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Fe9.0
Iron – Forschung
Hilft wahrscheinlich
57 begutachtete Studien
Was die Evidenz sagt
Hilft wahrscheinlich
Iron scheint in 12 von 16 Studien mit messbaren Effekten zu helfen — die Evidenz tendiert klar ins Positive.
Die meiste Evidenz stammt aus hochwertigen Meta-Analysen und randomisierten Studien, veröffentlicht 2012–2026 mit einer typischen Studiengröße von 449 Teilnehmenden.
Basierend auf 57 Studien · 20 Meta-Analysen · 12 RCTs · 553,720 Teilnehmende insgesamt
Konfidenz
Hohe Konfidenz
Was die Studien gefunden haben
12geholfen2unklar2nicht geholfen· 41 weitere ohne bewertete Effektdaten
Nach Outcome
Iron deficiency & anemia
Hilft wahrscheinlich50 Studien
Women's healthKann helfen, menstruelle Beschwerden und PMS-Symptome zu reduzieren · 1-3 Zyklen · Liefert essenzielle Nährstoffe für eine gesunde Schwangerschaft · Fortlaufend
Hilft wahrscheinlich19 Studien
Safety profile
Überwiegend Mechanismus / Beobachtung10 Studien
Therapeutic & clinical
Hilft vermutlich8 Studien
Energy & fatigueDeutliche Verbesserung der Energie bei Mangel · 2-4 Wochen für Symptome; 3-6 Monate zur Auffüllung der Speicher
Hilft wahrscheinlich5 Studien
Digestive health
Überwiegend Mechanismus / Beobachtung5 Studien
Endurance & exercise performanceVerbesserte Ausdauer und Erholung bei Mangel · 4-8 Wochen · Stellt VO2max und Ausdauer bei Mangel wieder her · 4-12 Wochen
Überwiegend Mechanismus / Beobachtung4 Studien
Cognitive function
Zu wenige bewertete Studien2 Studien
Heart & blood pressure
Zu wenige bewertete Studien1 Studie
Kidney & renal health
Zu wenige bewertete Studien1 Studie
In Zahlen
Aus 39 Studien mit messbaren Effekten gezogen
Wahrscheinlich echte Effekte
100%
über Studien hinweg
Untersuchte Personen
554k
typische Studie: 449 Personen
Stärkste Designs
32
20 gepoolt, 12 randomisiert
Zeigte Nutzen
75%
12/16 Studien
Wie lange Studien liefen
1–4 Wochen
1
1–3 Monate
4
Untersuchte Populationen
Adults2
General population2
Pregnant women1
Women1
Aktives Forschungsgebiet
48 Studien in den letzten 5 Jahren · Neueste Meta-Analyse: 2026
201220192026
1Meta-Analysen=7,475 · very large study2026
Iron supplementation may lead to improved blood indices and iron stores, but we are uncertain about the effect due to heterogeneity in the population and different methods and doses of iron supplementation.
Geneen LJ et al. · The Cochrane database of systematic reviews (2026)
Overall, we downgraded the certainty of the evidence primarily for risk of bias, high heterogeneity (between-study inconsistency) that was not explained through subgrouping, and imprecision (wide confidence intervals (CIs)), largely due to very small sample sizes in some studies.
More participants may experience adverse events with oral iron compared to no iron, including abdominal pain, constipation, and diarrhoea (RR 1.69, 95% CI 1.15 to 2.47; 8 studies, 2641 participants), but the evidence is very uncertain.
Serum ferritin may also be higher with IV iron at the first donation since commencement of treatment (MD 78.16, 95% CI 37.20 to 119.12 ng/mL higher; 2 studies, 479 participants), but the evidence is very uncertain.
2Low birthweightMeta-AnalyseCited 22×n=48,971 · very large study2024
Daily oral iron supplementation during pregnancy may reduce maternal anaemia and iron deficiency at term.
Finkelstein JL et al. · The Cochrane database of systematic reviews (2024)
Spürbar Nutzen
← SchlechterKein EffektBesser →
There is probably little to no difference in maternal death (2 versus 4 events, RR 0.57, 95% CI 0.12 to 2.69; 3 trials, 14,060 women; moderate-certainty evidence).
Infant outcomes: Women taking iron supplements are probably less likely to have infants with low birthweight (5.2% versus 6.1%; RR 0.84, 95% CI 0.72 to 0.99; 12 trials, 18,290 infants; moderate-certainty evidence), compared to placebo or no iron supplementation.
However, the evidence is very uncertain for infant birthweight (MD 24.9 g, 95% CI -125.81 to 175.60; 16 trials, 18,554 infants; very low-certainty evidence).
3Lung cancer riskMeta-AnalyseCited 8×n=21,943 · very large study2024
However, a positive association was observed between dietary heme iron and the risk of lung cancer in women, which may require further investigation.
Mohammadzadeh M et al. · International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition (2024)
Spürbar Schaden
← SchlechterKein EffektBesser →
Methods: 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).
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.
However, in the subgroup of women (cases n=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).
4Iron deficiency at termMeta-AnalyseCited 19×n=2,822 · very large study2023
Daily iron supplementation in iron replete non-anemic pregnant women probably reduces the risk of maternal iron deficiency anemia at term and low birthweight.
Hansen R et al. · Acta obstetricia et gynecologica Scandinavica (2023)
Groß Nutzen
← SchlechterKein EffektBesser →
In addition, it may reduce iron deficiency at term (RR: 0.74, 95% CI: 0.60-0.92; 4 RCTs, 1663 women; I2 = 58%; low-certainty evidence) and the incidence of small for gestational age babies (RR: 0.39, 95% CI: 0.17-0.86; 1 RCT, 213 infants; I2 not estimable; low-certainty evidence).
Daily iron supplementation in iron replete non-anemic pregnant women probably reduces the risk of maternal iron deficiency anemia at term and low birthweight.
5Hemoglobin levelsMeta-AnalyseCited 4×n=529 · large study2024
ALA supplementation had no statistically significant effect on iron-related parameters.
Sharifi-Zahabi E et al. · International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition (2024)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
In subgroup analysis, ALA significantly increased hemoglobin in patients with hematological disorders (WMD = 1.23 g/dL; 95% CI: 1.00, 1.45 g/dL; I2 = 96.6%, p < 0.001) and in studies with durations longer than 8 weeks (WMD = 1.03 g/dL; 95% CI: 0.82, 1.25 g/dL; I2 = 96.5%, p = 0.02).
ALA supplementation had no statistically significant effect on iron-related parameters.
6Anemia prevalenceMeta-AnalyseCited 19×n=722 · large study2024
It was found that dietary factors were one of the major causes of anemia, and iron-containing supplements and nutrition counseling could be effective interventions to reduce the prevalence of anemia, ID, and IDA among Chinese pregnant women.
Zhou Y et al. · Nutrients (2024)
Kein klarer Effekt
← SchlechterKein EffektBesser →
The results showed that the prevalence of anemia, ID, and IDA among pregnant women in China were 30.7% (95% CI: 26.6%, 34.7%), 45.6% (95% CI: 37.0%, 54.2%), and 17.3% (95% CI: 13.9%, 20.7%), respectively.
Generally, lower prevalence was observed in the economically more advanced eastern region of the country, while the prevalence of ID was higher in the eastern region than that in the western region.
The prevalence of anemia and IDA in rural areas was higher than that in urban areas, but ID prevalence was higher in urban areas.
7Fatigue reductionMeta-AnalyseCited 5×n=572 · large study2024
Intravenous iron probably reduces fatigue slightly in the early postpartum weeks (8 to 28 days) compared to oral iron tablets, but probably results in little to no difference after four weeks.
Jensen MCH et al. · The Cochrane database of systematic reviews (2024)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
Intravenous iron versus oral iron supplementation The evidence is very uncertain about the effect of intravenous iron on mortality (risk ratio (RR) 2.95, 95% confidence interval (CI) 0.12 to 71.96; P = 0.51; I² = not applicable; 3 RCTs; 1 event; 572 women; very low-certainty evidence).
Intravenous iron probably results in a slight reduction in fatigue within 8 to 28 days (standardised mean difference -0.25, 95% CI -0.42 to -0.07; P = 0.006; I² = 47%; 2 RCTs; 515 women; moderate-certainty evidence).
Oral iron probably increases the risk of constipation compared to intravenous iron (RR 0.12, 95% CI 0.06 to 0.21; P < 0.001; I² = 0%; 10 RCTs; 1798 women; moderate-certainty evidence).
8Sports performanceSystematische ÜbersichtCited 12×n=669 · large study2025
However, endurance performance improved by 2%-20% when ID athletes were treated with 100 mg/day of elemental iron for up to 56 days via oral supplementation, or bi-daily via parenteral administration over 8-10 days.
Pengelly M, Pumpa K, Pyne DB, Etxebarria N · Journal of Sport and Health Science (2025)
9Meta-AnalyseCited 158×n=451,723 · very large study2020
In addition, they further contribute to the ongoing discourse of choosing antenatal MMN over IFA as the standard of care in LMICs.
Oh C et al. · Nutrients (2020)
IFA supplementation showed notable improvement in maternal anemia and the reduction in low birthweight, whereas LNS supplementation had no apparent effect on outcomes; further research that compares LNS and MMN supplementation could help understand differences with these commodities.
For single micronutrient supplementation, improvements were noted in only a few outcomes, mainly pre-eclampsia/eclampsia (calcium), maternal anemia (iron), preterm births (vitamin D), and maternal serum zinc concentration (zinc).
These findings highlight that micronutrient-specific supplementation should be tailored to specific groups or needs for maximum benefit.
10Haemoglobin concentrationMeta-AnalyseCited 125×n=8,506 · very large study2016
Daily iron supplementation effectively reduces the prevalence of anaemia and iron deficiency, raises haemoglobin and iron stores, improves exercise performance and reduces symptomatic fatigue.
Low MS et al. · The Cochrane database of systematic reviews (2016)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Women receiving iron had a higher haemoglobin concentration at the end of intervention compared to women receiving control (mean difference (MD) 5.30, 95% CI 4.14 to 6.45, 51 studies, 6861 women, high quality evidence).
Women receiving iron had a reduced risk of iron deficiency compared to women receiving control (RR 0.62, 95% CI 0.50 to 0.76, 7 studies, 1088 women, moderate quality evidence).
Seven trials recruiting 901 women reported on 'any side effect' and did not identify an overall increased prevalence of side effects from iron supplements (RR 2.14, 95% CI 0.94 to 4.86, low quality evidence).
11Blood iron parametersMeta-AnalyseCited 9×n=449 · medium study2024
The doses of OIS, that induced a beneficial effect on hematological parameters differed from 16 to 100 mg of elementary iron daily, over the period between 6 and 8 weeks.
Šmid AN, Golja P, Hadžić V, Abazović E, Drole K, Paravlić AH · Sports Medicine (2024)
12Gastrointestinal side-effectsMeta-AnalyseCited 516×n=3,168 · very large study2015
Our meta-analysis confirms that ferrous sulfate is associated with a significant increase in gastrointestinal-specific side-effects but does not find a relationship with dose.
Tolkien Z et al. · PloS one (2015)
Sehr groß Schaden
← SchlechterKein EffektBesser →
Likely real
Ferrous sulfate supplementation significantly increased risk of GI side-effects versus placebo with an odds ratio (OR) of 2.32 [95% CI 1.74-3.08, p<0.0001, I2 = 53.6%] and versus i.v. iron with an OR of 3.05 [95% CI 2.07-4.48, p<0.0001, I2 = 41.6%].
Subgroup analysis in IBD patients showed a similar effect versus i.v. iron (OR = 3.14, 95% CI 1.34-7.36, p = 0.008, I2 = 0%).
Likewise, subgroup analysis of pooled data from 7 RCTs in pregnant women (n = 1028) showed a statistically significant increased risk of GI side-effects for ferrous sulfate although there was marked heterogeneity in the data (OR = 3.33, 95% CI 1.19-9.28, p = 0.02, I2 = 66.1%).
13Hemoglobin levelsMeta-AnalyseCited 7×n=120 · medium study2024
There is moderate-quality evidence suggesting that probiotics, prebiotics, and synbiotics may improve anemia management, particularly by enhancing Hb levels.
Hu Q et al. · BMC gastroenterology (2024)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
The analysis revealed that probiotics, prebiotics, or synbiotics significantly improved Hb levels in patients with anemia (WMD = 10.760, 95% CI: 4.593 to 16.747, p = 0.001), though heterogeneity was high (I² = 96.5%).
Two RCTs (n = 120 participants) reported significant increases in serum iron levels in the probiotic group (WMD = 3.835, 95% CI: 3.271 to 4.400), with moderate heterogeneity (I² = 38.7%).
Two RCTs (n = 192 participants) reported no significant differences were observed between the groups in serum ferritin levels (WMD = 8.048, p = 0.115), and heterogeneity remained high (I² = 62.6%).
14Thyroid function parametersMeta-AnalyseCited 37×2023
Further studies are needed to understand the role played by iron in thyroid metabolism.
Garofalo V et al. · Nutrients (2023)
Likely real
Patients with ID showed TSH (MD: -0.24 mIU/L; 95% CI -0.41, -0.07; I2 = 100%, p = 0.005), FT4 (MD: -1.18 pmol/L; 95% CI -1.43, -0.94; I2 = 99%, p < 0.000001), and FT3 (MD: -0.22 pmol/L; 95% CI -0.32, -0.12; I2 = 99%, p < 0.00001) levels that were significantly lower.
Our systematic review of the literature found that ID significantly increases the prevalence of thyroid autoantibody (anti-thyroglobulin antibodies and anti-thyroid peroxidase antibodies) positivity both individually and collectively.
Conclusion: Studies currently published in the literature indicate a possible relationship between ID, thyroid function, and autoimmunity, especially in some patient groups.
15Allogeneic blood transfusionMeta-AnalyseCited 65×n=372 · medium study2019
The use of iron therapy for preoperative anaemia does not show a clinically significant reduction in the proportion of trial participants who received an allogeneic blood transfusion compared to no iron therapy.
Ng O et al. · The Cochrane database of systematic reviews (2019)
Kein klarer Effekt
← SchlechterKein EffektBesser →
The 372 participants in our analysis fall far short of the 819 required - as calculated by our information size calculation - to detect a 30% reduction in blood transfusions.
Meta-analysis of iron therapy versus placebo or standard care showed no difference in the proportion of participants who received a blood transfusion (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.87 to 1.70; 4 studies, 200 participants; moderate-quality evidence).
There was no difference between the iron therapy and placebo/standard care groups for haemoglobin level preoperatively at the end of the intervention (mean difference (MD) 0.63 g/dL, 95% CI -0.07 to 1.34; 2 studies, 83 participants; low-quality evidence).
Ferrous bisglycinate shows some benefit over other iron supplements in increasing hemoglobin concentration and reducing GI adverse events among pregnant women.
Fischer JAJ et al. · Nutrition reviews (2023)
Ferrous bisglycinate shows some benefit over other iron supplements in increasing hemoglobin concentration and reducing GI adverse events among pregnant women.
More trials are needed to assess the efficacy of ferrous bisglycinate against other iron supplements in other populations.
17Serum ferritin levelsMeta-AnalyseCited 135×n=27 · very small study2018
In conclusion our results showed that vegetarians are more likely to have lower iron stores compared with non-vegetarians.
Haider LM et al. · Critical reviews in food science and nutrition (2018)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
The meta-analysis which combined data of 24 cross-sectional studies showed that adult vegetarians have significantly lower serum ferritin levels than their non-vegetarian controls (-29.71 µg/L, 95% CI [-39.69, -19.73], p < 0.01).
Inclusion of semi-vegetarian diets did not change the results considerably (-23.27 µg/L, 95% CI [-29.77, -16.76], p < 0.01).
The effects were more pronounced in men (-61.88 µg/L, 95% CI [-85.59, -38.17], p < 0.01) than in both premenopausal women (-17.70 μg/L, 95% CI [-29.80, -5.60], p < 0.01) and all women (-13.50 μg/L, 95% CI [-22.96, -4.04], p < 0.01), respectively.
18Iron-deficiency anemia diagnosis and treatmentSystematische ÜbersichtCited 25×2020
These recommendations may serve as a starting point for clinicians to better diagnose and treat IDA in patients with gastrointestinal bleeding, which ultimately may improve health outcomes in these patients.
Cotter J et al. · World journal of gastroenterology (2020)
These recommendations may serve as a starting point for clinicians to better diagnose and treat IDA in patients with gastrointestinal bleeding, which ultimately may improve health outcomes in these patients.
20Muscle wasting and functional declineSystematische Übersicht2026
Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.
Zeidan RS et al. · Aging cell (2026)
We delineate key knowledge gaps, including the absence of ferroptosis-specific biomarkers in human muscle and limited longitudinal data linking ferroptotic stress to mobility outcomes.
Finally, we highlight potential therapeutic opportunities targeting iron handling and lipid peroxidation pathways.
A better understanding of the contribution of ferroptosis to muscle aging may enable development of mechanistically informed biomarkers and interventions to preserve strength and mobility in older adults.