The Maastricht researchers and twenty-five partner universities in several European countries studied umbilical cord samples from 1,151 new-born babies for the presence of known carcinogens such as dioxins, dioxin-like PCB's, acrylamides, PAH's (polycyclic aromatic hydrocarbons) and nitrosamines. They also examined whether these substances could pass through the placenta. They found that the placenta does not protect the foetus against exposure to carcinogens in food and that these substances were indeed present in umbilical cord blood.

But does this exposure cause cancer in children? To answer this question, the researchers measured molecular changes in the umbilical blood samples that could indicate tumour development. They found that boys were more susceptible to exposure to carcinogens, particularly with regard to leukaemia. This could explain why leukaemia is more common in boys than in girls. 'These research results show a link between carcinogenic substances in food and an increased risk for developing childhood cancers,' says Kleinjans. 'However, we only examined a limited number of substances, which means further research is needed. Studies are currently being conducted under the EU project Exposomics, in which we are also collaborating.'

It's not possible for pregnant women to avoid all carcinogenic substances in their diets, at best they can try to avoid consuming well-known carcinogens like burnt foods and foods that has been deep-fried for too long. The most important advice for pregnant women is to try to eat a balanced and varied diet and to abstain from drinking and smoking during pregnancy. Food producers can also play their part by paying close attention to the quality of their raw ingredients and by using potatoes that contain less sugar to make crisps and chips.