Citric acid in iron-fortified milk formulas and iron absorption
What it found
In 15 women, iron from two milk formulas stabilized with citric acid and maltodextrin was absorbed about three times better than iron from fortified cow's milk.
The women took the formulas after an overnight fast.
What they found
Studies in people
Iron absorption from formulas
The geometric mean iron absorption, corrected to 40% of the reference dose, was 20.6% for Formula A and 20.7% for Formula B. These were not significantly different from each other.
Iron absorption from cow's milk
Iron-fortified cow's milk had a corrected geometric mean absorption of 7.5%. This was significantly lower than both formulas.
Prebiotics had no effect
Formula A contained prebiotics and Formula B did not, but iron absorption was similar from both. The authors conclude that prebiotics did not affect iron absorption.
Iron status of the women
The women were iron deficient: one had iron deficiency anemia and eight had iron deficiency without anemia. The reference dose absorption was 38.3%, typical of iron-deficient people.
Other findings
Estimated daily iron absorbed
The authors estimate that a toddler drinking 500 mL of Formulas A or B daily would absorb about 1.2 mg of iron per day. This would cover over 100% of their Recommended Daily Intakes.
What the authors conclude
“In conclusion, both A and B milk formulas contain highly bioavailable iron, which contributes to covering the requirements of this micronutrient in toddlers.”
Also in their conclusions
- They conclude that both Formulas A and B contain highly bioavailable iron.
- They say this iron contributes to covering toddlers' requirements for this micronutrient.
- They advise that even if the formulas provide enough iron, children's diets should still include meat, fish, fruits, and vegetables for other nutrients.
How it was done
Iron deficiency is common in young children, and fortifying milk with iron is a widely used strategy. The authors wanted to measure how well the iron in two toddler milk formulas, stabilized with maltodextrin and citric acid, is absorbed.
15 women aged 33 to 47 took 200 mL of Formula A, 200 mL of Formula B, a reference iron and ascorbic acid solution, and 200 mL of iron-fortified cow's milk on different days after an overnight fast. Iron absorption was measured by radioactive iron incorporated into red blood cells over 28 days.
What it can’t tell you
- The study was in adult women, not toddlers. The authors note that results from adults can be extrapolated to infants, but this is not a direct test in children.
- The women were iron deficient, so absorption may be higher than in people with normal iron stores.
- This was a short-term study measuring absorption from single meals, not long-term health outcomes like anemia or growth.
Who paid
- Authors work at
- University of Chile, Chile
The paper
- Title
- Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Pizarro F, Olivares M, Maciero E, Krasnoff G, Cócaro N, Gaitan D (2015). Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid. Nutrients. doi:10.3390/nu7115448Free full textPubMed 26529007DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error