No reason to fear the chemicals (Image: Monkey Business Images/REX)
Once again, headlines this week screamed about everyday chemicals that are supposedly “cancer causing”. People could be forgiven for being alarmed. But while stories like this seem to appear almost daily, the claims aren’t often supported by the science.
The publication that sparked the latest was a large of pre-existing studies published in the journal Carcinogenesis. It assessed the state of the evidence around cancer and a group of common chemicals that many people are likely to be exposed to, ranging from (used to make plastics more mouldable) to the antibacterial agent (found in some soaps) to iron.
Advertisement
All are widely present in the environment but aren’t considered carcinogenic. What these chemicals have in common is that, while they don’t cause cancer, they can affect cells in other ways, including causing them to exhibit some of the .
These are characteristics that together set cancer cells apart from normal cells. They include things like resisting natural cell death, being able to induce a blood supply and evading destruction by the immune system.
But while as a group these hallmarks have helped our understanding of what is happening inside cancerous cells, and how they function differently from their normal counterparts, each one on its own doesn’t mean a cell is cancerous.
Cancer hallmarks
The researchers argue that, although the chosen chemicals “were not selected to somehow imply (based on current information) that they are endangering us”, there is a gap in the evidence when it comes to the impact of exposure to a combination of them, all at low doses. Classically, chemicals are tested in isolation to determine an often very conservative safe level.
The key question raised by this review was if individual chemicals can lead to one hallmark change in cells in the lab, is it possible that many chemicals together could cause a number of these changes in cells? And could that lead to cancer?
Unfortunately, the evidence so far can’t answer this question. It also can’t tell us whether the result of any studies of cells in the lab exposed to chemical mixtures will hold true for the general public.
When it comes to cancer risk, research has shown that there are other factors which play a clear and important role. We can say with certainty that lifestyle has a big impact. More than 4 in 10 cases of cancer could be prevented, largely through lifestyle changes like giving up smoking, maintaining a healthy weight, eating a balanced diet and cutting down on alcohol.
When it comes to everyday chemicals and cancer there are still some very big ifs and buts that research needs to iron out. Until we have solid evidence I wouldn’t read too much into the hype on “cancer-causing chemicals”.
