Nonheme-iron absorption from a phytate-rich meal is increased by the addition of small amounts of pork meat

Nutrition in chronic inflammatory conditions: Bypassing the mucosal block for micronutrients

Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.

Factors affecting iron absorption and the role of fortification in enhancing iron levels

Iron is an important micronutrient required for a number of biological processes including oxygen transport, cellular respiration, the synthesis of nucleic acids and the activity of key enzymes. The World Health Organization has recognised iron deficiency as the most common nutritional deficiency globally and as a major determinant of anaemia. Iron deficiency anaemia affects 40% of all children between the ages of 6 and 59 months, 37% of mothers who are pregnant and 30% of women between the ages of 15 and 49 years worldwide. Dietary iron exists in two main forms known as haem iron and non-haem iron. Haem iron is obtained from animal sources such as meat and shows higher bioavailability than non-haem iron, which can be obtained from both plant and animal sources. Different components in food can enhance or inhibit iron absorption from the diet. Components such as meat proteins and organic acids increase iron absorption, while phytate, calcium and polyphenols reduce iron absorption. Iron levels in the body are tightly regulated since both iron overload and iron deficiency can exert harmful effects on human health. Iron is stored mainly as haemoglobin and as iron bound to proteins such as ferritin and hemosiderin. Iron deficiency affects individuals at increased risk due to factors such as age, pregnancy, menstruation and various diseases. Different solutions for iron deficiency are applied at individual and community levels. Iron supplements and intravenous iron can be used to treat individuals with iron deficiency, while various types of iron-fortified foods and biofortified crops can be employed for larger communities. Foods such as rice, flour and biscuits have been used to prepare fortified iron products. However, it is important to ensure the fortification process does not exert significant negative effects on organoleptic properties and the shelf life of the food product.

Recent advances in iron encapsulation and its application in food fortification

Iron (Fe) is an important element for our body since it takes part in a huge variety of metabolic processes. However, the direct incorporation of Fe into food fortification causes a number of problems along with undesirable organoleptic properties. Thus, encapsulation has been suggested to alleviate this problem. This study first sheds more light on the Fe encapsulation strategies and comprehensively explains the results of Fe encapsulation studies in the last decade. Then, the latest attempts to use Fe (in free or encapsulated forms) to fortify foods such as bakery products, dairy products, rice, lipid-containing foods, salt, fruit/vegetable-based products, and infant formula are presented. Double emulsions are highly effective at keeping their Fe content and display encapsulation efficiency (EE) > 88% although it decreases upon storage. The encapsulation by gel beads possesses several advantages including high EE, as well as reduced and great Fe release in gastric and duodenal conditions, respectively. Cereals, particularly bread and wheat, are common staple foods globally; they are very suitable for food fortification by Fe derivatives. Nevertheless, the majority of Fe in flour is available as salts of phytic acid (IP6) and phytates, reducing Fe bioavailability in the human body. The sourdough process degrades IP6 completely while Chorleywood Bread Making Process and conventional processes decrease it by 75% in comparison with whole meal flour.

The role of oral iron in the treatment of adults with iron deficiency

Iron deficiency is the most common nutrient deficiency in the world, affecting over 20% of premenopausal women worldwide. Oral iron supplementation is often the first-line treatment for the acute and chronic management of iron deficiency due to its ease and accessibility. However, there is no consensus on the optimal formulation or dosing strategy, or which patients should be preferentially treated with intravenous iron. Management of iron deficiency is complicated by the hepcidin-ferroportin iron regulatory pathway, which has evolved to prevent iron overload and thereby creates an inherent limit on gastrointestinal iron uptake and efficacy of oral iron. Unabsorbed iron propagates many of the side effects that complicate oral iron use including dyspepsia and constipation, all of which can thus be exacerbated by excessive oral iron doses. Daily low dose and every other day dosing protocols have attempted to bypass this physiologic bottleneck to allow for effective absorption and limit side effects; however, this approach has still resulted in low fractional iron absorption. In the following manuscript, we review the pathophysiology of iron absorption and current evidence for various preparations of oral iron. Lastly, we highlight opportunities for further study to advance the care of individuals affected by iron deficiency.

The effect of dechitinization on iron absorption from mealworm larvae (Tenebrio molitor) flour added to maize meals: stable-isotope studies in young females with low iron stores

BACKGROUND

Edible insects have a low ecological footprint and could serve as an alternative dietary iron source. However, chitin, a major component of insects, avidly binds iron and might inhibit iron absorption.

OBJECTIVES

We aimed to measure fractional iron absorption (FIA) from Tenebrio molitor-based test meals with and without dechitinization, and to assess the effect of native and low chitin T. molitor on FIA from iron-fortified maize porridge.

METHODS

We measured iron absorption in young females with low iron stores (n = 21) from 1) labeled (54FeSO4) fortified maize porridge (maize alone); 2) intrinsically labeled (57Fe added during rearing) T. molitor larvae with native chitin content (NC) added to maize alone; and 3) dechitinized intrinsically labeled (57Fe) T. molitor larvae with low chitin content (LC) added to maize alone. We determined FIA using erythrocyte isotope incorporation and measured in vitro iron dialyzability from the 3 meals.

RESULTS

NC and LC T. molitor had similar mean ± SD iron content (12.0 ± 0.1 mg/100 g). Geometric mean (95% CI) FIAs from the 3 test meals were 1) maize alone: 5.8% (3.2%, 10.8%); 2) maize + NC T. molitor: 5.3% (2.5%, 11.3%) and 4.1% (1.9%, 8.7%); and 3) maize + LC T. molitor: 4.6% (2.0%, 10.3%) and 4.0% (1.8%, 9.2%), for extrinsic and intrinsic labels, respectively. FIA from NC and LC T. molitor did not significantly differ, and both were lower (P < 0.005) than FIA from the labeled maize porridge in the 3 meals, which did not significantly differ. The slopes of the relations between FIA and serum ferritin in the different meals and from the intrinsic and extrinsic labels did not significantly differ.

CONCLUSIONS

T. molitor biomass does not strongly affect iron absorption when added to maize porridge. Our data suggest T. molitor iron is absorbed from the common nonheme iron pool. Native T. molitor is high in iron which is moderately well absorbed, suggesting it could be a valuable dietary iron source.This trial was registered at clinicaltrials.gov as NCT04510831.

Benefits and Risks Associated with Meat Consumption during Key Life Processes and in Relation to the Risk of Chronic Diseases

Red meat has been an important part of the diet throughout human evolution. Overall, when included as part of a healthy and varied diet, red meat can provide a rich source of bioavailable essential nutrients and high biological value protein. The present paper discusses the dietary role/impact of red and processed meat, with some reference to the relative effect of white meat, in a range of chronic conditions including iron-deficiency anaemia, cardiovascular diseases (CVD), cancer and dementia. The role of red meat in relation to key physiological conditions such as maintaining skeletal muscle and bone health and during pregnancy is also discussed. The inclusion of lean red meat in a healthy, varied diet may be beneficial during these critical conditions. There is however increasing evidence that red meat and especially processed meat are associated with increased risks of CVD, cancer and dementia whereas white meat is neutral or associated with a lower risk. There now seems little doubt that processed and unprocessed meat should have separate public dietary guidance.

Iron Absorption: Factors, Limitations, and Improvement Methods

Iron is an essential element for human life since it participates in many functions in the human body, including oxygen transport, immunity, cell division and differentiation, and energy metabolism. Iron homeostasis is mainly controlled by intestinal absorption because iron does not have active excretory mechanisms for humans. Thus, efficient intestinal iron bioavailability is essential to reduce the risk of iron deficiency anemia. There are two forms of iron, heme and nonheme, found in foods. The average daily dietary iron intake is 10 to 15 mg in humans since only 1 to 2 mg is absorbed through the intestinal system. Nutrient-nutrient interactions may play a role in dietary intestinal iron absorption. Dietary inhibitors such as calcium, phytates, polyphenols and enhancers such as ascorbic acid and proteins mainly influence iron bioavailability. Numerous studies have been carried out for years to enhance iron bioavailability and combat iron deficiency. In addition to traditional methods, innovative techniques are being developed day by day to enhance iron bioavailability. This review will provide information about iron bioavailability, factors affecting absorption, iron deficiency, and recent studies on improving iron bioavailability.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

Plant-Based Dietary Practices and Socioeconomic Factors That Influence Anemia in India

While rates of malnutrition have declined over the last decade in India due to successful government interventions, the prevalence of anemia remains high. Staple foods provide almost 70% of the daily iron intake. As staple foods are a rich source of phytate, this ingested iron is poorly absorbed. Currently, 59% of children below 3 years of age, 50% of expectant mothers and 53% of women aged 15-19 years are anemic. The most common intervention strategy has been through the use of iron supplements. While the compliance has been low and supplies irregular, such high rates of anemia cannot be explained by iron deficiency alone. This review attempts to fit dietary and cooking practices, field-level diagnostics, cultural beliefs and constraints in implementation of management strategies into a larger picture scenario to offer insights as to why anemia continues to plague India. Since the rural Indian diet is predominantly vegetarian, we also review dietary factors that influence non-heme iron absorption. As a reference point, we also contrast anemia-related trends in India to the U.S.A. Thus, this review is an effort to convey a holistic evaluation while providing approaches to address this public health crisis.

Nutritional Qualities and Enhancement of Edible Insects

Over the last decade, the urgency to find alternative and sustainable protein sources has prompted an exponential increase in the interest in insects as a human food source. Edible insects contribute suitable amounts of energy and protein, fatty acids, and micronutrients to the human diet. Nutritional values of insects can be manipulated to meet specific needs. Edible insects in food-insecure countries can contribute to improving diets and preventing undernutrition. Bioactive compounds in insects may reduce health risks. Food safety risks are low and mainly relate to those of allergenicity. Strategies to overcome barriers to the consumption of insect products include emphasizing their sustainability, increasing their tastiness, and developing the ability to disguise insects in familiar products. A new sector of insects as food and feed is emerging. Major challenges include legislation, lowering prices by automation and cheap substrates, developing insect products that appeal to consumers, and exploring the health benefits. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Iron-Enriched Nutritional Supplements for the 2030 Pharmacy Shelves

Iron deficiency (ID) affects people of all ages in many countries. Due to intestinal blood loss and reduced iron absorption, ID is a threat to IBD patients, women, and children the most. Current therapies can efficiently recover normal serum transferrin saturation and hemoglobin concentration but may cause several side effects, including intestinal inflammation. ID patients may benefit from innovative nutritional supplements that may satisfy iron needs without side effects. There is a growing interest in new iron-rich superfoods, like algae and mushrooms, which combine antioxidant and anti-inflammatory properties with iron richness.

The Association with Dietary Patterns and Risk of Anemia in Japanese Elderly

Anemia is a risk factor for frailty. Although various factors can reduce the risk of anemia, information on dietary contributions is limited. This study aimed to evaluate the association between anemia and eating patterns in Japanese elderly. Our study included 6,864 elderly individuals, aged ≥65 y, whose data were obtained from the 2010-2015 National Health and Nutritional Survey, Japan. Anemia was defined as whole blood hemoglobin concentrations <13 g/dL in men, and <12 g/dL in women. We classified eating patterns into 33 food groups, using food items obtained from dietary records, and identified three dietary patterns using principal component analysis method. Participants were assigned and divided into quartiles according to pattern-specific factor scores. We calculated adjusted odds ratios (ORs) for anemia using multivariate logistic regression, and assigned the first quartile (minimum) as the reference. The overall prevalence of anemia was 17.1%. The meats and vegetables eating pattern was characterized by red meat and other vegetables, the Japanese eating pattern by rice and salted or pickled vegetables, and the fruits and vegetables eating pattern by fruits and green-yellow vegetables. Participants in the highest meats and vegetables eating pattern quartile had a 20% lower risk of anemia than those in the lowest quartile (OR 0.81; 95% confidence interval (CI) 0.66-1.00); the Japanese eating pattern participants had a 20% higher risk of anemia (OR 1.28; 95% CI 1.06-1.53). The fruits and vegetables eating pattern participants had no significant change in their risk of anemia. This study may indicate that consuming a high red meat diet prevents anemia in elderly Japanese individuals.

A Perspective on the Transition to Plant-Based Diets: a Diet Change May Attenuate Climate Change, but Can It Also Attenuate Obesity and Chronic Disease Risk?

Current dietary guidelines advocate more plant-based, sustainable diets on the basis of scientific evidence about diet-health relations but also to address environmental concerns. Here, we critically review the effects of plant-based diets on the prevalence of obesity and other health outcomes. Plant-based diets per se have limited efficacy for the prevention and treatment of obesity, but most have beneficial effects in terms of chronic disease risk. However, with the considerable possibilities of translating plant-based diets into various types of dietary patterns, our analysis suggests that potential adverse health effects should also be considered in relation to vulnerable groups of the population. A transition to more plant-based diets may exert beneficial effects on the environment, but is unlikely to affect obesity, and may also have adverse health effects if this change is made without careful consideration of the nutritional needs of the individual relative to the adequacy of the dietary intake.

Spray-Dried Whey Protein Concentrate-Iron Complex: Preparation and Physicochemical Characterization

Poor absorption of iron from food and oral iron formulations results in extensive use of high-dose oral iron, which is not tolerated. Disposal of whey, a byproduct of the cheese industry, causes environmental pollution. Whey proteins have the ability to bind significant amount of iron, thereby reducing its chemical reactivity and incompatibility with other components in foods. To make iron compatible with food, it was complexed with whey protein concentrate (WPC). After complexation, centrifugation and ultrafiltration techniques were utilised to eliminate the insoluble and free iron from the solution. To enable the availability of whey protein concentrate–iron (WPC–Fe) complex in the powder form, spray drying technique was used. Optimized spray drying conditions used for the preparation were: inlet temperature 180 °C, flow rate 2.66 mL/min and solution of total solids 15%. The complex was observed to be stable under different processing conditions. The in vitro bioaccessibility (iron uptake) of the bound iron from the WPC–Fe complex was significantly higher (p<0.05) than that from iron(II) sulphate under simulated gastrointestinal conditions. WPC–Fe complex with improved iron bioaccessibility could safely substitute iron fortificants in different functional food preparations.

Enzymatic treatment of pork protein for the enhancement of iron bioavailability

The typical intervention for iron-deficiency anaemia is through oral supplementation with iron salts, which have unpleasant side effects. Therefore, there is a need for the development of supplements which will be absorbed more effectively and may have fewer side effects. This study investigated the effects of partially hydrolysed pork proteins on the bioavailability of non-haem iron. The peptides were derived using either pepsin or a combination of bacterial and fungal proteases, and their ability to deliver iron was evaluated in a rat intestine epithelial tissue model. The greatest iron absorption was achieved with peptides hydrolysed by pepsin of low molecular weight (<6-8 kDa). The peptides hydrolysed with bacterial and fungal enzymes may have bound to the iron too strongly, affecting bioavailability. Finally, hydrolysing proteins using pepsin in the presence of iron produces a complex that resulted in more ferritin expression than mixing the peptides with iron after hydrolysis.

An Animal-Source Food Supplement Increases Micronutrient Intakes and Iron Status among Reproductive-Age Women in Rural Vietnam

Background: Few studies have examined the impact of local animal-source foods (ASFs) on the nutritional status of reproductive-age women in developing countries.Objective: We hypothesized that a midmorning snack of local ASF for 6 mo would reduce dietary micronutrient deficiencies [usual intake less than the estimated average requirement (EAR)] and improve blood biomarkers of iron, zinc, and vitamins A and B-12 status among nonpregnant, reproductive-age women in rural Vietnam.Methods: One hundred seventeen women, 18-30 y old, were randomly assigned to receive either an ASF (mean: 144 kcal, 8.9 mg Fe, 2.7 mg Zn, 1050 μg retinoic acid equivalent vitamin A, and 5.5 μg vitamin B-12) or a control snack (mean: 150 kcal, 2.0 mg Fe, 0.9 mg Zn, 0 μg retinoic acid equivalent vitamin A, and 0 μg vitamin B-12) 5 d/wk for 6 mo. Usual nutrient intakes were estimated by repeated 24-h dietary recalls. Blood samples were collected at baseline and 3 and 6 mo. Because of the relation between nutritional status and inflammation, serum C-reactive protein, α-1-acid-glycoprotein, and urinary tract infections (UTIs) were also monitored.Results: Eighty-nine women (47 in the ASF group and 42 controls) completed the study. In the ASF group, intakes of iron and vitamins A and B-12 below the EAR were eliminated, and the prevalence of a low zinc intake was reduced to 9.6% compared with 64.7% in controls (P < 0.001). At 6 mo, a modest increase (P < 0.05) in hemoglobin and iron status occurred in the ASF group compared with the control group, but plasma zinc, retinol, and serum vitamin B-12 concentrations did not differ. UTI relative risk was 3.9 (P < 0.05) among women assigned to the ASF group who had a low whole-body iron status at baseline.Conclusions: Adding a small amount of locally produced ASF to the diets of reproductive-age Vietnamese women improved micronutrient intakes and iron status. However, the increased UTI incidence in women in the ASF group with initially lower iron stores warrants further investigation.

Impact of small-quantity lipid-based nutrient supplement on hemoglobin, iron status and biomarkers of inflammation in pregnant Ghanaian women

We examined hemoglobin (Hb, g/L), iron status (zinc protoporphyrin, ZPP, µmol/mol heme, and transferrin receptor, TfR, mg/L) and inflammation (C-reactive protein, CRP and alpha-1 glycoprotein, AGP) in pregnant Ghanaian women who participated in a randomized controlled trial. Women (n = 1320) received either 60 mg Fe + 400-µg folic acid (IFA); 18 micronutrients including 20-mg Fe (MMN) or small-quantity lipid-based nutrient supplements (SQ-LNS, 118 kcal/d) with the same micronutrient levels as in MMN, plus four additional minerals (LNS) daily during pregnancy. Intention-to-treat analysis included 349, 354 and 354 women in the IFA, MMN and LNS groups, respectively, with overall baseline mean Hb and anemia (Hb <100) prevalence of 112 and 13.3%, respectively. At 36 gestational weeks, overall Hb was 117, and anemia prevalence was 5.3%. Compared with the IFA group, the LNS and MMN groups had lower mean Hb (120 ± 11 vs. 115 ± 12 and 117 ± 12, respectively; P < 0.001), higher mean ZPP (42 ± 30 vs. 50 ± 29 and 49 ± 30; P = 0.010) and TfR (4.0 ± 1.3 vs. 4.9 ± 1.8 and 4.6 ± 1.7; P < 0.001), and greater prevalence of anemia (2.2% vs. 7.9% and 5.8%; P = 0.019), elevated ZPP (>60) [9.4% vs. 18.6% and 19.2%; P = 0.003] and elevated TfR (>6.0) [9.0% vs. 19.2% and 15.1%; P = 0.004]. CRP and AGP concentrations did not differ among groups. We conclude that among pregnant women in a semi-urban setting in Ghana, supplementation with SQ-LNS or MMN containing 20 mg iron resulted in lower Hb and iron status but had no impact on inflammation, when compared with iron (60 mg) plus folic acid (400 µg). The amount of iron in such supplements that is most effective for improving both maternal Hb/iron status and birth outcomes requires further evaluation. This trial was registered at ClinicalTrials.gov as: NCT00970866.

Animal Proteins as Important Contributors to a Healthy Human Diet

Adequate protein intake is critical for health and development. Generally, protein of animal origin is of higher quality for humans owing to its amino acid pattern and good digestibility. When administered in mixtures it can enhance the quality of plant proteins, but its availability is often low in low-income communities, especially in young children, the elderly, and pregnant and lactating women, who have increased requirements and in whom high-quality protein also stimulates (bone) growth and maintenance. Although high protein intake was associated with increased type 2 diabetes mellitus risk, milk and seafood are good sources of branched chain amino acids and taurine, which act beneficially on glucose metabolism and blood pressure. However, high consumption of protein-rich animal food is also associated with adverse health effects and higher risk for noncommunicable diseases, partly related to other components of these foods, like saturated fatty acids and potential carcinogens in processed meat but also the atherogenic methionine metabolite homocysteine. In moderation, however, animal proteins are especially important for health maintenance in vulnerable persons.

Mineral nutrient interaction: Improving bioavailability of calcium and iron

Insufficient uptake of essential metals leads to serious malnutrition, which is a worldwide problem. Low bioavailability of iron and calcium may lead to anemia and osteoporosis, respectively, even in individuals with a high dietary intake. For iron, fractionation of meat proteins was studied in order to increase iron bioavailability from other meal components, and uptake of iron was found to increase with minimal risk of increasing oxidative damage. Calcium binding to peptides was found to prevent formation of insoluble calcium salts otherwise hampering absorption particularly in combination with calcium hydroxycarboxylates, entailing spontaneous supersaturation. Based on a review of results from different strategies available for increasing bioavailability, safe iron fortification is suggested to be supported by calcium, with modulation of iron as a prooxidant.

Iron Bioavailability from Pate Enriched with Encapsulated Ferric Pyrophosphate or Ferrous Gluconate in Rats

Fortifying food with iron has been widely studied as a strategy to prevent iron deficiency anaemia. This work comparatively assessed the bioavailability of two forms of iron, ferrous gluconate or ferric pyrophosphate encapsulated in liposomes (lipofer®), when used as fortificants in meat pate. Three groups of growing rats consumed during 28 days either a control diet (AIN-93G), or two diets prepared with enriched pate as the unique source of iron and fat. Body weight and diet intake were measured weekly, and during the last week faeces were collected. On day 28 animals were sacrificed, livers and spleens were removed and stored. Haemoglobin and total iron binding capacity (TIBC) were determined. There were not significant differences among the three groups in body weight and apparent iron absorption, although food intake in the two pate groups was significantly higher compared to the control group. There were not differences in liver and spleen iron content and concentration, neither in haemoglobin and TIBC values. These results indicated that iron bioavailability of pate enriched with ferrous gluconate or ferric pyrophosphate encapsulated in liposomes was similar, and thus both sources of iron are good candidates to be used as fortifiers in meat based products. The present outcome needs to be validated in humans.

Ethiopian pre-school children consuming a predominantly unrefined plant-based diet have low prevalence of iron-deficiency anaemia

Objective

Children from low-income countries consuming predominantly plant-based diets but little animal products are considered to be at risk of Fe deficiency. The present study determined the Fe status of children from resource-limited rural households.

Design

A cross-sectional study.

Setting

Twenty six kebeles (the smallest administrative unit) from six zones of the Amhara region, Ethiopia.

Subjects

Children aged 54–60 months (n 628).

Results

Grain, roots or tubers were the main dietary components consumed by 100 % of the study participants, followed by pulses, legumes or nuts (66·6 %). Consumption of fruit and vegetables (19·3 %) and meat, poultry and fish (2·2 %) was low. Children had a mean dietary diversity score of 2·1 (sd 0·8). Most children (74·8 %, n 470) were in the lowest dietary diversity group (1–2 food groups). Rate of any morbidity in the preceding 14 d was 22·9 % (n 114). Infection or inflammation (α1-acid glycoprotein >1·2 g/l) was present in 30·2 % (n 184) of children. Children had a high rate of stunting (43·2 %). Of the total sample, 13·6 % (n 82) of children were anaemic, 9·1 % (n 57) were Fe deficient and 5·3 % (n 32) had Fe-deficiency anaemia. Fe-deficiency erythropoiesis was present in 14·2 % (n 60) of children.

Conclusions

Despite consuming a predominantly plant-based diet and little animal-source foods, there was a low prevalence of Fe-deficiency anaemia. This illustrates that dietary patterns can be inharmonious with Fe biochemical status; thus, Fe-related interventions require biochemical screening.

Food-Based Interventions to Modify Diet Quality and Diversity to Address Multiple Micronutrient Deficiency

Global data indicate a high prevalence of hidden hunger among population. Deficiencies of certain micronutrients such as folic acid, iodine, iron, and vitamin A have long lasting effects on growth and development and therefore have been a National priority from many decades. The strategy implemented so far limits to the use of supplemental sources or fortified foods in alleviating the burden of deficiencies. These approaches however undermine the food-based strategies involving dietary diversification as the long-term sustainable strategy. There is lack of understanding on the level of evidence needed to implement such strategies and the level of monitoring required for impact evaluation. Dietary diversity concerns how to ensure access for each individual to a quality and safe diet with adequate macro- and micronutrients. The key to success in using dietary diversity as a strategy to tackle hidden hunger is in integrating it with the principles of bioavailability, translated to efficient food synergies with due emphasis on food accessibility, affordability, and outdoor physical activity/life style modifications. Promoting enabling environment and sustainable agriculture is crucial for practicing dietary diversification with behavior change communication as an integral segment. It can be concluded that food-based strategies require careful understanding of the factors associated with it and moderate it to form an effective strategy for controlling multiple micronutrient deficiencies.

Review: The potential of the common bean (Phaseolus vulgaris) as a vehicle for iron biofortification

Common beans are a staple food and the major source of iron for populations in Eastern Africa and Latin America. Bean iron concentration is high and can be further increased by biofortification. A major constraint to bean iron biofortification is low iron absorption, attributed to inhibitory compounds such as phytic acid (PA) and polyphenol(s) (PP). We have evaluated the usefulness of the common bean as a vehicle for iron biofortification. High iron concentrations and wide genetic variability have enabled plant breeders to develop high iron bean varieties (up to 10 mg/100 g). PA concentrations in beans are high and tend to increase with iron biofortification. Short-term human isotope studies indicate that iron absorption from beans is low, PA is the major inhibitor, and bean PP play a minor role. Multiple composite meal studies indicate that decreasing the PA level in the biofortified varieties substantially increases iron absorption. Fractional iron absorption from composite meals was 4%–7% in iron deficient women; thus the consumption of 100 g biofortified beans/day would provide about 30%–50% of their daily iron requirement. Beans are a good vehicle for iron biofortification, and regular high consumption would be expected to help combat iron deficiency (ID).

Iron and zinc nutrition in the economically-developed world: a review

This review compares iron and zinc food sources, dietary intakes, dietary recommendations, nutritional status, bioavailability and interactions, with a focus on adults in economically-developed countries. The main sources of iron and zinc are cereals and meat, with fortificant iron and zinc potentially making an important contribution. Current fortification practices are concerning as there is little regulation or monitoring of intakes. In the countries included in this review, the proportion of individuals with iron intakes below recommendations was similar to the proportion of individuals with suboptimal iron status. Due to a lack of population zinc status information, similar comparisons cannot be made for zinc intakes and status. Significant data indicate that inhibitors of iron absorption include phytate, polyphenols, soy protein and calcium, and enhancers include animal tissue and ascorbic acid. It appears that of these, only phytate and soy protein also inhibit zinc absorption. Most data are derived from single-meal studies, which tend to amplify impacts on iron absorption in contrast to studies that utilize a realistic food matrix. These interactions need to be substantiated by studies that account for whole diets, however in the interim, it may be prudent for those at risk of iron deficiency to maximize absorption by reducing consumption of inhibitors and including enhancers at mealtimes.

Advantages and disadvantages of the animal models v. in vitro studies in iron metabolism: a review

Iron deficiency is the most common nutritional deficiency in the world. Special molecules have evolved for iron acquisition, transport and storage in soluble, nontoxic forms. Studies about the effects of iron on health are focused on iron metabolism or nutrition to prevent or treat iron deficiency and anemia. These studies are focused in two main aspects: (1) basic studies to elucidate iron metabolism and (2) nutritional studies to evaluate the efficacy of iron supplementation to prevent or treat iron deficiency and anemia. This paper reviews the advantages and disadvantages of the experimental models commonly used as well as the methods that are more used in studies related to iron. In vitro studies have used different parts of the gut. In vivo studies are done in humans and animals such as mice, rats, pigs and monkeys. Iron metabolism is a complex process that includes interactions at the systemic level. In vitro studies, despite physiological differences to humans, are useful to increase knowledge related to this essential micronutrient. Isotopic techniques are the most recommended in studies related to iron, but their high cost and required logistic, making them difficult to use. The depletion-repletion of hemoglobin is a method commonly used in animal studies. Three depletion-repletion techniques are mostly used: hemoglobin regeneration efficiency, relative biological values (RBV) and metabolic balance, which are official methods of the association of official analytical chemists. These techniques are well-validated to be used as studies related to iron and their results can be extrapolated to humans. Knowledge about the main advantages and disadvantages of the in vitro and animal models, and methods used in these studies, could increase confidence of researchers in the experimental results with less costs.

Inulin modifies the bifidobacteria population, fecal lactate concentration, and fecal pH but does not influence iron absorption in women with low iron status

BACKGROUND

Bioavailability of nonheme iron is influenced by the concentration of inhibitors and enhancers in the diet. The fructans inulin and oligofructose have been shown to improve iron absorption in animals through colonic uptake, but this has not been confirmed in humans.

OBJECTIVE

The aim of the intervention study was to evaluate the influence of inulin on iron absorption, bifidobacteria, total bacteria, short-chain fatty acids (SCFAs), and fecal pH in women with low iron status (plasma ferritin <25 μg/L).

DESIGN

The subjects (n = 32) consumed inulin or placebo 3 times/d (∼20 g/d) for 4 wk, separated by a 2-wk washout period. Iron absorption was measured after 3 wk of inulin and placebo consumption from a standard test meal by using stable-iron-isotope techniques. Fecal bacteria were measured by quantitative polymerase chain reaction, and fecal acids by HPLC.

RESULTS

Mean fractional iron absorption in the inulin (15.2%; 95% CI: 8.0%, 28.9%) and placebo (13.3%; 95% CI: 8.1%, 24.3%) periods did not differ significantly (P = 0.10). Inulin decreased fecal pH (P < 0.001) and increased fecal bifidobacteria (P < 0.001) and fecal lactate (P < 0.001) but had no effect on fecal SCFAs and total bacteria. Changes in lactate and acetate concentrations were positively correlated with changes in propionate (P < 0.001) and butyrate (P < 0.02) concentrations, respectively. Iron absorption correlated with fecal pH in the placebo period (P < 0.01) but not in the inulin period (P = 0.37).

CONCLUSION

Although inulin showed prebiotic activity, we were unable to show an increase in iron absorption in women with low iron status. This trial was registered at clinicaltrials.gov as NCT0148309.

Iron uptake by Caco-2 cells following in vitro digestion: effects of heat treatments of pork meat and pH of the digests

The present in vitro studies report on iron uptake by Caco-2 cells from pepsin and pepsin+pancreatin-digested pork meat proteins at pH values between 4.6 and 7 mimicking conditions in the duodenum and the proximal jejunum, respectively. Heat treatment of the pork meat resulted in increased iron uptake from pepsin-digested samples to Caco-2 cells at pH 4.6. The major enhancing effects on iron uptake by Caco-2 cells were observed after pepsin digestion in the pH range 4.6-6.0, whereas the pepsin+pancreatin-digested samples resulted in negligible iron uptake in Caco-2 cells at pH 7. Thus, the results emphasize the importance of separating pepsin-digested and pepsin+pancreatin-digested proteins during in vitro studies on iron availability. Furthermore, the present results showed the pH dependency of iron uptake anticipated. The enhancing effect of ascorbic acid was verified by increased iron uptake from pepsin-digested pork meat samples at pH 4.6, while no effect of ascorbic acid was observed at pH 7 in pepsin+pancreatin-digested samples.

Iron bioavailability and dietary reference values

Iron differs from other minerals because iron balance in the human body is regulated by absorption only because there is no physiologic mechanism for excretion. On the basis of intake data and isotope studies, iron bioavailability has been estimated to be in the range of 14-18% for mixed diets and 5-12% for vegetarian diets in subjects with no iron stores, and these values have been used to generate dietary reference values for all population groups. Dietary factors that influence iron absorption, such as phytate, polyphenols, calcium, ascorbic acid, and muscle tissue, have been shown repeatedly to influence iron absorption in single-meal isotope studies, whereas in multimeal studies with a varied diet and multiple inhibitors and enhancers, the effect of single components has been, as expected, more modest. The importance of fortification iron and food additives such as erythorbic acid on iron bioavailability from a mixed diet needs clarification. The influence of vitamin A, carotenoids, and nondigestible carbohydrates on iron absorption and the nature of the "meat factor" remain unresolved. The iron status of the individual and other host factors, such as obesity, play a key role in iron bioavailability, and iron status generally has a greater effect than diet composition. It would therefore be timely to develop a range of iron bioavailability factors based not only on diet composition but also on subject characteristics, such as iron status and prevalence of obesity.

Dietary iron intake and risk of endometrial cancer: a population-based case-control study in Shanghai, China

Dietary red meat and animal fat have been linked to endometrial cancer (EC) risk, but the impact of bioavailable iron in animal-derived foods has been less well studied. Our objective was to investigate the effects of iron and fats on the risk of EC in a large, population-based, case-control study. The Shanghai Endometrial Cancer Study enrolled 1,204 EC cases and 1,212 controls who completed in-person interviews, including a food frequency questionnaire. Animal-derived iron and fat intakes were calculated from dietary intakes and food composition tables. Logistic regression models were used to evaluate independent and joint effects of iron and fat on EC risk. Animal-derived iron intake was positively associated with EC risk [adjusted OR = 1.9; 95% CI = 1.4-2.7, P(trend) < 0.01, highest vs. lowest quartile], predominantly after menopause (OR = 2.2; 95%CI = 1.4-3.4, P(trend) < 0.01) and in women with BMI >or= 25 kg/m(2)(OR = 3.2; 95% CI = 1.4-7.5 in postmenopausal obese women, P(trend) < 0.01). Animal-derived fat was also associated with postmenopausal EC risk (OR = 1.7; 95% CI = 1.2-2.5, P(trend) < 0.01). Multiplicative interactions between animal-derived iron and BMI or animal-derived fat intake were not observed. Animal-derived iron intake is associated with increased risk of EC after menopause and among obese women. Avoidance of animal-derived (heme) iron may reduce the risk of EC in these women.

Iron excess in recreational marathon runners

BACKGROUND/OBJECTIVES

Iron deficiency and anemia may impair athletic performance, and iron supplements are commonly consumed by athletes. However, iron overload should be avoided because of the possible long-term adverse health effects.

METHODS

We investigated the iron status of 170 male and female recreational runners participating in the Zürich marathon. Iron deficiency was defined either as a plasma ferritin (PF) concentration <15 microg/l (iron depletion) or as the ratio of the concentrations of transferrin receptor (sTfR) to PF (sTfR:log(PF) index) of > or =4.5 (functional iron deficiency).

RESULTS

After excluding subjects with elevated C-reactive protein concentrations, iron overload was defined as PF >200 microg/l. Iron depletion was found in only 2 out of 127 men (1.6% of the male study population) and in 12 out of 43 (28.0%) women. Functional iron deficiency was found in 5 (3.9%) and 11 (25.5%) male and female athletes, respectively. Body iron stores, calculated from the sTfR/PF ratio, were significantly higher (P<0.001) among male compared with female marathon runners. Median PF among males was 104 microg/l, and the upper limit of the PF distribution in males was 628 microg/l. Iron overload was found in 19 out of 127 (15.0%) men but only 2 out of 43 in women (4.7%). Gender (male sex), but not age, was a predictor of higher PF (P<0.001).

CONCLUSIONS

Iron depletion was present in 28% of female runners but in <2% of males, whereas one in six male runners had signs of iron overload. Although iron supplements are widely used by athletes in an effort to increase performance, our findings indicate excess body iron may be common in male recreational runners and suggest supplements should only be used if tests of iron status indicate deficiency.

Choice of foods and ingredients for moderately malnourished children 6 months to 5 years of age

There is consensus on how to treat severe malnutrition, but there is no agreement on the most cost-effective way to treat infants and young children with moderate malnutrition who consume cereal-dominated diets. The aim of this review is to give an overview of the nutritional qualities of relevant foods and ingredients in relation to the nutritional needs of children with moderate malnutrition and to identify research needs. The following general aspects are covered: energy density, macronutrient content and quality, minerals and vitamins, bioactive substances, antinutritional factors, and food processing. The nutritional values of the main food groups--cereals, legumes, pulses, roots, vegetables, fruits, and animal foods--are discussed. The special beneficial qualities of animal-source foods, which contain high levels of minerals important for growth, high-quality protein, and no antinutrients or fibers, are emphasized. In cereal-dominated diets, the plant foods should be processed to reduce the contents of antinutrients and fibers. Provision of a high fat content to increase energy density is emphasized; however, the content of micronutrients should also be increased to maintain nutrient density. The source of fat should be selected to supply optimal amounts of polyunsaturated fatty acids (PUFAs), especially n-3 fatty acids. Among multiple research needs, the following are highlighted: to identify the minimum quantity of animal foods needed to support acceptable child growth and development, to examine the nutritional gains of reducing contents of antinutrients and fibers in cereal- and legume-based diets, and to examine the role of fat quality, especially PUFA content and ratios, in children with moderate malnutrition.

Effectiveness of fortification of corn flour-derived products with hydrogen-reduced elemental iron on iron-deficiency anaemia in children and adolescents in southern Brazil

OBJECTIVE

To find the ideal combination of Fe fortifier and its food vehicle is an essential measure in developing countries. However, its cost also plays an important role. In the present study, the effect on blood parameter values of corn flour-derived products fortified with powdered elemental Fe in the form of H2-reduced Fe was investigated in children and adolescents.

METHODS

One hundred and sixty-two individuals (eighty-six boys and seventy-six girls) from public educational centres in Londrina, Paraná (southern Brazil) participated in the study. Fe-deficiency anaemia (IDA) was defined when Hb and serum ferritin values fell below 12 g/dl and 20 microg/l, respectively; Fe deficiency (ID) was considered when serum ferritin was below 20 microg/l.

RESULTS

The prevalence of ID and IDA decreased from 18.0 % and 14.9 %, values found at the beginning of the study, to respectively 5.6 % and 1.2 % after 6 months. Changes from altered to normal values occurred more often than normal to altered values with transferrin saturation (14.2 % v. 6.8 %; P < 0.04) and ferritin (12.4 % v. 0 %; P < 0.001). Hb, transferrin saturation and ferritin showed differences between normal and altered parameters after 6 months (P < 0.001).

CONCLUSION

A pronounced reduction in the prevalence of ID and IDA was observed in children and adolescents following 6 months' ingestion of corn flour-derived products enriched with elemental Fe.

Oily fish increases iron bioavailability of a phytate rich meal in young iron deficient women

BACKGROUND

Iron deficiency is a major health problem worldwide, and is associated with diets of low iron bioavailability. Non-heme iron absorption is modulated by dietary constituents, one of which is the so-called "meat factor", present in meat, fish (oily and lean) and poultry, which is an important enhancer of iron absorption in humans. Food processing also affects iron bioavailability.

OBJECTIVE

To evaluate the effect of consuming sous vide cooked salmon fish on non-heme iron bioavailability from a bean meal, rich in phytate, in iron-deficient women.

DESIGN

Randomized crossover trial in 21 young women with low iron stores (ferritin < 30 microg/L). Two test meals were extrinsically labelled with stable isotopes of iron (Fe-57 or Fe-58). Iron bioavailability was measured as the incorporation of stable isotopes into erythrocytes 14 d after meals consumption.

RESULTS

The addition of fish to the bean meal significantly increased (p < 0.001) iron absorption. Serum ferritin concentration and iron absorption were inversely correlated for both the bean meal (R(2) = 0.294, p = 0.011) and the fish and bean meal (R(2) = 0.401, p = 0.002).

CONCLUSION

Sous vide cooked salmon fish increases iron absorption from a high phytate bean meal in humans.

The impact of a meat- versus a vegetable-based diet on iron status in women of childbearing age with small iron stores

BACKGROUND

Single-meal and short-term studies have shown an enhancing effect of meat on iron absorption, but there are few interventions of longer duration comprising measurements of biomarkers of iron status.

AIMS OF THE STUDY

To assess the impact of a meat-based and a vegetable-based diet on iron status of women of childbearing age.

METHODS

For 20 weeks, 57 women aged 19-39 years with low iron stores (serum ferritin < or =30 microg/l and haemoglobin > or =120 g/l) consumed either a meat-based or a vegetable-based diet. Haemoglobin and serum ferritin concentrations were measured at baseline, after 10 and 20 weeks. Information about dietary intake before and during intervention, meat/fish intake, menstruation and contraceptive methods were recorded.

RESULTS

The women who consumed the meat-based diet had a significantly (P < 0.001) higher intake of meat/fish, 152 (147-168) g/day (median (Q1-Q3)) compared to the women consuming the vegetable-based diet 31 (24-36) g/day, while the total iron intake was similar in the two groups (mean +/- SE) 11.0 +/- 0.5 and 12.3 +/- 0.3/day mg/day, respectively. Serum ferritin remained unchanged in women on the meat-based diet (n = 29)(before intervention (median (Q1-Q3)): 16.3 (12.7-25.3) microg/l and after intervention: 16.5 (10.3-25.3) microg/l, but declined from 17.3 (10.9-23.7) to 11.2 (8.8-14.6) mug/l (P < 0.001) in women on the vegetable-based diet (n = 28).

CONCLUSION

Our results emphasize the importance of the delicate balance between dietary iron content and iron bioavailability for the maintenance of blood indicators of iron stores in women with initially low iron status.

An Analysis of the Etiology of Anemia and Iron Deficiency in Young Women of Low Socioeconomic Status in Bangalore, India

Background

Anemia and iron deficiency are significant public health problems in India, particularly among women and children. Recent figures suggest that nearly 50% of young Indian women are anemic.

Objectives

Few studies have comprehensively assessed etiologic factors contributing to anemia and iron deficiency in India. Hence, this study assessed the relative importance of various factors contributing to these problems in young women of low socioeconomic status in Bangalore, India.

Methods

A random sample of 100 nonpregnant, nonlactating women 18 to 35 years of age, selected from among 511 women living in a poor urban settlement, participated in this study. Data were obtained on demography, socioeconomic status, anthropometry, three-day dietary intake, blood hemoglobin, hemoglobinopathies, serum ferritin, serum C-reactive protein, and stool parasites.

Results

The prevalence rates of anemia and iron deficiency were 39% and 62%, respectively; 95% of the anemic women were iron deficient. The mean dietary iron intake was 9.5 mg per day, predominantly from the consumption of cereals, pulses, and vegetables (77%). The estimated bioavailability of nonheme iron in this diet was 2.8%. Dietary intakes were suboptimal for several nutrients. Blood hemoglobin was significantly correlated with dietary intake of fat, riboflavin, milk and yogurt, and coffee. Serum ferritin was significantly correlated with intake of niacin, vitamin B12, and selenium. Parasitic infestation was low.

Conclusions

An inadequate intake of dietary iron, its poor bioavailability, and concurrent inadequate intake of dietary micronutrients appear to be the primary factors responsible for the high prevalence of anemia and iron deficiency in this population.

Nonheme iron absorption in young women is not influenced by purified sulfated and unsulfated glycosaminoglycans

Meat is a well-known enhancer of iron absorption, yet the molecular entity mediating the effect remains obscure. Recently published data indicate that highly acidic sulfated glycosaminoglycans (GAG) from fish and chicken muscle are effective stimulants of iron uptake in Caco-2 cells. Two fully randomized stable isotope studies with crossover design were performed in a group of 16 apparently healthy young women to assess the effect of purified sulfated and unsulfated GAG on human iron absorption. Iron absorption was measured on the basis of erythrocyte incorporation of (57)Fe or (58)Fe 14 d after the administration of labeled semisynthetic meals (SSM) based on egg albumin, corn oil, maltodextrin, and water. The meals were consumed with or without added sodium hyaluronate (NaH, 300 mg) or chondroitin sulfate (CS, 360 mg) as representative unsulfated and sulfated GAG, respectively. The level of GAG added was 3 times (NaH) to about 10 times (CS), the amount expected to be present in 150 g beef muscle. Geometric mean iron absorption from SSM containing NaH (21.2%) or CS (19.4%) did not differ from that of SSM without GAG (19.5 and 20.3%, respectively). NaH and CS at those levels do not affect human nonheme iron absorption.