Friday, November 2, 2007

Red Meat gives you cancer....oh really?!

You will not have missed the shock/horror scare stories in recent days following the publication of a report from the "World Cancer Research Fund."
The BBC: Be thin to cut cancer, study says
The Scotsman: Red meat increases cancer risk
The Independent: Consumers ignore cancer risks of eating red meat

The "scientists" carried out what was reported to be the largest ever inquiry into lifestyle and cancer, and issued several stark recommendations:
  • Limit red meat
  • Limit alcohol
  • Avoid bacon, ham, and other processed meats
  • No sugary drinks
  • No weight gain after 21
  • Exercise every day
  • Breastfeed children
  • Do not take dietary supplements to cut cancer
The media by and large concentrated on one thing .....Here we go meat is bad ?! (everyone has focussed on this for some reason, rather than the need to limit sugar). OK, good headlines, scary story, ( and I would agree with some of those recommendations, like dumping the sugar) but what do we make of the science?

Well one thing to watch out for is the difference between association and causation. Lots of things can be associated with each other, but they do not necessarily cause each other. For example, if the sun rises at 6am and then my alarm clock goes off you could say that the sunrise and the alarm were associated....but the sunrise did not cause the alarm clock to go off. They happened at the same time but there was no cause/effect relationship.

Keep that idea in mind if you read the report. Anyway, I do not mean to go through the report, but suffice it to say that I think that we can be quite sceptical of its findings and recommendations.

There are three posts you need to read to get a handle on this stuff:

What’s the evidence cancers are our own fault? - a brilliant and exhaustive demolition of the poor science involved in this report, especially the confusion between correlation and causation. The post also explains how the report seems to ignore studies that do not support their position. For example with respect to red meat:
Here again, larger, stronger and newer studies were not included in this Report, including the largest meat study to date. For example, researchers at Harvard examined 14 studies on 725,258 people in North America and Europe investigating meat and fat and associations with colorectal cancer risk. As they reported in the Proceedings of the American Association of Cancer Research in 2004: “Greater intake of either red meat (excluding processed meat) or processed meat was not related to colorectal cancer risk.” This study was found nowhere in the list of references in this Report

Are the recent recommendations designed to ward off cancer justified? - Dr Briffa again talks about the difference between association and causation:

....... these recommendations come from what are known a epidemiological studies, which look for associations betweens things. Clearly, the panel has found a stack of evidence that links, say, excess weight with cancer. However, this link does not mean that one is causing the other.

Let’s for a moment imagine that a study finds that owning a television is associated with obesity. The question is, does owning a TV cause heart disease? Imagine you bought a TV but left it in its box and stored it in the attic. Would you be at increased risk of heart disease? Probably not. However, watching the TV endlessly for hours might be a problem. However, it’s not really owning a TV, but watching it and therefore being more sedentary that is the likely true cause of an enhanced risk of heart disease. It doesn’t matter whether we have 1 or a hundred such studies – they still cannot be used to impugn TV ownership, because we just don’t know that it is this or something associated with TV ownership (such as being more sedentary) that is the true cause of heart disease.

The same argument can be made for any association found in epidemiological studies, including those found between body weight and cancer.

He also notes that the study only looks at cancer, not other causes of death. If you don't get cancer you will die of something else anyway:

...again, the focus is on cancer. When we broaden the debate and focus on overall mortality rates, we find that these are not any higher in meat-eaters than vegetarians. In light of this, meat somehow doesn’t look quite so ‘deadly’.

Does red meat really increase colon cancer risk? - we have been eating all of these meats for several thousands of years – without any history of colon cancer. Many peoples in the world still do. So why should they be carcinogenic now? Indeed the writer points out that when you look closely at some of these studies you find some odd things that the scientists and journalists do not really emphasise:

.......... red meat intake does not increase the risk in Aarhus and Potsdam (1.00 means no effect) and it is protective in Italy (0.96 means 4% lower cancer risk in relative terms). ....So in some countries eating red meat seems to be harmful, in another it is beneficial, and in yet more it has no effect one way or the other!

Don't Panic

I know it winds some people up, but I'd still come back to the question of what were we designed for. We have been eating red meat for millennia. It is full of nutrients that are often unavailable elsewhere. I am not planning to cut back!

We need to be a bit sceptical about all this science!


Bryce said...

Red meat? Has anyone been paying attention to what fish and chicken can do to you lately?

It's immediate, very ugly and can seriously ruin your evening.

The main thing with fish is less immediate. However if anyone is unsure of the effects, try experimenting by breaking old thermostat switches and sucking out the contents.

In fact here in Ca. We just had a terrible experience with spinach, the stuff that popeye ate...Try imagining him singing that popeye song from the restroom for about six hours and you have the idea.


Chris said...

LOL - good point!

thanks for stopping by Bryce

Bryce said...

We must all stop eating, immediately :-|

Since we really...actually have no protection about poisonous food-Not food poisonous in twenty to thirty years, but things
which if you eat now, they kill you hours later.

Worrying about meat giving you trouble is like being afraid of early onset alzheimers during a war. Sure it matters-but there are more pressing issues buzzing about.

Thank you for permitting me the occasional rant by the way.


Franz Snideman said...

Great post! I am not about stop eating red meat...never!

Chris said...

Thanks Franz

Bryce - feel free to rant

Bryce said...

The real trouble with the present and probably the future is that we keep either trying to throw things "away" from us or keep things "away" from us. The trouble is that this "away" surrounds us and tightens its circle around us every day. Soon "Away" will be a quaint old illusion-like pensions and retirement perhaps.

What is "bad" in one thing will be bad in another in due time. Most of what's bad , like dioxin or mercury doesn't restrict its badness to one food.

This is not to be depressing, though it is. It's simply a set of conditions you must accept and do your best with in order to live. You can still do everything right and be laid low by lousy arugula ;-)


Goi said...

I haven't read through the reports, but based on the blog posts, one of the factors that doesn't seem to be mentioned is the type of red meat, specifically is it grass fed/organic or grain fed? There are significant differences in the 2 types in terms of quality of fats(omega6:omega3 ratio) and toxins/hormonal profile. There might be some merit to the carcinogenic properties of grain fed/growth hormone injected red meat, but I believe grass fed/free range red meat is perfectly natural and is in fact one of nature's best health foods!

Bryce said...

What was said above perhaps and the fact that much of what you get isn't meat at all. They often inject this broth of other stuff into chicken and beef to increase the weight and help the flavor out.

Considering what the words "natural flavoring" on a label really mean. I'd be more afraid of that. Why does a plain ol' cut of beef or a chicken need "natural flavoring"?


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Brain Reed said...
This comment has been removed by the author.
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