Iron for Athletic Performance
Verdict: Published with Warning
Across 5 PubMed studies, the evidence for Iron in Athletic Performance grades Tier B — preliminary evidence. Effective, but with safety or population caveats.
B 🟡 B Preliminary Evidence Published with Warning
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.63
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
B · Published with Warning
Confidence
82%
Highly consistent evidence
Evidence level
E2
Multiple high-quality MAs (≥2 independent, consistent)
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.627
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 1 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (5)L2 · primary research & systematic reviews
Effects of Oral Iron Supplementation on Blood Iron Status in Athletes: A Systematic Review, Meta-Analysis and Meta-Regression of Randomized Controlled Trials
Finding: Oral iron significantly raised serum ferritin (SMD=1.27, 95% CI 0.44-2.10, p=0.006) but produced only a small, non-significant trend toward higher VO2max (SMD=0.49, 95% CI -0.09 to 1.07, p=0.086), with no change in haemoglobin (p=0.099) in mostly non-deficient athletes.
View on PubMed Iron supplementation benefits physical performance in women of reproductive age: a systematic review and meta-analysis
Finding: Daily iron raised relative VO2max by 2.35 mL/kg/min (95% CI 0.82-3.88, p=0.003; 18 studies) and overall VO2max SMD=0.37 (95% CI 0.11-0.62, p=0.005; 20 studies) and lowered exercise heart rate by 4.05 bpm (95% CI -7.25 to -0.85, p=0.01).
View on PubMed Does Iron Supplementation Improve Performance in Iron-Deficient Nonanemic Athletes?
Finding: Results were equivocal: performance improved in 6 of 12 studies (146 athletes) and was unchanged in the other 6 (137 athletes); every positive study used a serum ferritin cutoff <=20 ug/L and oral iron, with no benefit when sFer >20 ug/L.
View on PubMed Iron deficiency, supplementation, and sports performance in female athletes: A systematic review
Finding: Across 23 studies (669 athletes), iron deficiency lowered endurance by 3%-4%; supplementing deficient athletes with ~100 mg/day elemental iron for up to 56 days improved endurance 2%-20% and VO2max 6%-15%, while anaerobic power effects were inconsistent (-5% to +9%).
View on PubMed Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials
Finding: Iron reduced self-reported fatigue (SMD=-0.38, 95% CI -0.52 to -0.23; 4 trials, 714 participants) but did NOT improve objective maximal oxygen consumption (SMD=0.11, 95% CI -0.15 to 0.37; 9 trials, 235 participants), separating a subjective benefit from any measurable performance gain.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
NUTRIENT SUPPLEMENT source↗
L4b EU EFSA
Supportive
contributes to normal oxygen transport in the body source↗
L4c UK NHS
Cautious
You should be able to get all the iron you need from your daily diet. source↗
L4d TW TFDA / 衛福部
Supportive
育齡婦女及懷孕婦女每日建議攝取鐵量為15毫克，至懷孕第3期婦女則應增加每日攝取量至45毫克。 source↗
L4e WHO
Supportive
Daily oral iron and folic acid supplementation is recommended as part of antenatal care source↗
L5a NIH Office of Dietary Supplements
Supportive
Iron is an essential component of hemoglobin source↗
L5b Mayo Clinic
Cautious
Mayo Clinic experts found that women who exercise for long periods of time and/or participate in sports where there is repetitive heel striking are at increased risk of iron deficiency and iron-deficient anemia. Iron deficiency anemia can usually be corrected with iron supplementation. source↗
L5c Cleveland Clinic
Supportive
Iron is important for the formation of red blood cells, but also for energy production (metabolism) and brain performance, including concentration and cognition. Patients with low iron commonly present with complaints of low energy, fatigue, decreased endurance or generally reduced athletic performance. Athletes must ensure that the supplements they are taking are pure. source↗
L5d Harvard Health
Cautious
Iron plays a fundamental role in muscle function by helping deliver oxygen to muscles and supporting energy production. Low iron levels can prevent the body from making enough myoglobin (the protein within muscle cells that stores and transports oxygen), which can weaken muscle performance. source↗
L5e Specialty Society (condition-mapped)
Cautious
oral iron supplements and injections improve iron status in athletes, these methods often cause side effects including abdominal discomfort, constipation and nausea and may present a risk of iron overload source↗