Iron supplements in the fight against lead

https://www.eurekalert.org/pub_releases/2016-10/ez-isi102616.php

Public Release: 26-Oct-2016
Iron supplements in the fight against lead
ETH Zurich

Lead is a toxic heavy metal that was added to petrol for use in cars until as recently as 25 years ago. It is particularly harmful to the developing brains of infants, children and teenagers, and the damage it does is irreversible.

The situation becomes significantly worse if people are exposed to a high level of lead at the same time as they are suffering from iron deficiency. In the small intestine, lead and iron bind to the same transport protein, which absorbs the metals into the bloodstream. If someone consumes too little iron with their food, the transporter increases its activity, and can carry lead into the bloodstream instead, leading to increased levels of the toxic heavy metal in the body and brain.

A team of researchers led by ETH professor Michael B. Zimmermann from the Laboratory of Human Nutrition have now shown in a study that fortifying food with iron produces a striking reduction in blood lead concentration in children exposed to high levels of the metal.

This is the result of a trial involving over 450 children carried out by Zimmermann's former doctoral student Raschida Bouhouch and colleagues in southern Morocco. It is the first controlled prospective study to investigate the connection between iron deficiency and lead poisoning and to demonstrate that iron fortification can reduce blood lead levels. The study came about within the framework of a North-South project conducted by ETH Zurich and the University and University Hospital of Marrakesh.

Mining in the surrounding area meant that children of preschool and school age were exposed to an increased quantity of lead. At the same time, the level of iron in their blood was relatively low, placing them in a high-risk group.

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Before the study began, the children's blood contained on average 4.3 micrograms of lead per decilitre. Biscuits with added sodium iron EDTA facilitated a reduction in blood lead concentration to 2.9 micrograms per decilitre. The biscuits also brought about an improvement in the children's iron status. On the other hand, the reduction in lead concentration had no effect on cognitive performance, as the researchers discovered during the corresponding tests.

Nevertheless, Zimmermann is very happy with the study's results: "The finding - that you can reduce blood lead concentration in exposed individuals with just a short intervention - is hugely significant for public health services," says the ETH professor.

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Zimmermann attributes the lack of improvement in cognitive performance to the fact that lead leaves behind lasting damage that cannot be reversed by administering iron. "Nevertheless, it definitely makes sense to use iron fortification to prevent brain damage in exposed sectors of the population," says the nutrition specialist. Iron supplementation may even provides foetuses in the womb with effective protection against subsequent brain damage.

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Lead contamination of food and water is still a serious problem in mining and heavy industry areas in Africa, India and China, but the issue is not yet resolved even in industrialised Western countries.

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