study investigated the iron bioavailability of Pneumatophorus japonicus meat using in vitro digestion/Caco-2 cell culture system. These results could be used to improve the utilization of Pneumatophorus japonicus byproduct (dark meat) and develop the potential of the byproduct as an iron fortifier for whole-wheat flour.

Rapidly Reversible Leukoencephalopathy After Acute Kidney Graft Rejection in a Patient With Systemic Lupus Erythematosus

The finding of white matter damage on brain magnetic resonance imaging may correspond to a wide variety of etiologies. The differential diagnosis may be particularly difficultin immunocompromised patients with a specific autoimmune disease or who are receiving medications after a solid-organ transplant. Herein, we describe the case of a 22-year-old woman who developed serious neurological complications after an acute rejection of a kidney graft that she had received a few months previous to treat a systemic lupus erythematosus-related nephritis.We discuss the possible hypotheses underlying the development of acute leukoencephalopathy in this setting.

The mechanistic effects of human digestion on magnesium oxide nanoparticles: implications for probiotics Lacticaseibacillus rhamnosus GG and Bifidobacterium bifidum VPI 1124

The effects of nanoparticles (NPs) on the human gut microbiota are of high interest due to the link between the gut homeostasis and overall human health. The human intake of metal oxide NPs has increased due to its use in the food industry as food additives. Specifically, magnesium oxide nanoparticles (MgO-NPs) have been described as antimicrobial and antibiofilm. Therefore, in this work we investigated the effects of the food additive MgO-NPs, on the probiotic and commensal Gram-positive Lactobacillus rhamnosus GG and Bifidobacterium bifidum VPI 1124. The physicochemical characterization showed that food additive MgO is formed by nanoparticles (MgO-NPs) and after a simulated digestion, MgO-NPs partially dissociate into Mg2+. Moreover, nanoparticulate structures containing magnesium were found embedded in organic material. Exposures to MgO-NPs for 4 and 24 hours increased the bacterial viability of both L. rhamnosus and B. bifidum when in biofilms but not when as planktonic cells. High doses of MgO-NPs significantly stimulated the biofilm development of L. rhamnosus, but not B. bifidum. It is likely that the effects are primarily due to the presence of ionic Mg2+. Evidence from the NPs characterization indicate that interactions bacteria/NPs are unfavorable as both structures are negatively charged, which would create repulsive forces.

Soilless biofortification, bioaccessibility, and bioavailability: Signposts on the path to personalized nutrition

Propelled by an ever-growing awareness about the importance of following dietary recommendations meeting specific biological requirements linked to a person health status, interest in personalized nutrition is on the rise. Soilless biofortification of vegetables has opened the door to the potential for adapting vegetable production to specific dietary requirements. The evolution of vegetables biofortification toward tailored food is examined focusing on some specific categories of people in a context of personalized nutrition instead to simple describe developments in vegetables biofortification with reference to the single element or compound not adequately present in the daily diet. The concepts of bioavailability and bioaccessibility as a useful support tool for the precision biofortification were detailed. Key prospects for challenges ahead aiming to combine product quality and sustainable are also highlighted. Hydroponically cultivation of vegetables with low potassium content may be effective to obtain tailored leafy and fruit vegetable products for people with impaired kidney function. Simultaneous biofortification of calcium, silicon, and boron in the same vegetable to obtain vegetable products useful for bone health deserve further attention. The right dosage of the lithium in the nutrient solution appears essential to obtain tailored vegetables able to positively influence mental health in groups of people susceptible to mental illness. Modulate nitrogen fertilization may reduce or enhance nitrate in vegetables to obtain tailored products, respectively, for children and athletes. Future research are needed to produce nickel-free vegetable products for individuals sensitized to nickel. The multidisciplinary approach toward tailored foods is a winning one and must increasingly include a synergy between agronomic, biological, and medical skills.

Preparation, characterization and bioavailability studies of Tegillarca granosa hemoglobin and its glycosylated products

Iron deficiency anemia (IDA) is a common micronutrient deficiency. Tegillarca granosa (T. granosa) is a good source of iron due to its high content of hemoglobin. The present study aimed to determine the effects of glycosylation on structure, physicochemical characteristics and iron bioavailability of hemoglobin. Using Box-Behnken design and response surface methodology, the optimal conditions for hemoglobin-chitosan glycosylation were obtained: 61.8 °C, pH 6.3, hemoglobin/chitosan mass ratio of 4.3 and reaction time of 15 min. The formation of hemoglobin-chitosan conjugates was verified by SDS-PAGE and fluorescence spectroscopy. The surface hydrophobicity of hemoglobin was reduced by 20.90-65.05 % after glycosylation, along with the observations of elevated water-holding capacity, likely owing to the introduction of hydrophilic groups. Antioxidant capacity of glycosylated products (0.41-0.66 μM Trolox/mg protein) was markedly greater than that of original protein (0.06 μM Trolox/mg protein) due to the formation of brown polymers with antioxidant activity. In addition, glycosylation improved in vitro digestibility of hemoglobin by 41.15-69.09 %, which could be attributed to less β-sheet in secondary structures. Moreover, hemoglobin (324.38 ng/mg) exhibited better iron absorption than FeSO₄ (121.63 ng/mg), with the value being further enhanced by glycosylation (442.73 ng/mg), which may be due to the improved protein digestibility and iron-chelating capacity.

Intestinal Absorption Study of a Granular Form of Ferric Pyrophosphate

Iron deficiency is one of the most prevalent nutritional disorders worldwide. The standard treatment involves iron supplementation, but this task is challenging because of poor solubility and organoleptic issues. Moreover, the need to increase iron bioavailability represents a challenge for treating iron-related disorders. In this study, gastroresistance and iron intestinal absorption of an innovative granular formulation composed of ferric pyrophosphate, modified starch and phospholipids branded as Ferro Fosfosoma® was investigated. Gastroresistant properties were studied using standard protocols, and a bioaccessible fraction was obtained by exposing a food supplement to in vitro digestion. This fraction was used for investigating iron absorption in Caco-2 and human follicle-associated intestinal epithelium (FAE) models. Ferro Fosfosoma® showed an improved resistance to gastric digestion and higher intestinal absorption than ferric pyrophosphate salt used as a control in both models. In the FAE model, Ferro Fosfosoma® induces larger iron absorption than in the Caco-2 monolayer, most likely due to the transcytosis ability of M cells. The larger iron absorption in the Ferro Fosfosoma®-treated FAE model corresponds to higher ferritin level, proving physiological iron handling that was once delivered by granular formulation. Finally, the formulation did not induce any alterations in viability and barrier integrity. To conclude, Ferro Fosfosoma® favors iron absorption and ferritin expression, while preserving any adverse effects.

Multi-year field evaluation of nicotianamine biofortified bread wheat

Conventional breeding efforts for iron (Fe) and zinc (Zn) biofortification of bread wheat (Triticum aestivum L.) have been hindered by a lack of genetic variation for these traits and a negative correlation between grain Fe and Zn concentrations and yield. We have employed genetic engineering to constitutively express (CE) the rice (Oryza sativa) nicotianamine synthase 2 (OsNAS2) gene and upregulate biosynthesis of two metal chelators - nicotianamine (NA) and 2'-deoxymugineic acid (DMA) - in bread wheat, resulting in increased Fe and Zn concentrations in wholemeal and white flour. Here we describe multi-location confined field trial (CFT) evaluation of a low-copy transgenic CE-OsNAS2 wheat event (CE-1) over 3 years and demonstrate higher concentrations of NA, DMA, Fe, and Zn in CE-1 wholemeal flour, white flour, and white bread and higher Fe bioavailability in CE-1 white flour relative to a null segregant (NS) control. Multi-environment models of agronomic and grain nutrition traits revealed a negative correlation between grain yield and grain Fe, Zn, and total protein concentrations, yet no correlation between grain yield and grain NA and DMA concentrations. White flour Fe bioavailability was positively correlated with white flour NA concentration, suggesting that NA-chelated Fe should be targeted in wheat Fe biofortification efforts.

Effect of dietary supplements on Se bioavailability: A comprehensive in vitro and in vivo study

Selenium (Se) is an essential micronutrient for animals and humans, and it is present in many different forms with different levels of bioaccessibility in food. Based on the maldistribution of Se and overall low level of Se dietary intake in China, an integrated study was conducted in this thesis to provide references for the regulation of Se nutrition. An in vitro simulation test was used to monitor the concentration effects, the impacts of dietary supplement combinations on the bioaccessibility of Se were examined in rice, and a model animal experiment (in vivo) was used to evaluate the practicability of the Se nutrition regulation scheme. The main results were as follows: the bioaccessibility of Se was effectively increased by 30 mg·d^-1 VE (VE), 300 mg·d^-1 VC + 300 μg·d^-1 VB9 (VC+VB9) and 30 mg·d^-1 VE + 300 mg·d^-1 VC + 300 μg·d^-1 VB9 (3IN1) (P < 0.05). The results of the healthy broiler tests showed that the 3 treatments increased the weight and Se content of the broilers, and 3IN1 had the most significant effect (P < 0.05). VC+VB9 was the best at promoting GPx activity, while 3IN1 was the best at promoting SOD activity and the inhibition of MDA content in broilers. The results suggested that VE, VC+VB9 and 3IN1 can benefit the bioavailability of Se and the antioxidant capacity of the body. The results can be used as a scientific reference for Se nutrition regulation.

Iron Bioavailability from Infant Cereals Containing Whole Grains and Pulses: A Stable Isotope Study in Malawian Children

BACKGROUND

Compared with infant cereals based on refined grains, an infant cereal containing whole grains (WGs) and pulses with adequate amounts of ascorbic acid to protect against absorption inhibitors could be a healthier source of well-absorbed iron. However, iron absorption from such cereals is uncertain.

OBJECTIVE

We measured iron bioavailability from ferrous fumarate (Fefum) added to commercial infant cereals containing 1) refined wheat flour (reference meal), 2) WG wheat and lentil flour (WG-wheat-lentil), 3) WG wheat and chickpea flour (WG-wheat-chickpeas), and 4) WG oat flour (WG-oat) and from ferrous bisglycinate (FeBG) added to the same oat-based cereal (WG-oat-FeBG).

METHODS

In a prospective, single-blinded randomized crossover study, 6- to 14-mo-old Malawian children (n = 30) consumed 25-g servings of all 5 test meals containing 2.25 mg stable isotope-labeled iron and 13.5 mg ascorbic acid. Fractional iron absorption (FIA) was assessed by erythrocyte incorporation of isotopes after 14 d. Comparisons were made using linear mixed models.

RESULTS

Seventy percent of the children were anemic and 67% were iron deficient. Geometric mean FIA percentages (-SD, +SD) from the cereals were as follows: 1) refined wheat, 12.1 (4.8, 30.6); 2) WG-wheat-lentil, 15.8 (6.6, 37.6); 3) WG-wheat-chickpeas, 12.8 (5.5, 29.8); and 4) WG-oat, 9.2 (3.9, 21.5) and 7.4 (2.9, 18.9) from WG-oat-FeBG. Meal predicted FIA (P ≤ 0.001), whereas in pairwise comparisons, only WG-oat-FeBG was significantly different compared with the refined wheat meal (P = 0.02). In addition, FIAs from WG-wheat-lentil and WG-wheat-chickpeas were significantly higher than from WG-oat (P = 0.002 and P = 0.04, respectively) and WG-oat-FeBG (P < 0.001 and P = 0.004, respectively).

CONCLUSION

In Malawian children, when given with ascorbic acid at a molar ratio of 2:1, iron bioavailability from Fefum-fortified infant cereals containing WG wheat and pulses is ≈13-15%, whereas that from FeBG- and Fefum-fortified infant cereals based on WG oats is ≈7-9%.

Sensory Characteristics and Nutritional Quality of Food Products Made with a Biofortified and Lectin Free Common Bean (Phaseolus vulgaris L.) Flour

Common beans (Phaseolus vulgaris L.) are an important source of nutrients with beneficial effects on human health. However, they contain lectins, that limit the direct use of flour in food preparations without thermal treatment, and phytic acid, that reduces mineral cation bioavailability. The objectives of this research were: to obtain biofortified snacks and a cream using an untreated common bean flour devoid of active lectins (lec^-) and with reduced content of phytic acid (lpa) and to evaluate the sensorial appreciation for these products. The main results of the present work were: the products with the lpa lec^- flour did not retain residual hemagglutinating activity due to lectins; they showed higher residual α-amylase inhibitor activity (from 2.2 to 135 times), reduced in vitro predicted glycemic index (about 5 units reduction) and increased iron bioavailability compared to the products with wild type flour; products with common bean flour were less appreciated than the reference ones without this flour, but the presence of an intense umami taste can be a positive attribute. Results confirmed that the use of the lpa lec^- flour has important advantages in the preparation of safe and nutritionally improved products, and provide useful information to identify target consumers, such as children and elderly people.

Nutritional properties of selected superfood extracts and their potential health benefits

Background

The term 'superfoods' is used to market foods considered to have significant health benefits. 'Superfoods' are claimed to prevent diseases as well as improving overall health, though the lack of explicit criteria means that any food can be labelled 'super' without support from scientific research. Typically, these 'superfoods' are rich in a particular nutrient for example antioxidants or omega-3 fatty acids. The objective of this study was to investigate the nutritional properties of a selection of superfood seeds: flax, chia, hulled sunflower and two types of processed hemp seeds and determine whether they may have potential health benefits.

Methods

We developed a simple aqueous extraction method for ground seeds and analysed their composition by mineral, protein and monosaccharide analyses. Cell viability assays were performed on Caco-2 and IEC-6 intestinal epithelial cells using increasing doses of the prepared extracts.

Results

Increased cell viability was observed in both cell lines with increasing concentrations of the flax seed, chia seed or hulled sunflower extracts (P < 0.05). Compositional analyses revealed the presence of polysaccharides, proteins and essential minerals in the aqueous extracts and in vitro assays showed sunflower had the highest antioxidant activity. However, differences in extract composition and antioxidant properties could not be directly related to the observed increase in cell viability suggesting that other components in the extracts may be responsible. Future studies will further characterize these extracts and investigate whether they are beneficial for gastrointestinal health.

Effect of ascorbic acid and citric acid on bioavailability of iron from Tegillarca granosa via an in vitro digestion/Caco-2 cell culture system

Iron deficiency anaemia (IDA) has been receiving worldwide attention. Developing safe and effective iron supplements is of great significance for IDA treatment. Tegillarca granosa (T. granosa), a traditional aquaculture bivalve species in China, is considered to be an excellent source of micronutrients, but the distribution and bioavailability of these minerals have yet to be investigated. The present research was conducted to determine the contents and in vitro enzymatic digestibility of minerals in T. granosa, using beef and wheat flour as reference foods. Meanwhile, two iron-binding proteins, hemoglobin and ferritin, were extracted from T. granosa, and their structures, iron accessibility and bioavailability were investigated. Moreover, the effects of ascorbic acid (AA) and citric acid (CA), two commonly applied dietary factors, on these parameters were evaluated. Our results indicated that the mineral levels varied significantly among different food matrices, with T. granosa showing the highest contents of the tested elements. Comparison of iron absorption of meat versus wheat flour and hemoglobin versus ferritin confirmed that heme iron exhibited higher bioavailability than non-heme iron. The addition of the two organic acids notably enhanced the cellular iron uptake of T. granosa-derived proteins. This could be because AA/CA weakened hydrogen bonds within proteins and caused disordered secondary structures, thereby improving their enzymatic digestibility and releasing more soluble iron to be available for absorption. The results of this study provided a basis for the development of T. granosa-derived protein-based iron supplements, promoting the diverse utilization of marine aquatic resources.

Iron Bioavailability from Multiple Biofortified Foods Using an In Vitro Digestion, Caco-2 Assay for Optimizing a Cyclical Menu for a Randomized Efficacy Trial

BACKGROUND

Inadequate nutritional status contributes to substantial losses in human health and productivity globally. A multiple biofortified food crop trial targeting iron, zinc, and vitamin A deficiencies among young children and their breastfeeding mothers is being conducted in India.

OBJECTIVE

We sought to determine the relative iron bioavailability from biofortified and conventional crops and crop combinations representative of a cyclical menu using crops targeted for inclusion in the feeding trial.

METHODS

Crops were procured from India, cooked, freeze-dried, and analyzed with an established in vitro digestion/Caco-2 iron bioavailability assay using a fixed sample weight. Crop proportions representative of meals planned for the human study were determined and combined such that samples included either all biofortified or all control crops. Crops were analyzed as single crops (n = 4) or crop combinations (n = 7) by variety (biofortified or control) in triplicate. The primary outcome was iron uptake measured by Caco-2 ferritin production normalized to total Caco-2 protein (nanograms of ferritin/milligrams of cell protein) analyzed for effects of crop variety and crop proportion using generalized linear models.

RESULTS

Biofortified pearl millet alone demonstrated higher iron uptake than conventional varieties (5.01 ± 1.66 vs. 2.17 ± 0.96; P = 0.036). Addition of sweet potato or sweet potato + pulse improved iron uptake for all proportions tested in control varieties and select proportions for biofortified varieties (P ≤ 0.05). Two multiple crop combinations demonstrated modestly higher iron uptake from biofortified crops.

CONCLUSIONS

Optimizing total iron delivery should consider matrix effects, processing, and promoters/inhibitors of iron absorption in addition to total iron concentration. Future directions include evaluating recipes as prepared for consumption and comparison against human iron bioavailability studies.

Agronomic Performance in Low Phytic Acid Field Peas

Field pea is a pulse that delivers high protein content, slowly digestible starch and fiber, and many vitamins and minerals, including iron. Naturally occurring plant phytic acid molecules bind iron, lowering its availability for absorption during digestion. Two low phytic acid (lpa) pea lines, 1-2347-144 and 1-150-81, developed by our group had 15% lower yield and 6% lower seed weight relative to their progenitor cultivar. Subsequently, we crossed the two lpa lines and two cultivars, and derived 19 promising lpa pea breeding lines; here we document their agronomic performance based on 10 replicated field trials in Saskatchewan. Seventeen of these lpa lines yielded greater than 95% of the check mean (associated cultivars) and 16 were above 98% of the check mean for 1000 seed weight. The 19 lpa lines showed 27 to 55% lower phytic acid concentration than the check mean. Iron concentrations were similar in all the lpa lines and cultivars, yet the Caco-2 human cell culture assay revealed 14 of the 19 lpa lines had 11 to 55% greater iron bioavailability than check means. Thus, a single round of plant breeding has allowed for closing the gap in performance of low phytic acid pea.

Bioavailability of iron from novel hydrogen reduced iron powders: Studies in Caco-2 cells and rat model

The bioavailability of iron from elemental iron powders, including hydrogen reduced iron powder (HRIP), is influenced by particle size and surface area. In the present study, we investigated the solubility, bioaccessibility, and bioavailability of iron from novel HRIPs (particle size ≤25 and 38 µm generated at low [LT] and high [HT] temperature), with porous morphology and high surface area, in intestinal Caco-2 cells and in rat models. The acceptability of fortified wheat flour was tested in human volunteers. The iron solubility and ferritin induction in Caco-2 cells were significantly higher from wheat flour fortified with HRIPs compared to electrolytic iron powder (EIP, ≤45 µm size) either in the absence or presence of ascorbic acid. Nevertheless, ferritin induction in Caco-2 cells was significantly higher with FeSO₄ compared to HRIP or EIP. The relative biological value of HRIPs was significantly higher (≤38HT) or similar compared to EIP in rats. However, serum ferritin was significantly higher in rats fed HRIPs than EIP. Further, wheat flour fortified with HRIP was found to be acceptable for consumption. These findings demonstrate higher iron bioavailability from novel HRIPs compared to the reference EIP (≤45 µm) and merits further studies on toxicity and efficacy. PRACTICAL APPLICATION: The use of elemental iron powders for food fortification to alleviate iron deficiency is limited due to its poor bioavailability. The novel hydrogen-reduced elemental iron powders used in this study had higher bioaccessibility and bioavailability compared to reference EIP (≤45 µm) in in vitro and in vivo models, respectively. Further, there were no sensory differences between roti prepared with fortified or unfortified wheat flour. These results suggest that the novel hydrogen reduced elemental iron powders used in the present study are suitable for wheat flour fortification.

Redefining Bean Iron Biofortification: A Review of the Evidence for Moving to a High Fe Bioavailability Approach

Iron biofortification of the common bean (Phaseolus vulgaris) commenced in earnest ~18 years ago. Based on knowledge at the time, the biofortification approach for beans was simply to breed for increased Fe concentration based on 3 major assumptions: (1) The average bean Fe concentration is ~50 μg/g; (2) Higher Fe concentration results in more bioavailable Fe delivered for absorption; (3) Breeding for high Fe concentration is a trait that can be achieved through traditional breeding and is sustainable once a high Fe bean sample is released to farmers. Current research indicates that the assumptions of the high Fe breeding approach are not met in countries of East Africa, a major focus area of bean Fe biofortification. Thus, there is a need to redefine bean Fe biofortification. For assumption 1, recent research indicates that the average bean Fe concentration in East Africa is 71 μg/g, thus about 20 μg/g higher than the assumed value. For assumption 2, recent studies demonstrate that for beans higher Fe concentration does not always equate to more Fe absorption. Finally, for assumption 3, studies show a strong environment and genotype by environment effect on Fe concentration, thus making it difficult to develop and sustain high Fe concentrations. This paper provides an examination of the available evidence related to the above assumptions, and offers an alternative approach utilizing tools that focus on Fe bioavailability to redefine Fe biofortification of the common bean.

Investigation of Genotype by Environment Interactions for Seed Zinc and Iron Concentration and Iron Bioavailability in Common Bean

Iron and zinc malnutrition are global public health concerns afflicting mostly infants, children, and women in low- and middle-income countries with widespread consumption of plant-based diets. Common bean is a widely consumed staple crop around the world and is an excellent source of protein, fiber, and minerals including iron and zinc. The development of nutrient-dense common bean varieties that deliver more bioavailable iron and zinc with a high level of trait stability requires a measurement of the contributions from genotype, environment, and genotype by environment interactions. In this research, we investigated the magnitude of genotype by environment interaction for seed zinc and iron concentration and seed iron bioavailability (FeBIO) using a set of nine test genotypes and three farmers' local check varieties. The research germplasm was evaluated for two field seasons across nine on-farm locations in three agro-ecological zones in Uganda. Seed zinc concentration ranged from 18.0 to 42.0 μg g^-1 and was largely controlled by genotype, location, and the interaction between location and season [28.0, 26.2, and 14.7% of phenotypic variability explained (PVE), respectively]. Within a genotype, zinc concentration ranged on average 12 μg g^-1 across environments. Seed iron concentration varied from 40.7 to 96.7 μg g^-1 and was largely controlled by genotype, location, and the interaction between genotype, location, and season (25.7, 17.4, and 13.7% of PVE, respectively). Within a genotype, iron concentration ranged on average 28 μg g^-1 across environments. Seed FeBIO ranged from 8 to 116% of Merlin navy control and was largely controlled by genotype (68.3% of PVE). The red mottled genotypes (Rozi Koko and Chijar) accumulated the most seed zinc and iron concentration, while the yellow (Ervilha and Cebo Cela) and white (Blanco Fanesquero) genotypes had the highest seed FeBIO and performed better than the three farmers' local check genotypes (NABE-4, NABE-15, and Masindi yellow). The genotypes with superior and stable trait performance, especially the Manteca seed class which combine high iron and zinc concentrations with high FeBIO, would serve as valuable parental materials for crop improvement breeding programs aimed at enhancing the nutritional value of the common bean.

Bioaccessibility and bioavailability of calcium in sprouted brown and golden flaxseed

BACKGROUND

Germination promotes changes in the composition of seeds by providing potential nutritional and health benefits compared with unsprouted seeds. This study investigated the influence of germination on the bioaccessibility and bioavailability of calcium in brown flaxseed (BF) and golden flaxseed (GF).

RESULTS

Germination did not influence the calcium levels of BF or GF, but the sprouted GF (SGF, 265.6 ± 12.9 mg) presented higher levels of calcium than the sprouted BF (SBF, 211.6 ± 3.20 mg). Tannin levels were similar among the groups (GF = 79.97 ± 3.49 mg; SGF = 78.81 ± 0.77 mg; BF = 81.82 ± 2.61 mg; SBF = 79.24 ± 4.58 mg), whereas phytate and oxalate levels decreased after germination. Germination reduced the phytate:calcium and oxalate:calcium molar ratios. In the in vitro study, germination increased calcium bioaccessibility (GF = 35.60 mg versus SGF = 41.45 mg; BF = 31.01 mg versus SBF = 38.84 mg). In the in vivo study, all groups present similar levels of urinary calcium (GF = 1.04 mg versus SGF = 2.06 mg; BF = 1.68 mg versus SBF = 1.35 mg) and fecal calcium (GF = 5.06 mg versus SGF = 6.14 mg; BF = 6.47 mg versus SBF = 8.40 mg). The calcium balance/day of the SBF group (37.97 mg) was smaller than the control group (47.22 mg). The germination maintained the plasma levels of calcium, phosphorus, creatinine, and alkaline phosphatase similar among the groups. No changes were observed in morphology and calcium levels of animal femurs.

CONCLUSION

The germination reduced the antinutritional factor in both flaxseed varieties. Although there was an improvement in the in vitro bioaccessibility of calcium, the germination did not increase calcium absorption and balance in the animals, which may be due to the interaction with other compounds in the organism. © 2020 Society of Chemical Industry.

A versatile, compartmentalised gut-on-a-chip system for pharmacological and toxicological analyses

A novel, integrated, in vitro gastrointestinal (GI) system is presented to study oral bioavailability parameters of small molecules. Three compartments were combined into one hyphenated, flow-through set-up. In the first compartment, a compound was exposed dynamically to enzymatic digestion in three consecutive microreactors, mimicking the processes of the mouth, stomach, and intestine. The resulting solution (chyme) continued to the second compartment, a flow-through barrier model of the intestinal epithelium allowing absorption of the compound and metabolites thereof. The composition of the effluents from the barrier model were analysed either offline by electrospray-ionisation-mass spectrometry (ESI-MS), or online in the final compartment using chip-based ESI-MS. Two model drugs, omeprazole and verapamil, were used to test the integrated model. Omeprazole was shown to be broken down upon treatment with gastric acid, but reached the cell barrier unharmed when introduced to the system in a manner emulating an enteric-coated formulation. In contrast, verapamil was unaffected by digestion. Finally, a reduced uptake of verapamil was observed when verapamil was introduced to the system dissolved in apple juice, a simple food matrix. It is envisaged that this integrated, compartmentalised GI system has potential for enabling future research in the fields of pharmacology, toxicology, and nutrition.

A LCMS Metabolomic Workflow to Investigate Metabolic Patterns in Human Intestinal Cells Exposed to Hydrolyzed Crab Waste Materials

We have developed a LCMS metabolomic workflow to investigate metabolic patterns from human intestinal cells treated with simulated gastrointestinal-digested hydrolyzed crab waste materials. This workflow facilitates smart and reproducible comparisons of cell cultures exposed to different treatments. In this case the variable was the hydrolysis methods, also accounting for the GI digestion giving an output of direct correlation between cellular metabolic patterns caused by the treatments. In addition, we used the output from this workflow to select treatments for further evaluation of the Caco-2 cell response in terms of tentative anti-inflammatory activity in the hopes to find value in the crab waste materials to be used for food products. As hypothesized, the treatment identified to change the cellular metabolomic pattern most readily, was also found to cause the greatest effect in the cells, although the response was pro-inflammatory rather than anti-inflammatory, it proves that changes in cellular metabolic patterns are useful predictors of bioactivity. We conclude that the developed workflow allows for cost effective, rapid sample preparation as well as accurate and repeatable LCMS analysis and introduces a data pipeline specifically for probe the novel metabolite patterns created as a means to assess the performing treatments.

Structure, functional properties and iron bioavailability of Pneumatophorus japonicus myoglobin and its glycosylation products

Developing safe and efficient iron supplements is significant for the alleviation of iron-deficient anemia (IDA). Myoglobin (Mb) is a heme-protein rich in bioavailable iron. Pneumatophorus japonicus (P. japonicus), one important economic fish in China, contain a high Mb level in its dark meat normally discarded during processing. The present study aimed to determine the structure, physicochemical properties, and iron bioavailability of Mb extracted from P. japonicus. Meanwhile, the effects of glycosylation, a commonly applied chemical modification of proteins, on these parameters were evaluated. Using Box-Behnken design, the optimal conditions for Mb-chitosan glycosylation were obtained: 45.07 °C, pH 6.10 and Mb/chitosan mass ratio of 6.29. The structure and functional properties of the glycosylated Mb (Mb-gly) were investigated. Compared with the original Mb, Mb-gly obtained a more ordered secondary structure. The surface hydrophobicity of Mb-gly was found to be decreased together with the observations of elevated water solubility. Moreover, glycosylation enhanced the Mb antioxidant capacity, and improved its stability in enzymatic digestion system. Regarding to the iron bioavailability, the cellular uptake of Mb‑iron was significantly higher than FeSO₄, and further elevated by glycosylation. These results provided a basis for the development of Mb-based iron supplements, promoting the utilization of fish-processing industries wastes.

Iron- and Zinc-Fortified Lentil (Lens culinaris Medik.) Demonstrate Enhanced and Stable Iron Bioavailability After Storage

Lentil (Lens culinaris Medik.) is a quick-cooking, rapidly expanding protein-rich crop with high iron (Fe) and zinc (Zn), but low bioavailability due to the presence of phytate, similar to other grains. Lentils dual fortified with Fe and Zn can significantly improve the bioavailable Fe and Zn content. Three milled lentil product types (LPTs) were fortified with Fe using NaFeEDTA [ethylenediaminetetraacetic acid iron (III) sodium salt] (Fe fortified) or Zn from ZnSO₄·H₂O (Zn fortified), or both (dual fortified). Fe, Zn, phytic acid (PA) concentration, and relative Fe bioavailability (RFeB%) were assessed for samples from two fortified batches (initial and for 1 year stored). Fe, Zn, and RFeB% increased significantly in two batches of samples from the three LPTs, and decreased by 5–15% after 1 year of storage. PA concentration decreased from 8 to 15% after fortification of all samples from two batches of the three LPTs but showed different patterns of influence after storage. Dual-fortified lentil fortified with 24 mg Fe and 12 mg Zn 100 g⁻¹ lentil had the highest amount of Fe and Zn, and the lowest PA concentration, and RFeB% was increased from 91.3 to 519.5%. Significant (p ≤ 0.01) Pearson correlations were observed between Fe concentration vs. PA:Fe molar ratio (MR), Fe concentration vs. RFeB%, RFeB% vs. PA:Fe MR, and Zn concentration vs. PA:Zn MR in all samples from two batches of the three LPTs. In conclusion, dual-fortified lentil can contribute significant bioavailable Fe and Zn to populations at risk of Fe and Zn deficiency.

Biofortification and bioavailability of Zn, Fe and Se in wheat: present status and future prospects

Knowledge of genetic variation, genetics, physiology/molecular basis and breeding (including biotechnological approaches) for biofortification and bioavailability for Zn, Fe and Se will help in developing nutritionally improved wheat. Biofortification of wheat cultivars for micronutrients is a priority research area for wheat geneticists and breeders. It is known that during breeding of wheat cultivars for productivity and quality, a loss of grain micronutrient contents occurred, leading to decline in nutritional quality of wheat grain. Keeping this in view, major efforts have been made during the last two decades for achieving biofortification and bioavailability of wheat grain for micronutrients including Zn, Fe and Se. The studies conducted so far included evaluation of gene pools for contents of not only grain micronutrients as above, but also for phytic acid (PA) or phytate and phytase, so that, while breeding for the micronutrients, bioavailability is also improved. For this purpose, QTL interval mapping and GWAS were carried out to identify QTLs/genes and associated markers that were subsequently used for marker-assisted selection (MAS) during breeding for biofortification. Studies have also been conducted to understand the physiology and molecular basis of biofortification, which also allowed identification of genes for uptake, transport and storage of micronutrients. Transgenics using transgenes have also been produced. The breeding efforts led to the development of at least a dozen cultivars with improved contents of grain micronutrients, although land area occupied by these biofortified cultivars is still marginal. In this review, the available information on different aspects of biofortification and bioavailability of micronutrients including Zn, Fe and Se in wheat has been reviewed for the benefit of those, who plan to start work or already conducting research in this area.

Retention, stability, iron bioavailability and sensory evaluation of extruded rice fortified with iron, folic acid and vitamin B12

Fortification of rice with micronutrients using extrusion technology is considered a sustainable strategy to prevent nutritional deficiencies in general population. The objective of the present study is to assess the retention, stability and iron bioavailability from indigenously developed triple fortified rice (iron, folic acid and vitamin B12 ) during rinsing and different cooking methods. Further, we also assessed the acceptability of fortified rice in adult human volunteers. The retention of iron during rinsing with excess water was ≥90%, whereas folic acid and vitamin B12 levels were reduced by ~25% during rinsing. Watertight cooking of rice (in electric cooker or on flame) had no additional effect on the nutrient levels as compared with rinsed rice, implying their stability during cooking. However, cooking with excess water followed by decanting led to loss of 45% iron and ≥70% folic acid and vitamin B12 . The dialyzable iron and ferritin synthesis in Caco-2 cells was significantly (P < .01) higher from fortified rice compared with unfortified rice. In addition, inclusion of ascorbic acid significantly (P < .01) increased the iron bioavailability from the fortified rice. Triangle tests in adult human subjects revealed that there are no significant sensory differences among fortified and unfortified rice. Further, fortified rice consumption appears to bridge the gaps in dietary iron intake deficits in children and women of reproductive age. These results suggest that the iron-, folic acid- and vitamin B12 -fortified rice has higher retention and stability of fortified nutrients and is acceptable for consumption in adult human volunteers.

The Role of Metal Oxide Nanoparticles, Escherichia coli, and Lactobacillus rhamnosus on Small Intestinal Enzyme Activity

Engineered nanomaterials (ENMs) have become common in the food industry, which motivates the need to evaluate ENM effects on human health. Gastrointestinal (GI) in vitro models (e.g. Caco-2, Caco-2/HT29-MTX) have been used in nanotoxicology research. However, the human gut environment is composed of both human cells and the gut microbiota. The goal of this study is to increase the complexity of the Caco-2/HT29-MTX in vitro model by co-culturing human cells with the Gram-positive, commensal Lactobacillus rhamnosus or the Gram-negative, opportunistic Escherichia coli; with the hypothesis that the presence of bacteria would ameliorate the effects of exposure to metal oxide nanoparticles (NPs) such as iron oxide (Fe2O3), silicone dioxide (SiO2), titanium dioxide (TiO2), or zinc oxide (ZnO). To understand this relationship, Caco-2/HT29-MTX cell barriers were acutely co-exposed (4 hours) to bacteria and/or NPs (pristine or in vitro digested). The activity of the brush border membrane (BBM) enzymes intestinal alkaline phosphatase (IAP), aminopeptidase-N (APN), sucrase isomaltase (SI) and the basolateral membrane enzyme (BLM) Na+/K+ ATPase were assessed. Findings show that (i) the human digestion process alters the physicochemical properties of NPs, (ii) large agglomerates of NPs remain entrapped on the apical side of the intestinal barrier, which (iii) affects the activity of BBM enzymes. Interestingly, some NPs effects were attenuated in the presence of either bacterial strains. Confocal microscopy detected bacteria-NPs interactions, which may impede the NP-intestinal cell contact. These results highlight the importance of improving in vitro models to closely mimic the complexities of the human body.