Scientific Publications
Modeling tool for calculating dietary iron bioavailability in iron-sufficient adults
American Journal of Clinical Nutrition, 105, 1408-14
Background: Values for dietary iron bioavailability are required for
setting dietary reference values. These are estimated from predictive
algorithms, nonheme iron absorption from meals, and models of iron
intake, serum ferritin concentration, and iron requirements.
Objective: We developed a new interactive tool to predict dietary
iron bioavailability.
Design: Iron intake and serum ferritin, a quantitative marker of
body iron stores, from 2 nationally representative studies of adults
in the United Kingdom and Ireland and a trial in elderly people in
Norfolk, United Kingdom, were used to develop a model to predict
dietary iron absorption at different serum ferritin concentrations.
Individuals who had raised inflammatory markers or were taking
iron-containing supplements were excluded.
Results: Mean iron intakes were 13.6, 10.3, and 10.9 mg/d and mean
serum ferritin concentrations were 140.7, 49.4, and 96.7 mg/L in
men, premenopausal women, and postmenopausal women, respectively.
The model predicted that at serum ferritin concentrations of
15, 30, and 60 mg/L, mean dietary iron absorption would be 22.3%,
16.3%, and 11.6%, respectively, in men; 27.2%, 17.2%, and 10.6%,
respectively, in premenopausal women; and 18.4%, 12.7%, and
10.5%, respectively, in postmenopausal women.
Conclusions: An interactive program for calculating dietary iron absorption
at any concentration of serum ferritin is presented. Differences
in iron status are partly explained by age but also by diet, with meat
being a key determinant. The effect of the diet is more marked at lower
serum ferritin concentrations. The model can be applied to any adult
population in whom representative, good-quality data on iron intake
and iron status have been collected. Values for dietary iron bioavailability
can be derived for any target concentration of serum
ferritin, thereby giving risk managers and public health professionals
a flexible and transparent basis on which to base their dietary
recommendations. This trial was registered at clinicaltrials. gov as NCT01754012.
American Journal of Clinical Nutrition, 105, 1408-14
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