More than 900 chemicals in food, drink and consumer products have been found to cause breast cancer, according to a new study.

Scientists have found a quick new way to predict what chemicals are likely to cause breast cancer, based on specific traits.

The traits included chemicals which cause tumours in animals, alter the body's hormones and damage our DNA.

Through searches of multiple international government databases, the researchers identified a total of 921 chemicals that could promote the development of breast cancer.


Ninety per cent of these chemicals are ones that people are commonly exposed to in consumer products, food and drink, pesticides, medications, and workplaces.

More than half of these chemicals were found to alter the hormones in our bodies which can lead to breast cancer.

Around 4,900 cases of breast cancer are diagnosed in Scotland each year. It is the most common form of the disease among women, and claims more than 1000 lives a year in Scotland. 

Dr Jennifer Kay from Silent Spring Institute in the US, said: "Breast cancer is a hormonal disease, so the fact that so many chemicals can alter oestrogen and progesterone is concerning."

A further breakdown of the data shows that 278 of the chemicals cause tumours in animals and 420 of them damage our DNA and alter hormones.

Studying which chemicals will cause tumours in animals can now be predicted by looking at DNA damaging and hormone-disrupting characteristics. This will be a much easier and more affordable method of experimentation.

Co-author and research director Ruthann Rudel said: "Historically, chemicals that cause mammary tumours in animals were seen as the best predictor of whether they might cause breast cancer in humans.

"But animal studies are expensive and time consuming, which is why so many chemicals have not been tested.

"Our findings show that screening chemicals for these hormonal traits could be an effective strategy for flagging potential breast carcinogens."

The Herald: Previously, cancer links with chemical have had to be gauged retrospectively after hundreds or thousands of cases had been diagnosedPreviously, cancer links with chemical have had to be gauged retrospectively after hundreds or thousands of cases had been diagnosed (Image: PA)

In the past scientists would have to wait until hundreds or thousands of children and women have been exposed to a chemical and check, often many years later, to see who develops breast cancer.

The team believe that their new method of screening databases for characteristics that may cause breast cancer has completely transformed scientific research on the topic.

Ms Rudel continued: "It's not feasible, nor is it ethical, to wait that long.

"And it's another reason why we need better tools for predicting which chemicals are likely to lead to breast cancer so we can avoid those exposures."

This study, published in Environmental Health Perspectives, revealed that 30 pesticides previously approved by the Environmental Protection Agency (EPA) for use could cause breast cancer.

Therefore, this research may change how they assess chemicals for safety in the future.

Dr Kay added: "We need new tools to identify environmental exposures that could be contributing to this trend so we can develop prevention strategies and reduce the burden of the disease.

"This new study provides a roadmap for regulators and manufacturers to quickly flag chemicals that could contribute to breast cancer in order to prevent their use in consumer products and find safer alternatives."