A pill a day might not cure iron deficiency

"To improve the percentage of iron absorbed, it would likely be more efficient to wait longer between doses," says study leader Diego Moretti. (Credit: iStockphoto)

People who take daily iron supplements may not be absorbing enough. Scientists say a molecule called hepcidin blocks absorption in the intestine more profoundly than previously thought.

As soon as iron enters the body, hepcidin production begins in the liver. This tiny protein, which is composed of just 25 amino acid building blocks, then is released into the bloodstream and reaches the intestine, where one of its functions is to regulate the amount of iron absorbed into the body through the cells of the gastrointestinal tract.

Scientists observed more than 50 young women whose iron reserves were depleted but who did not yet suffer from anemia. The women received a daily dose of at least 40 milligrams of iron, as is commonly prescribed in cases of iron deficiency. Afterwards, the researchers measured how the hepcidin concentration developed and quantified its effect on the absorption of subsequent doses of iron.

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Hepcidin reached its peak concentration after six to eight hours, but even 24 hours after the first dose of iron it was still present in high enough quantities to markedly reduce absorption of the second dose. The body was only partly able to absorb this second dose of iron, which was given either on the same day or 24 hours after the first dose.

The team’s results appear in the journal Blood.

Traditional iron supplementation is often associated with undesirable side effects such as gastrointestinal complaints. Such issues are closely related to the dosage of iron given, and they are also one of the reasons why many patients stop taking supplements.

If absorption efficiency were to be improved, it would be possible to achieve a greater biological effect from a smaller dose of iron while also reducing side effects.

“To improve the percentage of iron absorbed, it would likely be more efficient to wait longer between doses,” says study leader Diego Moretti, a researcher at ETH Zurich.

However, he does concede two limitations of the study: The participants were all healthy young women without anemia, and their iron absorption was observed only over a two-day period. The step is to study the behavior of the hepcidin concentration over the course of an iron supplementation regimen lasting several weeks.

Source: ETH Zurich