Enhancing the absorption of fortification iron. A SUSTAIN Task Force report

Nicotianamine, a novel enhancer of rice iron bioavailability to humans

Background

Polished rice is a staple food for over 50% of the world's population, but contains little bioavailable iron (Fe) to meet human needs. Thus, biofortifying the rice grain with novel promoters or enhancers of Fe utilization would be one of the most effective strategies to prevent the high prevalence of Fe deficiency and iron deficiency anemia in the developing world.

Methodology/Principal Findings

We transformed an elite rice line cultivated in Southern China with the rice nicotianamine synthase gene (OsNAS1) fused to a rice glutelin promoter. Endosperm overexpression of OsNAS1 resulted in a significant increase in nicotianamine (NA) concentrations in both unpolished and polished grain. Bioavailability of Fe from the high NA grain, as measured by ferritin synthesis in an in vitro Caco-2 cell model that simulates the human digestive system, was twice as much as that of the control line. When added at 1∶1 molar ratio to ferrous Fe in the cell system, NA was twice as effective when compared to ascorbic acid (one of the most potent known enhancers of Fe bioavailability) in promoting more ferritin synthesis.

Conclusions

Our data demonstrated that NA is a novel and effective promoter of iron utilization. Biofortifying polished rice with this compound has great potential in combating global human iron deficiency in people dependent on rice for their sustenance.

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

Background

Dietary treatment is often recommended as the first line of treatment for women with mild iron deficiency. Although it is well established that ascorbic acid enhances iron absorption, it is less clear whether the consumption of ascorbic acid rich foods (such as kiwifruit) with meals fortified with iron improves iron status. The aim of this study is to investigate whether the consumption of ZESPRI^® GOLD kiwifruit (a fruit high in ascorbic acid and carotenoids) with an iron fortified breakfast cereal meal increases iron status in women with low iron stores.

Methods/Design

Eighty nine healthy women aged 18-44 years with low iron stores (serum ferritin (SF) ≤ 25 μg/L, haemoglobin (Hb) ≥ 115 g/L) living in Auckland, New Zealand were randomised to receive an iron fortified breakfast cereal (16 mg iron per serve) and either two ZESPRI^® GOLD kiwifruit or a banana (low ascorbic acid and carotenoid content) to eat at breakfast time every day for 16 weeks. Iron status (SF, Hb, C-reactive protein (CRP) and soluble transferrin receptor (sTfR)), ascorbic acid and carotenoid status were measured at baseline and after 16 weeks. Anthropometric measures, dietary intake, physical activity and blood loss were measured before and after the 16 week intervention.

Discussion

This randomised controlled intervention study will be the first study to investigate the effect of a dietary based intervention of an iron fortified breakfast cereal meal combined with an ascorbic acid and carotenoid rich fruit on improving iron status in women with low iron stores.

Trial registration

ACTRN12608000360314

Social mobilization and social marketing to promote NaFeEDTA-fortified soya sauce in an iron-deficient population through a public–private partnership

Objective

The present pilot project aimed to assess the effectiveness of social mobilization and social marketing in improving knowledge, attitudes and practices (KAP) and Fe status in an Fe-deficient population.

Design

In an uncontrolled, before–after, community-based study, social mobilization and social marketing strategies were applied. The main outcomes included KAP and Hb level and were measured at baseline, 1 year later and 2 years later.

Setting

One urban county and two rural counties in Shijiazhuang Municipality, Hebei Province, China.

Subjects

Adult women older than 20 years of age and young children aged from 3 to 7 years were selected from three counties to attend the evaluation protocol.

Results

After 1 year, most knowledge and attitudes had changed positively towards the prevention and control of anaemia. The percentage of women who had adopted NaFeEDTA-fortified soya sauce increased from 8·9 % to 36·6 % (P ≤ 0·001). After 2 years, Hb levels had increased substantially, by 9·0 g/l (P ≤ 0·001) in adult women and 7·7 g/l (P ≤ 0·001) in young children.

Conclusion

Social mobilization and social marketing activities had a positive impact on the KAP of adult women, and resulted in marked improvements in Hb levels in both adult women and young children. This should be recommended as a national preventive strategy to prevent and control Fe deficiency and Fe-deficiency anaemia.

Household Income and Expenditure Surveys: A Tool for Accelerating the Development of Evidence-Based Fortification Programs

Background

One-third of the world's population suffers from micronutrient deficiencies due primarily to inadequate dietary intake. Food fortification is often touted as the most promising short- to medium-term strategy for combating these deficiencies. Despite its appealing characteristics, progress in fortification has been slow.

Objective

To assess the potential of household food-purchase data to fill the food-consumption information gap, which has been an important factor contributing to the slow growth of fortification programs.

Methods

Household income and expenditure survey (HIES) data about: (a) a population's distribution of apparent household consumption, which are essential to setting safe fortification levels, (b) the proportion of households purchasing “fortifiable” food, and (c) the quantity of food being purchased were used to proxy food-consumption data and develop suggested fortification levels.

Results

The usefulness of the approach in addressing several common fortification program design issues is demonstrated. HIES-based suggested fortification levels are juxtaposed with ones developed using the most common current approach, which relies upon Food and Agriculture Organization (FAO) Food Balance Sheets.

Conclusions

Despite its limitations, the use of HIES data constitutes a generally unexploited opportunity to address the food-consumption information gap by using survey data that nearly every country of the world is already routinely collecting. HIES data enable the design of fortification programs to become more based on country-specific data and less on general rules of thumb. The more routine use of HIES data constitutes a first step in improving the precision of fortification feasibility analyses and improving estimates of the coverage, costs, and impact of fortification programs.

Effect of sodium iron ethylenediaminetetra-acetate (NaFeEDTA) on haemoglobin and serum ferritin in iron-deficient populations: a systematic review and meta-analysis of randomised and quasi-randomised controlled trials

We aimed to synthesise evidence to assess the effect and safety of NaFeEDTA on Hb and serum ferritin in Fe-deficient populations. We performed a systematic review, identifying potential studies by searching the electronic databases of Medline, Cochrane Library, Embase, WHO Library and China National Knowledge Infrastructure. We also hand-searched relevant conference proceedings and reference lists. Finally, we contacted experts in the field. The selection criteria included randomised or quasi-randomised controlled trials of NaFeEDTA compared with placebo. Hb, serum ferritin and adverse effects were outcomes of interest. Inclusion decisions, quality assessment and data extraction were performed by two reviewers independently. Seven studies met the inclusion criteria. All included studies assessed the effect of NaFeEDTA on Hb concentration, four studies assessed the effect on serum ferritin concentration, and one study on serum Zn concentration. After the intervention, Hb concentration and serum ferritin concentration were both higher in the NaFeEDTA group compared with the control group. For Hb, data from six studies could be pooled and the pooled estimate (weighted mean difference) was 8·56 (95 % CI 2·21, 14·90) g/l (P = 0·008). For serum ferritin, data from four studies could be pooled and the pooled difference was 1·58 (95 % CI 1·20, 2·09) μg/l (P < 0·001). Subgroup analysis indicated that a lower baseline Hb level was associated with a greater increase in Hb concentration. No significant difference in serum Zn concentration was found. We concluded that NaFeEDTA increased both Hb concentration and serum ferritin concentration substantially in Fe-deficient populations, and could be an effective Fe preparation to combat Fe deficiency.

Phytate: impact on environment and human nutrition. A challenge for molecular breeding

Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair, signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes of phytases are compared, and the application of phytase in food and feed is discussed.

Suitability of instant noodles for iron fortification to combat iron-deficiency anemia among primary schoolchildren in rural Vietnam

BACKGROUND

Anemia is a significant public health problem among schoolchildren in Vietnam. Food fortification is considered one of the most sustainable long-term strategies to control iron-deficiency anemia in Vietnam. The success of a food-fortification program depends on the choice of the food vehicle.

OBJECTIVES

The aim of the present study was to identify an appropriate vehicle for iron fortification to be used in a school-feeding program aimed at improving the iron and anemia status of schoolchildren in rural Vietnam.

METHODS

Children 6 to 8 years of age in two primary schools in Tam Nong District, Phu Tho Province, and their parents were included in this study. The study consisted of three substudies: a food-consumption study with 24-hour recalls of two nonconsecutive days; a food-beliefs study, with focus group discussions, a pile-sorting test, and a food attributes and differences exercise; and a food-acceptance study using noodles and biscuits fortified with sodium iron ethylenediaminetetraacetic acid (NaFeEDTA).

RESULTS

The average number of meals consumed daily was 3.2 +/- 0.4, and the average intakes of energy and iron were 1,218 +/- 406 kcal and 7.5 +/- 4.0 mg, respectively. Compared with biscuits and instant rice soup, instant noodles were consumed more frequently and in larger portion sizes and are more acceptable as children's food in the culture of the local people. The iron level of the fortified product did not affect the mean consumption of noodles, but a higher level of iron was associated with a lower mean consumption of biscuits (p < .05). The production process did not affect the NaFeEDTA level in noodles; however, during preparation at least 70% of the iron is leaked into the soup.

CONCLUSIONS

Instant noodles are a suitable vehicle for iron fortification for use in school-based intervention to improve iron-deficiency anemia among primary schoolchildren in rural Vietnam.

Nutritional iron deficiency

Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming monotonous plant-based diets. The high prevalence of iron deficiency in the developing world has substantial health and economic costs, including poor pregnancy outcome, impaired school performance, and decreased productivity. Recent studies have reported how the body regulates iron absorption and metabolism in response to changing iron status by upregulation or downregulation of key intestinal and hepatic proteins. Targeted iron supplementation, iron fortification of foods, or both, can control iron deficiency in populations. Although technical challenges limit the amount of bioavailable iron compounds that can be used in food fortification, studies show that iron fortification can be an effective strategy against nutritional iron deficiency. Specific laboratory measures of iron status should be used to assess the need for fortification and to monitor these interventions. Selective plant breeding and genetic engineering are promising new approaches to improve dietary iron nutritional quality.

Redox-active labile iron in fortified flours from the Brazilian market

OBJECTIVE: To quantify the fraction of redox-active labile iron in iron-fortified flours acquired on the Brazilian market. METHODS: Samples of wheat flour, maize flour and breadcrumbs were extracted with buffers that mimic gastric juice, saliva and intestinal juice. Redox-active labile iron levels were assessed through the reaction of autoxidation of ascorbic acid catalyzed by iron in the presence of a fluorescence probe. RESULTS: Redox-active labile iron represents 1% to 9% of the total iron in the flour and breadcrumb samples, with the lowest values found under gastric juice conditions and the highest in the more alkaline media. Redox-active labile iron possibly arises from the decomposition of an iron-phytic acid complex. A positive correlation between redox-active labile iron and total iron was found in saline biomimetic fluids. CONCLUSION: Redox-active labile iron may be a risk factor for people with impaired antioxidant defenses, such as those who are atransferrinemic or iron overloaded (e.g. thalassemic). Total iron can be used to predict redox-active labile iron absorption at each stage of the gastrointestinal tract after ingestion of iron-fortified flours.

The importance of bioavailability of dietary iron in relation to the expected effect from iron fortification

BACKGROUND

The most common method of combating iron deficiency is iron fortification, especially in developing countries. However, few studies have shown a significant effect on iron status following iron fortification of low bioavailability diets.

OBJECTIVE

To investigate how iron fortification and dietary modifications affect iron absorption and rates of changes in iron stores.

METHODS

Research has made it possible to predict both iron absorption and the effects of iron fortification and diet modifications on iron stores using recently developed algorithms. Iron absorption and rate of change in iron stores were calculated from nine diets representing a broad range of iron bioavailability and iron contents. The calculations were related to the main target group for iron fortification, that is, women of reproductive age having empty stores but normal haemoglobin concentrations.

RESULTS

As the only measure, iron fortification has practically no effect on iron status if the original diet has low bioavailability. However, after dietary modifications such a diet shows a positive effect on iron stores. The combined action of fortification (6 mg/day) and modest bioavailability changes in a low bioavailability diet results approximately in 40 and 70% greater increases in iron stores than through iron fortification or dietary modification alone.

CONCLUSIONS

It is difficult to achieve good effects on iron status from iron fortification as the only measure if the diet has low bioavailability. Both dietary modifications as well as iron fortification are required to improve effectively the iron status of a population.

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren

The effect of iron fortification is generally assumed to be less than iron supplementation; however, the magnitude of difference in effects is not known. The present study aims to compare the efficacy of these two strategies on anaemia and iron status. After screening on low Hb, 425 anaemic children in six primary schools in Tam Nong district of Phu Tho province were included in a randomized, placebo-controlled trial comparing two groups receiving iron fortified instant noodles or iron supplementation for 6 months and a control group, with children in all groups having been dewormed. Blood samples were collected before and after intervention for haemoglobin, serum ferritin (SF), serum transferrin receptor (TfR), C-reactive protein (CRP), and haemoglobinopathies analysis. Regression analysis was used to assess the effect of iron fortification and iron supplementation on haemoglobin concentration, SF, TfR, body iron, and anaemic status as outcome variables. The improvement of haemoglobin, SF, and body iron level in the group receiving iron fortification was 42% (2.6 g/L versus 6.2 g/L), 20% (23.5 microg/L versus 117.3 microg/L), and 31.3% (1.4 mg/kg versus 4.4 mg/kg) of that in the iron supplementation group. The prevalence of anaemia dropped to 15.1% in the control group, with an additional reduction of anaemia of 8.5% in the iron supplementation group. The additional reduction due to iron fortification was 5.4%, which amounts to well over 50% of the impact of supplementation. In conclusion, the efficacy of iron fortification based on reduction of prevalence of anaemia, and on the change in haemoglobin level, is about half of the maximum impact of supplementation in case of optimal compliance. Thus, in a population of anaemic children with mild iron deficiency, iron fortification should be the preferred strategy to combat anaemia.

Improving the bioavailability of nutrients in plant foods at the household level

Plant foods are the major staples of diets in developing countries, in which the consumption of animal-source foods is often low because of economic and/or religious concerns. However, such plant-based diets are often associated with micronutrient deficits, exacerbated in part by poor micronutrient bioavailability. Diet-related factors in plant foods that affect bioavailability include: the chemical form of the nutrient in food and/or nature of the food matrix; interactions between nutrients and other organic components (e.g. phytate, polyphenols, dietary fibre, oxalic acid, protein, fat, ascorbic acid); pretreatment of food as a result of processing and/or preparation practices. Consequently, household strategies that reduce the content or counteract the inhibiting effects of these factors on micronutrient bioavailability are urgently needed in developing-country settings. Examples of such strategies include: germination, microbial fermentation or soaking to reduce the phytate and polyphenol content of unrefined cereal porridges used for young child feeding; addition of ascorbic acid-containing fruits to enhance non-haem-Fe absorption; heating to destroy heat-labile anti-nutritional factors (e.g. goitrogens, thiaminases) or disrupt carotenoid-protein complexes. Such strategies have been employed in both experimental isotope-absorption and community-based studies. Increases in Fe, Zn and Ca absorption have been reported in adults fed dephytinized cereals compared with cereals containing their native phytate. In community-based studies in rural Malawi improvements in dietary quality and arm-muscle area and reductions in the incidence of anaemia and common infections in young children have been observed.

New approaches for designing and evaluating food fortification programs

Historically, food fortification programs were often undertaken with little attention to issues such as micronutrient bioavailability, optimal levels of addition, or efficacy or to monitoring impact on nutritional status, health, and human function. Several developments in recent years have enabled substantial progress to be made in the design and evaluation of fortification programs. The methodology for estimating the prevalence of inadequate nutrient intakes in a population and tolerable upper intake levels has been established and can be used as the basis for estimating desirable amounts of nutrient addition. More attention is being paid to assessing the bioavailability of nutrients (especially minerals) using stable and radioactive isotopes, and bioavailability of iron compounds can be estimated from changes in total body iron calculated from the ratio of transferrin receptors to serum ferritin. Procedures for quality control of the fortification process have been established. New approaches to monitoring the impact of fortification over time include assessment of liver retinol stores using retinol isotope dilution. In summary, the design and evaluation of food fortification programs now requires a series of formative research procedures on the part of nutritionists, which were not often expected or conducted in the past.

Relevance, essentiality and toxicity of trace elements in human health

The metals Mn, Fe, Cu, and Zn, and the non-metal Se are considered "trace elements" (TE) because of their essentiality and very limited quantity in humans. The biological activities of Cu, Fe, Mn, and Se are strongly associated with the presence of unpaired electrons that allow their participation in redox reactions. In biological systems these metals are mostly bound to proteins, forming metalloproteins. Many of the metals in metalloproteins are part of enzymatic systems, have structural and storage functions, or use the protein to be transported to their target site in the organism. In humans Mn, Fe, Cu, Zn, and Se accomplish decisive functions to maintain human health. Deficiency in any of these TE leads to undesirable pathological conditions that can be prevented or reversed by adequate supplementation. In sufficiently nourished persons, supplementation should be carefully controlled, given the toxic effects ascribed to TE when present in quantities exceeding those required for accomplishing their biological functions. The dietary reference intakes provided by national regulatory agencies are guides to define intake, supplementation and toxicity of Mn, Fe, Cu, Zn, and Se, as well other elements considered micronutrients for humans.

Malnutrition and health in developing countries

Malnutrition, with its 2 constituents of protein-energy malnutrition and micronutrient deficiencies, continues to be a major health burden in developing countries. It is globally the most important risk factor for illness and death, with hundreds of millions of pregnant women and young children particularly affected. Apart from marasmus and kwashiorkor (the 2 forms of protein- energy malnutrition), deficiencies in iron, iodine, vitamin A and zinc are the main manifestations of malnutrition in developing countries. In these communities, a high prevalence of poor diet and infectious disease regularly unites into a vicious circle. Although treatment protocols for severe malnutrition have in recent years become more efficient, most patients (especially in rural areas) have little or no access to formal health services and are never seen in such settings. Interventions to prevent protein- energy malnutrition range from promoting breast-feeding to food supplementation schemes, whereas micronutrient deficiencies would best be addressed through food-based strategies such as dietary diversification through home gardens and small livestock. The fortification of salt with iodine has been a global success story, but other micronutrient supplementation schemes have yet to reach vulnerable populations sufficiently. To be effective, all such interventions require accompanying nutrition-education campaigns and health interventions. To achieve the hunger- and malnutrition-related Millennium Development Goals, we need to address poverty, which is clearly associated with the insecure supply of food and nutrition.