BackgroundCurrently, there is a lot of interest in improving gut health, and consequently increasing Fe absorption, by managing the colonic microbial population. This is traditionally done by the consumption of probiotics, live microbial food supplements. However, an alternative, and often very effective approach, is the consumption of food ingredients known as prebiotics. Fructans and arabinoxylans are naturally occurring non-digestible oligosaccharides in wheat that exhibit prebiotic properties and may enhance intestinal iron (Fe) absorption. The aim of this study was to assess the effect of prebiotics from wheat on Fe bioavailability in vitro (Caco-2 cells) and in vivo (broiler chickens, Gallus gallus).MethodsIn the current study, the effect of intra-amniotic administration of wheat samples extracts at 17 d of embryonic incubation on the Fe status and possible changes in the bacterial population in intestinal content of broiler hatchlings were investigated. A group of 144 eggs were injected with the specified solution (1 ml per egg) into the amniotic fluid. Immediately after hatch (21 d) and from each treatment group, 10 chicks were euthanized and their small intestine, liver and cecum were removed for relative mRNA abundance of intestinal Fe related transporters, relative liver ferritin amounts and bacterial analysis of cecal content, respectively.ResultsThe in vivo results are in agreement with the in vitro observations, showing no differences in the hatchling Fe status between the treatment groups, as Fe bioavailability was not increased in vitro and no significant differences were measured in the intestinal expression of DMT1, Ferroportin and DcytB in vivo. However, there was significant variation in relative amounts of bifidobacteria and lactobacilli in the intestinal content between the treatments groups, with generally more bifidobacteria being produced with increased prebiotic content.ConclusionsIn this study we showed that prebiotics naturally found in wheat grains/bread products significantly increased intestinal beneficial bacterial population in Fe deficient broiler chickens. With this short-term feeding trial we were not able to show differences in the Fe-status of broilers. Nevertheless, the increase in relative amounts of bifidobacteria and lactobacilli in the presence of wheat prebiotics is an important finding as these bacterial populations may affect Fe bioavailability in long-term studies.

The amount of Zn absorbed from Zn-biofortified wheat material has been determined using an in vivo model of Zn absorption. The erythrocyte linoleic:dihomo -γ-linolenic acid (LA:DGLA) ratio was used as a biomarker of Zn status. Two groups of chickens (n = 15) were fed different diets: a high-Zn (46.5 μg Zn g) and a low-Zn wheat-based diet (32.8 μg Zn g). Dietary Zn intakes, body weight, serum Zn, and the erythrocyte fatty acid profile were measured, and tissues were taken for gene expression analysis. Serum Zn concentrations were greater in the high Zn group (p < 0.05). Duodenal mRNA expression of various Zn transporters demonstrated expression upregulation in the birds fed a low Zn diet (n = 15, p < 0.05). The LA:DGLA ratio was higher in the birds fed the low Zn diet (p < 0.05). The higher amount of Zn in the biofortified wheat resulted in a greater Zn uptake.

The structure and function of cecal microbiota following the consumption of a zinc (Zn) biofortified wheat diet was evaluated in a well-studied animal model of human nutrition ( Gallus gallus) during a six-week efficacy trial. Using 16S rRNA gene sequencing, a significant increase in β- but not α-microbial diversity was observed in the animals receiving the Zn biofortified wheat diet, relative to the control. No significant taxonomic differences were found between the two groups. Linear discriminant analysis revealed a group of metagenomic biomarkers that delineated the Zn replete versus Zn deficient phenotypes, such that enrichment of lactic acid bacteria and concomitant increases in Zn-dependent bacterial metabolic pathways were observed in the Zn biofortified group, and expansion of mucin-degraders and specific bacterial groups able to participate in maintaining host Zn homeostasis were observed in the control group. Additionally, the Ruminococcus genus appeared to be a key player in delineating the Zn replete microbiota from the control group, as it strongly predicts host Zn adequacy. Our data demonstrate that the gut microbiome associated with Zn biofortified wheat ingestion is unique and may influence host Zn status. Microbiota analysis in biofortification trials represents a crucial area for study as Zn biofortified diets are increasingly delivered on a population-wide scale.

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Zinc (Zn) deficiency is a common aliment predicted to affect 17% of the world’s population. Zinc is a vital micronutrient used for over 300 enzymatic reactions and multiple biochemical and structural processes in the body. Although whole blood, plasma, and urine zinc decrease in severe zinc deficiency, accurate assessment of zinc status, especially in mild to moderate deficiency, is difficult as studies with these biomarkers are often contradictory and inconsistent. Hence, as suggested by the World Health Organization, sensitive and specific biological markers of zinc status are still needed. In this review, we provide evidence to demonstrate that the LA:DGLA ratio (linoleic acid:dihomo-γ-linolenic acid ratio) may be a useful additional indicator for assessing Zn status more precisely. However, this biomarker needs to be tested further in order to determine its full potential.

This study is an initial step in evaluating LA: DGLA ratio as a biomarker of Zn status in humans. The results are encouraging as they show that concentration of DGLA is decreased and LA: DGLA ratio increased in people with lower dietary Zn intake. However, additional studies are needed to fully examine the sensitivity of this biomarker.

The prevalence of obesity and dyslipidemia has increased worldwide. The role of trace elements in the pathogenesis of these conditions is not well understood. This study examines the relationship between dietary zinc (Zn) intake and plasma concentrations of Zn, copper (Cu) and iron (Fe) with lipid profile indicators, fatty acid composition in plasma phospholipids and desaturase enzyme activities in a dyslipidemic population. The role of the newly proposed biomarker of Zn status, the linoleic:dihomo-gama-linolenic acid (LA:DGLA) ratio, in predicting Zn status of dyslipidemic subjects has been explored. The study included 27 dyslipidemic adults, 39-72 years old. Trace elements were determined using atomic absorption spectrometry and fatty acid composition by a liquid gas chromatography. Desaturase activities were calculated from product-precursor fatty acid ratios. Dietary data were obtained using 24 h recall questionnaires. Insufficient dietary intake of Zn, low plasma Zn concentrations and an altered Cu:Zn ratio is related to modified fatty acid profile in subjects with dyslipidemia. Plasma Zn status was associated with obesity. There was no correlation between dietary Zn intake and plasma Zn status. The LA:DGLA ratio was inversely linked to dietary Zn intake. Cu, in addition to Zn, may directly or indirectly, affect the activity of desaturase enzymes. region of Europe (54% for both sexes). Successful treatment of dyslipidemia significantly reduces morbidity and mortality from cardiovascular diseases [7]. Basically 10% reduction in serum lipid levels has been reported to result in a 50% reduction in heart disease within 5 years [1].Trace elements have crucial roles in metabolism, growth, immunological and neurological functions [8][9][10]. Zinc (Zn) is required for an adequate activity of more than 300 enzymes involved in protein synthesis, fatty acid metabolism, reproduction and oxidative clearance [11]. Iron (Fe) is needed for proper oxygen transport, while copper (Cu) is important for the oxido-reduction and detoxification and is involved in growth, development of cellular elements of arterial walls, lipoprotein metabolism and immune function [9,12,13]. The concentrations of serum/plasma minerals Zn, Cu and Fe are associated with the development of chronic diseases [10,14,15]. Deficiency in microelements leads to an increase in fat deposition and obesity [16]. Hypoferremia is often seen in people suffering from hypertension and plasma Zn concentrations have been directly correlated with total cholesterol and LDL-C levels [15,17]. Zn, Cu and Fe plasma levels are related to the extent of myocardial damage [18]. Epidemiological studies show a direct correlation between low plasma Zn and Fe concentrations and increased risk of cardiovascular diseases [19]. Elevated plasma levels of Cu were reported in patients with coronary artery disease [20]. Although deficiencies of trace elements may alter metabolism of lipids and lipoproteins, the mechanism of their action is not yet completely understood. The fatty acid (FA)...

Iron deficiency is the most prevalent nutritional deficiency, affecting more than 30% of the total world's population. It is a major public health problem in many countries around the world. Over the years various methods have been used with an effort to try and control iron-deficiency anemia. However, there has only been a marginal reduction in the global prevalence of anemia. Why is this so? Iron and zinc are essential trace elements for humans. These metals influence the transport and absorption of one another across the enterocytes and hepatocytes, due to similar ionic properties. This paper describes the structure and roles of major iron and zinc transport proteins, clarifies iron-zinc interactions at these sites, and provides a model for the mechanism of these interactions both at the local and systemic level. This review provides evidence that much of the massive extent of iron deficiency anemia in the world may be due to an underlying deficiency of zinc. It explains the reasons for predominance of cellular zinc status in determination of iron/zinc interactions and for the first time thoroughly explains mechanisms by which zinc brings about these changes.