Low IQ linked to poor diet
Scientists from Britain and Pakistan are working on a project to prove the link between iron deficiency and susceptibility to poisoning from lead pollution.
Speaking to edie Dr Ahmed said: "We're going to look at children who have got differing degrees of iron deficiency.
"We'll have four groups, some will be normal and healthy, some will be borderline or have a very mild deficiency, some will be clearly deficient and some will be severely deficient to the extent of being anaemic.
"We'll be recording both the lead and manganese levels in the blood of these children."
He explained how the gut had a mechanism to absorb more iron if the body had a deficiency, but in the absence of iron it could shoot itself in the foot by absorbing increased levels of other metals - including pollutants such as lead and manganese.
"The consequences of absorbing this extra lead are not good at all," he said.
"It can cause damage to the nervous system resulting in brain damage and a lower IQ.
"With manganese there are similar problems, and children can develop a condition called manganism which causes irreversible damage similar to Parkinson's Disease."
Dr Ahmed said his team had carried out similar research in Liverpool, but with iron deficiency less common and less severe and lead levels much lower than in Karachi it was difficult to get a clear picture. "We chose Karachi because it has a very poor record for lead pollution," he told edie.
According to World Health Organisation (WHO) figures over 80% of Karachi's children are exposed to levels of lead poisoning likely to affect their IQ.
In tests carried out in 2001 the average level of lead in the blood of the city's children was at almost four times the point where it starts to have a significant impact on intelligence.
Meanwhile, 65% of the children have iron deficiencies to a greater or lesser extent.
"Lead is everywhere - cars don't use lead-free petrol, quacks use lead in their medication for treating people, there's a lot of heavy industry and the use of a lead-based make-up known as surma is popular," said Dr Ahmed.
"At the same time iron deficiency is very common throughout Pakistan and indeed the developing world in general."
"All this makes it a very good environment to do this study in."
Once the study has produced results on the relationship between IQ, iron deficiency and lead poisoning, the research will move on to a second phase.
"We'll be treating the people worst affected by the pollution and give them some sort of iron fortification, either by encouraging them to change their diet or giving them supplements," said Dr Ahmed.
"We hope to be able to get some concrete data to prove our hypothesis so we can go to the Pakistani government and say this really is an issue.
"We'll use it to try to persuade them that iron deficiency needs to be taken much more seriously because it's so common.
"I think it can be addressed. "It will take a lot of awareness raising and education, but it can be done through schools and the media.
"It's not an expensive treatment but even trying to alter people's diets can help."
Dr Ahmed said that while he did not have the data, it seemed likely that the situation was similar in other parts of the developing world where heavy industry was commonplace.
If a link is proven, a simple course of supplements could prevent irreversible brain damage in millions of children in Asia, Latin America and Eastern Europe and prevent many more from suffering reduced IQs.
"This isn't just about Pakistan," he said. "It's a global problem."
By Sam Bond