Bacon may cause cancer but here is why you shouldn’t be worried

    30 October 2015

    The presenter Karl Pilkington once said that if he could be a super hero he would like to be ‘Bullshit Man’. He would fly into meetings and point the finger at anyone talking bullshit. This week, reading the headlines about the World Health Organisation report on meat and cancer, I was desperately hoping for this character to make an appearance.

    Alas, he did not — and, if you believed the coverage, what was once a deliciously tasty food consumed for centuries is now analogous to smoking; a 40-a-day habit is the same as a predilection for Serrano.

    The BBC headlined a story with ‘Is processed meat going to kill me?’ before quietly saying no. Its ‘reassuring’ sign-off was that the ‘odd butty will do no harm as long as it is not too big’. I didn’t sleep that night, pondering sizes of butties and when they become harmful.

    Startling figures were quoted with little context. Meat consumption, reports said, led to an ‘18 per cent increased risk of bowel cancer’. Yet the data was not available for anyone to look through. One of the report advisers, Dr Teresa Norat, said there were many causes for bowel cancer, but then definitely suggested completely avoiding processed meats. I wonder if she eats any. Professor Tim Key from Cancer Research UK was more balanced, suggesting that ‘eating a bacon bap every once in a while isn’t going to do much harm; having a healthy diet is all about moderation’. Head scratching again for me — I was scrabbling for a sensible weekly consumption.

    Eventually, I found sense — the World Cancer Research Fund suggested a weekly consumption of no more than 500g a week personally, and as a population goal 300g a week. Sir David Spiegelhalter, a professor of the public understanding of risk at Cambridge, more reassuringly suggested that if 100 people ate 50g of bacon daily for the rest of their lives, statistically, one more person would have bowel cancer versus the control group (six people out of 100 rather than five out of 100).

    And that, for me, is the clincher — eating little to no red or processed meat offers a small lifetime modification of risk. An 18 per cent increase in risk sounds dramatic; 18 per cent out of five per cent, not so much. So if I am a dilettante I should be fine. The distance between the best and worst outcomes over a lifetime is one per cent. (For comparison’s sake, adults aged between 19 and 64 eat 71g of red meat daily; those over 65 eat 63g. The amount seems to have been falling over the last 15 years or so.)

    Let’s go back to the report. Limited evidence has been used to recommend a probable link of carcinogenicity to humans for red meat with strong mechanistic evidence of a carcinogenic effect in the colon, with associations for pancreatic and prostatic cancer. Put into plain terms, there’s a strong link between red meat and bowel cancer which has been suspected for some time. The role of the report was to identify a causation, but not to quantify or assess risk.

    Processed meats were labelled in the more definite ‘carcinogenic to humans’ category, alongside, frustratingly, anti-cancer medication, Tamoxifen and the UV component of sunlight. I see no people refusing their hormonal therapy for breast cancer or cancelling a holiday.

    However, the report did suggest a dose-dependence relationship with consumption — the more processed meat you eat, the greater the risk.

    There are, of course, a lot of factors that can affect the development of cancer — lifestyle, amount of dietary fibre, family history, presence of co-existent bowel disease, medication usage, smoking history, and so on. I eagerly await the release of the full report.

    There is an important point to make here. If you have persistent signs and symptoms of a problem with your guts, go and speak to your GP without delay. Be reassured that rarely does bowel cancer present under the age of 50. A good intake of fibre, regularly, is suggested to be protective. The guidance on detecting bowel cancer suggests a change in bowel habit over four to six weeks. There also exists bowel cancer screening, which is an imperfect test but is helpful, especially in picking up polyps. Be aware that a lot of things can create a false positive result, however.

    Please, though, don’t let wild reporting drive you to paranoia.