FERRONYL® IRON

Bioavailability
The amount of iron absorbed by the body per unit dosage from a particular iron source is a function of
several factors - particle size, surface area, ionic charge, iron content. The first three of these factors
contribute to the relative biological value (RBV) of the iron source - a measure of how quickly the iron
enters the blood stream. The iron content is a function of molecular structure, i.e., elemental iron versus
ferrous salts like ferrous sulfate (FeSO 4 ) and is a measure of the percentage of iron in a unit dose.
Multiplying the RBV by the iron content produces the iron absorption per unit dosage. Table 3 shows that
the high iron absorption from Ferronyl iron results from its small particle size, which contributes to a
higher RBV than other forms of elemental iron, and its high iron content relative to ferrous sulfate.
Table 3. The small particle size of Ferronyl iron contributes to its high RBV, which together with its high iron
content leads to high absorption per unit dose.
Iron Source Particle Size, µm RBV, % Iron Content, % Absorption, %
FeSO 4
*
N/A 100 20 20
Reduced Iron 10 - 20 34 96 33
Electrolytic Iron 10 - 20 48 97 47
Ferronyl iron 7 - 9 70 98 69
*FeSO 4
● 4H 2 O
In a study of iron-deficient rats, Sacks and Houchin (1978 a,b) concluded that, for similar iron dosage
levels, carbonyl iron powder was as effective as ferrous sulfate and more so than ferrous pyrophosphate
in restoring normal hematocrit levels (Table 4). Due to its finer particle size, carbonyl iron powder was also
found to be more efficacious than the other forms of elemental iron (e.g., electrolytic and reduced).
Table 4. Effect of various iron supplements on rat hematocrit levels.
Iron Source
Supplement Dose
(mg/kg)
Iron Dose
(mg/kg)
Increase in Hematocrit with 2 weeks
Supplementation
Control (Basal Diet) 0 0 -2
FeSO 4 30 6 4
FeSO 4 60 12 11
FeSO 4 120 24 22
CIP 12 12 6
CIP 24 24 15
A Better Choice 7