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Wheat flour fortification with iron and other micronutrients for reducing anaemia and improving iron status in populations.
Field, MS, Mithra, P, Peña-Rosas, JP
The Cochrane database of systematic reviews. 2021;(1):CD011302
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Abstract
BACKGROUND Anaemia is a condition where the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body's physiological needs. Fortification of wheat flour is deemed a useful strategy to reduce anaemia in populations. OBJECTIVES To determine the benefits and harms of wheat flour fortification with iron alone or with other vitamins and minerals on anaemia, iron status and health-related outcomes in populations over two years of age. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, CINAHL, 21 other databases and two trials registers up to 21 July 2020, together with contacting key organisations to identify additional studies. SELECTION CRITERIA We included cluster- or individually-randomised controlled trials (RCTs) carried out among the general population from any country, aged two years and above. The interventions were fortification of wheat flour with iron alone or in combination with other micronutrients. We included trials comparing any type of food item prepared from flour fortified with iron of any variety of wheat DATA COLLECTION AND ANALYSIS Two review authors independently screened the search results and assessed the eligibility of studies for inclusion, extracted data from included studies and assessed risks of bias. We followed Cochrane methods in this review. MAIN RESULTS Our search identified 3538 records, after removing duplicates. We included 10 trials, involving 3319 participants, carried out in Bangladesh, Brazil, India, Kuwait, Philippines, South Africa and Sri Lanka. We identified two ongoing studies and one study is awaiting classification. The duration of interventions varied from 3 to 24 months. One study was carried out among adult women and one trial among both children and nonpregnant women. Most of the included trials were assessed as low or unclear risk of bias for key elements of selection, performance or reporting bias. Three trials used 41 mg to 60 mg iron/kg flour, three trials used less than 40 mg iron/kg and three trials used more than 60 mg iron/kg flour. One trial used various iron levels based on type of iron used: 80 mg/kg for electrolytic and reduced iron and 40 mg/kg for ferrous fumarate. All included studies contributed data for the meta-analyses. Iron-fortified wheat flour with or without other micronutrients added versus wheat flour (no added iron) with the same other micronutrients added Iron-fortified wheat flour with or without other micronutrients added versus wheat flour (no added iron) with the same other micronutrients added may reduce by 27% the risk of anaemia in populations (risk ratio (RR) 0.73, 95% confidence interval (CI) 0.55 to 0.97; 5 studies, 2315 participants; low-certainty evidence). It is uncertain whether iron-fortified wheat flour with or without other micronutrients reduces iron deficiency (RR 0.46, 95% CI 0.20 to 1.04; 3 studies, 748 participants; very low-certainty evidence) or increases haemoglobin concentrations (in g/L) (mean difference MD 2.75, 95% CI 0.71 to 4.80; 8 studies, 2831 participants; very low-certainty evidence). No trials reported data on adverse effects in children (including constipation, nausea, vomiting, heartburn or diarrhoea), except for risk of infection or inflammation at the individual level. The intervention probably makes little or no difference to the risk of Infection or inflammation at individual level as measured by C-reactive protein (CRP) (mean difference (MD) 0.04, 95% CI -0.02 to 0.11; 2 studies, 558 participants; moderate-certainty evidence). Iron-fortified wheat flour with other micronutrients added versus unfortified wheat flour (nil micronutrients added) It is unclear whether wheat flour fortified with iron, in combination with other micronutrients decreases anaemia (RR 0.77, 95% CI 0.41 to 1.46; 2 studies, 317 participants; very low-certainty evidence). The intervention probably reduces the risk of iron deficiency (RR 0.73, 95% CI 0.54 to 0.99; 3 studies, 382 participants; moderate-certainty evidence) and it is unclear whether it increases average haemoglobin concentrations (MD 2.53, 95% CI -0.39 to 5.45; 4 studies, 532 participants; very low-certainty evidence). No trials reported data on adverse effects in children. Nine out of 10 trials reported sources of funding, with most having multiple sources. Funding source does not appear to have distorted the results in any of the assessed trials. AUTHORS' CONCLUSIONS Fortification of wheat flour with iron (in comparison to unfortified flour, or where both groups received the same other micronutrients) may reduce anaemia in the general population above two years of age, but its effects on other outcomes are uncertain. Iron-fortified wheat flour in combination with other micronutrients, in comparison with unfortified flour, probably reduces iron deficiency, but its effects on other outcomes are uncertain. None of the included trials reported data on adverse side effects except for risk of infection or inflammation at the individual level. The effects of this intervention on other health outcomes are unclear. Future studies at low risk of bias should aim to measure all important outcomes, and to further investigate which variants of fortification, including the role of other micronutrients as well as types of iron fortification, are more effective, and for whom.
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Using iron-based phosphate binders in phosphate reduction and anemia improvement in patients receiving dialysis: a meta-analysis of randomized controlled trials.
Zhu, Y, Rao, J, Liao, X, Ou, J, Li, W, Xue, C
International urology and nephrology. 2021;(9):1899-1909
Abstract
PURPOSE A study was conducted to determine whether iron-based phosphate binders (IBPBs) need to be preferred for hyperphosphatemia and anemia management in patients on dialysis. METHODS For this meta-analysis, we searched PubMed, Embase, and Cochrane Central Register of Controlled Trials for randomized controlled trials that evaluated the efficacy and safety of IBPBs in decreasing phosphate and correcting anemia in dialysis patients. RESULTS Nineteen trials comprising 4719 participants were included. Compared with placebo, serum phosphate decreased significantly after treatment with ferric citrate (FC), fermagate (one study), and SBR759 (one study). Hemoglobin increased significantly after treatment with FC and sucroferric oxyhydroxide (PA21). In addition, FC and PA21 reduced serum intact parathyroid hormone (iPTH) and increased ferritin and transferrin saturation, but SBR759 did not. Compared with active treatment, the non-inferiority of IBPBs in reducing serum phosphate and iPTH was demonstrated. FC significantly improved serum hemoglobin and iron-related parameters and decreased the use of intravenous iron and erythropoiesis-stimulating agent, whereas PA21 did not increase serum hemoglobin level. The incidences of infection and hospitalization were similar between the two groups, with FC having a higher risk of diarrhea than the placebo and active treatments. CONCLUSION FC was associated with the control of hyperphosphatemia and the improvement of anemia. However, PA21 did not show superiority for alleviating anemia compared with the active treatment. Other IBPBs, such as fermagate and SBR759, remained poorly understood due to the limited number of studies. Further trials are required to assess the effect of IBPBs on the risk of cardiovascular events and all-cause mortality.
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Effects of dietary polyphenol supplementation on iron status and erythropoiesis: a systematic review and meta-analysis of randomized controlled trials.
Xu, T, Zhang, X, Liu, Y, Wang, H, Luo, J, Luo, Y, An, P
The American journal of clinical nutrition. 2021;(2):780-793
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Abstract
BACKGROUND The iron-chelating activities of polyphenols raise concern whether there is a risk of iron deficiency or anemia induced by polyphenol supplementation. Results from clinical trials regarding the effects of polyphenol supplementation on iron status and erythropoiesis are inconclusive. OBJECTIVE We performed a systematic review and meta-analysis of randomized controlled trials to determine the effects of polyphenol supplementation on iron status and erythropoiesis. METHODS Published articles were searched between May 1988 and 7 December, 2020. Finally, we identified 34 randomized controlled trials. Random-effects meta-analyses were performed to obtain the weighted mean difference of serum iron (SI), transferrin saturation (TS), ferritin, and hemoglobin concentration. Funnel plots and Egger's test were used to determine the risk of bias. The robustness of the effect sizes was examined by sensitivity analysis. RESULTS Polyphenol supplementation had an inhibitory effect on the SI concentration (-13.72 μg/dL; 95% CI: -20.74, -6.71) and TS (-3.10%; 95% CI: -4.93, -1.27), with no effect on ferritin (-9.34 ng/mL; 95% CI: -28.55, 9.87). Polyphenols increased the hemoglobin concentration (8.53 g/L; 95% CI: 3.33, 13.73). In healthy participants, polyphenol reduced the TS (-3.83%; 95% CI: -7.47, -0.19) and increased the hemoglobin concentration (12.87 g/L; 95% CI: 1.61, 24.14). Similarly, polyphenol reduced the SI concentration (-8.60 μg/dL; 95% CI: -16.10, -1.10) and increased the hemoglobin concentration (8.50 g/L; 95% CI: 0.86, 16.15) in patients with metabolic diseases. In patients with β-thalassemia, polyphenol decreased the SI concentration (-23.19 μg/dL; 95% CI: -35.84, -10.55), TS (-3.23%; 95% CI: -5.54, -0.91), and ferritin concentration (-223.62 ng/mL; 95% CI: -359.32, -87.91), but had no effect on the hemoglobin concentration. CONCLUSION Healthy individuals and patients with metabolic diseases may benefit from the positive impact of polyphenols on erythropoiesis. Patients with β-thalassemia may benefit from the effect of polyphenols on reducing SI. This trial was registered at PROSPERO (International prospective register of systematic reviews) as CRD42020161983.
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Effects of hypoxia-inducible factor prolyl hydroxylase inhibitors on iron regulation in non-dialysis-dependent chronic kidney disease patients with anemia: A systematic review and meta-analysis.
Li, J, Xie, QH, You, L, Xu, NX, Hao, CM
Pharmacological research. 2021;:105256
Abstract
Phase 2 and phase 3 clinical studies showed that hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) efficiently increased hemoglobin levels in both dialysis-dependent and non-dialysis-dependent chronic kidney disease (CKD) patients. However, the effects of HIF-PHIs on iron regulation have not been consistent among clinical trials. We performed a systematic review and meta-analysis of randomized controlled trials to evaluate the effects of six HIF-PHIs on iron regulation in non-dialysis CKD patients. Electronic databases were searched from inception to April 20, 2020, for eligible studies. Changes from baseline in transferrin saturation (TSAT), total iron-binding capacity (TIBC), iron, ferritin, and hepcidin levels were pooled using the inverse-variance method and presented as the mean difference (MD) or standardized MD (SMD) with 95 % confidence intervals (CIs). Meta-analysis of the included studies showed that, in non-dialysis-dependent CKD patients, HIF-PHIs decreased TSAT (MD, -4.51; 95 % CI, -5.81 to -3.21), ferritin (MD, -47.29; 95 % CI, -54.59 to -40.00) and hepcidin (SMD, -0.94; 95 % CI, -1.25 to -0.62), increased TIBC (MD, 9.15; 95 % CI, 7.08-11.22), and did not affect serum iron (MD, -0.31; 95 % CI, -2.05 to 1.42) despite enhanced erythropoiesis. This systematic review suggests that HIF-PHIs promote iron utilization in non-dialysis-dependent CKD patients. Importantly, HIF-PHIs are associated with increased transferrin levels (and TIBC), leading to reduced TSAT. Therefore, the reduction of TSAT after HIF-PHIs should not be interpreted as iron deficiency.
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Iron therapy in iron-deficiency patients with heart failure with preserved ejection fraction: A protocol for meta-analysis.
Fukuta, H, Hagiwara, H, Kamiya, T
Medicine. 2021;(32):e26919
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BACKGROUND Nearly half of patients with heart failure (HF) have preserved ejection fraction (EF) and the mortality and morbidity of patients with HF with preserved EF (HFpEF) are high. However, there is no established therapy to improve survival in these patients. HFpEF patients are often elderly and their primary chronic symptom is severe exercise intolerance. Thus, improvement of exercise capacity presents another important clinical outcome in HFpEF patients. Iron deficiency is common in HF patients, and the presence of iron deficiency, regardless of concomitant anemia, is associated with worse symptoms, impaired exercise capacity, and higher mortality and hospitalization in these patients. Several meta-analyses of randomized controlled trials reported that iron administration improved HF symptoms, exercise capacity, and clinical outcomes in iron-deficiency patients with HF with reduced EF. However, there is insufficient evidence as to the effect of iron administration in iron-deficiency HFpEF patients. METHODS AND RESULTS This meta-analysis will include randomized controlled trials on the effects of iron administration on HF symptoms, exercise capacity, and health-related quality of life in iron-deficiency HFpEF patients. Information of studies will be collected from PubMed, Web of Science, Cochrane Library, and ClinicalTrials.gov. The primary outcome will be exercise capacity (6-minute walking distance). The secondary outcomes will be HF symptoms, health-related quality of life, and mortality and hospitalization rates. CONCLUSION This meta-analysis will evaluate the effect of iron therapy in iron-deficiency HFpEF patients, providing evidence as to the iron administration in these patients. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42020205297.
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Intravenous iron for heart failure with evidence of iron deficiency: a meta-analysis of randomised trials.
Graham, FJ, Pellicori, P, Ford, I, Petrie, MC, Kalra, PR, Cleland, JGF
Clinical research in cardiology : official journal of the German Cardiac Society. 2021;(8):1299-1307
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BACKGROUND The recent AFFIRM-AHF trial assessing the effect of intravenous (IV) iron on outcomes in patients hospitalised with worsening heart failure who had iron deficiency (ID) narrowly missed its primary efficacy endpoint of recurrent hospitalisations for heart failure (HHF) or cardiovascular (CV) death. We conducted a meta-analysis to determine whether these results were consistent with previous trials. METHODS We searched for randomised trials of patients with heart failure investigating the effect of IV iron vs placebo/control groups that reported HHF and CV mortality from 1st January 2000 to 5th December 2020. Seven trials were identified and included in this analysis. A fixed effect model was applied to assess the effects of IV iron on the composite of first HHF or CV mortality and individual components of these. RESULTS Altogether, 2,166 patients were included (n = 1168 assigned to IV iron; n = 998 assigned to control). IV iron reduced the composite of HHF or CV mortality substantially [OR 0.73; (95% confidence interval 0.59-0.90); p = 0.003]. Outcomes were consistent for the pooled trials prior to AFFIRM-AHF. Whereas first HHF were reduced substantially [OR 0.67; (0.54-0.85); p = 0.0007], the effect on CV mortality was uncertain but appeared smaller [OR 0.89; (0.66-1.21); p = 0.47]. CONCLUSION Administration of IV iron to patients with heart failure and ID reduces the risk of the composite outcome of first heart failure hospitalisation or cardiovascular mortality, but this outcome may be driven predominantly by an effect on HHF. At least three more substantial trials of intravenous iron are underway.
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Intravenous iron therapy for patients with preoperative iron deficiency or anaemia undergoing cardiac surgery reduces blood transfusions: a systematic review and meta-analysis.
Gupta, S, Panchal, P, Gilotra, K, Wilfred, AM, Hou, W, Siegal, D, Whitlock, RP, Belley-Cote, EP
Interactive cardiovascular and thoracic surgery. 2020;(2):141-151
Abstract
OBJECTIVES The benefits of preoperative intravenous (IV) iron treatment in cardiac surgery patients with preoperative anaemia or iron deficiency have not been well-established. We performed a systematic review and meta-analysis to determine the effects of treating preoperative anaemia or iron deficiency with IV iron in adult cardiac surgery patients. METHODS We searched Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval Systems Online and Excerpta Medica Database for randomized controlled trials (RCTs) and observational studies comparing IV iron to oral iron or no iron. We performed title and abstract, full-text screening, data extraction and risk of bias assessment independently and in duplicate. We pooled data using a random effects model and evaluated the overall quality of evidence. RESULTS We identified 4 RCTs and 7 observational studies. Pooled data from observational studies suggested a benefit of IV iron compared to no iron on mortality [relative risk 0.39, 95% confidence interval (CI) 0.23-0.65; P < 0.001, very low quality], units transfused per patient (mean difference -1.22, 95% CI -1.85 to -0.60; P < 0.001, very low quality), renal injury (relative risk 0.50, 95% CI 0.36-0.69; P < 0.001, very low quality) and hospital length of stay (mean difference -4.24 days, 95% CI -6.86 to -1.63; P = 0.001, very low quality). Pooled data from RCTs demonstrated a reduction in the number of patients transfused with IV iron compared to oral or no iron (relative risk 0.81, 95% CI 0.70-0.94; P = 0.005, moderate quality). The pooled estimates of effect from RCTs for mortality, hospital length of stay, units transfused per patient and renal injury were consistent in direction with observational studies. CONCLUSIONS This meta-analysis suggests that IV iron improves postoperative morbidity in adult cardiac surgery patients with preoperative anaemia or iron deficiency. A large, rigorous, placebo-controlled, double-blinded, multicentre trial is needed to clarify the role of IV iron in this patient population. CLINICAL TRIAL REGISTRATION International prospective register of systematic reviews ID Number CRD42019122844.
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Iron homeostasis alterations and risk for akathisia in patients treated with antipsychotics: A systematic review and meta-analysis of cross-sectional studies.
Schoretsanitis, G, Nikolakopoulou, A, Guinart, D, Correll, CU, Kane, JM
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology. 2020;:1-11
Abstract
Iron homeostasis may be implicated in the pathophysiology of antipsychotic-related akathisia. We performed a systematic review in six databases from database inception until 03/2020, conducting a meta-analysis of studies investigating iron metabolism in antipsychotic-treated patients with versus without akathisia. Using a fixed- and a random-effects model, standardized mean difference (SMD) was estimated for levels of iron, ferritin, transferrin and total iron-binding capacity. Meta-regression analyses included sex, age, illness duration and antipsychotic treatment and dose. Subgroup analyses included chronic vs. acute akathisia and different diagnoses. Study quality was assessed using the Newcastle-Ottawa scale. In 10 studies (n = 395), compared to non-akathisia patients (n = 213), iron levels were lower in patients with akathisia (n = 182; fixed-effect model: SMD=-0.49, 95%CI=-0.28,-0.70, p<0.001; random-effects model: SMD=-0.55, 95%CI=-0.14,-0.96, p = 0.008). For secondary outcomes, differences were significant regarding lower ferritin levels in patients with akathisia in the fixed-effect model (SMD=-0.32, 95%CI=-0.08,-0.55, p = 0.007), but not in the random-effects model (SMD=-0.29, 95%CI=0.20,-0.79, p = 0.24). None of the moderators/mediators had a significant effect on the group difference of iron levels. Subgroup analyses reported lower iron levels in both patients with chronic and acute akathisia vs. patients without. Iron levels for schizophrenia patients were lower in the fixed-effect model (SMD=-0.55, 95%CI=-0.23, -0.86, p<0.001), while a trend was observed in the random-effects model (SMD=-0.52, 95%CI=-0.07, -1.12, p = 0.08). The studies' quality was overall poor, with one exception. This meta-analysis suggests lower iron levels in akathisia patients, while ferritin differences were significant only in the fixed-effect model. Further data are required to promote the understanding of related pathways.
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Can diet-induced weight loss improve iron homoeostasis in patients with obesity: A systematic review and meta-analysis.
Teng, IC, Tseng, SH, Aulia, B, Shih, CK, Bai, CH, Chang, JS
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2020;(12):e13080
Abstract
Despite the increasing worldwide prevalence of obesity and iron deficiency (ID), there are still no guidelines on how to treat and manage obesity-related ID. The aim of this systematic review and meta-analysis was to investigate whether weight loss can re-establish iron homoeostasis among subjects with unhealthy weight (overweight [OW] or obesity). PubMed, Medline, Embase, Web of Science, and the Cochrane Library were systemically searched for studies that compared the iron status before and after a weight-loss intervention. A random-effects model was used to calculate the pooled and subgroup weighted mean differences (WMDs) of iron biomarkers. In total, 879 subjects were pooled across 14 studies. Improved haemoglobin was found in longitudinal studies (WMD = 2.50 g/dl, 95% confidence interval [CI]: 0.88, 4.12 g/dl, I2 = 14%) but not in randomized controlled trials or after being stratified by dietary programmes. Significantly increased transferrin saturation was observed in pooled (WMD = 1.68%, 95% CI: 0.97%, 2.39%, I2 = 44%) and subgroup analyses. A meta-regression showed that changes in the iron status were positively correlated with changes in the body mass index (BMI) and the intervention duration but negatively correlated with the baseline body weight/BMI, age, gender and a standard hypocaloric diet. Our data suggested that in spite of energy restrictions, weight loss may help re-establish iron homoeostasis in people who are OW or obese.
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10.
Wheat flour fortification with iron for reducing anaemia and improving iron status in populations.
Field, MS, Mithra, P, Estevez, D, Peña-Rosas, JP
The Cochrane database of systematic reviews. 2020;(7):CD011302
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Abstract
BACKGROUND Anaemia is a condition where the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body's physiologic needs. Fortification of wheat flour is deemed a useful strategy to reduce anaemia in populations. OBJECTIVES To determine the benefits and harms of wheat flour fortification with iron alone or with other vitamins and minerals on anaemia, iron status and health-related outcomes in populations over two years of age. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, CINAHL, and other databases up to 4 September 2019. SELECTION CRITERIA We included cluster- or individually randomised controlled trials (RCT) carried out among the general population from any country aged two years and above. The interventions were fortification of wheat flour with iron alone or in combination with other micronutrients. Trials comparing any type of food item prepared from flour fortified with iron of any variety of wheat were included. DATA COLLECTION AND ANALYSIS Two review authors independently screened the search results and assessed the eligibility of studies for inclusion, extracted data from included studies and assessed risk of bias. We followed Cochrane methods in this review. MAIN RESULTS Our search identified 3048 records, after removing duplicates. We included nine trials, involving 3166 participants, carried out in Bangladesh, Brazil, India, Kuwait, Phillipines, Sri Lanka and South Africa. The duration of interventions varied from 3 to 24 months. One study was carried out among adult women and one trial among both children and nonpregnant women. Most of the included trials were assessed as low or unclear risk of bias for key elements of selection, performance or reporting bias. Three trials used 41 mg to 60 mg iron/kg flour, two trials used less than 40 mg iron/kg and three trials used more than 60 mg iron/kg flour. One trial employed various iron levels based on type of iron used: 80 mg/kg for electrolytic and reduced iron and 40 mg/kg for ferrous fumarate. All included studies contributed data for the meta-analyses. Seven studies compared wheat flour fortified with iron alone versus unfortified wheat flour, three studies compared wheat flour fortified with iron in combination with other micronutrients versus unfortified wheat flour and two studies compared wheat flour fortified with iron in combination with other micronutrients versus fortified wheat flour with the same micronutrients (but not iron). No studies included a 'no intervention' comparison arm. None of the included trials reported any other adverse side effects (including constipation, nausea, vomiting, heartburn or diarrhoea). Wheat flour fortified with iron alone versus unfortified wheat flour (no micronutrients added) Wheat flour fortification with iron alone may have little or no effect on anaemia (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.61 to 1.07; 5 studies; 2200 participants; low-certainty evidence). It probably makes little or no difference on iron deficiency (RR 0.43, 95% CI 0.17 to 1.07; 3 studies; 633 participants; moderate-certainty evidence) and we are uncertain about whether wheat flour fortified with iron increases haemoglobin concentrations by an average 3.30 (g/L) (95% CI 0.86 to 5.74; 7 studies; 2355 participants; very low-certainty evidence). No trials reported data on adverse effects in children, except for risk of infection or inflammation at the individual level. The intervention probably makes little or no difference to risk of Infection or inflammation at individual level as measured by C-reactive protein (CRP) (moderate-certainty evidence). Wheat flour fortified with iron in combination with other micronutrients versus unfortified wheat flour (no micronutrients added) Wheat flour fortified with iron, in combination with other micronutrients, may or may not decrease anaemia (RR 0.95, 95% CI 0.69 to 1.31; 2 studies; 322 participants; low-certainty evidence). It makes little or no difference to average risk of iron deficiency (RR 0.74, 95% CI 0.54 to 1.00; 3 studies; 387 participants; moderate-certainty evidence) and may or may not increase average haemoglobin concentrations (mean difference (MD) 3.29, 95% CI -0.78 to 7.36; 3 studies; 384 participants; low-certainty evidence). No trials reported data on adverse effects in children. Wheat flour fortified with iron in combination with other micronutrients versus fortified wheat flour with same micronutrients (but not iron) Given the very low certainty of the evidence, the review authors are uncertain about the effects of wheat flour fortified with iron in combination with other micronutrients versus fortified wheat flour with same micronutrients (but not iron) in reducing anaemia (RR 0.24, 95% CI 0.08 to 0.71; 1 study; 127 participants; very low-certainty evidence) and in reducing iron deficiency (RR 0.42, 95% CI 0.18 to 0.97; 1 study; 127 participants; very low-certainty evidence). The intervention may make little or no difference to the average haemoglobin concentration (MD 0.81, 95% CI -1.28 to 2.89; 2 studies; 488 participants; low-certainty evidence). No trials reported data on the adverse effects in children. Eight out of nine trials reported source of funding with most having multiple sources. Funding source does not appear to have distorted the results in any of the assessed trials. AUTHORS' CONCLUSIONS Eating food items containing wheat flour fortified with iron alone may have little or no effect on anaemia and probably makes little or no difference in iron deficiency. We are uncertain on whether the intervention with wheat flour fortified with iron increases haemoglobin concentrations improve blood haemoglobin concentrations. Consuming food items prepared from wheat flour fortified with iron, in combination with other micronutrients, has little or no effect on anaemia, makes little or no difference to iron deficiency and may or may not improve haemoglobin concentrations. In comparison to fortified flour with micronutrients but no iron, wheat flour fortified with iron with other micronutrients, the effects on anaemia and iron deficiency are uncertain as certainty of the evidence has been assessed as very low. The intervention may make little or no difference to the average haemoglobin concentrations in the population. None of the included trials reported any other adverse side effects. The effects of this intervention on other health outcomes are unclear.