Research to cut carcinogens out of our food

PRINTHEATOX

Heatox
In 2002, the food safety world was rocked by the discovery that many processed foods such as chips and crisps contained high levels of a potentially carcinogenic molecule called acrylamide.

Acrylamide had long been used in the manufacture of plastics, glues, paper and cosmetics, and in the construction of dams and tunnels. When it was found in food, very little was known about how it was formed, or its impact on our health, although it had already been found to cause cancer in animals, and the International Agency for Research on Cancer had classified it as ‘probably carcinogenic in humans’.

The World Health Organization (WHO) and the Food and Agriculture Organisation quickly set up an international network of researchers studying acrylamide in food, and the HEATOX (‘Heat-Generated Food Toxicants, Identification, Characterisation and Risk Minimisation’) project represents a key EU contribution to this effort. HEATOX features in the EU’s acrylamide information database, which in turn feeds into the WHO’s acrylamide infonet.

Thanks to HEATOX, we now have a much better understanding of how acrylamide is formed, its effect on our health, and importantly, how different methods of preparing and cooking food affect the levels of acrylamide in the final product.

The project brought together 24 partners from 11 EU Member States as well as Norway, Switzerland, Turkey and Chile.

READ MORE

‘Know thy enemy’

Research has revealed that acrylamide is formed when carbohydraterich foods are heated, for example by toasting bread, roasting coffee or frying potatoes. At the heart of acrylamide formation is a process known as the Maillard reaction, which takes place when the amino acid asparagine reacts at high temperatures with certain sugars.

The problem is that this reaction is what gives fried foods their distinctive flavour and golden brown colouring. The challenge for food scientists is to develop methods of food preparation that keep acrylamide levels low while preserving the special tastes and colours that come from the Maillard reaction.

The HEATOX project partners studied the Maillard reaction in great detail, and developed models to predict the levels of acrylamide formation in different foods and at different temperatures.

A toolbox for the food industry

The HEATOX findings fed into a toolbox produced by the food industry with the aim of helping food manufacturers reduce the amount of acrylamide in their products. The toolbox covers potato products, bread, biscuits and bakery wares, breakfast cereals, and coffee. For each food type, the entire production chain is addressed, from the farm, through processing, to final preparation.

For potatoes, for example, the toolbox recommends using low-sugar varieties, and frying them at temperatures between 145 °C and 170 °C. For breads, the project highlighted the importance of long yeast fermentation; new baking technologies such as the use of infrared radiation can also reduce acrylamide levels. In coffee, the amount of acrylamide in the final product is influenced by the variety of coffee bean used (Arabica varieties tend to form less acrylamide than Robusta varieties) and how long the beans are roasted.

According to the project partners, if all these mitigation measures are applied to these basic foods, acrylamide consumption can be reduced by up to 40 %.

How worried should we be?

Having established that it is not possible to totally eliminate acrylamide from these foods, the HEATOX team set out to investigate how dangerous the substance is. The results of tests in animals were alarming – even a low exposure to acrylamide constitutes a risk.

Very young mice exposed to low doses of acrylamide shortly after birth, during the period when the brain’s growth spurt takes place, showed signs of developmental neurotoxicity. This can cause lasting neurological defects.

Another study in humans found that women with higher levels of acrylamide in the blood appeared to have a higher risk of developing breast cancer, and particularly oestrogen receptor positive breast cancer. The researchers emphasise that their study does not prove the existence of a direct link between acrylamide in food and cancer. Nevertheless, it does underline the importance of carrying out further research on the matter.

Next steps

The project partners also devoted some of their efforts to the identification of other compounds which could be formed in a similar way. It turns out that acrylamide is just the tip of the iceberg; in heated foods there are some 40 to 50 similar compounds whose chemical structure marks them out as potential carcinogens. According to scientists, more research into these compounds is urgently needed.

Tips for cooking in the home

When discussing the risks associated with acrylamide, it is important to bear in mind the fact that people have been heating starchy foods for centuries, and the food group forms an important part of a healthy diet. Most of the foods which contribute to our acrylamide intake are industrially produced, so the contribution from home cooking is relatively small but dependent on cooking practices.

As acrylamide is mainly found in carbohydrate-rich foods, eating a lowfat diet will probably reduce the intake from products such as crisps.

Furthermore, there are things we can do to minimise the production of this harmful substance in our kitchen. The main advice is to avoid overcooking foods, as most acrylamide formation happens during the last few minutes of cooking. This means aiming for a golden yellow colouring, as opposed to golden brown, when toasting bread or roasting or baking potato products in the oven.