Bioavailability Of Micronutrients Research Articles

Large-extent spatial heterogeneity of soil bioavailable micronutrients and the relative roles of environmental indicators on them within maize fields

Soil bioavailable micronutrients have a significant impact on soil fertility, soil quality, maize production, and even environmental quality. However, minimal research has been conducted to characterize the spatial patterns of soil bioavailable micronutrients at the large spatial extent within the maize filed and to reveal the relative control of environmental factors on them at the global and local scale. In the study, topsoil samples (0–20 cm of plough depth, totaling 4,448) were collected from maize field to determine the spatial heterogeneity of soil bioavailable micronutrients including iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and boron (B), and to assess the relative effect of environmental indicators on them. Based on the 2-dimensional empirical mode decomposition (2D-EMD), the spatial pattern of micronutrients at the residues and their relationships with influencing indicators were explored. The results demonstrated that the distribution of Fe and Mn had the dominant longitudinal zonality, the distribution of Cu and Zn had the prominent vertical zonality, and the spatial characteristic of B did not exhibit any particular pattern at the large spatial extent. Based on the stepwise multivariate linear regression with the residues, environmental indicators had less global effect on the distribution of soil bioavailable micronutrients. However, based on the combination of geographically weighted regression (GWR) and 2D-EMD, environmental indicators had a good and significant interpretation on the dynamics of micronutrients bioavailability, which ranged from 53% to 75% in the study area. Specifically, the impact of environmental indicators on Fe, Mn, and Zn were greater, and the impact of human activities on B was greater. Our findings indicated that the local and scale effects on the soil available micronutrients should be integrated into the prediction methods, and the combined method of GWR and 2D-EMD would be a good choice for the high-quality digital mapping at large spatial extent.

Micronutrient supply from global marine fisheries under climate change and overfishing

Fish are rich in bioavailable micronutrients, such as zinc and iron, deficiencies of which are a global food security concern.1,2 Global marine fisheries yields are threatened by climate change and overfishing,3,4 yet understanding of how these stressors affect the nutrients available from fisheries is lacking.5,6 Here, using global assessments of micronutrient content2 and fisheries catch data,7 we investigate how the vulnerability status of marine fish species8,9 may translate into vulnerability of micronutrient availability at scales of both individual species and entire fishery assemblages for 157 countries. We further quantify the micronutrient evenness of catches to identify countries where interventions can optimize micronutrient supply. Our global analysis, including >800 marine fish species, reveals that, at a species level, micronutrient availability and vulnerability to both climate change and overfishing varies greatly, with tropical species displaying a positive co-tolerance, indicating greater persistence to both stressors at a community level.10 Global fisheries catches had relatively low nutritional vulnerability to fishing. Catches with higher species richness tend to be nutrient dense and evenly distributed but are more vulnerable to climate change, with 40% of countries displaying high vulnerability. Countries with high prevalence of inadequate micronutrient intake tend to have the most nutrient-dense catches, but these same fisheries are highly vulnerable to climate change, with relatively lower capacity to adapt.11 Our analysis highlights the need to consolidate fisheries, climate, and food policies to secure the sustainable contribution of fish-derived micronutrients to food and nutrition security.

Biofortified sweet potatoes as a tool to combat vitamin A deficiency: Effect of food processing in carotenoid content

The supply of food products that present adequate nutritional quality is extremely important for maintaining the health of the population. Thus, different techniques have been used to obtain biofortified foods, with the aim of combating malnutrition caused by the absence of essential micronutrients, especially in the poorest populations. This review presents an overview of biofortification, with an emphasis on orange-flesh sweet potatoes (OFSP), and points out the effects of food processing on nutritional compounds. The identification of cultivars and biofortification actions to obtain biofortified OFSP by conventional breeding are presented as affordable strategies to supply β-carotene to alleviate vitamin A deficiency, without having ethical dilemmas related to transgenics. Studies using OFSP have shown promising results in obtaining foods with high levels of carotenoids. However, biofortified species must be validated for crop production viability, target micronutrient bioavailability and bioaccessibility, as well as the effect of processing on nutrients, so that the benefits to human health are effectively achieved.

Foliar Application of Zn Agrichemicals Affects the Bioavailability of Arsenic, Cadmium and Micronutrients to Rice (Oryza sativa L.) in Flooded Paddy Soil

Zinc (Zn) is a key micronutrient affecting bio-functions of crops. Impacts of foliar application of three forms of Zn-containing agrichemicals on the physiology of rice seedlings and their uptake of heavy metal(loid)s and micronutrients from fully flooded paddy soils were investigated in a greenhouse study. Rice seedlings 45 days after germination were randomly exposed to an equivalent amount of 100 mg L−1 of zinc oxide nanoparticles (ZnONPs), zinc oxide bulk particles (ZnOBPs), and zinc salts (Zn2+) through foliar exposure. At termination, rice seedlings were divided into roots and shoots and the concerned metal contents in plant tissues were determined with an inductively coupled plasma mass spectrometry (ICP-MS). Our results demonstrated that all Zn agrichemicals displayed a similar effect on plant growth, but ZnONPs led to the greatest root exudate excretion and greatest inhibition in arsenic (As) uptake. Foliar application of ZnONPs resulted in 28% less As in rice shoots while Zn2+ only caused a 15% decrease in As accumulation in the same tissues. ZnOBPs had minimal impact on As concentration in rice shoots. ZnONPs also promoted iron (Fe) and copper (Cu) uptake in rice shoots, both of which are essential micronutrients for humans. The results suggest that foliar application of ZnONPs resulted in more favorable outcomes for plant growth and food safety than other two types of Zn. Overall, our results showed that application of nanoagrichemicals have important food safety and nutrition implications in addition to their agronomical roles and ZnONPs could be potentially used to alleviate As uptake and fortify Zn and other essential micronutrients in rice grains.

Fruit Juices: Are They Helpful or Harmful? An Evidence Review.

Dietary guidelines often deal with 100% fruit juice (FJ) inconsistently because it represents a source of free sugars. However, FJ also provides bioavailable micronutrients and plant bioactives at levels similar to those found in whole fruits. The present review weighs up the evidence from high-quality studies investigating a potential health harm for FJ against evidence from studies which indicate a potential health benefit. The findings reveal that FJ consumption, at moderate intakes consistent with the dietary guidelines for the US and some European countries (75–224 mL daily), does not increase the risk of obesity, type 2 diabetes, cardiovascular disease or poor glycaemic control. In contrast, regular consumption of FJ—even up to 500 mL per day in short-to-medium-term studies—appears to confer a health benefit in terms of vascular function and reduced blood pressure. Emerging evidence for cognitive health benefits requires further investigation in human trials. Observational studies report associations between FJ and nutrient adequacy and suggest that FJ consumption is associated with reduced risk of stroke. In conclusion, FJ appears to offer more benefit than risk and there appears to be no justification for discouraging FJ within a balanced diet for children and adults.

Nanotechnology: A novel tool to enhance the bioavailability of micronutrients.

Nanotechnology has revolutionized the field of food systems, diagnostics, therapeutics, pharmaceuticals, the agriculture sector, and nutraceuticals. Nanoparticles are playing important role in giving the solution to enhance bioavailability of oral delivery of bioactive compounds. This review revealed that nanoparticles can improve the bioavailability of micronutrients, for example, vitamin B12, vitamin A, folic acid, and iron. However, toxicity associated with nanoparticle‐based delivery systems is still a major concern after ingestion of nano‐based supplements. The mode of the mechanism of nanomaterial along with bioactive components in different physiological conditions of the human body is also a major gap in the field of nanoceuticals. In the future, more evidence‐based clinical investigations are needed to confirm the exact approach to physiological changes in the human body.

Transcriptome analysis identifies differentially expressed genes in the progenies of a cross between two low phytic acid soybean mutants

Phytic acid (PA) is a major antinutrient that cannot be digested by monogastric animals, but it can decrease the bioavailability of micronutrients (e.g., Zn and Fe). Lowering the PA content of crop seeds will lead to enhanced nutritional traits. Low-PA mutant crop lines carrying more than one mutated gene (lpa) have lower PA contents than mutants with a single lpa mutant gene. However, little is known about the link between PA pathway intermediates and downstream regulatory activities following the mutation of these genes in soybean. Consequently, we performed a comparative transcriptome analysis using an advanced generation recombinant inbred line with low PA levels [2mlpa (mips1/ipk1)] and a sibling line with homozygous non-mutant alleles and normal PA contents [2MWT (MIPS1/IPK1)]. An RNA sequencing analysis of five seed developmental stages revealed 7945 differentially expressed genes (DEGs) between the 2mlpa and 2MWT seeds. Moreover, 3316 DEGs were associated with 128 metabolic and signal transduction pathways and 4980 DEGs were annotated with 345 Gene Ontology terms related to biological processes. Genes associated with PA metabolism, photosynthesis, starch and sucrose metabolism, and defense mechanisms were among the DEGs in 2mlpa. Of these genes, 36 contributed to PA metabolism, including 22 genes possibly mediating the low-PA phenotype of 2mlpa. The expression of most of the genes associated with photosynthesis (81 of 117) was down-regulated in 2mlpa at the late seed developmental stage. In contrast, the expression of three genes involved in sucrose metabolism was up-regulated at the late seed developmental stage, which might explain the high sucrose content of 2mlpa soybeans. Furthermore, 604 genes related to defense mechanisms were differentially expressed between 2mlpa and 2MWT. In this study, we detected a low PA content as well as changes to multiple metabolites in the 2mlpa mutant. These results may help elucidate the regulation of metabolic events in 2mlpa. Many genes involved in PA metabolism may contribute to the substantial decrease in the PA content and the moderate accumulation of InsP3–InsP5 in the 2mlpa mutant. The other regulated genes related to photosynthesis, starch and sucrose metabolism, and defense mechanisms may provide additional insights into the nutritional and agronomic performance of 2mlpa seeds.

Enhancing Micronutrients Bioavailability through Fermentation of Plant-Based Foods: A Concise Review

Plant-based foods are rich sources of vitamins and essential micronutrients. For the proper functioning of the human body and their crucial role, trace minerals (iron, zinc, magnesium, manganese, etc.) are required in appropriate amounts. Cereals and pulses are the chief sources of these trace minerals. Despite these minerals, adequate consumption of plant foods cannot fulfill the human body’s total nutrient requirement. Plant foods also contain ample amounts of anti-nutritional factors such as phytate, tannins, phenols, oxalates, etc. These factors can compromise the bioavailability of several essential micronutrients in plant foods. However, literature reports show that fermentation and related processing methods can improve nutrient and mineral bioavailability of plant foods. In this review, studies related to fermentation methods that can be used to improve micronutrient bioavailability in plant foods are discussed.

Yield Enhancement and Better Micronutrients Uptake in Tomato Fruit through Potassium Humate Combined with Micronutrients Mixture

The deficiency of micronutrients and low organic matter (OM) status of soils are major hurdles in the optimum crop yield achievements. Humic substances can play an imperative role in the micronutrient bioavailability and improved crop yield by ameliorating the physicochemical soil properties. consumed as fresh food and in processed form. However, its susceptibility towards micronutrient deficiency causes a significant reduction in yield. That is why a current study was done to examine the influence of different potassium humate (KH) levels, i.e., 0, 5, 10, and 15 kg ha−1 with micronutrients mixture (MC), i.e., 0, 50 (Zn = 2.50, B = 0.75, Fe = 2.50 kg ha−1), 75 (Zn = 3.75, B = 1.125, Fe = 3.75 kg ha−1) and 100% (Zn = 5.0, B = 1.5, Fe = 5.0 kg ha−1) on the yield, biomass, harvesting index and uptake of the micronutrients in tomato. The results showed that increasing the level of K-humate significantly improved the yield (7.4 and 7.17%), total biomass (6.38 and 6.59%), and harvesting the index (0.46 and 0.76%) of tomato. It also enhanced Fe uptake but did not affect B and Zn concentrations in the tomato fruit at 100% MC + 15 kg ha−1 KH over control in the autumn and spring seasons. In conclusion, both levels of K-humate 10 and 15 kg ha−1 and MC 75 and 100% effectively enhance the yield, biomass, harvesting the index, and micronutrients (B, Zn, and Fe) uptake in tomatoes.

Proteomic Insight into the Symbiotic Relationship of Pinus massoniana Lamb and Suillus luteus towards Developing Al-Stress Resistance.

Global warming significantly impacts forest range areas by increasing soil acidification or aluminum toxicity. Aluminum (Al) toxicity retards plant growth by inhibiting the root development process, hindering water uptake, and limiting the bioavailability of other essential micronutrients. Pinus massoniana (masson pine), globally recognized as a reforestation plant, is resistant to stress conditions including biotic and abiotic stresses. This resistance is linked to the symbiotic relationship with diverse ectomycorrhizal fungal species. In the present study, we investigated the genetic regulators as expressed proteins, conferring a symbiotic relationship between Al-stress resistance and Suillus luteus in masson pine. Multi-treatment trials resulted in the identification of 12 core Al-stress responsive proteins conserved between Al stress conditions with or without S. luteus inoculation. These proteins are involved in chaperonin CPN60-2, protein refolding and ATP-binding, Cu-Zn-superoxide dismutase precursor, oxidation-reduction process, and metal ion binding, phosphoglycerate kinase 1, glycolytic process, and metabolic process. Furthermore, 198 Al responsive proteins were identified specifically under S. luteus-inoculation and are involved in gene regulation, metabolic process, oxidation-reduction process, hydrolase activity, and peptide activity. Chlorophyll a-b binding protein, endoglucanase, putative spermidine synthase, NADH dehydrogenase, and glutathione-S-transferase were found with a significant positive expression under a combined Al and S. luteus treatment, further supported by the up-regulation of their corresponding genes. This study provides a theoretical foundation for exploiting the regulatory role of ectomycorrhizal inoculation and associated genetic changes in resistance against Al stress in masson pine.

Bioavailability of soil Cu, Fe, Mn and Zn from soil fractions

Cationic micronutrients bioavailability depends on the chemical characteristics of soil fractions. Fourteen soils received individual doses of five micronutrients (Cu, Fe, Mn, Zn, B) arranged in seven treatments set according a Baconian Matrix. The soils incubated with treatments during 15 days had corn cultivated in greenhouse for 30 days, in three consecutive growth cycles. The cationic micronutrients were determined in the corn shoots after each growth cycle. Soil samples collected before the first and after each growth cycle had the available concentrations of Cu, Fe, Mn and Zn determined by single extractions (Mehlich-1 and DTPA-pH 7.3) and by sequential extraction. Correlation analysis was performed for the Cu, Fe, Mn and Zn concentrations determined in the corn shoots, the available concentrations of Cu, Fe, Mn and Zn in the soils (Mehlich-1 and DTPA) and the concentrations of Cu, Fe, Mn and Zn in the soil fractions (sequential extraction). The distribution of available metals forms in fractions reflected their affinity with soil components. Soil available Cu correlated with Cu bound to organic matter. The exchangeable fraction was the main source of soil available Mn and Zn. The Fe availability related mainly to the Mn oxides, Fe oxides, and exchangeable fractions. The plants absorbed Cu mainly from the Mn-oxides and organic matter fractions. Manganese absorbed by plants originated from the exchangeable and Mn-oxides fractions. The Zn absorbed by plants originated mainly from the exchangeable fraction. Correlations of single metal extractions (Mehlich-1 and DTPA) with Cu, Mn and Zn contents in plants were positive.

Genetic Analysis and Molecular Mapping of the Quantitative Trait Loci Governing Low Phytic Acid Content in a Novel LPA Rice Mutant, PLM11.

Breeding rice varieties with a low phytic acid (LPA) content is an effective strategy to overcome micronutrient deficiency in a population which consume rice as a staple food. An LPA mutant, Pusa LPA Mutant 11 (PLM11), was identified from an ethyl methane sulfonate (EMS)-induced population of Nagina 22. The present study was carried out to map the loci governing the LPA trait in PLM11 using an F2:3 population derived from a cross between a high phytic acid rice variety, Pusa Basmati 6, with PLM11. The genotyping of the F2 population with 78 polymorphic SSR markers followed by the estimation of phytic acid content in the seeds harvested from 176 F2 plants helped in mapping a major QTL, qLPA8.1, explaining a 22.2% phenotypic variation on Chromosome 8. The QTL was delimited to a 1.96 cM region flanked by the markers RM25 and RM22832. Since there are no previous reports of a QTL/gene governing the LPA content in rice in this region, the QTL qLPA8.1 is a novel QTL. In silico analysis based on the annotated physical map of rice suggested the possible involvement of a locus, Os08g0274775, encoding for a protein similar to a phosphatidylinositol 3- and 4-kinase family member. This needs further validation and fine mapping. Since this QTL is currently specific to PLM11, the linked markers can be utilized for the development of rice varieties with reduced phytic acid (PA) content using PLM11 as the donor, thus enhancing the bioavailability of mineral micronutrients in humans.

Evaluation of vitamin D bioaccessibility and mineral solubility from test meals containing meat and/or cereals and/or pulses using in vitro digestion

In this study, we evaluated vitamin D and mineral (iron, zinc, magnesium) transfer to the bolus aqueous phase during the digestion of meals with/without pulses. We performed in vitro digestions using test meals made either of i) beef and/or semolina and/or chickpeas, or of ii) potatoes supplemented or not with fibers, phytates, tannins and saponins. Chickpea presence led to a decrease in vitamin D bioaccessibility (−56%, p ≤ 0.05) and mineral solubility (−28% for iron, p ≤ 0.05) compared with meals with beef and/or semolina only. This effect was largely compensated for vitamin D by the fact that this vitamin was more stable during digestion of meals based on plant foods only than of meals with beef. Tannins were the most deleterious compounds for iron solubility, while phytates and tannins decreased vitamin D bioaccessibility. Agronomical or technical solutions to selectively decrease the amount in pulses of compounds that affect micronutrient bioavailability should be further explored.

Interactive Effects of Biochar and Sewage Sludge on Bioavailability and Plant Uptake of Cu, Fe, and Zn, and Spinach (Spinacia oleracea L.) Yields under Wastewater Irrigation

Biochar can influence bioavailability of micronutrients and crop yields in sewage sludge-treated soils, but the mechanisms of its effects remain poorly understood. Therefore, this field experiment was conducted on a Luvisol and Cambisol to investigate the bioavailability and uptake of some micronutrients and spinach (Spinacia oleracea L.) yields grown in soil amended with biochar and sewage sludge. Ten treatments arranged in randomized complete block design with three levels of biochar (0, 2.5, 5 t/ha) and sewage sludge (0, 6, 12 t/ha) and combinations thereof were applied. High rate of sole sewage sludge, and its combination with biochar significantly (p < 0.05) increased yield on the Luvisol. On the Cambisol, only marginal yield increase resulted from high rates of sole organic amendments and chemical fertilizer, while co-applications decreased yields. Co-amendments generally increased bioavailability of micronutrients relative to sole amendments in the order Fe > Cu = Zn, with greater increase on the Cambisol, but uptake of micronutrients decreased with co-application rates of amendments. Contents of micronutrients in plant leaves were within the normal range, except for a combination of highest dosage of co-amendments on the Cambisol (Fe; 560 mg/kg), which resulted in leaf necrosis and 7% yield depression. The results showed greater yield response of spinach to co-application of amendments on the Luvisol.

Variability for Glutenins, Gluten Quality, Iron, Zinc and Phytic Acid in a Set of One Hundred and Fifty-Eight Common Wheat Landraces from Iran

Bread wheat can be used to make different products thanks to the presence of gluten, a protein network that confers unique visco-elastic properties to wheat doughs. Gluten is composed by gliadins and glutenins. The glutenins can be further divided into high and low-molecular-weight glutenins (HMWGs and LMWGs, respectively) and are encoded by Glu-1 and Glu-3 loci. The variability of these genes is associated with differences in quality. Because of this, the identification of novel glutenin alleles is still an important target. In this study, 57 haplotypes or glutenin combinations were registered among a set of 158 Iranian landraces and five novel HMWGs alleles were identified. The landraces were also characterized for several quality traits, including gluten quality, which allowed to associate the different glutenin alleles with low or high quality. Other quality traits examined were iron, zinc, and phytate contents, which are intimately related with the nutritional quality. Important variation for these components was found as well as for the phytate:iron/zinc molar ratios (related to the potential bioavailability of these important micronutrients). The landraces identified in the present study (some of them combining high gluten quality with low phytate:zinc values) could be a useful resource for breeders who aim to improve the wheat end-use quality and especially the content of zinc and its relative bioavailability.

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.

Response of wheat, pea, and canola to micronutrient fertilization on five contrasting prairie soils

A polyhouse study was conducted to evaluate the relative effectiveness of different micronutrient fertilizer formulation and application methods on wheat, pea and canola, as indicated by yield response and fate of micronutrients in contrasting mineral soils. The underlying factors controlling micronutrient bioavailability in a soil–plant system were examined using chemical and spectroscopic speciation techniques. Application of Cu significantly improved grain and straw biomass yields of wheat on two of the five soils (Ukalta and Sceptre), of which the Ukalta soil was critically Cu deficient according to soil extraction with DTPA. The deficiency problem was corrected by either soil or foliar application of Cu fertilizers. There were no significant yield responses of pea to Zn fertilization on any of the five soils. For canola, soil placement of boric acid was effective in correcting the deficiency problem in Whitefox soil, while foliar application was not. Soil extractable Cu, Zn, and B concentration in post-harvest soils were increased with soil placement of fertilizers, indicating that following crops in rotation could benefit from this application method. The chemical and XANES spectroscopic speciation indicates that carbonate associated is the dominant form of Cu and Zn in prairie soils, where chemisorption to carbonates is likely the major process that determines the fate of added Cu and Zn fertilizer.

Food Structure Modulates the Bioavailability of Triglycerides and Vitamin D, and Partly That of Lutein: A Randomized Trial with a Crossover Design in Adults.

The specific effect of the food matrix structure on fat-soluble micronutrient bioavailability is only partly understood. Evaluating fat-soluble micronutrient bioavailability after consumption of foods displaying similar composition but different structure is aimed at. Twelve healthy subjects are enrolled in a randomized, open label, crossover postprandial trial. Four different model foods are tested: custard, pudding, sponge cake, and biscuit. Vitamin D3 , lutein, and triglyceride chylomicron responses, evaluated as postprandial areas under the curve, are then assayed. Custard triglyceride response is higher than pudding and biscuit responses (up to +122.7%, p<0.0001). Sponge cake vitamin D3 response is higher than biscuit response (+26.6%, p = 0.047). No difference between the model foods are observed regarding lutein responses. Triglyceride responses peak at 3 h for all conditions, while vitamin D3 and lutein peaks are delayed by 1 h with the biscuit matrix compared to other model foods. Food structure can significantly impact on triglyceride and vitamin D3 bioavailability in terms of absorbed amounts and/or maximum absorption time. The data highlight positive correlations between triglyceride, vitamin D, and lutein nutrient responses. These results are of particular interest to develop functional foods for population subgroups such as the elderly.

Bioavailability of zinc and iron in durum wheat: A trade‐off between grain weight and nutrition?

Societal Impact StatementMicronutrients such as zinc and iron are critical for human health. For the world's population that relies on cereal products to obtain micronutrients, the bioavailability (absorption of nutrients in the gut) can be hindered by an anti‐nutritional compound, phytate. Phytate accumulation in grain is affected by soil properties including phosphorus availability and arbuscular mycorrhizal (AM) fungi. Here, we investigated the effects of AM fungi and soil phosphorus fertilization on micronutrient bioavailability in durum wheat and found that fertilization greatly decreased the bioavailability of micronutrients, but AM fungi can take up more micronutrients, which can lead to improved bioavailability when the soil is not fertilized.Summary The bioavailability of micronutrients (zinc [Zn] and iron [Fe]) in cereal crops such as durum wheat is critically important for human nutrition. Bioavailability is a product of complex interactions between plant phosphorus (P) uptake and storage in grain (as phytate), and plant micronutrient uptake. The bioavailability of Zn and Fe in cereal grain is affected by soil nutrient concentrations and associations with arbuscular mycorrhizal (AM) fungi, but has been scarcely studied. A geographically diverse collection of 101 durum wheat genotypes was surveyed for grain bioavailability of Zn and Fe. Ten genotypes were then selected and grown with and without AM fungal inoculation and soil P fertilization to understand the effects of manipulating soil P availability and uptake on micronutrient bioavailability. The strongest negative effect on grain micronutrient bioavailability was soil P fertilization, however, it also led to increased grain weight. Crop variety selection had the greatest variation in the P‐fertilized soil, but AM fungal inoculation had a positive effect on bioavailability in one variety in the non‐fertilized soil. In order to grow more nutritious durum wheat crops, variety selection and AM fungal inoculation are important considerations. In general, there is a trade‐off between grain weight (yield) and micronutrient bioavailability in grain that could be addressed through breeding P‐deficiency tolerant varieties.

What is food-to-food fortification? A working definition and framework for evaluation of efficiency and implementation of best practices.

Food-to-food fortification (FtFF) is an emerging food-based strategy that can complement current strategies in the ongoing fight against micronutrient deficiencies, but it has not been defined or characterized. This review has proposed a working definition of FtFF. Comparison with other main food-based strategies clearly differentiates FtFF as an emerging strategy with the potential to address multiple micronutrient deficiencies simultaneously, with little dietary change required by consumers. A review of literature revealed that despite the limited number of studies (in vitro and in vivo), the diversity of food-based fortificants investigated and some contradictory data, there are promising fortificants, which have the potential to improve the amount of bioavailable iron, zinc, and provitamin A from starchy staple foods. These fortificants are typically fruits and vegetables, with high mineral as well as ascorbic acid and β-carotene contents. However, as the observed improvements in micronutrient bioavailability and status are relatively small, measuring the positive outcomes is more likely to be impactful only if the FtFF products are consumed as regular staples. Considering best practices in implementation of FtFF, raw material authentication and ingredient documentation are critical, especially as the contents of target micronutrients and bioavailability modulators as well as the microbiological quality of the plant-based fortificants can vary substantially. Also, as there are only few developed supply chains for plant-based fortificants, procurement of consistent materials may be problematic. This, however, provides the opportunity for value chain development, which can contribute towards the economic growth of communities, or hybrid approaches that leverage traditional premixes to standardize product micronutrient content.