Elemental Iron Content in Ferrous Pyrophosphate
15 mg of ferrous pyrophosphate contains approximately 4.5 mg of elemental iron, representing roughly 30% elemental iron content by weight.
Understanding the Conversion
The molecular weight ratio of ferrous pyrophosphate determines its elemental iron content:
- Ferrous pyrophosphate has an elemental iron content of approximately 25-30% 1, 2
- Using the standard conversion factor, 15 mg of ferrous pyrophosphate yields approximately 4.5 mg of elemental iron 1
- This is substantially lower than other common iron salts like ferrous sulfate (20% elemental iron per 325 mg tablet = 65 mg elemental iron) or ferrous fumarate (33% elemental iron per 325 mg tablet = 108 mg elemental iron) 3
Clinical Context for Iron Supplementation
When prescribing iron therapy, understanding elemental iron content is critical for achieving therapeutic goals:
- Adult patients typically require 200 mg of elemental iron daily in divided doses to adequately replace iron stores and support erythropoiesis 3
- Pediatric patients require 2-3 mg/kg/day of elemental iron 3
- To achieve 200 mg elemental iron daily using ferrous pyrophosphate alone would require approximately 650-800 mg of the compound, making it impractical as a sole iron source 3
Bioavailability Considerations
Ferrous pyrophosphate has unique absorption characteristics:
- Micronized, dispersible ferric pyrophosphate formulations demonstrate bioavailability comparable to ferrous sulfate (3.4% vs 4.1% absorption in cereal; 3.9% vs 4.2% in yogurt drinks) 2
- Standard ferric pyrophosphate is sparingly soluble at physiologic pH (3-6), limiting its absorption 1
- Iron absorption is enhanced when ferrous pyrophosphate is combined with pyrophosphate ions, increasing total ionic iron concentration 8-10 fold at pH 5-8.5 1
Important Clinical Caveats
- Ferrous pyrophosphate is primarily used in food fortification and specialized applications (like dialysate iron delivery) rather than standard oral supplementation 3, 4
- For standard iron deficiency treatment, ferrous sulfate, ferrous fumarate, or ferrous gluconate are preferred due to their higher elemental iron content per dose and lower cost 3
- Iron absorption is best when taken without food, though this must be balanced against gastrointestinal tolerability 3