Polyphenolic compounds appear to limit the nutritional benefit of biofortified higher iron black bean (Phaseolus vulgaris L.)

Prevalence of stunting and associated factors among under-five children in sub-Saharan Africa: Multilevel ordinal logistic regression analysis modeling

INTRODUCTION

Stunting is still a major public health problem all over the world, it affecting more than one-third of under-five children in the world that leads to growth retardation, life-threatening complication and accelerate mortality and morbidity. The evidence is scarce on prevalence and associated factors of stunting among under-five children in Sub-Saharan Africa for incorporated intervention. Therefore this study aimed to investigate the prevalence and determinants of stunting among under-five children in Sub-Saharan Africa using recent demographic and health surveys of each country.

METHODS

This study was based on the most recent Demographic and Health Survey data of 36 sub-Saharan African countries. A total of 203,852(weighted sample) under-five children were included in the analysis. The multi-level ordinal logistic regression was fitted to identify determinants of stunting. Parallel line (proportional odds) assumption was cheeked by Brant test and it is satisfied (p-value = 0.68) which is greater than 0.05. Due to the nested nature of the dataset deviance was used model comparison rather than AIC and BIC. Finally the adjusted odds ratio (AOR) with 95% CI was reported identify statistical significant determinants of stunting among under-five children.

RESULTS

In this study, the prevalence of stunting among under-five children in Sub-Saharan Africa 34.04% (95% CI: 33.83%, 34.24%) with a large difference between specific countries which ranges from 16.14% in Gabon to 56.17% in Burundi. In the multi-level ordinal logistic regression good maternal education, born from mothers aged above 35 years, high household wealth status, small family size, being female child, being female household head, having media exposure and having consecutive ANC visit were significantly associated with lower odds of stunting. Whereas, living from rural residence, being 24-59 month children age, single or divorced marital status, higher birth order and having diarrhea in the last two weeks were significantly associated with higher odds of stunting.

CONCLUSION

Stunting among under-five children is still public health problem in Sub-Saharan Africa. Therefore designing interventions to address diarrhea and other infectious disease, improving the literacy level of the area and increase the economic level of the family to reduce the prevalence of stunting in the study area.

Empire Apple (Malus domestica) Juice, Pomace, and Pulp Modulate Intestinal Functionality, Morphology, and Bacterial Populations In Vivo (Gallus gallus)

Approximately $20 billion of apple sales are generated annually in the United States. With an estimated 5 million tons produced yearly in the U.S. within the last decade, apple consumption is considered ubiquitous. Apples are comprised of bioactive constituents such as phytochemicals and prebiotics that may potentiate intestinal health and the gut microbiome. This study aimed to evaluate the effects of Empire apple juice, pomace, and pulp soluble extracts on intestinal functionality, morphology, and the microbiome in vivo (Gallus gallus). There were five treatment groups: non-injected (NI); 18 MΩ H2O (H2O); 6% apple juice (AJ); 6% apple pomace (APo); 6% apple pulp (APu). The eggs were treated by intra-amniotic administration of the samples on day 17 of incubation. After hatching, the blood, tissue, and cecum samples were collected for further analyses—including duodenal histomorphology, hepatic and duodenal mRNA expression, and cecal bacterial populations. Crypt depth was significantly (p < 0.5) shortest in AJ when compared to APo and APu. APo and APu soluble extracts significantly improved villi surface area compared to NI and H2O control groups. The highest count of Paneth cells per crypt was observed in APo as compared to all groups. In addition, the expression of brush border membrane micronutrient metabolism and functional proteins varied between treatments. Lastly, Lactobacillus cecal microbial populations increased significantly in the AJ group, while AJ, APu, and APu increased the abundance of Clostridium (p < 0.5). Ultimately, these results indicate the potential of Empire apple pomace to improve host intestinal health and the gut microbiome.

Antinutritional factors, nutritional improvement, and future food use of common beans: A perspective

Common bean seeds are an excellent source of protein as well as of carbohydrates, minerals, vitamins, and bioactive compounds reducing, when in the diet, the risks of diseases. The presence of bioactive compounds with antinutritional properties (e.g., phytic acid, lectins, raffinosaccharides, protease inhibitors) limits, however, the bean's nutritional value and its wider use in food preparations. In the last decades, concerted efforts have been, therefore, made to develop new common bean genotypes with reduced antinutritional compounds by exploiting the natural genetic variability of common bean and also applying induced mutagenesis. However, possible negative, or positive, pleiotropic effects due to these modifications, in terms of plant performance in response to stresses or in the resulting technological properties of the developed mutant genotypes, have yet not been thoroughly investigated. The purpose of the perspective paper is to first highlight the current advances, which have been already made in mutant bean characterization. A view will be further provided on future research directions to specifically explore further advantages and disadvantages of these bean mutants, their potential use in innovative foods and representing a valuable genetic reservoir of combinations to assess the true functional role of specific seed bioactive components directly in the food matrix.

Biofortification of Three Cultivated Mushroom Species with Three Iron Salts—Potential for a New Iron-Rich Superfood

Mushrooms fortified with iron (Fe) can offer a promising alternative to counter the worldwide deficiency problem. However, the factors that may influence the efficiency of fortification have not yet been fully investigated. The aim of this study was to compare the effects of three Fe forms (FeCl₃ 6H₂O, FeSO₄ 7H₂O, or FeHBED) in three concentrations (5, 10, or 50 mM) for three mushroom species (Pleurotus eryngii, P. ostreatus, or Pholiota nameko) on their chemical composition, phenolic compounds, and organic acid production. The most effective metal accumulation of all the investigated species was for the 50 mM addition. FeCl₃ 6H₂O was the most favorable additive for P. eryngii and P. nameko (up to 145 and 185% Fe more than in the control, respectively) and FeHBED for P. ostreatus (up to 108% Fe more than in control). Additionally, P. nameko showed the highest Fe accumulation among studied species (89.2 ± 7.51 mg kg⁻¹ DW). The creation of phenolic acids was generally inhibited by Fe salt supplementation. However, an increasing effect on phenolic acid concentration was observed for P. ostreatus cultivated at 5 mM FeCl₃ 6H₂O and for P. eryngii cultivated at 5 mM FeCl₃ 6H₂O and 5 mM FeSO₄ 7H₂O. In the case of organic acids, a similar situation was observed. For P. ostreatus, FeSO₄ 7H₂O and FeHBED salts increased the formation of the determined organic acids in fruiting bodies. P. eryngii and P. nameko were characterized by a much lower content of organic acids in the systems supplemented with Fe. Based on the obtained results, we recommend starting fortification by preliminarily indicating which form of the element is preferred for the species of interest for supplementation. It also seems that using an additive concentration of 50 mM or higher is most effective.

Seed coat color genetics and genotype × environment effects in yellow beans via machine-learning and genome-wide association

Common bean (Phaseolus vulgaris L.) is consumed worldwide, with strong regional preferences for seed appearance characteristics. Colors of the seed coat, hilum ring, and corona are all important, along with susceptibility to postharvest darkening, which decreases seed value. This study aimed to characterize a collection of 295 yellow bean genotypes for seed appearance and postharvest darkening, evaluate genotype × environment (G × E) effects and map those traits via genome-wide association analysis. Yellow bean germplasm were grown for 2 yr in Michigan and Nebraska and seed were evaluated for L*a*b* color values, postharvest darkening, and hilum ring and corona colors. A model to exclude the hilum ring and corona of the seeds, black background, and light reflection was developed by using machine learning, allowing for targeted and efficient L*a*b* value extraction from the seed coat. The G × E effects were significant for the color values, and Michigan-grown seeds were darker than Nebraska-grown seeds. Single-nucleotide polymorphisms (SNPs) were associated with L* and hilum ring color on Pv10 near the J gene involved in mature seed coat color and hilum ring color. A SNP on Pv07 associated with L*, a*, postharvest darkening, and hilum ring and corona colors was near the P gene, the ground factor gene for seed coat color expression. The machine-learning-aided model used to extract color values from the seed coat, the wide variability in seed morphology traits, and the associated SNPs provide tools for future breeding and research efforts to meet consumers' expectations for bean seed appearance.

Quinoa Soluble Fiber and Quercetin Alter the Composition of the Gut Microbiome and Improve Brush Border Membrane Morphology In Vivo (Gallus gallus)

Quinoa (Chenopodium quinoa Willd.), a gluten-free pseudo-cereal, has gained popularity over the last decade due to its high nutritional value. Quinoa is a rich source of proteins, carbohydrates, fibers, tocopherols (Vitamin E), unsaturated fatty acids and a wide range of polyphenols. The study used Gallus gallus intra-amniotic feeding, a clinically validated method, to assess the effects of quinoa soluble fiber (QSF) and quercetin 3-glucoside (Q3G) versus control. Quercetin is a pharmacologically active polyphenol found in quinoa. Six groups (no injection, 18 Ω H2O, 5% inulin, 1% Q3G, 5% QSF, 1% Q3G + 5% QSF) were assessed for their effect on the brush border membrane (BBM) functionality, intestinal morphology and cecal bacterial populations. Our results showed a significant (p < 0.05) improvement in BBM morphology, particularly goblet and Paneth cell numbers, in the group administered with quinoa and quercetin. However, there were no significant changes seen in the expression of the genes assessed both in the duodenum and liver between any of the treatment groups. Furthermore, fibrous quinoa increased the concentration of probiotic L. plantarum populations compared to the control (H2O). In conclusion, quercetin and quinoa fiber consumption has the potential to improve intestinal morphology and modulate the microbiome.

Corrosion Inhibition of Carob Pod Pulp (Ceratonia siliqua L.) on Carbon Steel Surface C38 in Hydrochloric Acid

The effect of C. siliqua pulp corrosion inhibition on carbon steel has been studied by gravimetric testing and electrochemical methods. In this study, two raw extracts were prepared from the pod pulp of C. siliqua: the first is methanolic and the second is aqueous. The UHPLC/DAD analysis indicated gallic acid's presence in the extracts (methanolic and aqueous) of C. siliqua as a major compound. The inhibition results achieved revealed that the aqueous extract with gallic acid had a good anticorrosion activity with an inhibition rate of 91.32% at 3 g/l for a temperature of 323 K. Potentiodynamic polarization was performed in 1 M HCl without and with different concentrations of C. siliqua extracts clearly proves that inhibitor extracts behave as mixed type. Adsorption of this inhibitor for different extracts studied on the surface of the carbon steel obeys Langmuir adsorption with negative values of Δ G ads ∘ , suggesting a stable and spontaneous inhibition process.

Saffron (Crocus sativus L.) Flower Water Extract Disrupts the Cecal Microbiome, Brush Border Membrane Functionality, and Morphology In Vivo (Gallus gallus)

Saffron (Crocus sativus L.) is known as the most expensive spice. C. sativus dried red stigmas, called threads, are used for culinary, cosmetic, and medicinal purposes. The rest of the flower is often discarded, but is now being used in teas, as coloring agents, and fodder. Previous studies have attributed antioxidant, anti-inflammatory, hepatoprotective, neuroprotective, anti-depressant, and anticancer properties to C. sativus floral bio-residues. The aim of this study is to assess C. sativus flower water extract (CFWE) for its effects on hemoglobin, brush boarder membrane (BBM) functionality, morphology, intestinal gene expression, and cecal microbiome in vivo (Gallus gallus), a clinically validated model. For this, Gallus gallus eggs were divided into six treatment groups (non-injected, 18 Ω H₂O, 1% CFWE, 2% CFWE, 5% CFWE, and 10% CFWE) with n~10 for each group. On day 17 of incubation, 1 mL of the extracts/control were administered in the amnion of the eggs. The amniotic fluid along with the administered extracts are orally consumed by the developing embryo over the course of the next few days. On day 21, the hatchlings were euthanized, the blood, duodenum, and cecum were harvested for assessment. The results showed a significant dose-dependent decrease in hemoglobin concentration, villus surface area, goblet cell number, and diameter. Furthermore, we observed a significant increase in Paneth cell number and Mucin 2 (MUC2) gene expression proportional to the increase in CFWE concentration. Additionally, the cecum microbiome analysis revealed C. sativus flower water extract altered the bacterial populations. There was a significant dose-dependent reduction in Lactobacillus and Clostridium sp., suggesting an antibacterial effect of the extract on the gut in the given model. These results suggest that the dietary consumption of C. sativus flower may have negative effects on BBM functionality, morphology, mineral absorption, microbial populations, and iron status.

Modifications in the Intestinal Functionality, Morphology and Microbiome Following Intra-Amniotic Administration (Gallus gallus) of Grape (Vitis vinifera) Stilbenes (Resveratrol and Pterostilbene)

This efficacy trial evaluated the effects of two polyphenolic stilbenes, resveratrol and pterostilbene, mostly found in grapes, on the brush border membrane functionality, morphology and gut microbiome. This study applied the validated Gallus gallus intra-amniotic approach to investigate the effects of stilbene administration versus the controls. Three treatment groups (5% resveratrol; 5% pterostilbene; and synergistic: 4.75% resveratrol and 0.25% pterostilbene) and three controls (18 MΩ H₂O; no injection; 5% inulin) were employed. We observed beneficial morphological changes, specifically an increase in the villus length, diameter, depth of crypts and goblet cell diameter in the pterostilbene and synergistic groups, with concomitant increases in the serum iron and zinc concentrations. Further, the alterations in gene expression of the mineral metabolism proteins and pro-inflammatory cytokines indicate a potential improvement in gut health and mineral bioavailability. The cecal microbiota was analyzed using 16S rRNA sequencing. A lower α-diversity was observed in the synergistic group compared with the other treatment groups. However, beneficial compositional and functional alterations in the gut microbiome were detected. Several key microbial metabolic pathways were differentially enriched in the pterostilbene treatment group. These observations demonstrate a significant bacterial–host interaction that contributed to enhancements in intestinal functionality, morphology and physiological status. Our data demonstrate a novel understanding of the nutritional benefits of dietary stilbenes and their effects on intestinal functionality, morphology and gut microbiota in vivo.

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.

Genetic control of iron bioavailability is independent from iron concentration in a diverse winter wheat mapping population

BACKGROUND

Anemia is thought to affect up to 1.6 billion people worldwide. One of the major contributors to low iron (Fe) absorption is a higher proportion of cereals compared to meats and pulse crops in people's diets. This has now become a problem in both the developed and developing world, as a result of both modern food choice and food availability. Bread wheat accounts for 20 % of the calories consumed by humans and is an important source of protein, vitamins and minerals meaning it could be a major vehicle for bringing more bioavailable Fe into the diet.

RESULTS

To investigate whether breeding for higher concentrations of Fe in wheat grains could help increase Fe absorption, a multiparent advanced generation intercross (MAGIC) population, encompassing more than 80 % of UK wheat polymorphism, was grown over two seasons in the UK. The population was phenotyped for both Fe concentration and Fe bioavailability using an established Caco-2 cell bioassay. It was found that increasing Fe concentrations in the grains was not correlated with higher Fe bioavailability and that the underlying genetic regions controlling grain Fe concentrations do not co-localise with increased Fe absorption. Furthermore, we show that phytate concentrations do not correlate with Fe bioavailability in our wheat population and thus phytate-binding is insufficient to explain the lack of correlation between Fe bioavailability and Fe concentrations in the wheat grain. Finally, we observed no (Fe bioavailability) or low (Fe concentration) correlation between years for these traits, confirming that both are under strong environmental influence.

CONCLUSIONS

This suggests that breeders will have to select not only for Fe concentrations directly in grains, but also increased bioavailability. However the use of numerous controls and replicated trials limits the practicality of adoption of screening by Caco-2 cells by many breeders.

Nutritional and antinutritional composition of fava bean (Vicia faba L., var. minor) cultivars

A dietary shift from resource-demanding animal protein to sustainable food sources, such as protein-rich beans, lowers the climate footprint of food production. In this study, we examined the nutrients and antinutrients in 15 fava bean varieties cultivated in Sweden to select varieties with high nutritional value. On a dry weight basis, the fava beans were analyzed for their content of protein (range 26-33%), amino acids (leucine range: 50.8-72.1 mg/g protein, lysine range: 44.8-74.8 mg/g protein), dietary fiber (soluble fraction range: 0.55-1.06%, insoluble fraction range: 10.7-16.0%), and iron (1.8-21.3 mg/100 g) and zinc contents (0.9-5.2 mg/100 g), as well as for the following antinutrients: lectin (0.8-3.2 HU/mg); trypsin inhibitor (1.2-23.1 TIU/mg) and saponin (18-109 µg/g); phytate (112-1,281 mg/100 g); total phenolic content (1.4-5 mg GAE/g); and vicine(403 µg/g - 7,014 µg/g), convicine (35.5 µg/g - 3,121 µg/g) and the oligosaccharides raffinose (1.1-3.9 g/kg), stachyose (4.4-13.7 g/kg) and verbascose (8-15 g/kg). The results indicate substantial differences between cultivars in relation to their contents of nutrients and antinutrients. Only one of the cultivars studied (Sunrise) have adequate estimated bioavailability of iron, which is of major concern for a diet in which legumes and grains serve as important sources of iron. The nutritional gain from consuming fava beans is significantly affected by the cultivar chosen as the food source.

Pectin and phytic acid reduce mineral bioaccessibility in cooked common bean cotyledons regardless of cell wall integrity

Common bean cotyledons are rich in minerals (Mg, Ca, Fe and Zn), but they also contain natural barriers that can potentially prevent mineral absorption during digestion. In this study, both the cell wall integrity and mineral chelators/antinutrients (phytic acid and pectin) were investigated as natural barriers in common bean cotyledons. To examine the cell wall integrity as a physical barrier for mineral diffusion, soluble mineral content was determined in a cooked cotyledon sample before and after disruption of intact cell walls. While this study showed that the cell wall in cooked common bean cotyledons does not hinder mineral diffusion, it also demonstrated that the presence of antinutrients decreases mineral bioaccessibility. It was shown that a certain mineral fraction is naturally bound to phytic acid and/or pectin and, by enzymatically degrading these antinutrients, the antinutrient-chelated mineral fraction decreased. Moreover, although pH changes are occurring during simulated digestion experiments, which might affect charge of the antinutrients and thus their chelating capacity for minerals, no difference in mineral distribution over antinutrients was observed due to digestion. In addition, this study showed that mineral bioaccessibility in common bean cotyledons could be potentially increased by degrading antinutrients during digestion in the small intestinal phase.

Biofortification of Common Bean for Higher Iron Concentration

Common bean (Phaseolus vulgaris L.) is a staple food of smallholder farmers and poor urban consumers in Latin America and eastern-southern Africa among whom iron deficiency is frequent. Bean was domesticated in Mexico and the southern Andes, creating two distinct gene pools. Evaluation of a core collection of 1,441 entries revealed average concentrations of 55 mg kg−1 iron. A breeding target was set at 44 mg kg−1 iron above the level in a local check variety, while 50% of goal or a 22 mg kg−1 advantage was accepted as “biofortified.” In a bioefficacy trial among college-age women in Rwanda, high iron beans improved iron status and enhanced cognitive ability, brain function, and work efficiency. However, breeding progress has been slow, likely due in part to homeostatic mechanisms whereby organisms moderate iron and zinc uptake. This phenomenon may represent resistance to increasing concentration of these elements. Crosses between gene pools may “jumble” genes for homeostasis and permit high levels. A second breeding strategy is the use of sister species that evolved in iron-poor environments and that could be more receptive to iron uptake. Future breeding may also increase attention on improving bioavailability through mechanisms such as non-or-slow darkening grain or low phytate mutants. Changing dietary patterns in developed countries could increase iron deficiency and create demand for iron biofortified beans.

Iron Concentrations in Biofortified Beans and Nonbiofortified Marketplace Varieties in East Africa Are Similar

BACKGROUND

The predominant bean iron (Fe) biofortification approach is to breed for high Fe concentration and assumes the average Fe concentration is 50 μg/g. This approach also assumes that a 40 μg/g increase is sustainable and Fe bioavailability will not decrease to negate the increase in Fe.

OBJECTIVE

The overall objective was to determine if bean Fe biofortification via breeding for high Fe is producing beans with higher Fe concentration relative to nonbiofortified lines found in the East Africa marketplace.

METHODS

Seventy-six marketplace samples (East Africa Marketplace Collection; EAMC), and 154 genotypes known to be representative of the marketplace were collected from breeders in the Pan-Africa Bean Research Alliance (designated the East Africa Breeder Collection; EABC). Within the EAMC and EABC were 18 and 35 samples, respectively, that were released as biofortified lines. All samples were measured for Fe concentration. The Caco-2 cell bioassay assessed Fe bioavailability of the EAMC. Biofortified versus nonbiofortified samples were compared by the appropriate t-test or ANOVA.

RESULTS

The Fe concentration of the 58 nonbiofortified EAMC lines was (mean ± SD [range]) 71 ± 9 μg/g (52-93 μg/g) which did not differ significantly from the 18 biofortified EAMC varieties (71 ± 11 μg/g [55-94 μg/g]). The Fe concentration of the 119 nonbiofortified EABC varieties was 66 ± 7 μg/g (51-90 μg/g) which was significantly different (P < 0.0001) from the 35 EABC biofortified lines (73 ± 9 μg/g [60-91 μg/g]). However, the EABC biofortified lines were not different from the nonbiofortified EAMC samples. In the Caco-2 cell bioassay, biofortified EAMC varieties did not deliver more Fe compared with nonbiofortified EAMC varieties.

CONCLUSIONS

The assumptions of the high Fe bean biofortification approach are not met in the East African marketplace. Iron concentration and bioavailability measurement indicate the biofortified bean varieties are providing no additional dietary Fe.

Revisiting phytate-element interactions: implications for iron, zinc and calcium bioavailability, with emphasis on legumes

Myo-Inositol hexakisphosphate or phytic acid concentration is a prominent factor known to impede divalent element bioavailability in vegetal foods including legumes. Both in vivo and in vitro studies have suggested that phytic acid and other plant-based constituents may synergistically form insoluble complexes affecting bioavailability of essential elements. This review provides an overview of existing investigations on the role of phytic acid in the binding, solubility and bioavailability of iron, zinc and calcium with a focus on legumes. Given the presence of various interference factors within legume matrices, current findings suggest that the commonly adapted approach of using phytic acid-element molar ratios as a bioavailability predictor may only be valid in limited circumstances. In particular, differences between protein properties and molar concentrations of other interacting ions are likely responsible for the observed poor correlations. The role of phytate degradation in element bioavailability has been previously examined, and in this review we re-emphasize its importance as a tool to enhance mineral bioavailability of mineral fortified legume crops. Food processing strategies to achieve phytate reduction were identified as promising tools to increase mineral bioavailability and included germination and fermentation, particularly when other bioavailability promoters (e.g. NaCl) are simultaneously added.

Low Phytate Peas (Pisum sativum L.) Improve Iron Status, Gut Microbiome, and Brush Border Membrane Functionality In Vivo (Gallus gallus)

The inclusion of pulses in traditional wheat-based food products is increasing as the food industry and consumers are recognizing the nutritional benefits due to the high protein, antioxidant activity, and good source of dietary fiber of pulses. Iron deficiency is a significant global health challenge, affecting approximately 30% of the world's population. Dietary iron deficiency is the foremost cause of anemia, a condition that harms cognitive development and increases maternal and infant mortality. This study intended to demonstrate the potential efficacy of low-phytate biofortified pea varieties on dietary iron (Fe) bioavailability, as well as on intestinal microbiome, energetic status, and brush border membrane (BBM) functionality in vivo (Gallus gallus). We hypothesized that the low-phytate biofortified peas would significantly improve Fe bioavailability, BBM functionality, and the prevalence of beneficial bacterial populations. A six-week efficacy feeding (n = 12) was conducted to compare four low-phytate biofortified pea diets with control pea diet (CDC Bronco), as well as a no-pea diet. During the feeding trial, hemoglobin (Hb), body-Hb Fe, feed intake, and body weight were monitored. Upon the completion of the study, hepatic Fe and ferritin, pectoral glycogen, duodenal gene expression, and cecum bacterial population analyses were conducted. The results indicated that certain low-phytate pea varieties provided greater Fe bioavailability and moderately improved Fe status, while they also had significant effects on gut microbiota and duodenal brush border membrane functionality. Our findings provide further evidence that the low-phytate pea varieties appear to improve Fe physiological status and gut microbiota in vivo, and they highlight the likelihood that this strategy can further improve the efficacy and safety of the crop biofortification and mineral bioavailability approach.

Iron, Zinc and Phytic Acid Retention of Biofortified, Low Phytic Acid, and Conventional Bean Varieties When Preparing Common Household Recipes

Biofortification is an effective method to improve the nutritional content of crops and nutritional intake. Breeding for higher micronutrient mineral content in beans is correlated with an increase in phytic acid, a main inhibitor of mineral absorption in humans. Low phytic acid (lpa) beans have a 90% lower phytic acid content compared to conventional beans. This is the first study to investigate mineral and total phytic acid retention after preparing common household recipes from conventional, biofortified and lpa beans. Mineral retention was determined for two conventional, three biofortified and two lpa bean genotypes. Treatments included soaking, boiling (boiled beans) and refrying (bean paste). The average true retention of iron after boiling was 77.2-91.3%; for zinc 41.2-84.0%; and for phytic acid 49.9-85.9%. Soaking led to a significant decrease in zinc and total phytic acid after boiling and refrying, whereas for iron no significant differences were found. lpa beans did not exhibit a consistent pattern of difference in iron and phytic acid retention compared to the other groups of beans. However, lpa beans had a significantly lower retention of zinc compared to conventional and biofortified varieties (p < 0.05). More research is needed to understand the underlying factors responsible for the differences in retention between the groups of beans, especially the low retention of zinc. Combining the lpa and biofortification traits could further improve the nutritional benefits of biofortified beans, by decreasing the phytic acid:iron and zinc ratio in beans.

Polyphenolic Profiles of Yellow Bean Seed Coats and Their Relationship with Iron Bioavailability

Previous work with Caco-2 cell cultures has shown that individual polyphenols can either promote or inhibit iron uptake. This investigation was designed to characterize the relationship between iron bioavailability and seed coat polyphenol composition in a panel of 14 yellow beans representing five market classes with the potential for fast cooking time and high iron content. The study included two white and two red mottled bean lines, which represent high and low iron bioavailability capacity in dry beans, respectively. Polyphenols were measured quantitatively by high-performance liquid chromatography-mass spectrometry (HPLC-MS)/UV and iron bioavailability of seed coat extracts was measured in Caco-2 assays. Thirteen of the yellow bean seed types contained high concentrations (up to 35.3 ± 2.7 μmol/g) of kaempferol 3-glucoside (k 3-g), a known promoter of iron uptake. A general association between the ratio of promoting to inhibiting polyphenols (P/I) and iron uptake was observed. The presence of iron uptake inhibiting condensed tannins proportionately countered the promotional effects of kaempferol compounds. Unidentified factors present in seed coats other than polyphenols also appeared to affect iron uptake.

Intra-amniotic administration (Gallus gallus) of TiO2, SiO2, and ZnO nanoparticles affect brush border membrane functionality and alters gut microflora populations

Metal oxide nanoparticles (NP) are increasingly used in the food and agriculture industries, making human consumption nearly unavoidable. The goal of this study was to use the Gallus gallus (broiler chicken) intra-amniotic administration of physiologically relevant concentrations of TiO₂, SiO₂, and ZnO to better understand the effects of NP exposure on gut health and function. Immediately after hatch, blood, cecum, and small intestine were collected for assessment of iron (Fe)-metabolism, zinc (Zn)-metabolism, brush border membrane (BBM) functional, and pro-inflammatory related proteins gene expression; blood Fe and Zn levels; cecum weight; and the relative abundance of intestinal microflora. NP type, dose, and the presence or absence of minerals was shown to result in altered mineral transporter, BBM functional, and pro-inflammatory gene expression. Metal oxide NP also altered the abundance of intestinal bacterial populations. Overall, the data suggest that the in vivo results align with in vitro studies, and that NP have the potential to negatively affect intestinal functionality and health.

Traditional African Dishes Prepared From Local Biofortified Varieties of Pearl Millet: Acceptability and Potential Contribution to Iron and Zinc Intakes of Burkinabe Young Children

Biofortification is among the food-based strategies, recently implemented and still in development, to fight micronutrient deficiencies. Three cereal-based traditional dishes of Sub-Saharan Africa (tô paste, pancakes, and gruel) prepared from one local (Gampela), or two biofortified (GB 8735 and Tabi) varieties of millet were assessed for their (i) acceptability by local consumers, (ii) iron and zinc absorption predicted by phytate-to-mineral molar ratios and (iii) contribution to the iron and zinc requirements of young children. Tasters preferred the color, texture, and taste of dishes prepared with the local variety, whether or not the grains were decorticated. Hedonic and preference tests showed no significant difference between the two biofortified varieties, but the cooks reported different behaviors during processing. Biofortified millet contained up to two times more iron than the local variety, reaching 6.5 mg iron/100 g dry matter. Iron and zinc contents remained higher in biofortified varieties even after decortication. Iron content in the dishes was highly variable, depending on iron loss and potential contamination during processing. The phytate-to-mineral molar ratios of all dishes indicated low iron absorption, independent of the millet variety, but improved zinc absorption in dishes prepared with biofortified varieties. The contribution of a dish prepared with one of the two biofortified millet varieties to the recommended iron and zinc intakes for 6–11-month-old children was estimated to be about 5 and 7%, respectively, compared to 2 and 4% for the same dish prepared with local millet. For 12–23-month-old children, the contribution to the recommended intakes was estimated to be about 14 and 12% with biofortified millet, respectively, and about 6 and 7% with local millet. The use of biofortified millet varieties could be complementary to food diversification strategies to increase iron and zinc intakes. As in Ouagadougou, cereals are eaten in different forms by young children several times per day, iron and zinc intakes could be improved in the long term by using the biofortified varieties of pearl millet.

An In Vivo (Gallus gallus) Feeding Trial Demonstrating the Enhanced Iron Bioavailability Properties of the Fast Cooking Manteca Yellow Bean (Phaseolus vulgaris L.)

The common dry bean (Phaseolus vulgaris L.) is a globally produced pulse crop and an important source of micronutrients for millions of people across Latin America and Africa. Many of the preferred black and red seed types in these regions have seed coat polyphenols that inhibit the absorption of iron. Yellow beans are distinct from other market classes because they accumulate the antioxidant kaempferol 3-glucoside in their seed coats. Due to their fast cooking tendencies, yellow beans are often marketed at premium prices in the same geographical regions where dietary iron deficiency is a major health concern. Hence, this study compared the iron bioavailability of three faster cooking yellow beans with contrasting seed coat colors from Africa (Manteca, Amarillo, and Njano) to slower cooking white and red kidney commercial varieties. Iron status and iron bioavailability was assessed by the capacity of a bean based diet to generate and maintain total body hemoglobin iron (Hb-Fe) during a 6 week in vivo (Gallus gallus) feeding trial. Over the course of the experiment, animals fed yellow bean diets had significantly (p ≤ 0.05) higher Hb-Fe than animals fed the white or red kidney bean diet. This study shows that the Manteca yellow bean possess a rare combination of biochemical traits that result in faster cooking times and improved iron bioavailability. The Manteca yellow bean is worthy of germplasm enhancement to address iron deficiency in regions where beans are consumed as a dietary staple.

Iron Biofortified Carioca Bean (Phaseolus vulgaris L.)-Based Brazilian Diet Delivers More Absorbable Iron and Affects the Gut Microbiota In Vivo (Gallus gallus)

Biofortification aims to improve the micronutrient concentration and bioavailability in staple food crops. Unlike other strategies utilized to alleviate Fe deficiency, studies of the gut microbiota in the context of Fe biofortification are scarce. In this study, we performed a 6-week feeding trial in Gallus gallus (n = 15), aimed to investigate the Fe status and the alterations in the gut microbiome following the administration of Fe-biofortified carioca bean based diet (BC) versus a Fe-standard carioca bean based diet (SC). The tested diets were designed based on the Brazilian food consumption survey. Two primary outcomes were observed: (1) a significant increase in total body Hb-Fe values in the group receiving the Fe-biofortified carioca bean based diet; and (2) changes in the gut microbiome composition and function were observed, specifically, significant changes in phylogenetic diversity between treatment groups, as there was increased abundance of bacteria linked to phenolic catabolism, and increased abundance of beneficial SCFA-producing bacteria in the BC group. The BC group also presented a higher intestinal villi height compared to the SC group. Our results demonstrate that the Fe-biofortified carioca bean variety was able to moderately improve Fe status and to positively affect the intestinal functionality and bacterial populations.

Reduction in nutritional quality and growing area suitability of common bean under climate change induced drought stress in Africa

Climate change impacts on food security will involve negative impacts on crop yields, and potentially on the nutritional quality of staple crops. Common bean is the most important grain legume staple crop for human diets and nutrition worldwide. We demonstrate by crop modeling that the majority of current common bean growing areas in southeastern Africa will become unsuitable for bean cultivation by the year 2050. We further demonstrate reductions in yields of available common bean varieties in a field trial that is a climate analogue site for future predicted drought conditions. Little is known regarding the impact of climate change induced abiotic stresses on the nutritional quality of common beans. Our analysis of nutritional and antinutritional compounds reveals that iron levels in common bean grains are reduced under future climate-scenario relevant drought stress conditions. In contrast, the levels of protein, zinc, lead and phytic acid increase in the beans under such drought stress conditions. This indicates that under climate-change induced drought scenarios, future bean servings by 2050 will likely have lower nutritional quality, posing challenges for ongoing climate-proofing of bean production for yields, nutritional quality, human health, and food security.

Reduction in nutritional quality and growing area suitability of common bean under climate change induced drought stress in Africa

Climate change impacts on food security will involve negative impacts on crop yields, and potentially on the nutritional quality of staple crops. Common bean is the most important grain legume staple crop for human diets and nutrition worldwide. We demonstrate by crop modeling that the majority of current common bean growing areas in southeastern Africa will become unsuitable for bean cultivation by the year 2050. We further demonstrate reductions in yields of available common bean varieties in a field trial that is a climate analogue site for future predicted drought conditions. Little is known regarding the impact of climate change induced abiotic stresses on the nutritional quality of common beans. Our analysis of nutritional and antinutritional compounds reveals that iron levels in common bean grains are reduced under future climate-scenario relevant drought stress conditions. In contrast, the levels of protein, zinc, lead and phytic acid increase in the beans under such drought stress conditions. This indicates that under climate-change induced drought scenarios, future bean servings by 2050 will likely have lower nutritional quality, posing challenges for ongoing climate-proofing of bean production for yields, nutritional quality, human health, and food security.

Bioavailable Iron and Vitamin A in Newly Formulated, Extruded Corn, Soybean, Sorghum, and Cowpea Fortified-Blended Foods in the In Vitro Digestion/Caco-2 Cell Model

BACKGROUND

Fortified-blended foods (FBFs), particularly corn-soybean blend (CSB), are food aid products distributed in developing countries. The US Agency for International Development food aid quality review recommended developing extruded FBFs with the use of alternative commodities such as sorghum.

OBJECTIVE

The objective of the study was to determine bioavailable iron and vitamin A content from newly developed extruded corn, soybean, sorghum, and cowpea FBFs compared with the nonextruded traditional food aid FBFs, corn-soy blend 13 (CSB13) and corn-soy blend plus (CSB+).

METHODS

Eleven extruded FBFs-sorghum-cowpea (n = 7), sorghum-soy (n = 3), and corn-soy (n = 1)-along with 2 nonextruded FBFs-CSB13 and CSB+, and Cerelac (Nestlé), a commercially available fortified infant food, were prepared. Bioavailable iron and vitamin A contents were assessed by using the in vitro digestion/Caco-2 cell model. Dry FBFs, aqueous fractions, and Caco-2 cell pellet vitamin A contents were analyzed by HPLC. Dry FBF and aqueous fraction iron contents were measured by atomic absorptiometry, and bioavailable iron was assessed by measuring Caco-2 ferritin contents via ELISA.

RESULTS

Iron and vitamin A concentrations in Cerelac and dry FBFs ranged from 8.0 to 31.8 mg/100 g and 0.3 to 1.67 mg/100 g, respectively. All of the extruded FBFs contained 4- to 7-fold significantly higher (P < 0.05) aqueous fraction iron concentrations compared with CSB13 and CSB+. However, there were no significant differences in Caco-2 cell ferritin and vitamin A concentrations between extruded FBFs, nonextruded FBFs, and or the basal salt solution negative control.

CONCLUSION

Results support the theory that the consumption of newly developed extruded sorghum-cowpea, sorghum-soy, and corn-soy FBFs would result in iron and vitamin A concentrations comparable to traditional nonextruded CSB13 and CSB+ FBFs.

Nutrient and Total Polyphenol Contents of Dark Green Leafy Vegetables, and Estimation of Their Iron Bioaccessibility Using the In Vitro Digestion/Caco-2 Cell Model

Dark green leafy vegetables (DGLVs) are considered as important sources of iron and vitamin A. However, iron concentration may not indicate bioaccessibility. The objectives of this study were to compare the nutrient content and iron bioaccessibility of five sweet potato cultivars, including three orange-fleshed types, with other commonly consumed DGLVs in Ghana: cocoyam, corchorus, baobab, kenaf and moringa, using the in vitro digestion/Caco-2 cell model. Moringa had the highest numbers of iron absorption enhancers on an “as-would-be-eaten” basis, β-carotene (14169 μg/100 g; p < 0.05) and ascorbic acid (46.30 mg/100 g; p < 0.001), and the best iron bioaccessibility (10.28 ng ferritin/mg protein). Baobab and an orange-fleshed sweet potato with purplish young leaves had a lower iron bioaccessibility (6.51 and 6.76 ng ferritin/mg protein, respectively) compared with that of moringa, although these three greens contained similar (p > 0.05) iron (averaging 4.18 mg/100 g) and β-carotene levels. The ascorbic acid concentration of 25.50 mg/100 g in the cooked baobab did not enhance the iron bioaccessibility. Baobab and the orange-fleshed sweet potato with purplish young leaves contained the highest levels of total polyphenols (1646.75 and 506.95 mg Gallic Acid Equivalents/100 g, respectively; p < 0.001). This suggests that iron bioaccessibility in greens cannot be inferred based on the mineral concentration. Based on the similarity of the iron bioaccessibility of the sweet potato leaves and cocoyam leaf (a widely-promoted “nutritious” DGLV in Ghana), the former greens have an added advantage of increasing the dietary intake of provitamin A.

Iron Bioavailability Studies of the First Generation of Iron-Biofortified Beans Released in Rwanda

This paper represents a series of in vitro iron (Fe) bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans (Phaseolus vulgaris) selected for human trials in Rwanda and released to farmers of that region. The objective of the present study was to demonstrate how the Caco-2 cell bioassay for Fe bioavailability can be utilized to assess the nutritional quality of Fe in such varieties and how they may interact with diets and meal plans of experimental studies. Furthermore, experiments were also conducted to directly compare this in vitro approach with specific human absorption studies of these Fe biofortified beans. The results show that other foods consumed with beans, such as rice, can negatively affect Fe bioavailability whereas potato may enhance the Fe absorption when consumed with beans. The results also suggest that the extrinsic labelling approach to measuring human Fe absorption can be flawed and thus provide misleading information. Overall, the results provide evidence that the Caco-2 cell bioassay represents an effective approach to evaluate the nutritional quality of Fe-biofortified beans, both separate from and within a targeted diet or meal plan.

Advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness

Biofortification aims to improve the micronutrient concentration of staple food crops through the best practices of breeding and modern biotechnology. However, increased zinc and iron concentrations in food crops may not always translate into proportional increases in absorbed zinc (Zn) and iron (Fe). Therefore, assessing iron and zinc bioavailability in biofortified crops is imperative to evaluate the efficacy of breeding programs. This review aimed to investigate the advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness. In vitro, animal and isotopic human studies have shown high iron and zinc bioavailability in biofortified staple food crops. Human studies provide direct knowledge regarding the effectiveness of biofortification, however, human studies are time consuming and are more expensive than in vitro and animal studies. Moreover, in vitro studies may be a useful preliminary screening method to identify promising plant cultivars, however, these studies cannot provide data that are directly applicable to humans. None of these methods provides complete information regarding mineral bioavailability, thus, a combination of these methods should be the most appropriate strategy to investigate the effectiveness of zinc and iron biofortification programs.

Characterization of Polyphenol Effects on Inhibition and Promotion of Iron Uptake by Caco-2 Cells

Polyphenolic compounds present in the seed coat of common bean (Phaseolus vulgaris L.) are known to act collectively as inhibitors of iron bioavailability. Recent research identified specific polyphenols as being potent Fe uptake inhibitors. That research also identified other polyphenols as being promoters of Fe uptake. The present study extends that work using a Caco-2 cell model to characterize the effects of 43 additional polyphenols on Fe uptake. In addition, this study indicates that the inhibitory compounds have a more potent effect that outweighs the ability of promoting compounds to increase Fe uptake. For example, a ratio of 100:0 epicatechin (a promoter)/myricetin (an inhibitor) produced 78.5 ± 6.7 ng ferritin/mg protein, 90:10 yielded 27.4 ± 3.0, 50:50 yielded 3.42 ± 0.54, and 0:100 yielded 2.26 ± 0.25 ng ferritin/mg protein. A simulation of the relative concentrations of eight major polyphenols (four inhibitors, four promoters) present in a sample of black bean seed coats demonstrated that most of the inhibitory compounds would need to be removed to reduce the negative effect on Fe uptake. In vivo studies are now warranted to confirm the above in vitro effects. Such work would be significant as other bean color classes exist that are likely to have polyphenolic profiles that are more favorable to Fe bioavailability.

Intra Amniotic Administration of Raffinose and Stachyose Affects the Intestinal Brush Border Functionality and Alters Gut Microflora Populations

This study investigates the effectiveness of two types of prebiotics—stachyose and raffinose—which are present in staple food crops that are widely consumed in regions where dietary Fe deficiency is a health concern. The hypothesis is that these prebiotics will improve Fe status, intestinal functionality, and increase health-promoting bacterial populations in vivo (Gallus gallus). By using the intra-amniotic administration procedure, prebiotic treatment solutions were injected in ovo (day 17 of embryonic incubation) with varying concentrations of a 1.0 mL pure raffinose or stachyose in 18 MΩ H₂O. Four treatment groups (50, 100 mg·mL⁻¹ raffinose or stachyose) and two controls (18 MΩ H₂O and non-injected) were utilized. At hatch the cecum, small intestine, liver, and blood were collected for assessment of the relative abundance of the gut microflora, relative expression of Fe-related genes and brush border membrane functional genes, hepatic ferritin levels, and hemoglobin levels, respectively. The prebiotic treatments increased the relative expression of brush border membrane functionality proteins (p < 0.05), decreased the relative expression of Fe-related proteins (p < 0.05), and increased villus surface area. Raffinose and stachyose increased the relative abundance of probiotics (p < 0.05), and decreased that of pathogenic bacteria. Raffinose and stachyose beneficially affected the gut microflora, Fe bioavailability, and brush border membrane functionality. Our investigations have led to a greater understanding of these prebiotics’ effects on intestinal health and mineral metabolism.

Zinc and selenium accumulation and their effect on iron bioavailability in common bean seeds

Common beans (Phaseolus vulgaris) are the most important legume crops. They represent a major source of micronutrients and a target for essential trace mineral enhancement (i.e. biofortification). To investigate mineral accumulation during seed maturation and to examine whether it is possible to biofortify seeds with multi-micronutrients without affecting mineral bioavailability, three common bean cultivars were treated independently with zinc (Zn) and selenium (Se), the two critical micronutrients that can be effectively enhanced via fertilization. The seed mineral concentrations during seed maturation and the seed Fe bioavailability were analyzed. Common bean seeds were found to respond positively to Zn and Se treatments in accumulating these micronutrients. While the seed pods showed a decrease in Zn and Se along with Fe content during pod development, the seeds maintained relatively constant mineral concentrations during seed maturation. Selenium treatment had minimal effect on the seed accumulation of phytic acid and polyphenols, the compounds affecting Fe bioavailability. Zinc treatment reduced phytic acid level, but did not dramatically affect the concentrations of total polyphenols. Iron bioavailability was found not to be greatly affected in seeds biofortified with Se and Zn. In contrast, the inhibitory polyphenol compounds in the black bean profoundly reduced Fe bioavailability. These results provide valuable information for Se and Zn enhancement in common bean seeds and suggest the possibility to biofortify with these essential nutrients without greatly affecting mineral bioavailability to increase the food quality of common bean seeds.

Biofortification in Millets: A Sustainable Approach for Nutritional Security

Nutritional insecurity is a major threat to the world's population that is highly dependent on cereals-based diet, deficient in micronutrients. Next to cereals, millets are the primary sources of energy in the semi-arid tropics and drought-prone regions of Asia and Africa. Millets are nutritionally superior as their grains contain high amount of proteins, essential amino acids, minerals, and vitamins. Biofortification of staple crops is proved to be an economically feasible approach to combat micronutrient malnutrition. HarvestPlus group realized the importance of millet biofortification and released conventionally bred high iron pearl millet in India to tackle iron deficiency. Molecular basis of waxy starch has been identified in foxtail millet, proso millet, and barnyard millet to facilitate their use in infant foods. With close genetic-relatedness to cereals, comparative genomics has helped in deciphering quantitative trait loci and genes linked to protein quality in finger millet. Recently, transgenic expression of zinc transporters resulted in the development of high grain zinc while transcriptomics revealed various calcium sensor genes involved in uptake, translocation, and accumulation of calcium in finger millet. Biofortification in millets is still limited by the presence of antinutrients like phytic acid, polyphenols, and tannins. RNA interference and genome editing tools [zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)] needs to be employed to reduce these antinutrients. In this review paper, we discuss the strategies to accelerate biofortification in millets by summarizing the opportunities and challenges to increase the bioavailability of macro and micronutrients.

Factors influencing micronutrient bioavailability in biofortified crops

Dietary and human factors have been found to be the major factors influencing the bioavailability of micronutrients, such as provitamin A carotenoid (pVAC), iron, and zinc, in biofortified crops. Dietary factors are related to food matrix structure and composition. Processing can improve pVAC bioavailability by disrupting the food matrix but can also result in carotenoid losses. By degrading antinutrients, such as phytate, processing can also enhance mineral bioavailability. In in vivo interventions, biofortified crops have been shown to be overall efficacious in reducing micronutrient deficiency, with bioconversion factors varying between 2.3:1 and 10.4:1 for trans-β-carotene and amounts of iron and zinc absorbed varying between 0.7 and 1.1 mg/day and 1.1 and 2.1 mg/day, respectively. Micronutrient bioavailability was dependent on the crop type and the presence of fat for pVACs and on antinutrients for minerals. In addition to dietary factors, human factors, such as inflammation and disease, can affect micronutrient status. Understanding the interactions between micronutrients is also essential, for example, the synergic effect of iron and pVACs or the competitive effect of iron and zinc. Future efficacy trials should consider human status and genetic polymorphisms linked to interindividual variations.

The Combined Application of the Caco-2 Cell Bioassay Coupled with In Vivo (Gallus gallus) Feeding Trial Represents an Effective Approach to Predicting Fe Bioavailability in Humans

Research methods that predict Fe bioavailability for humans can be extremely useful in evaluating food fortification strategies, developing Fe-biofortified enhanced staple food crops and assessing the Fe bioavailability of meal plans that include such crops. In this review, research from four recent poultry (Gallus gallus) feeding trials coupled with in vitro analyses of Fe-biofortified crops will be compared to the parallel human efficacy studies which used the same varieties and harvests of the Fe-biofortified crops. Similar to the human studies, these trials were aimed to assess the potential effects of regular consumption of these enhanced staple crops on maintenance or improvement of iron status. The results demonstrate a strong agreement between the in vitro/in vivo screening approach and the parallel human studies. These observations therefore indicate that the in vitro/Caco-2 cell and Gallus gallus models can be integral tools to develop varieties of staple food crops and predict their effect on iron status in humans. The cost-effectiveness of this approach also means that it can be used to monitor the nutritional stability of the Fe-biofortified crop once a variety has released and integrated into the food system. These screening tools therefore represent a significant advancement to the field for crop development and can be applied to ensure the sustainability of the biofortification approach.

Demonstrating a Nutritional Advantage to the Fast-Cooking Dry Bean (Phaseolus vulgaris L.)

Dry beans (Phaseolus vulgaris L.) are a nutrient-dense food rich in protein and micronutrients. Despite their nutritional benefits, long cooking times limit the consumption of dry beans worldwide, especially in nations where fuelwood for cooking is often expensive or scarce. This study evaluated the nutritive value of 12 dry edible bean lines that vary for cooking time (20-89 min) from four market classes (yellow, cranberry, light red kidney, and red mottled) of economic importance in bean-consuming regions of Africa and the Americas. When compared to their slower cooking counterparts within each market class, fast-cooking dry beans retain more protein and minerals while maintaining similar starch and fiber densities when fully cooked. For example, some of the highest protein and mineral retention values were measured in the fast-cooking yellow bean cultivar Cebo Cela, which offered 20% more protein, 10% more iron, and 10% more zinc with each serving when compared with Canario, a slow-cooking yellow bean that requires twice the cooking time to become palatable. A Caco-2 cell culture model also revealed the bioavailability of iron is significantly higher in faster cooking entries (r = -0.537, P = 0.009) as compared to slower cooking entries in the same market class. These findings suggest that fast-cooking bean varieties have improved nutritive value through greater nutrient retention and improved iron bioavailability.

Evaluation of iron and zinc bioavailability of beans targeted for biofortification using in vitro and in vivo models and their effect on the nutritional status of preschool children

BACKGROUND

Biofortified beans have been produced with higher nutrient concentrations. The objective was to evaluate the in vitro and in vivo iron and zinc bioavailability of common beans Pontal (PO), targeted for biofortification, compared with conventional Perola (PE) and their effects on the iron and zinc nutritional status of preschool children.

RESULTS

In Caco-2 cells, PO and PE beans did not show differences in ferritin (PO, 13.1 ± 1.4; PE, 13.6 ± 1.4 ng mg(-1) protein) or zinc uptake (PO, 15.9 ± 1.5; PE, 15.5 ± 3.5 µmol mg(-1) protein). In the rat, PO and PE beans presented high iron bioavailability (PO, 109.6 ± 29.5; PE, 110.7 ± 13.9%). In preschool children, no changes were observed in iron and zinc nutritional status comparing before and after PO consumption (ferritin, 41.2 ± 23.2 and 28.9 ± 40.4 µg L(-1) ; hemoglobin, 13.7 ± 2.2 and 13.1 ± 3.2 g dL(-1) ; plasma zinc, 119.2 ± 24.5 and 133.9 ± 57.7 µg dL(-1) ; erythrocyte zinc, 53.5 ± 13.8 and 59.4 ± 17.1 µg g(-1) hemoglobin).

CONCLUSION

Iron and zinc bioavailability in PO and PE beans was not statistically different using either cell culture, animal or human models. Efforts should focus on increasing mineral bioavailability of beans targeted for biofortification.

Rice and Bean Targets for Biofortification Combined with High Carotenoid Content Crops Regulate Transcriptional Mechanisms Increasing Iron Bioavailability

Iron deficiency affects thousands of people worldwide. Biofortification of staple food crops aims to support the reduction of this deficiency. This study evaluates the effect of combinations of common beans and rice, targets for biofortification, with high carotenoid content crops on the iron bioavailability, protein gene expression, and antioxidant effect. Iron bioavailability was measured by the depletion/repletion method. Seven groups were tested (n = 7): Pontal bean (PB); rice + Pontal bean (R + BP); Pontal bean + sweet potato (PB + SP); Pontal bean + pumpkin (PB + P); Pontal bean + rice + sweet potato (PB + R + P); Pontal bean + rice + sweet potato (PB + R + SP); positive control (Ferrous Sulfate). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency (HRE), gene expression of divalente metal transporter 1 (DMT-1), duodenal citocromo B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The test groups, except the PB, showed higher HRE (p < 0.05) than the control. Gene expression of DMT-1, DcytB and ferroportin increased (p < 0.05) in the groups fed with high content carotenoid crops (sweet potato or pumpkin). The PB group presented lower (p < 0.05) TAC than the other groups. The combination of rice and common beans, and those with high carotenoid content crops increased protein gene expression, increasing the iron bioavailability and antioxidant capacity.

Extrinsic Labeling of Staple Food Crops with Isotopic Iron Does Not Consistently Result in Full Equilibration: Revisiting the Methodology

Extrinsic isotopic labeling of food Fe has been used for over 50 years to measure Fe absorption. This method assumes that complete equilibration occurs between the extrinsic and the intrinsic Fe prior to intestinal absorption. The present study tested this assumption via in vitro digestion of varieties of maize, white beans, black beans, red beans, and lentils. Prior to digestion, foods were extrinsically labeled with (58)Fe at concentrations of 1, 10, 50, and 100% of the intrinsic (56)Fe. Following an established in vitro digestion protocol, the digest was centrifuged and the Fe solubilities of the extrinsic (58)Fe and the intrinsic (56)Fe were compared as a measure of extrinsic/intrinsic equilibration. In the beans, significantly more of the extrinsic Fe (up to 2-3 times, p < 0.001) partitioned into the supernatant. The effect varied depending upon the seed coat color, the harvest, and the concentration of the extrinsic Fe. For lentils and maize the extrinsic Fe tended to partition into the insoluble fraction and also varied depending on variety and harvest. There was no crop that consistently demonstrated full equilibration of the extrinsic Fe with the intrinsic Fe. These observations challenge the accuracy of Fe absorption studies in which isotopic extrinsic Fe was used to evaluate Fe absorption and bioavailability.

In Vitro Bioaccessibility and Bioavailability of Iron from Potatoes with Varying Vitamin C, Carotenoid, and Phenolic Concentrations

The bioaccessibility and bioavailability of iron from 12 Andean potato clones were estimated using an in vitro gastrointestinal digestion procedure and the Caco-2 cell line as a model of human intestine, with ferritin formation as a marker of iron absorption. We first showed that 63.7% (for the genotype CIP_311422.016) to 79.0% (for the genotype CIP_311575.003) of the iron is released from the potato tuber matrix during in vitro gastrointestinal digestion and is therefore available at the intestinal level. On average, 32 and 24.5% of the hydrophilic bioactive components, vitamin C and chlorogenic acid, respectively, were also bioaccessible from boiled tubers. Intestinal absorption of intrinsic iron from potato tubers could not be detected using our in vitro Caco-2 cell model. When an extrinsic source of iron (20 μM FeCl3 and 1 mM ascorbic acid) was added to the digestion mixture, iron absorption varied from 1.8 to 8% for the genotypes CIP_311422.016 and CIP_311624.021, respectively, as compared to the reference control. Principal component analysis revealed negative relationships between bioavailable iron values and phenolic concentrations, whereas vitamin C concentrations were positively associated with the ferritin values. Further controlled intervention trials would be needed to conclusively assess the bioavailability of intrinsic iron from potato tubers.

Studies of Cream Seeded Carioca Beans (Phaseolus vulgaris L.) from a Rwandan Efficacy Trial: In Vitro and In Vivo Screening Tools Reflect Human Studies and Predict Beneficial Results from Iron Biofortified Beans

Iron (Fe) deficiency is a highly prevalent micronutrient insufficiency predominantly caused by a lack of bioavailable Fe from the diet. The consumption of beans as a major food crop in some populations suffering from Fe deficiency is relatively high. Therefore, our objective was to determine whether a biofortified variety of cream seeded carioca bean (Phaseolus vulgaris L.) could provide more bioavailable-Fe than a standard variety using in-vivo (broiler chicken, Gallus gallus) and in-vitro (Caco-2 cell) models. Studies were conducted under conditions designed to mimic the actual human feeding protocol. Two carioca-beans, a standard (G4825; 58 μg Fe/g) and a biofortified (SMC; 106 μg Fe/g), were utilized. Diets were formulated to meet the nutrient requirements of Gallus gallus except for Fe (33.7 and 48.7 μg Fe/g, standard and biofortified diets, respectively). In-vitro observations indicated that more bioavailable-Fe was present in the biofortified beans and diet (P<0.05). In-vivo, improvements in Fe-status were observed in the biofortified bean treatment, as indicated by the increased total-body-Hemoglobin-Fe, and hepatic Fe-concentration (P<0.05). Also, DMT-1 mRNA-expression was increased in the standard bean treatment (P<0.05), indicating an upregulation of absorption to compensate for less bioavailable-Fe. These results demonstrate that the biofortified beans provided more bioavailable Fe; however, the in vitro results revealed that ferritin formation values were relatively low. Such observations are indicative of the presence of high levels of polyphenols and phytate that inhibit Fe absorption. Indeed, we identified higher levels of phytate and quercetin 3-glucoside in the Fe biofortified bean variety. Our results indicate that the biofortified bean line was able to moderately improve Fe-status, and that concurrent increase in the concentration of phytate and polyphenols in beans may limit the benefit of increased Fe-concentration. Therefore, specific targeting of such compounds during the breeding process may yield improved dietary Fe-bioavailability. Our findings are in agreement with the human efficacy trial that demonstrated that the biofortified carioca beans improved the Fe-status of Rwandan women. We suggest the utilization of these in vitro and in vivo screening tools to guide studies aimed to develop and evaluate biofortified staple food crops. This approach has the potential to more effectively utilize research funds and provides a means to monitor the nutritional quality of the Fe-biofortified crops once released to farmers.

Iron Bioavailability and Provitamin A from Sweet Potato- and Cereal-Based Complementary Foods

Iron and vitamin A deficiencies in childhood are public health problems in the developing world. Introduction of cereal-based complementary foods, that are often poor sources of both vitamin A and bioavailable iron, increases the risk of deficiency in young children. Alternative foods with higher levels of vitamin A and bioavailable iron could help alleviate these micronutrient deficiencies. The objective of this study was to compare iron bioavailability of β-carotene-rich sweet potato-based complementary foods (orange-flesh based sweet potato (OFSP) ComFa and cream-flesh sweet potato based (CFSP) ComFa with a household cereal-based complementary food (Weanimix) and a commercial cereal (Cerelac^®), using the in vitro digestion/Caco-2 cell model. Iron bioavailability relative to total iron, concentrations of iron-uptake inhibitors (fibre, phytates, and polyphenols), and enhancers (ascorbic acid, ß-carotene and fructose) was also evaluated. All foods contained similar amounts of iron, but bioavailability varied: Cerelac^® had the highest, followed by OFSP ComFa and Weanimix, which had equivalent bioavailable iron; CFSP ComFa had the lowest bioavailability. The high iron bioavailability from Cerelac^® was associated with the highest levels of ascorbic acid, and the lowest levels of inhibitors; polyphenols appeared to limit sweet potato-based food iron bioavailability. Taken together, the results do not support that CFSP- and OFSP ComFa are better sources of bioavailable iron compared with non-commercial/household cereal-based weaning foods; however, they may be a good source of provitamin A in the form of β-carotene.