Iron bioavailability in corn-masa tortillas is improved by the addition of disodium EDTA

Critical assessment of wheat biofortification for iron and zinc: a comprehensive review of conceptualization, trends, approaches, bioavailability, health impact, and policy framework

Addressing global hidden hunger, particularly in women of childbearing age and children under five, presents a significant challenge, with a focus on iron (Fe) and zinc (Zn) deficiency. Wheat, a staple crop in the developing world, is crucial for addressing this issue through biofortification efforts. While extensive research has explored various approaches to enhance Fe and Zn content in wheat, there remains a scarcity of comprehensive data on their bioavailability and impact on human and animal health. This systematic review examines the latest trends in wheat biofortification approaches, assesses bioavailability, evaluates the effects of biofortified wheat on health outcomes in humans and animals, and analyzes global policy frameworks. Additionally, a meta-analysis of per capita daily Fe and Zn intake from average wheat consumption was conducted. Notably, breeding-based approaches have led to the release of 40 biofortified wheat varieties for commercial cultivation in India, Pakistan, Bangladesh, Mexico, Bolivia, and Nepal, but this progress has overlooked Africa, a particularly vulnerable continent. Despite these advancements, there is a critical need for large-scale systematic investigations into the nutritional impact of biofortified wheat, indicating a crucial area for future research. This article can serve as a valuable resource for multidisciplinary researchers engaged in wheat biofortification, aiding in the refinement of ongoing and future strategies to achieve the Sustainable Development Goal of eradicating hunger and malnutrition by 2030.

Simulating human digestion: developing our knowledge to create healthier and more sustainable foods

The gold standard for nutrition studies is clinical trials but they are expensive and variable, and do not always provide the mechanistic information required, hence the increased use ofin vitroand increasinglyin silicosimulations of digestion.

Fortification of maize flour with iron for controlling anaemia and iron deficiency in populations

BACKGROUND

Approximately 800 million women and children have anaemia, a condition thought to cause almost 9% of the global burden of years lived with disability. Around half this burden could be amenable to interventions that involve the provision of iron. Maize (corn) is one of the world's most important cereal grains and is cultivated across most of the globe. Several programmes around the world have fortified maize flour and other maize-derived foodstuffs with iron and other vitamins and minerals to combat anaemia and iron deficiency.

OBJECTIVES

To assess the effects of iron fortification of maize flour, corn meal and fortified maize flour products for anaemia and iron status in the general population.

SEARCH METHODS

We searched the following international and regional sources in December 2017 and January 2018: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; MEDLINE (R) In Process; Embase; Web of Science (both the Social Science Citation Index and the Science Citation Index); CINAHL Ebsco; POPLINE; AGRICOLA (agricola.nal.usda.gov); BIOSIS (ISI); Bibliomap and TRoPHI; IBECS; Scielo; Global Index Medicus - AFRO (includes African Index Medicus); EMRO (includes Index Medicus for the Eastern Mediterranean Region); LILACS; PAHO (Pan American Health Library); WHOLIS (WHO Library); WPRO (includes Western Pacific Region Index Medicus); IMSEAR, Index Medicus for the South-East Asian Region; IndMED, Indian medical journals; and the Native Health Research Database. We searched clinicaltrials.gov and the International Clinical Trials Registry Platform (ICTRP) for any ongoing or planned studies on 17 January 2018 and contacted authors of such studies to obtain further information or eligible data if available.For assistance in identifying ongoing or unpublished studies, we also contacted relevant international organisations and agencies working in food fortification on 9 August 2016.

SELECTION CRITERIA

We included cluster- or individually randomised controlled trials and observational studies. Interventions included (central/industrial) fortification of maize flour or corn meal with iron alone or with other vitamins and minerals and provided to individuals over 2 years of age (including pregnant and lactating women) from any country.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of studies for inclusion, extracted data from included studies and assessed the risk of bias of the included studies. Trial designs with a comparison group were included to assess the effects of interventions. Trial designs without a control or comparison group (uncontrolled before-and-after studies) were included for completeness but were not considered in assessments of the overall effectiveness of interventions or used to draw conclusions regarding the effects of interventions in the review.

MAIN RESULTS

Our search yielded 4529 records. After initial screening of titles and abstracts, we reviewed the full text of 75 studies (80 records). We included 5 studies and excluded 70. All the included studies assessed the effects of providing maize products fortified with iron plus other vitamins and minerals versus unfortified maize flour. No studies compared this intervention to no intervention or looked at the relative effect of flour and products fortified with iron alone (without other vitamins and minerals). Three were randomised trials involving 2610 participants, and two were uncontrolled before-and-after studies involving 849 participants.Only three studies contributed data for the meta-analysis and included children aged 2 to 11.9 years and women. Compared to unfortified maize flour, it is uncertain whether fortifying maize flour or corn meal with iron and other vitamins and minerals has any effect on anaemia (risk ratio (RR) 0.90, 95% confidence interval (CI) 0.58 to 1.40; 2 studies; 1027 participants; very low-certainty evidence), or on the risk of iron deficiency (RR 0.75, 95% CI 0.49 to 1.15; 2 studies; 1102 participants; very low-certainty evidence), haemoglobin concentration (mean difference (MD) 1.25 g/L, 95% CI -2.36 to 4.86 g/L; 3 studies; 1144 participants; very low-certainty evidence) or ferritin concentrations (MD 0.48 µg/L, 95% CI -0.37 to 1.33 µg/L; 1 study; 584 participants; very low-certainty evidence).None of the studies reported on any adverse effects. We judged the certainty of the evidence to be very low based on GRADE, so we are uncertain whether the results reflect the true effect of the intervention. We downgraded evidence due to high risk of selection bias and unclear risk of performance bias in one of two included studies, high heterogeneity and wide CIs crossing the line of no effect for anaemia prevalence and haemoglobin concentration.

AUTHORS' CONCLUSIONS

It is uncertain whether fortifying maize flour with iron and other vitamins and minerals reduces the risk of anaemia or iron deficiency in children aged over 2 years or in adults. Moreover, the evidence is too uncertain to conclude whether iron-fortified maize flour, corn meal or fortified maize flour products have any effect on reducing the risk of anaemia or on improving haemoglobin concentration in the population.We are uncertain whether fortification of maize flour with iron reduces anaemia among the general population, as the certainty of the evidence is very low. No studies reported on any adverse effects.Public organisations funded three of the five included studies, while the private sector gave grants to universities to perform the other two. The presence of industry funding for some of these trials did not appear to positively influence results from these studies.The reduced number of studies, including only two age groups (children and women of reproductive age), as well as the limited number of comparisons (only one out of the four planned) constitute the main limitations of this review.

Consumption of galacto-oligosaccharides increases iron absorption from a micronutrient powder containing ferrous fumarate and sodium iron EDTA: a stable-isotope study in Kenyan infants

Background: Whether consumption of prebiotics increases iron absorption in infants is unclear.Objective: We set out to determine whether prebiotic consumption affects iron absorption from a micronutrient powder (MNP) containing a mixture of ferrous fumarate and sodium iron EDTA (FeFum+NaFeEDTA) in Kenyan infants.Design: Infants (n = 50; aged 6-14 mo) consumed maize porridge that was fortified with an MNP containing FeFum+NaFeEDTA and 7.5 g galacto-oligosaccharides (GOSs) (Fe+GOS group, n = 22) or the same MNP without GOSs (Fe group, n = 28) each day for 3 wk. Then, on 2 consecutive days, we fed all infants isotopically labeled maize porridge and MNP test meals containing 5 mg Fe as ⁵⁷FeFum+Na⁵⁸FeEDTA or ferrous sulfate (⁵⁴FeSO₄). Iron absorption was measured as the erythrocyte incorporation of stable isotopes. Iron markers, fecal pH, and bacterial groups were assessed at baseline and 3 wk. Comparisons within and between groups were done with the use of mixed-effects models.Results: There was a significant group-by-compound interaction on iron absorption (P = 0.011). The median percentages of fractional iron absorption from FeFum+NaFeEDTA and from FeSO₄ in the Fe group were 11.6% (IQR: 6.9-19.9%) and 20.3% (IQR: 14.2-25.7%), respectively, (P < 0.001) and, in the Fe+GOS group, were 18.8% (IQR: 8.3-37.5%) and 25.5% (IQR: 15.1-37.8%), respectively (P = 0.124). Between groups, iron absorption was greater from the FeFum+NaFeEDTA (P = 0.047) in the Fe+GOS group but not from the FeSO₄ (P = 0.653). The relative iron bioavailability from FeFum+NaFeEDTA compared with FeSO₄ was higher in the Fe+GOS group than in the Fe group (88% compared with 63%; P = 0.006). There was a significant time-by-group interaction on Bifidobacterium spp. (P = 0.008) and Lactobacillus/Pediococcus/Leuconostoc spp. (P = 0.018); Lactobacillus/Pediococcus/Leuconostoc spp. decreased in the Fe group (P = 0.013), and there was a nonsignificant trend toward higher Bifidobacterium spp. in the Fe+GOS group (P = 0.099). At 3 wk, iron absorption was negatively correlated with fecal pH (P < 0.001) and positively correlated with Lactobacillus/Pediococcus/Leuconostoc spp. (P = 0.001).Conclusion: GOS consumption by infants increased iron absorption by 62% from an MNP containing FeFum+NaFeEDTA, thereby possibly reflecting greater colonic iron absorption. This trial was registered at clinicaltrials.gov as NCT02666417.

In Haitian women and preschool children, iron absorption from wheat flour-based meals fortified with sodium iron EDTA is higher than that from meals fortified with ferrous fumarate, and is not affected by Helicobacter pylori infection in children

Fe fortification of wheat flour was proposed in Haiti to combat Fe deficiency, but Fe bioavailability from fortificants has never been investigated in Haitian women or preschool children, two key target groups. We aimed to investigate the bioavailability of ferrous fumarate (FeFum), NaFeEDTA and their combination from fortified wheat flour. We recruited twenty-two healthy mother-child pairs in Port au Prince, Haiti, for an Fe-absorption study. We administered stable Fe isotopes as FeFum or NaFeEDTA individually in low-extraction wheat flour bread rolls consumed by all participants in a randomised, cross-over design. In a final, identical meal, consumed only by the women, FeFum+NaFeEDTA was administered. We measured Fe absorption by using erythrocyte incorporation of stable isotopes 14 d after consumption of each meal, and determined Fe status, inflammatory markers and Helicobacter pylori infection. Fe absorption (geometric mean was 9·24 (95 % CI 6·35, 13·44) and 9·26 (95 % CI 7·00, 12·31) from FeFum and 13·06 (95 % CI 9·23, 19·10) and 12·99 (95 % CI 9·18, 18·39) from NaFeEDTA in mothers and children, respectively (P<0·05 between compounds). Fe absorption from FeFum+NaFeEDTA was 11·09 (95 % CI 7·45, 17·34) and did not differ from the other two meals. H. pylori infection did not influence Fe absorption in children. In conclusion, in Haitian women and children, Fe absorption from NaFeEDTA was 40 % higher than from FeFum, and the combination FeFum+NaFeEDTA did not significantly increase Fe absorption compared with FeFum alone. In the context of Haiti, where the high costs of NaFeEDTA may not be affordable, the use of FeFum at 60 mg Fe/kg flour may be a preferable, cost-effective fortification strategy.

Body mass index, iron absorption and iron status in childbearing age women

BACKGROUND

The prevalence of obesity has increased at an alarming rate worldwide. Some studies have observed an association between iron (Fe) deficiency (ID) and obesity, however more research is needed.

OBJECTIVE

To assess whether body mass index (BMI) is associated with both Fe absorption and Fe status.

METHODS

A cross sectional sample of 318 Chilean childbearing age women was studied. The women received either a single dose of 0.5mg of Fe (n=137, group 1) or 3mg of Fe plus ascorbic acid (1:2 molar ratio) (n=181, group 2), both as FeSO4 with labeled radioisotopes. Fe absorption was assessed through radio Fe erythrocyte incorporation. Fe status was determined by hemoglobin (Hb), mean corpuscular volume, serum Fe, total iron binding capacity, transferrin saturation, erythrocyte Zn protoporphyrin and serum ferritin (SF).

RESULTS

29%, 47% and 24% of the women were classified as normal, overweight or obese, respectively. Fe absorption was significantly lower in obese women (p<0.05). In group 1, the geometric mean and range ±1 SD of the percentage of Fe absorption for normal-weight women was 32.9% vs. 19.7% in obese. For group 2, this percentage was 36% vs. 30%, respectively (2-way ANOVA: BMI classification and Fe dose p<0.05; interaction p=0.34). Although Fe absorption was lower in obese women, they had higher SF (p<0.01) and Hb (p<0.05) concentrations.

CONCLUSION

Although we did not observe a relationship between BMI and Fe status, obese women displayed lower Fe absorption compared with overweight and normal weight women, possibly due to subclinical inflammation associated with obesity.

Bioavailability of iron, zinc, folic acid, and vitamin A from fortified maize

Several strategies appear suitable to improve iron and zinc bioavailability from fortified maize, and fortification per se will increase the intake of bioavailable iron and zinc. Corn masa flour or whole maize should be fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA), ferrous fumarate, or ferrous sulfate, and degermed corn flour should be fortified with ferrous sulfate or ferrous fumarate. The choice of zinc fortificant appears to have a limited impact on zinc bioavailability. Phytic acid is a major inhibitor of both iron and zinc absorption. Degermination at the mill will reduce phytic acid content, and degermed maize appears to be a suitable vehicle for iron and zinc fortification. Enzymatic phytate degradation may be a suitable home-based technique to enhance the bioavailability of iron and zinc from fortified maize. Bioavailability experiments with low phytic acid-containing maize varieties have suggested an improved zinc bioavailability compared to wild-type counterparts. The bioavailability of folic acid from maize porridge was reported to be slightly higher than from baked wheat bread. The bioavailability of vitamin A provided as encapsulated retinyl esters is generally high and is typically not strongly influenced by the food matrix, but has not been fully investigated in maize.

Application of in vitro bioaccessibility and bioavailability methods for calcium, carotenoids, folate, iron, magnesium, polyphenols, zinc, and vitamins B(6), B(12), D, and E

A review of in vitro bioaccessibility and bioavailability methods for polyphenols and selected nutrients is presented. The review focuses on in vitro solubility, dialyzability, the dynamic gastrointestinal model (TIM)™, and Caco-2 cell models, the latter primarily for uptake and transport, and a discussion of how these methods have been applied to generate data for a range of nutrients, carotenoids, and polyphenols. Recommendations are given regarding which methods are most justified for answering bioaccessibility or bioavailability related questions for specific nutrients. The need for more validation studies in which in vivo results are compared to in vitro results is also discussed.

Efficacy of different iron fortificants in wheat flour in controlling iron deficiency

OBJECTIVE

To observe the different impacts of electrolytic iron, FeSO4, and NaFeEDTA on body iron store of anemic school students.

METHODS

Four hundreds anemic students at the age of 11-18 years were divided into four groups. Of which, three consumed different iron fortificants from wheat flour as food vehicle for six months and one consumed non-fortified flour (control). The fortification level of electrolytic iron, FeSO4, and NaFeEDTA was 60 mg Fe/kg, 30 mg Fe/kg, and 20 mg Fe/kg, respectively. Blood samples were collected at 0, 2, 4, and 6 months and hemoglobin (Hb), serum ferritin (SF), and transferrin receptor (TfR) were measured.

RESULTS

The hemoglobin levels in three intervention groups increased, the increments of Hb in the NaFeEDTA group were significantly higher than that in the other groups. SF and TfR levels increased in the tested groups and body iron store in the NaFeEDTA group was higher than that in the other groups. These parameters did not show any significant changes in the control group.

CONCLUSION

NaFeEDTA and FeSO4 fortified wheat flour has positive impacts on iron status in anemic students and NaFeEDTA is more effective than FeSO4, while electrolytic iron is less effective in improving iron store in anemic students.

Predicted contribution of folic acid fortification of corn masa flour to the usual folic acid intake for the US population: National Health and Nutrition Examination Survey 2001-2004

BACKGROUND

Folic acid can prevent up to 70% of neural tube defects (NTDs) if taken before pregnancy. Compared with other race-ethnicities, Hispanic women have higher rates of NTDs, lower rates of folic acid supplement use, and lower total folic acid intakes.

OBJECTIVE

The objective was to assess potential effects of fortifying corn masa flour with folic acid on Mexican American women and other segments of the US population.

DESIGN

A model was developed by using data from the National Health and Nutrition Examination Survey 2001-2004 to estimate the folic acid content in foods containing corn masa flour if fortified at a level of 140 microg folic acid/100 g corn masa flour.

RESULTS

Had corn masa flour fortification occurred, we estimated that Mexican American women aged 15-44 y could have increased their total usual daily folic acid intake by 19.9% and non-Hispanic white women by 4.2%. Among the US population, estimated relative percentage increases in total usual daily folic acid intake with corn masa flour fortification were greatest among Mexican Americans (16.8%) and lowest among children aged 1-3 y (2%) and adults aged >51 y (0-0.5%).

CONCLUSION

Analyses suggest that corn masa flour fortification would have effectively targeted Mexican Americans, specifically, Mexican American women, without substantially increasing folic acid intake among other segments of the population. Such increases could reduce the disparity in total folic acid intake between Mexican American and non-Hispanic white women of childbearing age and implies that an additional NTD preventive benefit would be observed for Mexican American women.

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

Background

Lime-treated corn gruel ( atole) is a common weaning food in iron-deficient populations, especially in Mexico and Central America, and is a potential vehicle for fortification with iron.

Objective

The objective of this study was to screen promising iron compounds for use in the fortification of atole, using in vitro enzymatic digestion–dialysis techniques, while also considering their response to known iron absorption enhancers and inhibitors.

Methods

Atole, unaltered or preincubated with phytase, was fortified with iron (10 mg/L) from ferrous sulfate, ferrous bisglycinate, or ferrous fumarate, or with ferric chloride, ferric ammonium citrate, or ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA), and submitted to in vitro digestion. Dialysis of calcium, copper, iron, phosphorus, and zinc (analyzed by inductively coupled plasma atomic emission spectrometry) was measured when atole was fortified with iron compounds alone or together with ascorbic acid or disodium ethyl- enediaminetetraacetic acid (Na2 EDTA).

Results

Iron dialyzability was higher with NaFeEDTA ( p < .05) than with all other iron compounds, which did not differ among themselves in iron dialyzability. Addition of ascorbic acid had no significant effect on iron dialysis, whereas Na2 EDTA enhanced iron dialyzability by 7 to 10 times in unaltered atole and 15 to 20 times in phytase-preincubated atole ( p < .05). Addition of Na2 EDTA always increased intrinsic zinc dialyzability, and most of the time this increase was significant. Phytase pretreatment generally increased mineral dialysis.

Conclusions

Adding EDTA (either as NaFeEDTA or as Na2 EDTA) to atole can increase the dialyzability of ferrous and ferric iron compounds and enhance the dialyzability of intrinsic zinc without any negative effects on calcium, phosphorus, or copper dialysis.

Sodium iron (III) ethylenediaminetetraacetic acid synthesis to reduce iron deficiency globally

Despite major interest in sodium iron (III) ethylenediaminetetraacetic acid's (EDTA) potential use in food fortification programs in potentially curbing the global problem of iron deficiency and its anemia, synthesis methods of stable isotope-labeled sodium iron (III) EDTA for use in human bioavailability studies are incomplete, incorrect or totally lacking. Owing to a number of clinical research groups requiring this compound in bioavailability studies, in both developing and already developed countries, we simplified and optimized the synthesis of sodium iron (III) EDTA from a block of isotopically enriched iron metal, in order that it be easily reproduced, cheaply, using simple basic laboratory apparatus. The resulting product is of high purity (>99.0%), and may be used for human stable isotope bioavailability studies. The simplicity of this method allows for the many research groups, currently doing such studies, to perform their own syntheses. Additionally, more uniformity in this synthesis will reduce the variation observed between such studies.

Diet synergies and mortality--a population-based case-control study of 32,462 Hong Kong Chinese older adults

BACKGROUND

Food and drink are not consumed in isolation and can have complimentary effects enhancing or blocking the overall uptake of nutrients. We investigated how combinations of foods, drinks, and smoking affected mortality. Method Adjusted logistic regression was used to assess the joint effect of healthy foods, less healthy foods, smoking, and alcohol use on mortality in a case-control study of all Chinese adults aged 60 or over who died in 1998; 21,494 dead cases (81% of all registered deaths) and 10,968 live controls were included.

RESULTS

There was a significant trend of increasing all-cause mortality risk with decreasing healthy food consumption (P < 0.001), and the increase in risk was significantly steeper for people with high intakes of less healthy food (P for interaction <0.001). There was a steeper risk from increasing less healthy food intake in ever-smokers and people not drinking tea regularly (P < 0.001), while the J-shaped relationship between alcohol and mortality differed in shape with level of less healthy food intake.

CONCLUSION

Intake of some dietary items may modify the effect of others. An analysis framework explicitly recognizing complementary and potentially synergistic effects of food, drinks, and smoking could enhance our understanding of dietary epidemiology.

The poor bioavailability of elemental iron in corn masa flour is not affected by disodium EDTA

The most sustainable way to eradicate iron deficiency is through food fortification. Elemental iron powders are commonly utilized as fortificants due to their low cost and few sensory problems. However, their bioavailability is unknown. Our goals were to measure the bioavailability of elemental iron in Mexican style corn masa flour tortillas and to evaluate the effects of Na(2)EDTA. We used a stable isotope of H(2)-reduced iron powder, with and without Na(2)EDTA in tortillas prepared with corn masa flour. Two groups of 5- to 7-y-old children (n = 12/group) were fed tortillas to which was added 3 mg/100 g of H(2)-reduced (58)Fe with a mean particle size of 15 micro m. In one group, Na(2)EDTA was incorporated at a ratio of 1:2 mol/mol. The next day, (57)Fe ascorbate was given as a reference dose. After 14 d, blood samples were analyzed for isotopic enrichment. When normalized to 40% absorption of the reference dose, the geometric mean (+/-range 1 SD) bioavailability of reduced iron in tortilla was 3.8% (2.7-5.3). The addition of Na(2)EDTA, tended to increase it (P = 0.18) to 5.1% (2.8-9.2). This observed low absorption was compounded by the use of iron isotopes with smaller particle size (mean diameter 15 micro m) than typical of commercial elemental iron powder (<45 micro m). We conclude that H(2)-reduced iron powder is an ineffective fortificant in corn tortillas.