Non-Heme Iron Baseline Absorption in the Gut
Only a small fraction of dietary non-heme iron normally crosses the gut wall.
- 2–8%: Typical absorption (placeholder baseline figure)
- Fe³⁺: Iron form (ferric, poorly soluble)
- DMT1: Transporter (requires Fe²⁺ reduction)
- Plant foods: Main source (grains, legumes, greens)
Why non-heme iron absorbs poorly on its own
Ferric iron stays insoluble and needs reduction before transport.
Vitamin C Boosts Non-Heme Iron Absorption
Ascorbic acid reduces ferric iron and forms an absorbable chelate.
- Fe³⁺→Fe²⁺: Reduction (ascorbate donates electrons)
- up to 3–6×: Effect size (placeholder enhancement range)
- 25–500 mg: Dose used (simulator slider range)
- Chelation: Mechanism (keeps iron soluble at gut pH)
How ascorbate chemistry enhances uptake
Vitamin C keeps iron soluble and reduced through the intestine.
More vitamin C co-ingested raises the enhancer strength metric.
Tea and Coffee Tannins Block Iron Uptake
Polyphenols in tea and coffee bind iron into insoluble complexes.
- up to 60%: Inhibition (placeholder tannin effect)
- Tea, coffee: Source (polyphenol tannins)
- Iron-tannate: Binding (insoluble complex forms)
- Yes: Timing matters (strongest near meal time)
How tannins trap iron before absorption
Tannins clump with iron so it passes unabsorbed through the gut.
Calcium Competes With Iron for Transport
Calcium ions rival iron for the same DMT1 transporter site.
- Competitive: Mechanism (shared transporter site)
- Dairy, supplements: Common source (high-calcium foods)
- moderate: Effect size (placeholder inhibitor strength)
- Yes: Dose dependent (higher calcium, more blocking)
Why calcium lowers iron uptake at the wall
Calcium occupies transporter sites iron would otherwise use.
Timing Meals to Maximize Iron Absorption
Separating inhibitors from iron-rich meals preserves more absorption.
- 1–3.5 h: Suggested gap (placeholder spacing window)
- Vitamin C: Pair with (citrus, peppers, tomatoes)
- Tea, coffee, dairy: Avoid at meals (shift to between meals)
- variable: Net gain (depends on both sliders)
Practical spacing between inhibitors and iron meals
Waiting after inhibitors reclaims much of the lost absorption.
The recommended gap metric scales with the inhibitor slider.