Iron status in the elderly.
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ABSTRACT:
SUBMITTER: Fairweather-Tait SJ
PROVIDER: S-EPMC4157323 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Impaired iron metabolism is associated with increased risk of many morbidities. Exercise was shown to have a beneficial role; however, the mechanism is not well understood. The purpose of this study was to assess the relationship between exerkines and iron metabolism in elderly women before and after 12 weeks of Nordic Walking (NW) training. Exerkines like myostatin, adiponectin, and osteocalcin have been shown to have several positive effects on metabolism. Thirty-six post-menopausal women (66 ± 5 years old, mean ± SD) were randomly assigned to a NW intervention group (n = 18; body mass, 68.8 ± 11.37 kg; fat, 23.43 ± 7.5 kg; free fat mass, 45.37 ± 5.92 kg) or a control group (n = 18; body mass, 68.34 ± 11.81 kg; fat, 23.61 ± 10.03 kg; free fat mass, 44.73 ± 3.9 kg). The training was performed three times a week for 12 weeks, with the intensity adjusted to 70% of the individual maximum ability. Before and one day after the 12-weeks intervention, performance indices were assessed using a senior fitness test. Blood samples (5 mL) were obtained from the participants between 7 and 8 AM, following an overnight fast, at baseline and one day immediately after the 12-week training program. A significant and large time ´ group interaction was observed for iron (NW: 98.6 ± 26.68 to 76.1 ± 15.31; CON: 100.6 ± 25.37 to 99.1 ± 27.2; p = 0.01; = 0.21), myostatin (NW: 4.42 ± 1.97 to 3.83 ± 1.52; CON: 4.11 ± 0.95 to 4.84 ± 1.19; p = 0.00; = 0.62), adiponectin (NW: 12.0 ± 9.46 to 14.6 ± 10.64; CON: 12.8 ± 8.99 to 11.9 ± 8.53; p = 0.00; = 0.58), and osteocalcin (NW: 38.9 ± 26.04 to 41.6 ± 25.09; CON: 37.1 ± 33.2 to 37.2 ± 32.29; p = 0.03; = 0.13). Furthermore, we have observed the correlations: basal ferritin levels were inversely correlated with changes in myostatin (r = -0.51, p = 0.05), change in adiponectin, and change in serum iron (r = -0.45, p = 0.05), basal iron, and osteocalcin after training (r = -0.55, p = 0.04). These findings indicate that iron modulates NW training-induced changes in exerkine levels.
| S-EPMC7231223 | biostudies-literature
Project description:Currently there are no satisfactory methods for estimating dietary iron absorption (bioavailability) at a population level, but this is essential for deriving dietary reference values using the factorial approach. The aim of this work was to develop a novel approach for estimating dietary iron absorption using a population sample from a sub-section of the UK National Diet and Nutrition Survey (NDNS). Data were analyzed in 873 subjects from the 2000-2001 adult cohort of the NDNS, for whom both dietary intake data and hematological measures (hemoglobin and serum ferritin (SF) concentrations) were available. There were 495 men aged 19-64 y (mean age 42.7±12.1 y) and 378 pre-menopausal women (mean age 35.7±8.2 y). Individual dietary iron requirements were estimated using the Institute of Medicine calculations. A full probability approach was then applied to estimate the prevalence of dietary intakes that were insufficient to meet the needs of the men and women separately, based on their estimated daily iron intake and a series of absorption values ranging from 1-40%. The prevalence of SF concentrations below selected cut-off values (indicating that absorption was not high enough to maintain iron stores) was derived from individual SF concentrations. An estimate of dietary iron absorption required to maintain specified SF values was then calculated by matching the observed prevalence of insufficiency with the prevalence predicted for the series of absorption estimates. Mean daily dietary iron intakes were 13.5 mg for men and 9.8 mg for women. Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L). At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%). This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration.
| S-EPMC4214798 | biostudies-literature
Project description:Iron is unique among all minerals in that humans have no regulatable excretory pathway to eliminate excess iron after it is absorbed. Iron deficiency anemia occurs when absorbed iron is not sufficient to meet body iron demands, whereas iron overload and subsequent deposition of iron in key organs occur when absorbed iron exceeds body iron demands. Over time, iron accumulation in the body can increase risk of chronic diseases, including cirrhosis, diabetes, and heart failure. To date, only ∼30% of the interindividual variability in iron absorption can be captured by iron status biomarkers or iron regulatory hormones. Much of the regulation of iron absorption may be under genetic control, but these pathways have yet to be fully elucidated. Genome-wide and candidate gene association studies have identified several genetic variants that are associated with variations in iron status, but the majority of these data were generated in European populations. The purpose of this review is to summarize genetic variants that have been associated with alterations in iron status and to highlight the influence of ethnicity on the risk of iron deficiency or overload. Using extant data in the literature, linear mixed-effects models were constructed to explore ethnic differences in iron status biomarkers. This approach found that East Asians had significantly higher concentrations of iron status indicators (serum ferritin, transferrin saturation, and hemoglobin) than Europeans, African Americans, or South Asians. African Americans exhibited significantly lower hemoglobin concentrations compared with other ethnic groups. Further studies of the genetic basis for ethnic differences in iron metabolism and on how it affects disease susceptibility among different ethnic groups are needed to inform population-specific recommendations and personalized nutrition interventions for iron-related disorders.
| S-EPMC8483971 | biostudies-literature
Project description:Background and Purpose- Both iron deficiency and excess have been associated with stroke risk in observational studies. However, such associations may be attributable to confounding from environmental factors. This study uses the Mendelian randomization technique to overcome these limitations by investigating the association between genetic variants related to iron status and stroke risk. Methods- A study of 48?972 subjects performed by the Genetics of Iron Status consortium identified genetic variants with concordant relations to 4 biomarkers of iron status (serum iron, transferrin saturation, ferritin, and transferrin) that supported their use as instruments for overall iron status. Genetic estimates from the MEGASTROKE consortium were used to investigate the association between the same genetic variants and stroke risk. The 2-sample ratio method Mendelian randomization approach was used for the main analysis, with the MR-Egger and weighted median techniques used in sensitivity analyses. Results- The main results, reported as odds ratio (OR) of stroke per SD unit increase in genetically determined iron status biomarker, showed a detrimental effect of increased iron status on stroke risk (serum iron OR, 1.07; 95% CI, 1.01-1.14; [log-transformed] ferritin OR, 1.18; 95% CI, 1.02-1.36; and transferrin saturation OR, 1.06; 95% CI, 1.01-1.11). A higher transferrin, indicative of lower iron status, was also associated with decreased stroke risk (OR, 0.92; 95% CI, 0.86-0.99). Examining ischemic stroke subtypes, we found the detrimental effect of iron status to be driven by cardioembolic stroke. These results were supported in statistical sensitivity analyses more robust to the inclusion of pleiotropic variants. Conclusions- This study provides Mendelian randomization evidence that higher iron status is associated with increased stroke risk and, in particular, cardioembolic stroke. Further work is required to investigate the underlying mechanism and whether this can be targeted in preventative strategies.
| S-EPMC6257507 | biostudies-literature
Project description:Macrophages play crucial roles in innate immune response and in the priming of adaptive immunity, and are characterized by their phenotypic heterogeneity and plasticity. Reprogramming intracellular metabolism in response to microenvironmental signals is required for M1/M2 macrophage polarization and function. Here we assessed the influence of iron on the polarization of the immune response in vivo and in vitro. Iron-enriched diet increased M2 marker Arg1 and Ym1 expression in liver and peritoneal macrophages, while iron deficiency decreased Arg1 expression. Under LPS-induced inflammatory conditions, low iron diet exacerbated the proinflammatory response, while the IL-12/IL-10 balance decreased with iron-rich diet, thus polarizing toward type 2 response. Indeed, in vitro macrophage iron loading reduced the basal percentage of cells expressing M1 co-stimulatory CD86 and MHC-II molecules. Further, iron loading of macrophages prevented the pro-inflammatory response induced by LPS through reduction of NF-?B p65 nuclear translocation with decreased iNOS, IL-1?, IL-6, IL-12 and TNF? expression. The increase of intracellular iron also reduced LPS-induced hepcidin gene expression and abolished ferroportin down-regulation in macrophages, in line with macrophage polarization. Thus, iron modulates the inflammatory response outcome, as elevated iron levels increased M2 phenotype and negatively regulated M1 proinflammatory LPS-induced response.
| S-EPMC5957380 | biostudies-literature
Project description:We report the RNA-seq based analyses of the transcriptional changes in the Aedes aegypti midguts transcriptome 24,48 hours after blood feeding with or without 250 um ferric ammonium citrate.
2019-08-30 | GSE119036 | GEO
Project description:Iron deficiency is common worldwide and is associated with adverse pregnancy outcomes. The increasing prevalence of indiscriminate iron supplementation during pregnancy also raises concerns about the potential adverse effects of iron excess. We examined how maternal iron status affects the delivery of iron to the placenta and fetus. Using mouse models, we documented maternal homeostatic mechanisms that protect the placenta and fetus from maternal iron excess. We determined that under physiological conditions or in iron deficiency, fetal and placental hepcidin did not regulate fetal iron endowment. With maternal iron deficiency, critical transporters mediating placental iron uptake (transferrin receptor 1 [TFR1]) and export (ferroportin [FPN]) were strongly regulated. In mice, not only was TFR1 increased, but FPN was surprisingly decreased to preserve placental iron in the face of fetal iron deficiency. In human placentas from pregnancies with mild iron deficiency, TFR1 was increased, but there was no change in FPN. However, induction of more severe iron deficiency in human trophoblast in vitro resulted in the regulation of both TFR1 and FPN, similar to what was observed in the mouse model. This placental adaptation that prioritizes placental iron is mediated by iron regulatory protein 1 (IRP1) and is important for the maintenance of mitochondrial respiration, thus ultimately protecting the fetus from the potentially dire consequences of generalized placental dysfunction.
| S-EPMC6994143 | biostudies-literature
Project description:Although uncommon, iron deficiency (ID) occurs in breastfed infants. The regular provision of iron may prevent ID.The objective was to test the feasibility and effectiveness of 2 modalities of providing iron (medicinal iron or iron-fortified cereal) to breastfed infants. The study tested the hypothesis that regular provision of iron improves iron status of breastfed infants without adverse effects.In this prospective, randomized, open-label trial, breastfed infants received on a regular basis either medicinal iron (n = 48) or an iron-fortified fruit-cereal combination (n = 45) from 4 to 9 mo or no intervention (control group; n = 59). The interventions provided 7.0-7.5 mg ferrous sulfate/d. Infants were enrolled at 1 mo and were followed to 2 y. Iron-status indicators were determined periodically, stool characteristics were recorded, and growth was monitored.The regular provision of iron led to improved iron status during and for some months after the intervention. Both sources of iron were about equally effective. Iron affected stool color but had no effect on feeding-related behavior. However, medicinal iron was associated with a small but significant reduction in length gain and a trend toward reduced weight gain. ID anemia was observed in 4 infants (2.3%), most of whom had a low birth iron endowment. Mild ID was common in the second year of life.Regular provision of medicinal iron or iron-fortified cereal improves the iron status of breastfed infants and may prevent ID. Both modalities are equally effective, but medicinal iron leads to somewhat reduced growth. This trial was registered at ClinicalTrials.gov as NCT00760890.
| S-EPMC2696996 | biostudies-literature
Project description:PurposeIron is essential for oxygen transport and oxidative metabolism; however, elevated iron stores can trigger overproduction of reactive oxygen species and induce DNA damage. Little is known about the association between body iron stores and glioma risk. This study examined the associations of iron levels measured in toenails and genetic variants linked to body iron stores with risk of glioma in a clinic-based case-control study.MethodsSamples were collected a median of 24 days following glioma diagnosis in the cases (10th-90th percentile, range: 10-44 days). Nail iron levels were measured in 300 cases and 300 controls using neutron activation analysis. A total of 24 genetic variants associated with iron status were genotyped in 622 cases and 628 controls. Logistic regression was used to estimate odds ratios (OR) and 95 % confidence intervals (CI) for glioma risk according to toenail iron and the examined genotypes.ResultsNo association was observed between toenail iron and glioma risk when restricting to cases with nails collected within ~3 weeks of diagnosis (OR = 0.93; 95 % CI 0.46, 1.87 comparing those with high (≥14 μg/g) vs. low (<6 μg/g) iron levels). In contrast, an inverse association with increasing iron was observed after restricting to cases with a delay of 3 weeks or greater (OR = 0.42; 95 % CI 0.19, 0.95), reflecting potentially insidious effects of advancing disease on iron levels among the cases. No associations were observed for any of the examined genetic variants.ConclusionThe results do not support a role for body iron stores as a determinant of glioma risk.
| S-EPMC3823695 | biostudies-literature
Project description:Background & aimsSystemic iron status affects multiple health outcomes, however its net effect on life expectancy is not known. We conducted a two-sample Mendelian randomization (MR) study to investigate the association of genetically proxied iron status with life expectancy.MethodsUsing genetic data from 48,972 individuals, we identified three genetic variants as instrumental variables for systemic iron status. We obtained genetic associations of these variants with parental lifespan (n = 1,012,240) and individual survival to the 90th vs. 60th percentile age (11,262 cases and 25,483 controls). We used the inverse-variance weighted method to estimate the effect of a 1-standard deviation (SD) increase in genetically predicted serum iron on each of the life expectancy outcomes.ResultsWe found a detrimental effect of genetically proxied higher iron status on life expectancy. A 1-SD increase in genetically predicted serum iron corresponded to 0.70 (95% confidence interval [CI] -1.17, -0.24; P = 3.00 × 10-3) fewer years of parental lifespan and had odds ratio 0.81 (95% CI 0.70, 0.93; P = 4.44 × 10-3) for survival to the 90th vs. 60th percentile age. We did not find evidence to suggest that these results were biased by pleiotropic effects of the genetic variants.ConclusionsHigher systemic iron status may reduce life expectancy. The clinical implications of this finding warrant further investigation, particularly in the context of iron supplementation in individuals with normal iron status.
| S-EPMC8063605 | biostudies-literature