A few weeks ago the International Agency for Research on Cancer (IARC) and WHO announced that:

“After thoroughly reviewing the accumulated scientific literature, a Working Group of 22 experts from 10 countries convened by the IARC Monographs Programme classified the consumption of red meat as probably carcinogenic to humans (Group 2A), based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect.

This association was observed mainly for colorectal cancer, but associations were also seen for pancreatic cancer and prostate cancer.

Processed meat was classified as carcinogenic to humans (Group 1), based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.”

This was picked up by hundreds of media outlets throughout the world with headlines stating that bacon causes cancer.  Today we wanted to take a look at this and get to the bottom of the media headlines.

Firstly IARC and WHO’s announcement wasn’t really new information, a number of research studies over the years have shown that red and processed meats increases a person’s risk of developing bowel cancer and charities like Bowel Cancer UK and Beating Bowel Cancer have been raising awareness of this fact for a number of years.

The wording of the statement and the classification of red and processed meat suggested that bacon and other processed meats were in the same league as tobacco and asbestos but this is not the case and WHO has since clarified this.  They have said whilst they have placed them in the same category “this does NOT mean they are all equally dangerous.”

If we look at global statistics about one million cancer deaths a year are caused by smoking whilst 34,000 cancer deaths are caused by consuming high levels of processed meat and red meat could be responsible for about 50,000 cancer deaths a year.

Research by the World Cancer Research Fund has shown that people who consume the most processed meat have and 17% higher risk of developing bowel cancer that those who consumed the least.

If you put that into the UK context, 21% of bowel cancers are linked to high consumption of processed or red meat, that’s 8,732 cases per year. So by reducing consumption of red and processed meats we can prevent over 8,000 cases of bowel cancer every year.

You may be wondering why red and processed meats increase a person’s risk of developing bowel cancer and to answer that question we have to understand what processed and red meats are. Processed meats are any meat that has been preserved for example cured, salted,  smoked or had a preservative added. This includes bacon, ham, corned beef, pepperoni, hot dogs, salami etc. And, red meat includes beef, pork, lamb and goat; these are meats that are red when uncooked.

It is not entirely clear why red and processed meat increase a person’s risk of developing bowel cancer, but there are some theories. It is thought that processed meats increase risk of bowel cancer because the methods of preserving these meats lead to the development of cancer-causing substances.  When it comes to red meat,  scientist suggest that it may cause cancer due to the molecule that  gives red meat its colour (haem). This molecule may lead to the development of cancer-causing chemicals too. Additionally, cooking both red and processed meat at high temperatures may also generate cancer-causing substances.

The recommendation is that we should all cut down on red meat and avoid processed meat, these can be replaced with white meat or vegetarian options, and we should all be eating more fruits, vegetables and fibre.

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Sources
WHO
International Agency for Research on Cancer
Cancer Research UK
World Caner Research Fund