Impact of Ascorbic Acid on the In Vitro Iron Bioavailability of a Casein-Based Iron Fortificant

Ti3C2Tx Coated with TiO2 Nanosheets for the Simultaneous Detection of Ascorbic Acid, Dopamine and Uric Acid

Two-dimensional MXenes have become an important material for electrochemical sensing of biomolecules due to their excellent electric properties, large surface area and hydrophilicity. However, the simultaneous detection of multiple biomolecules using MXene-based electrodes is still a challenge. Here, a simple solvothermal process was used to synthesis the Ti3C2Tx coated with TiO2 nanosheets (Ti3C2Tx@TiO2 NSs). The surface modification of TiO2 NSs on Ti3C2Tx can effectively reduce the self-accumulation of Ti3C2Tx and improve stability. Glassy carbon electrode was modified by Ti3C2Tx@TiO2 NSs (Ti3C2Tx@TiO2 NSs/GCE) and was able simultaneously to detect dopamine (DA), ascorbic acid (AA) and uric acid (UA). Under concentrations ranging from 200 to 1000 μM, 40 to 300 μM and 50 to 400 μM, the limit of detection (LOD) is 2.91 μM, 0.19 μM and 0.25 μM for AA, DA and UA, respectively. Furthermore, Ti3C2Tx@TiO2 NSs/GCE demonstrated remarkable stability and reliable reproducibility for the detection of AA/DA/UA.

Novel and Extremely Sensitive NiAl2O4-NiO Nanostructures on an ITO Sensing Electrode for Enhanced Detection of Ascorbic Acid

The current study focused on the design of an extremely sensitive electrochemical sensor of ascorbic acid based on a mixture of NiAl2O4-NiO nanoparticles that, produced in a single step using the sol-gel method, on an ITO electrode. This new sensing platform is useful for the detection of ascorbic acid with a wide range of concentrations extending from the attomolar to the molar. SEM micrographs show the porous structure of the NiAl2O4-NiO sample, with a high specific surface area, which is beneficial for the catalytic performance of the nanocomposite. An XRD diffractogram confirmed the existence of two phases, NiAl2O4 and NiO, both corresponding to the face-centred cubic crystal structure. The performances of the modified electrode, as a biomolecule, in the detection of ascorbic acid was evaluated electrochemically by cyclic voltammetry and chronoamperometry. The sensor exhibited a sensitive electrocatalytic response at a working potential of E = +0.3 V vs. Ag/Ag Cl, reaching a steady-state current within 30 s after each addition of ascorbic acid solution with a wide dynamic range of concentrations extending from attolevels (10-18 M) to molar (10 mM) and limits of detection and quantification of 1.2 × 10-18 M and 3.96 × 10-18 M, respectively. This detection device was tested for the quantification of ascorbic acid in a 500 mg vitamin C commercialized tablet that was not pre-treated.

Ascorbic acid-induced warfarin resistance after breast cancer surgery: a case report and literature review

Warfarin is an anticoagulant that requires INR-based dosage adjustment. Ascorbic acid may impair warfarin effectiveness according to limited literature. We report a rare case of a 63-year-old woman with an aortic valve replacement history who developed warfarin resistance after taking ascorbic acid for anemia following breast cancer surgery. Despite increasing the warfarin dose from 6 mg to 10 mg daily, her INR remained below the therapeutic range. After ruling out other causes of warfarin resistance, we discontinued ascorbic acid and observed a rapid increase in INR to target values. The temporal relationship and the absence of other confounding factors confirmed the causality of ascorbic acid in this case. We recommend that patients concomitantly taking vitamin C and warfarin should monitor their INR values closely and discontinue ascorbic acid as soon as possible if they exhibit signs of warfarin resistance.

Development of a Predictive Model for Iron Levels in Bovine Muscle Tissue Using Hair as a Predictor

The assessment of iron levels in cattle muscle tissue is crucial for livestock management because it influences both animal health and meat quality, key factors in sustainable development. This study aimed to develop an optimal model for noninvasively predicting the iron content in Hereford cattle muscle tissue, contributing to a comprehensive understanding of the animals' elemental status. The research involved the atomic absorption analysis of muscle tissue and hair samples from cattle. A regression model was constructed using the least squares method to identify the most effective approach. These findings have ecological applications, aiding in evaluating environmental health and establishing acceptable iron thresholds for animals. The proposed mathematical model utilizing biomarkers (levels of Mg, K, Fe, Al, Cr in hair) will allow for the assessment of iron levels in cattle muscle tissue throughout the period of productive use, with the possibility of adjustment and tracking the changes in elemental status over time. The utilization of the developed method will enable the diagnosis of animal elementosis and assessment of the iron level burden. Subsequently, this will allow for the improvement of the qualitative characteristics of the final product. Thus, the obtained data contribute to fundamental knowledge regarding the content and variability of iron levels in the muscle tissue of cattle.

Influence of Dietary Fibre and Protein Fractions on the Trace Element Bioaccessibility of Turnip Tops (Brassica rapa) Growing under Mediterranean Conditions

The objective of this work was to study the influence of three dietary fibre fractions (pectin, gum arabic and cellulose) and three protein fractions (casein, lactalbumin and soy) on the trace element bioaccessibility (Fe, Mn, Ni, Se and Zn) of turnip tops (B. rapa subsp. Rapa) growing under Mediterranean conditions. Then, it aimed to promote the use of this vegetable not only for direct fresh consumption but also as a main ingredient in the development of food mixtures. The results showed that soluble fibre fractions, such as pectin and gum arabic, can enhance the bioaccessibility of trace elements, such as Fe, Mn, Se and Zn. This effect was not proved for cellulose (an insoluble fibre fraction), in which, at best, no bioaccessibility effect was observed. Regarding the protein fractions, with the exception of Se, caseins and lactalbumin had a neutral effect on improving the trace element bioaccessibility. This did not hold true for soy protein, in which a considerable improvement in the bioaccessibility of Fe, Mn, Se and Zn was determined.

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.

Microbial siderophores as molecular shuttles for metal cations: sources, sinks and application perspectives

Iron is one of the highly abundant elements on the earth's crust, an essential micronutrient for a majority of life forms, and exists in two frequent oxidation states such as ferrous (Fe2+) and ferric (Fe3+). These two oxidation states are interconvertible by redox reactions and form complexes with a wide range of siderophores. At neutral pH in soil, Fe2+ is highly soluble upto 100 mM but have less biological value, whereas Fe3+ is less soluble upto 10-9 M. This reduced bioavailability of Fe3+ induces competition among microorganisms. As many microorganisms need at least 10-6 M of Fe3+ form of iron for their growth, siderophores from these microbes readily withdraw Fe3+ iron from a variety of habitats for their survival. In this review, we bring into light the several recent investigations related to diverse chemistry of microbial siderophores, mechanisms of siderophore uptake, biosynthetic gene clusters in microbial genomes, various sources of heavy metal cations in soil, siderophore-binding protein receptors and commercialisation perspectives of siderophores. Besides, this review unearths the recent advancements in the characterisation of novel siderophores and its heavy metal complexes alongside the interaction kinetics with receptors.

Colorimetric/photothermal dual-mode sensing detection of ascorbic acid based on a Ag[i] ion/3,3',5,5'-tetramethylbenzidine (TMB) system

In this work, a novel strategy of colorimetric and photothermal dual-mode sensing determination of ascorbic acid (AA) based on a Ag⁺/3,3',5,5'-tetramethylbenzidine (TMB) system was developed. In this sensing system, Ag⁺ could oxidize TMB with a distinct color change from colorless to blue color, strong absorbance at 652 nm and a photothermal effect under 808 nm laser irradiation due to the formation of oxidized TMB (oxTMB). When AA was present, oxTMB was reduced accompanied by a change from blue to colorless, and a decrease in absorption peak intensity and the photothermal effect. AA concentration showed a negative linear correlation with the value of both the absorbance intensity at 652 nm and temperature in the range of 0.2-10 μM (A = -0.03C + 0.343 (R ², 0.9887; LOD, 50 nM); ΔT = -0.57C + 8.453 (R ², 0.997; LOD, 7.8 nM)). Based on this, a sensing approach for detection of AA was proposed with dual-mode and without the complicated synthesis of nanomaterials. The photothermal effect and colorimetric signal provided a dual-mode detection strategy for AA, overcoming the limitations of any single mode. This colorimetric and photothermal dual-mode detection has great potential in the detection of AA in clinical pharmaceuticals and the construction of portable and highly sensitive sensors.

Effectiveness of Dietary Intervention with Iron and Vitamin C Administered Separately in Improving Iron Status in Young Women

In order to maintain an adequate iron status in young women, effective dietary interventions should provide sufficient amounts of iron in everyday meals and improve the bioavailability of non-heme iron by providing vitamin C. While some intervention studies administering products rich in vitamin C in conjunction with iron sources showed improved iron status, it is unknown whether a separate administration of products rich in iron and vitamin C may be a successful strategy as well. The aim of this study was to assess the effectiveness of dietary intervention with iron and vitamin C administered separately in improving iron status in young women to prevent iron deficiency anemia. The study was conducted in a group of 29 women aged 18-30, and an 8-week dietary intervention was performed. Study participants with an adequate iron status received 50 g of iron-fortified oat flakes (as a source of non-heme iron) with breakfast and 200 mL of orange juice (as a source of vitamin C) in the second part of the day. Iron status was analyzed based on red blood cells, hemoglobin, hematocrit, serum ferritin, and serum iron, and it was assessed at baseline, after 4 weeks, and after 8 weeks of the intervention. The intakes of iron, vitamin C, and folate were controlled throughout the study period, and menstrual blood loss was estimated. After 8 weeks of intervention, statistically significant differences compared with baseline were observed only for hematocrit, as its level after 8 weeks of intervention was higher than the baseline (p = 0.0491). Comparing subsamples within the dietary intervention considered effective and ineffective for red blood cell levels, it was indicated that lower baseline vitamin C intake may result in a more effective dietary intervention (p = 0.0231). Comparing subsamples within the dietary intervention considered effective and ineffective for hemoglobin, hematocrit, iron, and serum ferritin levels, it was indicated that higher baseline levels of hemoglobin (p = 0.0143), hematocrit (p = 0.0497), iron (p = 0.0101), and serum ferritin (p = 0.0343) respectively may result in a more effective dietary intervention. It was concluded that dietary intervention with iron and vitamin C administered separately may be effective in improving iron status in young women to prevent iron deficiency anemia. It may be concluded that in the studied group, a better baseline iron status and lower baseline vitamin C intake may result in a more effective dietary intervention with iron and vitamin C administered separately to improve iron status in young women.

Safety of iron milk proteinate as a novel food pursuant to Regulation (EU) 2015/2283 and bioavailability of iron from this source in the context of Directive 2002/46/EC

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on iron milk proteinate as a novel food (NF) pursuant to Regulation (EU) 2015/2283 and to address the bioavailability of iron from this source in the context of Directive 2002/46/EC. The NF is a complex of iron, casein and phosphate, which is produced from iron salts (i.e. ferric chloride or ferric sulfate), sodium caseinate and potassium orthophosphate. The NF is proposed by the applicant to be used as a source of iron, of which the NF contains 2–4%. The applicant intends to market the NF as an ingredient in a number of food categories; in food supplements, in total diet replacement for weight control and in foods for special medical purposes. The Panel considers that, taking into account the composition of the NF and the proposed conditions of use, consumption of the NF is not nutritionally disadvantageous. The studies provided for ADME and bioavailability indicate that iron from the NF is bioavailable. Overall, the evidence indicates that upon ingestion the NF undergoes digestion into small peptides to yield iron‐bound caseinophosphopeptides that are normal constituents of the human diet, and that the iron from the NF does not bypass the homeostatic control of iron as a nutrient. The Panel concludes that the NF, iron milk proteinate, is safe under the proposed conditions of use. The Panel also concludes that the NF is a source from which iron is bioavailable.

Effectiveness of Dietary Interventions to Treat Iron-Deficiency Anemia in Women: A Systematic Review of Randomized Controlled Trials

Iron-deficiency anemia is the most frequent nutritional deficiency, with women of reproductive age being particularly at risk of its development. The aim of the systematic review was to assess the effectiveness of dietary interventions to treat iron-deficiency anemia in women based on the randomized controlled trials. The systematic review was conducted according to the PRISMA guidelines and registered in the PROSPERO database (CRD42021261235). The searching procedure was based on PubMed and Web of Science databases, while it covered records published until June 2021. It included all randomized controlled trials assessing effectiveness of various dietary interventions on treatment of iron-deficiency anemia in women of childbearing age. The total number of 7825 records were screened, while 14 of them were finally included in the systematic review. The studies were screened, included, and reported, and the risk of bias was assessed using the revised Cochrane risk-of-bias tool for randomized trials by two independent researchers. The included studies compared the effectiveness of various dietary interventions with supplementation, placebo, control, or any other dietary intervention, while the assessed dietary interventions were based either on increasing iron supply and/or on increasing its absorption (by increasing vitamin C or vitamin D or decreasing phytate intake). The duration of applied intervention was diversified from 3 months or less, through 4 or 5 months, to half of a year or more. Among the assessed biochemical measures, the following were analyzed in majority of studies: hemoglobin, ferritin, transferrin receptor, hematocrit, and transferrin. The majority of included studies supported the influence of dietary interventions on the treatment of iron-deficiency anemia, as the applied dietary intervention was not effective in only three studies. The majority of included studies were assessed as characterized by medium risk of bias, while the overall risk was high for only four studies, which resulted from the randomization process, deviations from the intended interventions, and selection of the reported result. The majority of included studies were conducted for increasing iron supply and/or increasing vitamin C supply; however, only for the interventions including increasing iron supply and simultaneously increasing its absorption by vitamin C supply were all results confirmed effective. Vitamin D also seems to be an effective dietary treatment, but further studies are necessary to confirm the observations. Considering this fact, dietary interventions recommended for anemic female patients should include increased intake of iron and vitamin C.

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 Bioavailability from Ferrous Ammonium Phosphate, Ferrous Sulfate, and Ferric Pyrophosphate in an Instant Milk Drink-A Stable Isotope Study in Children

Ferrous ammonium phosphate (FAP) is an iron salt that has been developed for the fortification of food matrices sensitive to color and flavor changes. The objective of the study was to measure iron absorption from FAP in young children and compare it to a previous evaluation of FAP in young women. A double-blind randomized crossover study with two parallel arms was used to evaluate the iron absorption from FAP added to reconstituted milk powder in comparison to that from ferrous sulfate (FeSO4) and ferric pyrophosphate (FePP). Iron absorption was measured in 39 children aged 3- to 6-years-old using erythrocyte incorporation of stable Fe isotopes (57Fe, 58Fe). The geometric mean iron absorption in iron replete children from FAP, FeSO4 and FePP from milk was 8.3%, 7.6% and 2.1%, respectively. Iron absorption from FAP and FeSO4 fortified milk was not significantly different (p = 0.199); however, it was significantly higher than from FePP fortified milk (p < 0.001). Iron bioavailability from FAP and FePP relative to FeSO4 (relative bioavailability (RBV)) was 110% and 33%, respectively. The RBV of FAP (110%) in iron replete children was higher than previously reported RBV (71%) in mainly iron deficient women. The difference in iron status between the children and women in the respective studies may explain the different RBV values and is discussed.

Assessment of intestinal injury of hexavalent chromium using a modified in vitro gastrointestinal digestion model

Intestinal injury assessment of hexavalent chromium (Cr-VI) in humans is crucial for quantifying assessment of adverse health risk posed by the intake of Cr (VI)-contaminated water. To overcome the deficiency in simulating human gastric reduction and intestinal absorption, we modified the constituents of simulated gastric fluid in in vitro digestion method by adding reductants glutathione (18 μM) and ascorbic acid (180 μM), which incorporated with human intestinal epithelial model to construct an in vitro gastrointestinal digestion (IVGD) model for intestinal injury assessment. Cr-VI bioaccessibility results from IVGD model showed that weak gastric acidity significantly increased the intestinal accessible Cr-VI dose by 22.41-38.43 folds. The time-course intestinal absorption indicated prolongation of intestinal exposure destroyed the intestinal epithelium, and 24 h after Cr-VI treatment was a good time point to perform intestinal absorption and toxicity assessment. A series of cell-based bioassays provided initial warning of adverse effect, suggesting that epithelial integrity exhibited greatest sensitivity to Cr-VI exposure and might be used as a sensitive marker for the toxicity assessment of oral exposure to Cr-VI. Notably, this study provides a feasible strategy for delineation of Cr-VI biotransformation and intestinal injury following ingestion exposure, which contributes to address the toxicity data gap of low-dose exposure in humans and puts forward a reference for intestinal toxicity assessment of other chemicals.

The role of legume peptides released during different digestion stages in modulating the bioaccessibility of exogenous iron and zinc: An in-vitro study

The effects of legume protein fractions on Fe and Zn bioaccessibility remain equivocal to date, largely due to the protein’s structure and the presence of anti-nutritional compounds. We administered Fe and Zn salts with legume concentrates consisting mainly of albumin or globulin from lupin, pea and faba to in vitro gastrointestinal digestion. Under the fasted intestinal state, faba globulins were found to enhance Fe²⁺ and Zn solubility compared to control salts without legume proteins. Meanwhile, other fractions had no effect or significantly lowered Fe and Zn solubility. Under the fed intestinal state, the presence globulins enhanced Fe solubility versus the control, where protein solubilization due to high bile concentration likely played a role in circumventing precipitation. The lupin albumin fraction significantly enhanced Fe²⁺ and Zn solubility, whilst other fractions generally reduced Zn solubility under fed state. Our results highlight the complex role of legume proteins towards Fe and Zn solubility.

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Bioaccessibility of Fe/Zn mineral salts were examined with and without legume protein fractions.

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Bile concentrations and/or digestion time affected Fe³⁺/Fe²⁺ and Zn solubility in presence of legume protein fractions.

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Globulins consistently enhanced Fe²⁺, but not Fe³⁺ solubility during the high-bile (fed state) intestinal digestion phase.

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Both enhancements and reductions in Zn solubility were reflected by different legume fractions.

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A non-linear relationship was observed between soluble protein and Fe/Zn bioaccessibility during simulated digestion.