Researchers identify new mechanism for iron absorption

The "groundbreaking"​ study – published in The Journal of Nutrition – ​is reportedly the first to uncover the existence of at least two independent mechanisms for iron absorption from non-meat source – offering a potential new treatment for iron deficiency using the legume based ferritin.

The discovery the alternative absorption mechanism using ferritin, by Dr Elizabeth Theil from the Children’s Hospital Oakland Research Institute (CHORI), USA, could provide the key to helping solve iron deficiency by providing an alternative, affordable, and readily available source of iron, said the researchers.

Theil and colleagues demonstrated the alternative mechanism for the absorption of ferritin, a large, protein-coated iron mineral rich in legumes, in addition to the more well-known mechanism for iron absorption of small iron complexes like those found in iron supplements.

“Our study shows that this different mechanism of iron absorption from plant ferritin is more efficient and gives the intestinal cells more control. It can be a new way to help solve global iron deficiency,”​ said Theil.

Study details​

The new study combines the results of two different experiments, one conducted in humans and the other using rats.

In the rat model, portions of the rat intestines were bathed with solutions of traceable iron, either as a typical type of iron supplement or as ferritin. Theil explained that the teams measurements revealed that both the large ferritin and the smaller iron complex were absorbed through the intestine.

In the human study, iron in ferritin was given to volunteers along with a non-meat iron dietary supplement, or with heme iron in meat – to investigate whether the different types of iron competed with ferritin iron for the same absorption mechanism.

In each case, the iron competitor had no effect on the iron absorption from ferritin, noted the researchers.

“What these studies show together is that during digestion, ferritin is not converted from its large, mineral complex, which contains a thousand iron atoms, to individual iron atoms like those found in many iron supplements,”​ explained Theil.

“Instead, ferritin iron is absorbed in its protein-coated, iron mineral form by a different, independent mechanism; iron absorbed as ferritin, leaves the intestine more slowly, but may, provide greater safety to the intestines than iron supplements,”​ she added.

Theil said that in addition to potentially being safer, and causing less irritation to the intestines, the absorption of iron as ferritin is easier for the intestine.

The authors said that further studies are needed to pinpoint the exact mechanism of ferritin absorption. However, they added that their results demonstrate that ferritin-rich foods – such as legumes – could provide a significant source of dietary iron for those in need of increasing iron.

Source: The Journal of Nutrition​
Published online ahead of print, doi: 10.3945/​jn.111.145854
“Absorption of Iron from Ferritin Is Independent of Heme Iron and Ferrous Salts in Women and Rat Intestinal Segments”​
Authors: E.C. Theil, H. Chen, C. Miranda, H. Janser, B. Elsenhans, et al​