Just how much iron and zinc do you get from your breakfast? Scientists in Denmark have been looking for the answer. 

Iron and zinc deficiencies are common nutritional disorders, particularly in the developing world where cereal grains are the most common food type. Measuring total concentrations of these elements in food crops is relatively easy but does not give any information about how much will be taken up by the body. This is a much bigger challenge, which Søren Husted at the University of Copenhagen and his team have set about solving. They say investigating how these elements are bound in the plant can give more information about their bioavailability.

Some elements can be indicators of the chemical binding form of others, explains Husted, so by analysing iron, zinc, phosphorus and sulfur in the plant simultaneously, they could determine how the iron and zinc are bound. 'Multi-elemental analysis of plant tissue with sufficient robustness and accuracy is absolutely not trivial,' says Husted. But by using a combination of analytical techniques such as mass spectrometry, size exclusion chromatography and enzymatic extraction, his team were able to do just that. 

They found iron and zinc have different chemical binding forms in the plant. This is contrary to the general view in the literature, says Husted, and shows that separate research strategies need to be applied in order to increase the bioavailability of both elements. 'We think that our methods will be an important tool in future molecular plant breeding programmes aimed at improving cereal plants with a higher amount of bioavailable iron and zinc,' he adds.  

Husted plans to extend the technique beyond plants. 'We would like to follow the chemical binding forms of iron and zinc from the plant, via the cooked meal, all the way through the human digestion system,' he says. 'This will give important answers to the questions remaining regarding bioavailability of micronutrients.'

Edward Morgan

Enjoy this story? Spread the word using the 'tools' menu on the left or add a comment to the Chemistry World blog