Iron absorption from food and how it is measured
What it found
Iron from mixed diets is absorbed at about 14 to 18 percent, while vegetarian diets give 5 to 12 percent in people with no iron stores.
A person's own iron levels matter more for absorption than what they eat.
What they found
Studies in people
Absorption from different diets
In people with no stored iron, mixed diets gave an estimated 14 to 18 percent absorption. Vegetarian diets gave 5 to 12 percent.
Food parts that change absorption
Single meal tests in people showed that phytate, polyphenols, calcium, vitamin C and muscle tissue all change how much iron is taken in. In studies with many meals and a varied diet, each part had a smaller effect on its own.
Personal iron levels matter most
A person's own iron status affects how much iron they absorb more than their diet does. Other personal factors like obesity also play a key role.
Other findings
Unresolved questions remain
Scientists do not yet know exactly how vitamin A, carotenoids and certain carbohydrates affect iron uptake. The helpful part found in meat is also still unclear.
What the authors conclude
- They say new guidelines should use a range of absorption values based on both diet and personal traits like iron stores and obesity.
- They note that the effects of added iron and certain food additives on absorption from mixed diets need more research.
How it was done
The body controls iron only by how much it takes in from food, because there is no natural way to get rid of it. Scientists needed these numbers to set daily intake targets for different groups of people.
Researchers looked at intake records and studies using special labelled iron to measure how much iron the body absorbs. They checked single meals and full varied diets to see which food parts help or block absorption.
What it can’t tell you
- We summarised it from the abstract only.
- These estimates come from short studies using labelled iron. They may not perfectly match long term absorption from everyday meals.
- Because this work looks across many studies, it cannot show exactly how one food will change iron levels in any single person.
Who paid
- Authors work at
- Institute of Food, Switzerland
The paper
- Title
- Iron bioavailability and dietary reference values
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Hurrell R, Egli I (2010). Iron bioavailability and dietary reference values. The American journal of clinical nutrition. doi:10.3945/ajcn.2010.28674FPubMed 20200263DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error