Scientists have shown for the first time how genetically modified (GM) maize could be a cost-effective way of tackling iron deficiency in developing countries.

Nearly two billion people, mostly women and children in poor countries, get too little dietary iron. This is the main cause of anaemia, which can stunt children's development and cause chronic fatigue in adults.

Lead researcher Dr. Eva Stoger of Aachen University in Germany and colleagues modified the maize by adding genes to its DNA from both soybean and the Aspergillus niger fungus.

The two genes work together to retain iron from the soil and make it available in a form that humans can absorb.

The soybean gene produces a protein that binds to iron the plants take up from the soil — a fact that has been known for a while. Once in the maize kernel, however, the iron can get locked away in such a way that people would not be able to benefit from eating the enriched maize.

The fungal gene therefore comes into play by 'unlocking' the iron and making it available to humans.

Stoger's team, who published their findings in the December 2005 issue of Plant Molecular Biology, showed that cells from the human intestine absorbed three-times more iron from the GM maize than from unmodified maize.

Iron uptake is a complicated process that can be affected by other nutrients. When ascorbic acid (vitamin C) is added to flour, for instance, people eating it take up more iron.

The presence of the fungal gene has a similar effect and Stoger says maize flour containing it would benefit communities that do not have access to other nutrients such as ascorbic acid.

Stoger adds that further studies are needed to assess any potential side-effects of the modification.

Reference: Plant Molecular Biology 59, 869 (2005) - Springer Science+Business Media B.V.