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Biometals : An International Journal on... Jun 2019Inadequate iron levels during early life can have adverse consequences for the developing infant. Iron deficiency during this critical period of growth can affect brain... (Review)
Review
Inadequate iron levels during early life can have adverse consequences for the developing infant. Iron deficiency during this critical period of growth can affect brain development and cognitive function, problems that can be lifelong despite subsequent correction of the iron deficit. Therefore, it is critical that the suckling infant has sufficient iron for their developmental needs. Much of the iron used in the immediate post-natal period is stored iron that was acquired from the mother in the final trimester of pregnancy, however, despite having low iron levels, breast milk can also make a significant contribution to infant iron needs. This reflects the ability of the suckling infant to absorb dietary iron far more efficiently than is possible after weaning. The mechanisms underlying this enhanced iron absorption are poorly understood. The iron export protein ferroportin is essential for this process, as it is in adults, however, the role of other molecules normally involved in iron absorption following weaning is less clear. The composition and distribution of iron in breast milk may be important, as could the contribution of more distal parts of the gastrointestinal tract. This review discusses the potential role of each of the above components in intestinal iron absorption during suckling and highlights the need for further research into this important process.
Topics: Animals; Animals, Suckling; Humans; Intestinal Absorption; Iron; Iron Deficiencies; Iron, Dietary
PubMed: 30798502
DOI: 10.1007/s10534-019-00181-9 -
Lancet (London, England) Aug 2007Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when... (Review)
Review
Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming monotonous plant-based diets. The high prevalence of iron deficiency in the developing world has substantial health and economic costs, including poor pregnancy outcome, impaired school performance, and decreased productivity. Recent studies have reported how the body regulates iron absorption and metabolism in response to changing iron status by upregulation or downregulation of key intestinal and hepatic proteins. Targeted iron supplementation, iron fortification of foods, or both, can control iron deficiency in populations. Although technical challenges limit the amount of bioavailable iron compounds that can be used in food fortification, studies show that iron fortification can be an effective strategy against nutritional iron deficiency. Specific laboratory measures of iron status should be used to assess the need for fortification and to monitor these interventions. Selective plant breeding and genetic engineering are promising new approaches to improve dietary iron nutritional quality.
Topics: Adolescent; Adult; Biological Availability; Child; Child, Preschool; Developing Countries; Female; Food, Fortified; Humans; Infant; Iron; Iron Deficiencies; Iron, Dietary; Male; Middle Aged; Nutritional Requirements; Prevalence
PubMed: 17693180
DOI: 10.1016/S0140-6736(07)61235-5 -
International Journal For Vitamin and... Jun 2024Animal models have suggested the carcinogenic effect of iron due to its oxidative potential. The lung is particularly vulnerable to oxidative stress. However,... (Meta-Analysis)
Meta-Analysis Review
Animal models have suggested the carcinogenic effect of iron due to its oxidative potential. The lung is particularly vulnerable to oxidative stress. However, epidemiological studies investigating the association between dietary iron and the risk of lung cancer have reported inconclusive results. In this systematic review and meta-analysis, we aimed to clarify this association. We searched PubMed, Web of Science, Scopus and Google scholar for eligible articles published through May 2023 reporting the Relative Risk (RR), Hazard Ratio (HR) or Odds Ratio (OR) with 95% confidence interval (95% CI). Case-control and cohort studies that examined the relationship between dietary iron and lung cancer risk were included and review and meta-analyses articles, experimental studies, abstracts, letters to editor and studies with insufficient data were excluded. Finally, three case-control studies and 6 cohort studies were included. Random effect models were used to calculate the pooled results. Nine studies (cases =21,943, participants =1,542,993) were included. There were no significant associations between the highest dietary total iron (heme and non-heme) (RR: 1.09, 95% CI: 0.78 to 1.51) or heme iron (RR: 1.01, 95% CI: 0.73 to 1.38) intake compared to the lowest intake with lung cancer risk. Null-associations were also observed in the subgroup analysis based on smoking status and lung cancer histology. However, in the subgroup of women (cases =5074), heme iron was associated with a 14% increase in the risk of lung cancer (RR: 1.14, 95% CI: 1.01 to 1.29). The current results demonstrated that there is no significant relationship between dietary iron intake and the risk of lung cancer. However, a positive association was observed between dietary heme iron and the risk of lung cancer in women, which may require further investigation.
Topics: Lung Neoplasms; Humans; Iron, Dietary; Risk Factors; Diet; Female; Heme; Male
PubMed: 37469109
DOI: 10.1024/0300-9831/a000789 -
Critical Reviews in Food Science and... 2016Iron is an essential micronutrient that is involved in many redox processes and serves as an integral component in various physiological functions. However, excess iron... (Review)
Review
Iron is an essential micronutrient that is involved in many redox processes and serves as an integral component in various physiological functions. However, excess iron can cause tissue damage through its pro-oxidative effects, potentiating the development of many diseases such as cancer through the generation of reactive oxidative species. The two major forms of iron in the diet are heme and nonheme iron, both of which are found in several different foods. In addition to natural food sources, intake of nonheme iron may also come from fortified foods or in supplement form. This review summarizes the results of human population studies that have examined the role of dietary iron (heme and nonheme), heme iron alone, and iron from supplements in colorectal carcinogenesis.
Topics: Colorectal Neoplasms; Diet; Dietary Supplements; Food, Fortified; Humans; Iron, Dietary; Risk Factors
PubMed: 25574701
DOI: 10.1080/10408398.2012.749208 -
Nutrition Reviews Jan 2017In light of evidence that high-dose iron supplements lead to a range of adverse events in low-income settings, the safety and efficacy of lower doses of iron provided... (Review)
Review
In light of evidence that high-dose iron supplements lead to a range of adverse events in low-income settings, the safety and efficacy of lower doses of iron provided through biological or industrial fortification of foodstuffs is reviewed. First, strategies for point-of-manufacture chemical fortification are compared with biofortification achieved through plant breeding. Recent insights into the mechanisms of human iron absorption and regulation, the mechanisms by which iron can promote malaria and bacterial infections, and the role of iron in modifying the gut microbiota are summarized. There is strong evidence that supplemental iron given in nonphysiological amounts can increase the risk of bacterial and protozoal infections (especially malaria), but the use of lower quantities of iron provided within a food matrix, ie, fortified food, should be safer in most cases and represents a more logical strategy for a sustained reduction of the risk of deficiency by providing the best balance of risk and benefits. Further research into iron compounds that would minimize the availability of unabsorbed iron to the gut microbiota is warranted.
Topics: Anemia, Iron-Deficiency; Biofortification; Diet; Dietary Supplements; Dose-Response Relationship, Drug; Food, Fortified; Gastrointestinal Microbiome; Hepcidins; Humans; Iron, Dietary; Malaria; Nutritional Status; Randomized Controlled Trials as Topic
PubMed: 27974599
DOI: 10.1093/nutrit/nuw055 -
European Journal of Sport Science Mar 2018Maintaining a positive iron balance is essential for female athletes to avoid the effects of iron deficiency and anaemia and to maintain or improve performance. A major... (Review)
Review
Maintaining a positive iron balance is essential for female athletes to avoid the effects of iron deficiency and anaemia and to maintain or improve performance. A major function of iron is in the production of the oxygen and carbon dioxide carrying molecule, haemoglobin, via erythropoiesis. Iron balance is under the control of a number of factors including the peptide hormone hepcidin, dietary iron intake and absorption, environmental stressors (e.g. altitude), exercise, menstrual blood loss and genetics. Menstruating females, particularly those with heavy menstrual bleeding are at an elevated risk of iron deficiency. Haemoglobin concentration [Hb] and serum ferritin (sFer) are traditionally used to identify iron deficiency, however, in isolation these may have limited value in athletes due to: (1) the effects of fluctuations in plasma volume in response to training or the environment on [Hb], (2) the influence of inflammation on sFer and (3) the absence of sport, gender and individually specific normative data. A more detailed and longitudinal examination of haematology, menstrual cycle pattern, biochemistry, exercise physiology, environmental factors and training load can offer a superior characterisation of iron status and help to direct appropriate interventions that will avoid iron deficiency or iron overload. Supplementation is often required in iron deficiency; however, nutritional strategies to increase iron intake, rest and descent from altitude can also be effective and will help to prevent future iron deficient episodes. In severe cases or where there is a time-critical need, such as major championships, iron injections may be appropriate.
Topics: Athletes; Athletic Performance; Dietary Supplements; Exercise; Female; Hemoglobins; Humans; Iron Deficiencies; Iron, Dietary; Menstruation; Nutritional Requirements; Sports Nutritional Physiological Phenomena
PubMed: 29280410
DOI: 10.1080/17461391.2017.1416178 -
BMC Medicine Oct 2012Excess iron has been shown to induce diabetes in animal models. However, the results from human epidemiologic studies linking body iron stores and iron intake to the... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Excess iron has been shown to induce diabetes in animal models. However, the results from human epidemiologic studies linking body iron stores and iron intake to the risk of type 2 diabetes mellitus (T2DM) are conflicting. In this study, we aimed to systematically evaluate the available evidence for associations between iron intake, body iron stores, and the risk of T2DM.
METHODS
A systematic search of the PubMed/MEDLINE and EMBASE databases to the end of 22 April 2012 was performed, and reference lists of retrieved articles were screened. Two reviewers independently evaluated the eligibility of inclusion and extracted the data. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random-effects models.
RESULTS
We reviewed 449 potentially relevant articles, and 11 prospective studies were included in the analysis. A meta-analysis of five studies gave a pooled RR for T2DM of 1.33 (95% CI 1.19 to 1.48; P<0.001) in individuals with the highest level of heme iron intake, compared with those with the lowest level. The pooled RR for T2DM for a daily increment of 1 mg of heme iron intake was 1.16 (1.09 to 1.23, P<0.001). Body iron stores, as measured by ferritin, soluble transferrin receptor (sTfR) and the sTfR:ferritin ratio, were significantly associated with the risk of T2DM. The pooled RRs for T2DM in individuals with the highest versus the lowest intake of ferritin levels was 1.70 (1.27-2.27, P<0.001) before adjustment for inflammatory markers and 1.63 (1.03-2.56, P = 0.036) after adjustment. We did not find any significant association of dietary intakes of total iron, non-heme, or supplemental iron intake with T2DM risk.
CONCLUSION
Higher heme iron intake and increased body iron stores were significantly associated with a greater risk of T2DM. Dietary total iron, non-heme iron, or supplemental iron intakes were not significantly associated with T2DM risk.
Topics: Adult; Aged; Animals; Diabetes Mellitus, Type 2; Female; Humans; Iron; Iron, Dietary; Male; Middle Aged; Risk Assessment; Young Adult
PubMed: 23046549
DOI: 10.1186/1741-7015-10-119 -
Protein and Peptide Letters 2017Dietary iron is a crucial nutrient element for biological processes of both hosts and gut microbiota. Deficiency in dietary iron is a highly common disorder in the... (Review)
Review
Dietary iron is a crucial nutrient element for biological processes of both hosts and gut microbiota. Deficiency in dietary iron is a highly common disorder in the developing locations of the world and can be healed by oral iron administration or complementary iron diet. While the redundant iron that enters the gut lumen leads to negative effects, and modulates the gut microbial composition and function. Such modulation led to a significant effect on vital biological pathways of the host, including metabolic disease (obesity and type 2 diabetes), metabolites (SCFA, blood glucose and cholesterol), bile acid metabolism, endocrine, neural, and other well-being patterns. This review covers the multifaceted aspects of different nutritional iron stress on the composition and function of microbial gut in monogastrics and consequential health conditions as well as it reveals unclear points that need further studies.
Topics: Anemia; Animals; Gastrointestinal Microbiome; Humans; Iron Deficiencies; Iron, Dietary; Metabolic Diseases
PubMed: 28266265
DOI: 10.2174/0929866524666170306094414 -
The American Journal of Clinical... Aug 2013Hereditary hemochromatosis (HH) leads to iron loading because of a disturbance in the negative-feedback mechanism between dietary iron absorption and iron status. The... (Review)
Review
BACKGROUND
Hereditary hemochromatosis (HH) leads to iron loading because of a disturbance in the negative-feedback mechanism between dietary iron absorption and iron status. The management of HH is achieved by repeated phlebotomies.
OBJECTIVE
We investigated whether HH patients would benefit from a diet with low iron intake and bioavailability.
DESIGN
We performed a systematic review of studies that linked iron bioavailability and status with dietary factors in subjects with diagnosed HH. Studies on heterozygotes for the HFE mutation were excluded.
RESULTS
No prospective, randomized study was reported. Nine studies that directly measured iron bioavailability from test meals in HH patients have been described as well as 3 small, prospective, longitudinal studies in HH patients. Eight cross-sectional studies were identified that investigated the effect of dietary composition on iron status. Calculations of iron bioavailability in HH were made by extrapolating data on hepcidin concentrations and their association with iron bioavailability. The potential reduction in the yearly amount of blood to be phlebotomized when restricting dietary iron absorbed was estimated in the 3 longitudinal studies and ranged between 0.5 and 1.5 L. This amount would be dependent on individual disease penetrance as well as the dietary intervention.
CONCLUSIONS
Despite the limited quantitative evidence and the lack of randomized, prospective trials, dietary interventions that modify iron intake and bioavailability may affect iron accumulation in HH patients. Although this measure may be welcome in patients willing to contribute to their disease management, limited data exist on the clinical and quality-of-life benefit.
Topics: Absorption; Antimicrobial Cationic Peptides; Biological Availability; Diet; Hemochromatosis; Hepcidins; Heterozygote; Humans; Iron, Dietary; Mutation; Penetrance
PubMed: 23803887
DOI: 10.3945/ajcn.112.048264 -
Current Opinion in Clinical Nutrition... Nov 2013Both dietary and nondietary factors contribute to iron deficiency, the most common nutritional deficiency worldwide. Identifying dietary factors associated with iron... (Review)
Review
PURPOSE OF REVIEW
Both dietary and nondietary factors contribute to iron deficiency, the most common nutritional deficiency worldwide. Identifying dietary factors associated with iron deficiency is challenging due to the number of components in food affecting iron absorption. This review describes recent advances in dietary approaches to assessing iron-related nutrition.
RECENT FINDINGS
Most research investigating the relationship between dietary intake and iron deficiency has focussed on individual foods and nutrients, despite several components in foods influencing iron absorption. More recently, studies have considered the overall diet and combinations of foods eaten, through the analysis of dietary patterns and practices. This includes the development and validation of dietary assessment tools to assess iron-related dietary patterns.
SUMMARY
Dietary pattern analysis which considers the whole diet and combinations of foods eaten may enhance our understanding of how diet impacts on iron deficiency. The analysis of dietary patterns offers an alternative and complementary approach to the traditional focus on individual foods and nutrients when investigating dietary factors associated with iron deficiency.
Topics: Anemia, Iron-Deficiency; Animals; Diet; Disease Models, Animal; Feeding Behavior; Humans; Iron, Dietary; Nutrition Assessment; Nutritional Status; Reproducibility of Results
PubMed: 23945220
DOI: 10.1097/MCO.0b013e328364f382