Na2EDTA enhances the absorption of iron and zinc from fortified rice flour in Sri Lankan children

Toward revising dietary zinc recommendations for children aged 0 to 3 years: a systematic review and meta-analysis of zinc absorption, excretion, and requirements for growth

CONTEXT

The Food and Agriculture Organization of the United Nations and the World Health Organization are updating their dietary zinc recommendations for children aged 0 to 3 years.

OBJECTIVE

The aim of this review was to retrieve and synthesize evidence regarding zinc needs for growth as well as zinc losses, absorption, and bioavailability from the diet.

DATA SOURCES

MEDLINE, Embase, and Cochrane Library databases were searched electronically from inception to August 2020. Studies assessing the above factors in healthy children aged 0 to 9 years were included, with no limits on study design or language.

DATA EXTRACTION

Ninety-four studies reporting on zinc content in tissue (n = 27); zinc absorption (n = 47); factors affecting zinc bioavailability (n = 30); and endogenous zinc losses via urine, feces, or integument (n = 40) met the inclusion criteria. Four reviewers extracted data and two reviewers checked for accuracy.

DATA ANALYSES

Studies were synthesized narratively, and meta-analyses of zinc losses and gains as well the subgroups of age, type of feeding, country's income, and molar ratio of phytate to zinc were conducted. Meta-analysis revealed an overall mean (95%CI) urinary and endogenous fecal zinc excretion of 17.48 µg/kg/d (11.80-23.15; I2 = 94%) and 0.07 mg/kg/d (0.06-0.08; I2 = 82%), respectively, with a mean fractional zinc absorption of 26.75% (23.69-29.81; I2 = 99%). Subgrouping by age revealed differences in mean values associated with the transition from milk-based diets to solid food during the first 3 years of life.

CONCLUSION

This review synthesizes data that may be used to formulate zinc requirements in young children. Results should be interpreted with caution because of considerable heterogeneity in the evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020215236.

Synchronization of Boron application methods and rates is environmentally friendly approach to improve quality attributes of Mangifera indica L. On sustainable basis

Micronutrient deficiency in the soil is one of the major causes of mango fruit and yield's poor quality. Besides, the consumption of such a diet also causes a deficiency of micronutrients in humans. Boron deficiency adversely affects the flowering and pollen tube formation, thus decreasing mango yield and quality attributes. Soil and foliar application of B are considered a productive method to alleviate boron deficiency. A field experiment was conducted to explore the Boron most suitable method and application rate in mango under the current climatic scenario. There were nine treatments applied in three replications. The results showed that application of T8 = RD + Borax (75 g plant ^-1 as a basal application) + H₃ BO₃ (0.8% as a foliar spray) and T9 = RD + Borax (150 g plant ^-1 as a basal application) + H₃ BO₃ (0.8% as a foliar spray) significantly enhanced the nitrogen, potassium, proteins, ash, fats, fiber, and total soluble solids in mango as compared to the control. A significant decrease in sodium, total phenolics contents, antioxidant activity, and acidity as citric acid also validated the effective functioning of T8 = RD + Borax (75 g plant ^-1 as a basal application) + H₃ BO₃ (0.8% as a foliar spray) and T9 = RD + Borax (150 g plant ^-1 as a basal application) + H₃ BO₃ (0.8% as a foliar spray) as compared to control. In conclusion, T8 = RD + Borax (75 g plant ^-1 as a basal application) + H₃ BO₃ (0.8% as a foliar spray) and T9 = RD + Borax (150 g plant ^-1 as a basal application) + H₃ BO₃ (0.8% as a foliar spray) is a potent strategy to improve the quality attributes of mango under the changing climatic situation.

Effects of Foods Fortified with Zinc, Alone or Cofortified with Multiple Micronutrients, on Health and Functional Outcomes: A Systematic Review and Meta-Analysis

Seventeen per cent of the world's population is estimated to be at risk of inadequate zinc intake, which could in part be addressed by zinc fortification of widely consumed foods. We conducted a review of efficacy and effectiveness studies to ascertain the effect of zinc fortification [postharvest fortification of an industrially produced food or beverage; alone or with multiple micronutrients (MMN)] on a range of health outcomes. Previous reviews have required that the effect of zinc be isolated; because zinc is always cofortified with MMN in existing fortification programs, we did not impose this condition. Outcomes assessed were zinc-related biomarkers (plasma or serum, hair or urine zinc concentrations, comet assay, plasma fatty acid concentrations, and the proportion of and total zinc absorbed in the intestine from the diet), child anthropometry, morbidity, mortality, cognition, plasma or serum iron and copper concentrations, and for observational studies, a change in consumption of the food vehicle. Fifty-nine studies were included in the review; 54 in meta-analyses, totaling 73 comparisons. Zinc fortification with and without MMN increased plasma zinc concentrations (efficacy, n = 27: 4.68 μg/dL; 95% CI: 2.62-6.75; effectiveness, n = 13: 6.28 μg/dL; 95% CI: 5.03-7.77 μg/dL) and reduced the prevalence of zinc deficiency (efficacy, n = 11: OR: 0.76, 95% CI: 0.60-0.96; effectiveness, n = 10: OR: 0.45, 95% CI: 0.31-0.64). There were statistically significant increases in child weight (efficacy, n = 11: 0.43 kg, 95% CI: 0.11-0.75 kg), improvements in short-term auditory memory (efficacy, n = 3: 0.32 point, 95% CI: 0.13-0.50 point), and decreased incidence of diarrhea (efficacy, n = 3: RR: 0.79, 95% CI: 0.68-0.92) and fever (efficacy, n = 2: RR: 0.85, 95% CI: 0.74-0.97). However, these effects cannot be solely attributed to zinc. Our review found that zinc fortification with or without MMN reduced the prevalence of zinc deficiency and may provide health and functional benefits, including a reduced incidence of diarrhea.

Conventional and food-to-food fortification: An appraisal of past practices and lessons learned

Food fortification is an important nutrition intervention to fight micronutrient deficiencies and to reduce their incidence in many low- and middle-income countries. Food fortification approaches experienced a significant rise in the recent years and have generated a lot of criticism. The present review aimed to shed light on the actual effect of food fortification approaches on the reduction of malnutrition. A set of 100 articles and reports, which have dealt with the impact of food fortification on malnutrition, were included in this review. This review identified a broad selection of local raw materials suitable for a food-to-food fortification approach.

Studies on in vitro bioavailability and starch hydrolysis in zinc fortified ready-to-eat parboiled rice (komal chawal)

Zinc fortified parboiled rice (komal chawal) was produced from a low amylose variety of rice by applying 'brown rice parboiling' method. In addition to the effect of milling on fortification, the effectiveness of fortification upon the amount of bioaccessible (in vitro digest) and bioavailable (cellular uptake) form of Zn was tested. The effect on glycaemic index was also assessed by employing an in vitro starch hydrolysis assay. The bioaccessible form of Zn in the unmilled fortified rice were ranged in between 4.24 and 11.07 mg/100 g, which was significantly higher (p < 0.05) than the milled and unfortified parboiled rice. Similarly, the % absorption of bioavailable Zn was negligible in the unfortified parboiled rice as compared to the fortified rice (14.5-24.5%). The estimated GI of fortified parboiled rice samples was in the range of 50.97-59.79, which was lower than the unfortified parboiled rice (58.80-62.53) and raw rice (78.71-84.64). The results thus demonstrated that Zn fortified komal chawal can be a novel and rapidly produced micronutrient enhanced ready-to-eat rice.

Fortification of zinc in a parboiled low-amylose rice: effects of milling and cooking

BACKGROUND

Rice is a staple diet for many people, however, it is not a good source of micronutrients. The process of parboiling induces several desirable changes in rice: it improves the retention of available micronutrients, and in the case of low-amylose varieties it eases the cooking requirement. During parboiling of brown rice, when soaking is conducted in micronutrient-rich solutions, it affects fortification. This study is aimed at examining the suitability of the method of zinc fortification by a brown rice parboiling process in a low-amylose rice.

RESULTS

Application of the method of zinc fortification by a brown rice parboiling process increased the zinc content in unmilled rice. Milling caused a reduction in zinc content per gram of grain, indicating a high concentration of zinc at the outer layer. Both milled and unmilled rice could retain more than 86% of zinc upon cooking. Changes in colour values in uncooked rice, due to zinc fortification, were non-significant at P ≤ 0.05. Rehydration of zinc-fortified rice at 60 °C for 25 min yielded hardness values similar to that of its cooked form.

CONCLUSION

The method of zinc fortification by brown rice parboiling is a pragmatic way to produce zinc-fortified parboiled rice to combat zinc deficiency with a reduced cooking requirement from a low-amylose rice variety. © 2019 Society of Chemical Industry.

In-home fortification with 2.5 mg iron as NaFeEDTA does not reduce anaemia but increases weight gain: a randomised controlled trial in Kenyan infants

In-home fortification of infants with micronutrient powders (MNPs) containing 12.5 mg iron may increase morbidity from infections; therefore, an efficacious low-dose iron-containing MNP might be advantageous. Effects of iron-containing MNPs on infant growth are unclear. We assessed the efficacy of a low-iron MNP on iron status and growth and monitored safety in a randomised, controlled, double-blind 1-year trial in 6-month-old infants (n = 287) consuming daily a maize porridge fortified with either a MNP including 2.5 mg iron as NaFeEDTA (MNP + Fe) or the same MNP without iron (MNP - Fe). At baseline, after 6 and 12 months, we determined haemoglobin (Hb), iron status [serum ferritin (SF), soluble transferrin receptor (sTfR) and zinc protoporphyrin (ZPP)], inflammation [C-reactive protein (CRP)] and anthropometrics. We investigated safety using weekly morbidity questionnaires asking for diarrhoea, cough, flu, bloody or mucus-containing stool and dyspnoea, and recorded any other illness. Furthermore, feeding history and compliance were assessed weekly. At baseline, 71% of the infants were anaemic and 22% iron deficient; prevalence of inflammation was high (31% had an elevated CRP). Over the 1 year, Hb increased and SF decreased in both groups, without significant treatment effects of the iron fortification. At end point, the weight of infants consuming MNP + Fe was greater than in the MNP - Fe group (9.9 vs. 9.5 kg, P = 0.038). Mothers of infants in the MNP + Fe group reported more infant days spent with cough (P = 0.003) and dyspnoea (P = 0.0002); there were no significant differences on any other of the weekly morbidity measures. In this study, low-dose iron-containing MNP did not improve infant's iron status or reduce anaemia prevalence, likely because absorption was inadequate due to the high prevalence of infections and the low-iron dose.

Fortification of staple foods with zinc for improving zinc status and other health outcomes in the general population

BACKGROUND

Zinc deficiency is a global nutritional problem, particularly in children and women residing in settings where diets are cereal based and monotonous. It has several negative health consequences. Fortification of staple foods with zinc may be an effective strategy for preventing zinc deficiency and improving zinc-related health outcomes.

OBJECTIVES

To evaluate the beneficial and adverse effects of fortification of staple foods with zinc on health-related outcomes and biomarkers of zinc status in the general population.

SEARCH METHODS

We searched the following databases in April 2015: Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3 of 12, 2015, the Cochrane Library), MEDLINE & MEDLINE In Process (OVID) (1950 to 8 April 2015), EMBASE (OVID) (1974 to 8 April 2015), CINAHL (1982 to April 2015), Web of Science (1900 to 9 April 2015), BIOSIS (1969 to 9 April 2015), POPLINE (1970 to April 2015), AGRICOLA, OpenGrey, BiblioMap, and Trials Register of Promoting Health Interventions (TRoPHI), besides regional databases (April 2015) and theses. We also searched clinical trial registries (17 March 2015) and contacted relevant organisations (May 2014) in order to identify ongoing and unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials, randomised either at the level of the individual or cluster. We also included non-randomised trials at the level of the individual if there was a concurrent comparison group. We included non-randomised cluster trials and controlled before-after studies only if there were at least two intervention sites and two control sites. Interventions included fortification (central/industrial) of staple foods (cereal flours, edible fats, sugar, condiments, seasonings, milk and beverages) with zinc for a minimum period of two weeks. Participants were members of the general population who were over two 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.

MAIN RESULTS

We included eight trials (709 participants); seven were from middle-income countries of Asia, Africa, Europe, and Latin America where zinc deficiency is likely to be a public health problem. Four trials compared the effect of zinc-fortified staple foods with unfortified foods (comparison 1), and four compared zinc-fortified staple foods in combination with other nutrients/factors with the same foods containing other nutrients or factors without zinc (comparison 2). The interventions lasted between one and nine months. We categorised most trials as having unclear or high risk of bias for randomisation, but low risk of bias for blinding and attrition. None of the studies in comparison 1 reported data on zinc deficiency.Foods fortified with zinc increased the serum or plasma zinc levels in comparison to foods without added zinc (mean difference (MD) 2.12 µmol/L, 95% confidence interval (CI) 1.25 to 3.00 µmol/L; 3 studies; 158 participants; low-quality evidence). Participants consuming foods fortified with zinc versus participants consuming the same food without zinc had similar risk of underweight (average risk ratio 3.10, 95% CI 0.52 to 18.38; 2 studies; 397 participants; low-quality evidence) and stunting (risk ratio (RR) 0.88, 95% CI 0.36 to 2.13; 2 studies; 397 participants; low-quality evidence). A single trial of addition of zinc to iron in wheat flour did not find a reduction in proportion of zinc deficiency (RR 0.17, 95% CI 0.01 to 3.94; very low-quality evidence). We did not find a difference in serum or plasma zinc levels in participants consuming foods fortified with zinc plus other micronutrients when compared with participants consuming the same foods with micronutrients but no added zinc (MD 0.03 µmol/L, 95% CI -0.67 to 0.72 µmol/L; 4 studies; 250 participants; low-quality evidence). No trial in comparison 2 provided information about underweight or stunting.There was no reported adverse effect of fortification of foods with zinc on indicators of iron or copper status.

AUTHORS' CONCLUSIONS

Fortification of foods with zinc may improve the serum zinc status of populations if zinc is the only micronutrient used for fortification. If zinc is added to food in combination with other micronutrients, it may make little or no difference to the serum zinc status. Effects of fortification of foods with zinc on other outcomes including zinc deficiency, children's growth, cognition, work capacity of adults, or on haematological indicators are unknown. Given the small number of trials and participants in each trial, further investigation of these outcomes is required.

Bioavailability of iron, vitamin A, zinc, and folic acid when added to condiments and seasonings

Seasonings and condiments can be candidate vehicles for micronutrient fortification if consumed consistently and if dietary practices ensure bioavailability of the nutrient. In this review, we identify factors that may affect the bioavailability of iron, vitamin A, zinc, and folic acid when added to seasonings and condiments and evaluate their effects on micronutrient status. We take into consideration the chemical and physical properties of different forms of the micronutrients, the influence of the physical and chemical properties of foods and meals to which fortified seasonings and condiments are typically added, and interactions between micronutrients and the physiological and nutritional status of the target population. Bioavailable fortificants of iron have been developed for use in dry or fluid vehicles. For example, sodium iron ethylenediaminetetraacetic acid (NaFeEDTA) and ferrous sulfate with citric acid are options for iron fortification of fish and soy sauce. Furthermore, NaFeEDTA, microencapsulated ferrous fumarate, and micronized elemental iron are potential fortificants in curry powder and salt. Dry forms of retinyl acetate or palmitate are bioavailable fortificants of vitamin A in dry candidate vehicles, but there are no published studies of these fortificants in fluid vehicles. Studies of zinc and folic acid bioavailability in seasonings and condiments are also lacking.

Efficacy of highly bioavailable zinc from fortified water: a randomized controlled trial in rural Beninese children

BACKGROUND

Zinc deficiency and contaminated water are major contributors to diarrhea in developing countries. Food fortification with zinc has not shown clear benefits, possibly because of low zinc absorption from inhibitory food matrices. We used a novel point-of-use water ultrafiltration device configured with glass zinc plates to produce zinc-fortified, potable water.

OBJECTIVE

The objective was to determine zinc bioavailability from filtered water and the efficacy of zinc-fortified water in improving zinc status.

DESIGN

In a crossover balanced study, we measured fractional zinc absorption (FAZ) from the zinc-fortified water in 18 healthy Swiss adults using zinc stable isotopes and compared it with zinc-fortified maize porridge. We conducted a 20-wk double-blind randomized controlled trial (RCT) in 277 Beninese school children from rural settings who were randomly assigned to receive a daily portion of zinc-fortified filtered water delivering 2.8 mg Zn (Zn+filter), nonfortified filtered water (Filter), or nonfortified nonfiltered water (Pump) from the local improved supply, acting as the control group. The main outcome was plasma zinc concentration (PZn), and the 3 groups were compared by using mixed-effects models. Secondary outcomes were prevalence of zinc deficiency, diarrhea prevalence, and growth.

RESULTS

Geometric mean (-SD, +SD) FAZ was 7-fold higher from fortified water (65.9%; 42.2, 102.4) than from fortified maize (9.1%; 6.0, 13.7; P < 0.001). In the RCT, a significant time-by-treatment effect on PZn (P = 0.026) and on zinc deficiency (P = 0.032) was found; PZn in the Zn+filter group was significantly higher than in the Filter (P = 0.006) and Pump (P = 0.025) groups. We detected no effect on diarrhea or growth, but our study did not have the duration and power to detect such effects.

CONCLUSIONS

Consumption of filtered water fortified with a low dose of highly bioavailable zinc is an effective intervention in children from rural African settings. Large community-based trials are needed to assess the effectiveness of zinc-fortified filtered water on diarrhea and growth. These trials were registered at clinicaltrials.gov as NCT01636583 and NCT01790321.

The potential for zinc stable isotope techniques and modelling to determine optimal zinc supplementation

It is well recognised that zinc deficiency is a major global public health issue, particularly in young children in low-income countries with diarrhoea and environmental enteropathy. Zinc supplementation is regarded as a powerful tool to correct zinc deficiency as well as to treat a variety of physiologic and pathologic conditions. However, the dose and frequency of its use as well as the choice of zinc salt are not clearly defined regardless of whether it is used to treat a disease or correct a nutritional deficiency. We discuss the application of zinc stable isotope tracer techniques to assess zinc physiology, metabolism and homeostasis and how these can address knowledge gaps in zinc supplementation pharmacokinetics. This may help to resolve optimal dose, frequency, length of administration, timing of delivery to food intake and choice of zinc compound. It appears that long-term preventive supplementation can be administered much less frequently than daily but more research needs to be undertaken to better understand how best to intervene with zinc in children at risk of zinc deficiency. Stable isotope techniques, linked with saturation response and compartmental modelling, also have the potential to assist in the continued search for simple markers of zinc status in health, malnutrition and disease.

Reasons for raising the maximum acceptable daily intake of EDTA and the benefits for iron fortification of foods for children 6-24 months of age

The current maximum acceptable daily intake (ADI) of ethylenediaminetetraacetic acid (EDTA) of 1.9 mg day(-1) per kilogram bodyweight (mg day(-1)  kgbw(-1) ) limits the daily intake of iron as iron EDTA [ferric sodium EDTA; sodium iron(III) EDTA] to approximately 2-2.5 mg day(-1) for children 6-24 months of age. This limit was defined by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1973 based on data from an animal-feed study published in 1963. Other animal studies indicate that this limit can be raised to 4.4 or possibly up to 21.7 mg day(-1)  kgbw(-1) , which is 2.3-11.4 times higher than the current value. For nearly 50 years, iron EDTA has been used in France in medicinal syrup for infants 1-6 months of age. The maximum recommended dosage of this drug is 37 times higher than the maximum ADI of EDTA. No adverse health effects have been reported as a result of this medicinal consumption of iron EDTA. Raising the maximum ADI of EDTA to only 4.4 mg day(-1)  kgbw(-1) would enable iron EDTA, an iron fortificant with proven bioavailability in phytate-rich meals, to be added in adequate amounts to cereal-based meals for children 6-24 months of age, who are at risk of iron deficiency.

Influence of phytase, EDTA, and polyphenols on zinc absorption in adults from porridges fortified with zinc sulfate or zinc oxide

Fortification of cereal staples with zinc is recommended to combat zinc deficiency. To optimize zinc absorption, strategies are needed to overcome the inhibitory effect of phytic acid (PA) and perhaps polyphenols. Five zinc absorption studies were conducted in young adults consuming maize or sorghum porridges fortified with 2 mg zinc as zinc sulfate (ZnSO4) or zinc oxide (ZnO) and containing combinations of PA or polyphenols as potential inhibitors and EDTA and phytase as potential enhancers. Fractional absorption of zinc (FAZ) was measured by using the double isotopic tracer ratio method. Adding phytase to the maize porridge immediately before consumption or using phytase for dephytinization during meal preparation both increased FAZ by >80% (both P < 0.001). Adding Na2EDTA at an EDTA:zinc molar ratio of 1:1 increased FAZ from maize porridge fortified with ZnSO4 by 30% (P = 0.01) but had no influence at higher EDTA ratios or on absorption from ZnO. FAZ was slightly higher from ZnSO4 than from ZnO (P = 0.02). Sorghum polyphenols had no effect on FAZ from dephytinized sorghum porridges but decreased FAZ by 20% from PA-rich sorghum porridges (P < 0.02). The combined inhibitory effect of polyphenols and PA was overcome by EDTA. In conclusion, ZnSO4 was better absorbed than ZnO, phytase used to degrade PA during digestion or during food preparation substantially increased zinc absorption from zinc-fortified cereals, EDTA at a 1:1 molar ratio modestly enhanced zinc absorption from ZnSO4-fortified cereals but not ZnO-fortified cereals, and sorghum polyphenols inhibited zinc absorption in the presence, but not absence, of PA. This trial was registered at clinicaltrials.gov as NCT01210794.

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.

Extruded rice grains fortified with zinc, iron, and vitamin A increase zinc status of Thai school children when incorporated into a school lunch program

Iron (Fe), zinc (Zn), and vitamin A (VA) deficiencies are common among children in developing countries and often occur in the same individual. Rice is widely consumed in the developing countries of Asia and the low phytate in polished rice makes it ideal for Zn and Fe fortification. Triple-fortified rice grains with Zn, Fe, and VA were produced using hot extrusion technology. The main objective of the present study was to determine the impact of triple-fortified extruded rice on Zn status in school children in Southern Thailand. Although serum zinc was the main outcome indicator, Fe and VA status were also assessed. School children with low serum zinc (n = 203) were randomized to receive either triple-fortified rice (n = 101) or natural control rice (n = 102) as a component of school lunch meals for 5 mo. Serum Zn, hemoglobin, serum ferritin, serum retinol, and C-reactive protein were measured at baseline and at the end of the study. After the intervention, serum Zn increased (P < 0.05) in both the fortification (11.3 ± 1.3 μmol/L) and control (10.6 ± 1.4 μmol/L) groups, most likely due to the proper implementation of the school lunch and school milk programs, with the increase greater in the group receiving the triple-fortified rice (P < 0.05). Because the children were not Fe or VA deficient at baseline, there was no change in Fe or VA status. We conclude that Zn fortification of extruded rice grains is efficacious and can be used to improve Zn status in school children.

EDTA disodium zinc has superior bioavailability compared to common inorganic or chelated zinc compounds in rats fed a high phytic acid diet

Different zinc (Zn) compounds have unique properties that may influence the amount of Zn absorbed particularly in the presence of phytic acid (PA), a common food component that binds Zn and decreases its bioavailability. In this study, 30-day-old male rats (n=12/diet group) were fed diets supplemented with PA (0.8%) and low levels (8mg Zn/kg diet) of inorganic (Zn oxide, Zn sulphate) or chelated (Zn gluconate, Zn acetate, Zn citrate, EDTA disodium Zn, Zn orotate) Zn compounds for 5 weeks. Two control groups were fed diets supplemented with low or normal (30mg Zn/kg diet) Zn (as Zn oxide) without added PA. Control rats fed the low Zn oxide diet showed depressed Zn status. Addition of PA to this diet exacerbated the Zn deficiency in rats. Growth (body weight gain and femur length) and Zn concentrations in plasma and tissues were similar in rats fed Zn oxide, Zn sulphate, Zn gluconate, Zn acetate, Zn citrate or Zn orotate. Rats fed EDTA disodium Zn showed enhanced growth compared to rats fed Zn oxide or Zn gluconate and had higher Zn concentrations in plasma and femur compared to rats fed all other Zn compounds. Only the haematological profile of rats fed EDTA disodium Zn did not differ from control rats fed normal Zn. These data indicate that in rats fed a high PA diet, bioavailability of commonly used inorganic or chelated Zn compounds does not differ appreciably, but Zn supplied as an EDTA disodium salt has superior bioavailability.

Nanocompounds of iron and zinc: their potential in nutrition

Recent studies suggest nanostructured oxides and phosphates of Fe and atomically mixed Fe/Zn may be useful for nutritional applications. These compounds may have several advantages over existing fortificants, such as ferrous sulfate (FeSO(4)), NaFeEDTA and electrolytic iron. Because of their very low solubility and formation of soft agglomerates of micron size at neutral pH as well as their light native color, they tend to be less reactive in difficult-to-fortify foods and thus have superior sensory performance. At gastric pH the soft agglomerates break up and the Fe compounds rapidly and completely dissolve due to their very high surface area. This results in in vitro solubility and in vivo bioavailability comparable to FeSO(4). Doping with Mg and/or Ca may increase solubility and improve sensory characteristics by lightening color. Feeding the nanostructured compounds at 150-400 µg Fe day(-1) for 15 days to weanling rats in two studies did not induce measurable histological or biochemical adverse effects. No significant Fe was detected in the submucosa of the gastrointestinal tract or lymphatic tissues, suggesting that the nanosized Fe is absorbed through usual non-heme Fe absorption pathways. Thus, these novel compounds show promise as food fortificants or supplements.

A micronutrient powder with low doses of highly absorbable iron and zinc reduces iron and zinc deficiency and improves weight-for-age Z-scores in South African children

Micronutrient powders (MNP) are often added to complementary foods high in inhibitors of iron and zinc absorption. Most MNP therefore include high amounts of iron and zinc, but it is no longer recommended in malarial areas to use untargeted MNP that contain the Reference Nutrient Intake for iron in a single serving. The aim was to test the efficacy of a low-iron and -zinc (each 2.5 mg) MNP containing iron as NaFeEDTA, ascorbic acid (AA), and an exogenous phytase active at gut pH. In a double-blind controlled trial, South African school children with low iron status (n = 200) were randomized to receive either the MNP or the unfortified carrier added just before consumption to a high-phytate maize porridge 5 d/wk for 23 wk; primary outcomes were iron and zinc status and a secondary outcome was somatic growth. Compared with the control, the MNP increased serum ferritin (P < 0.05), body iron stores (P < 0.01) and weight-for-age Z-scores (P < 0.05) and decreased transferrin receptor (P < 0.05). The prevalence of iron deficiency fell by 30.6% (P < 0.01) and the prevalence of zinc deficiency decreased by 11.8% (P < 0.05). Absorption of iron from the MNP was estimated to be 7-8%. Inclusion of an exogenous phytase combined with NaFeEDTA and AA may allow a substantial reduction in the iron dose from existing MNP while still delivering adequate iron and zinc. In addition, the MNP is likely to enhance absorption of the high native iron content of complementary foods based on cereals and/or legumes.

Zinc fortification of cereal flours: current recommendations and research needs

BACKGROUND

Zinc fortification is recommended as an appropriate strategy to enhance population zinc status, but guidelines are needed on the appropriate types and levels of zinc fortification of cereal flours for mass fortification programs.

OBJECTIVE

To review available information on the scientific rationale, efficacy, and effectiveness of zinc fortification programs, and to develop guidelines on appropriate levels of fortification of cereal flours, based on simulations of the amount of zinc absorbed under different dietary conditions and information on possible adverse effects.

METHODS

Systematic review of scientific literature and application of an existing prediction equation to estimate zinc absorption.

RESULTS

Previously completed research demonstrates that zinc intake and absorption are increased when zinc-fortified foods are consumed, but little information is, as yet, available on the biologic impact of large-scale fortification programs. Studies suggest that there are no disadvantages of the recommended ranges of zinc fortification with regard to the sensory properties of zinc-fortified foods, and most research indicates that there are no adverse effects of zinc fortification on the utilization of other minerals.

CONCLUSIONS

Zinc fortification of cereal flour is a safe and appropriate strategy for enhancing the zinc status of population subgroups who consume adequate amounts of fortified cereal flour, although additional information is needed to confirm the efficacy and effectiveness of large-scale zinc fortification programs to control zinc deficiency. The appropriate level of fortification depends on the population subgroup, their usual amount of flour intake, the degree of milling and fermentation that is practiced, and the usual intakes of zinc and phytate from other food sources. Fortification recommendations are presented for different dietary scenarios.

Development and optimization of iron- and zinc-containing nanostructured powders for nutritional applications

Reducing the size of low-solubility iron (Fe)-containing compounds to nanoscale has the potential to improve their bioavailability. Because Fe and zinc (Zn) deficiencies often coexist in populations, combined Fe/Zn-containing nanostructured compounds may be useful for nutritional applications. Such compounds are developed here and their solubility in dilute acid, a reliable indicator of iron bioavailability in humans, and sensory qualities in sensitive food matrices are investigated. Phosphates and oxides of Fe and atomically mixed Fe/Zn-containing (primarily ZnFe2O4) nanostructured powders were produced by flame spray pyrolysis (FSP). Chemical composition and surface area were systematically controlled by varying precursor concentration and feed rate during powder synthesis to increase solubility to the level of ferrous sulfate at maximum Fe and Zn content. Solubility of the nanostructured compounds was dependent on their particle size and crystallinity. The new nanostructured powders produced minimal color changes when added to dairy products containing chocolate or fruit compared to the changes produced when ferrous sulfate or ferrous fumarate were added to these foods. Flame-made Fe- and Fe/Zn-containing nanostructured powders have solubilities comparable to ferrous and Zn sulfate but may produce fewer color changes when added to difficult-to-fortify foods. Thus, these powders are promising for food fortification and other nutritional applications.

Changing the zinc:iron ratio in a cereal-based nutritional supplement has no effect on percent absorption of iron and zinc in Sri Lankan children

The Thriposha programme is a community-level nutrition intervention in Sri Lanka that provides a combination of energy, protein and micronutrients as a ‘ready-to-eat’ cereal-based food. We measured the bioavailability of Fe and Zn from Thriposha formula at two different molar ratios of Zn:Fe in order to determine the effect on Fe and Zn absorption. Children 4–7 years (n 53) were given a meal prepared with 50 g Thriposha containing 1·5 mg Zn as zinc sulphate and either 9 mg (high Fe concentration (HiFe)) or 4·5 mg (low Fe concentration (LoFe)) Fe as ferrous fumarate. Zn and Fe percent absorption were measured using stable isotopes by tracer:tracee ratio and by incorporation of erythrocytes, respectively. Percent Fe absorption from the two meals was similar (6·6 % (4·8) v. 4·8 % (2·6); P = 0·15), but total Fe absorption was significantly higher from the HiFe meal (0·59 (0·43) mg) than the LoFe meal (0·20 (0·12) mg; P = 0·01). There was no significant difference between the two groups in Zn absorption (10·7 % (0·9) v. 8·8 % (1·4), P = 0·13, respectively). Decreasing the amount of Fe in Thriposha did not cause a significant change in the percent absorption of Fe and Zn, but significantly lowered the total amount of absorbed Fe. These results demonstrate the utility of maintaining a higher Fe content in this supplement. Further studies to increase Zn content are warranted while maintaining a HiFe.

Impact of Zinc Fortification on Zinc Nutrition

Food fortification is increasingly recognized as an effective approach to improve a population's micronutrient status. The present report provides a critical review of the scientific evidence currently available on the impact of zinc fortification on zinc nutrition.

The available studies clearly show that zinc fortification can increase dietary zinc intake and total daily zinc absorption. Most absorption studies also indicate that adding zinc to food does not adversely affect the absorption of other minerals, such as iron. Despite the positive effect of zinc fortification on total zinc absorption, only a few studies have found positive impacts of zinc fortification on serum zinc concentrations or functional indicators of zinc status. The reasons for these inconsistent results are uncertain but may relate to the choice of food vehicles, the age group and zinc status of the study populations, or particular aspects of the study design. Thus, additional research is needed to determine the impact of zinc fortification, with or without other micronutrients, in populations at risk for zinc deficiency.

Because of the benefits of increasing intake in populations at high risk for zinc deficiency, the documented increase in total zinc absorption that occurs following zinc fortification, the absence of any adverse effects, and the relatively low cost of adding zinc, public health planners should consider including zinc in mass and targeted fortification programs in such populations. Because of the limited available information on program impact, it will be important to evaluate the outcomes of such programs.

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.

Community-level micronutrient fortification of a food supplement in India: a controlled trial in preschool children aged 36-66 mo

BACKGROUND

Children participating in the Integrated Child Development Service (ICDS) in India have high rates of iron and vitamin A deficiency.

OBJECTIVE

The objective was to assess the efficacy of a premix fortified with iron and vitamin A and added at the community level to prepared khichdi, a rice and dal mixture, in increasing iron and vitamin A stores and decreasing the prevalence of iron deficiency, anemia, and vitamin A deficiency.

DESIGN

This cluster, randomized, double-blind, controlled trial was initiated in 30 Anganwadi centers (daycare centers) in West Bengal state, India. Children aged 36-66 mo (n = 516) attending village-based ICDS centers were randomly assigned to receive either a fortified or a nonfortified premix for 24 wk. Blood was drawn at 0 and 24 wk by venipuncture for the measurement of hemoglobin, serum ferritin, and serum retinol.

RESULTS

The change in the hemoglobin concentration of anemic children was significantly different between fortified and nonfortified khichdi groups (P < 0.001). Prevalence rates of anemia, iron deficiency, and iron deficiency anemia were significantly lower after 24 wk in the fortified-khichdi group than in the nonfortified-khichdi group (P < 0.001). There were no significant differences in serum retinol concentrations or in the prevalence of vitamin A deficiency between the fortified- and nonfortified-khichdi groups.

CONCLUSION

A premix fortified with iron, vitamin A, and folic acid and added to supplementary food at the community level can be effective at increasing iron stores and reducing the prevalence of iron deficiency and anemia.

Comparison of the effects of zinc delivered in a fortified food or a liquid supplement on the growth, morbidity, and plasma zinc concentrations of young Peruvian children

BACKGROUND

Zinc supplementation decreases morbidity from infections and increases growth of stunted children, but there is little information on functional responses to zinc delivered in fortified foods.

OBJECTIVE

The aim was to examine the effects of zinc fortification on the growth, morbidity from infections, and plasma zinc concentrations of young children.

DESIGN

We compared the physical growth, morbidity, and micronutrient status of 6-8-mo-old Peruvian children with initial length-for-age z score (LAZ) < -0.50 who were randomly assigned to receive one of the following treatments daily for 6 mo: 1) 30 g dry weight of an iron-fortified cereal porridge and a separate dose of an aqueous multivitamin (MV) supplement between meals (control group), 2) the same porridge and MV with 3 mg Zn added to the supplement dose (ZnSuppl group), or 3) the porridge with added zinc (150 mg/kg dry weight) and MV without zinc (ZnFort group).

RESULTS

The children consumed a mean of 22-26 g dry porridge/d and 96% of the possible MV doses. After adjustment for small baseline differences in socioeconomic status and morbidity, no significant differences in weight or length increments were observed between the groups, even among the subset with an initial LAZ < -1.5, and no significant differences in the rates of common illnesses were observed. Mean plasma zinc concentrations decreased in the control group (-3.9 microg/dL), increased in the ZnSuppl group (4.3 microg/dL), and did not change significantly in the ZnFort group (-1.5 microg/dL; P < 0.001 for group-wise comparison).

CONCLUSIONS

Provision of additional zinc, either in an aqueous supplement or a fortified porridge, did not significantly affect the children's physical growth or morbidity from infections, possibly because they were not sufficiently growth-restricted or zinc-deficient initially or because the level of zinc intake or absorption was inadequate. Additional studies of the functional effect of zinc-fortified foods are needed in populations that are known to respond to zinc supplements.

Demonstrating zinc and iron bioavailability from intrinsically labeled microencapsulated ferrous fumarate and zinc gluconate Sprinkles in young children

Nutrient-nutrient interactions are an important consideration for any multiple-micronutrient formulation, including Sprinkles, a home-fortification strategy to control anemia. The objectives of this randomized controlled trial were as follows: 1) to compare the absorption of zinc at 2 doses given as Sprinkles; and 2) to examine the effect of zinc and ascorbic acid (AA) on iron absorption from Sprinkles. Seventy-five children aged 12-24 mo were randomly assigned to the following groups: 1) 5 mg of labeled zinc (67Zn) with 50 mg AA (LoZn group); b) 10 mg of labeled zinc (67Zn) with 50 mg AA (HiZn group); or 3) 5 mg zinc with no AA (control). All groups contained 30 mg of labeled iron (57Fe). Intravenous infusions labeled with 70Zn (LoZn and HiZn groups) and 58Fe (control) were administered. Blood was drawn at baseline, 48 h and 14 d later. The percentage of zinc absorbed did not differ between LoZn (geometric mean = 6.4%; min-max: 1.7-14.6) and HiZn (geometric mean = 7.5%; min-max: 3.3-18.0) groups. However, total zinc absorbed was significantly different between the LoZn (geometric mean = 0.31 mg; min-max: 0.08-0.73) and HiZn (geometric mean = 0.82 mg; min-max: 0.33-1.82) groups (P = 0.0004). Geometric mean percentage iron absorption values did not differ between the LoZn (5.9%; min-max: 0.8-21) and HiZn (4.4%; min-max: 0.6-12.3) groups and between the LoZn and control groups (5.0%; min-max: 1.4-24). We conclude that zinc in the form of Sprinkles has a low bioavailability, yet provides adequate amounts of absorbed zinc in young children, and that there is no effect of zinc or AA on iron absorption from the given formulations of Sprinkles.

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.