What’s the beef with red meat?

Here in the UK this week the media has been feasting on a recent pronouncement from the World Cancer Research Fund (WCRF) which urges us to strictly limit our consumption of red meat to protect ourselves from bowel cancer. The WCRF’s statement is based on research conducted recently at the Imperial College London, in the UK. It updated with more studies a similar review undertaken in 2007.

Here’s the opening salvo from the report linked to above: “The most authoritative ever report on bowel cancer risk has confirmed that red and processed meat increase [emphasis mine] risk of the disease…” Those are strong words, and the media has been only too happy to parrot them. Let’s have a look, though, and see if it’s desperately important for us to cut back on red meat for the sake of our health.

The first thing to note, I think, is that the evidence used as the basis for this recent review is epidemiological in nature. Such evidence looks for associations between things. However, just because two things are associated, does not mean one is causing the other. Owning a television is associated with an increased risk of heart disease. Does owning a television cause heart disease? If you bought a TV and left it in the boot of your car or buried it in a field, would you be at increased risk of heart disease? Probably not. The issue is not owning the television, it’s likely something associated with owning it (e.g. watching it and therefore being more sedentary). Related factors that can incriminate an innocent factor in this way are referred to as ‘confounding factors’.

We could have hundreds of studies linking TV ownership with increased risk of heart disease, but they still prove nothing. Likewise evidence regarding red meat and colon cancer.

The fact is, even when properly conducted, epidemiological evidence just simply does not tell us a great deal. And it can’t, honestly, be used to conclude that “red and processed meat increase risk of [colon cancer]”. Such conclusions are scientifically untenable, and are generally made by people who:

1. don’t understand the limitations of epidemiological evidence.

2. do understand the limitations but draw inappropriate conclusions anyway.

That latter category tends to be well populated by epidemiologists, by the way…

However, not all epidemiologists appear not to know better. Earlier this month saw the publication of a review of the evidence regarding red meat consumption and colon cancer in the European Journal of Cancer Prevention [1]. The review points out a range of inconsistencies and relevant issues in the evidence including:

  • significant variation in results from study to study
  • links with red meat and colon cancer but not rectal cancer (the rectum is the lowest part of the colon)
  • links in men but not in women
  • considerable potential for confounding, through lifestyle and other dietary factors

The authors conclusion? “The available epidemiologic data are not sufficient to support an independent and unequivocal positive association between red meat intake and CRC [colorectal cancer].”

The issue of confounding is particularly relevant here. We’ve heard about the perils of red meat for a long time now. Many health conscious people have acted on the warnings by eating less (or no) red meat. Others, perhaps less health conscious people, have ignored the advice. So is it possible that any increased risk of colon cancer in red meat eaters has nothing to do with the red meat, but the fact that they are more likely to engage in other ‘risky’ behaviours like smoking and being sedentary? You can read more about this concept here.

Also, it’s perhaps worth bearing in mind that not all epidemiological evidence supports a link between red meat consumption and colon cancer. In one study, for instance, vegetarians and vegans turned out to have an increased risk of colorectal (cancer in the colon or rectum) compared to those eating [2].

Another issue I have with the WCRF report is that it focuses on one disease (cancer) in one site (the colon). Does making recommendations on the basis of its relationship with a relatively rare disease make sense? Wouldn’t it make better sense to make recommendations based on a wider view, such as overall risk of death? Much that politically correct epidemiologists and scientists hate to admit this, but the fact remains those who eat meat are at no increased risk of disease or death, overall, compared to vegetarians. See here for more about this.

Put all of this together and what do we have? In my view – much ado about nothing.

References:

1. Alexander DD, et al. Meta-analysis of prospective studies of red meat consumption and colorectal cancer. Eur J Cancer Prev. 2011 May 2 [Epub ahead of print]

2. Key TJ, et al. Cancer incidence in vegetarians: results from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). 2009;89(suppl):1S-7S

20 Responses to What’s the beef with red meat?

  1. Michael Allen 24 May 2011 at 3:07 pm #

    Well said. This is no more than glorified common sense, really, but as usual common sense is in short supply. Especially among scientists, it seems, and especially among those under pressure to publish, and to demonstrate that they are doing ‘meaningful’ research and therefore deserve to be given further funds for research.

    Funny how more research is always needed. There is a school of thought which suggests that, as we have been pumping vast sums of money into cancer research for the past fifty years or more, to no valuable result, we should give up doing so and spend our money on disseminating sensible information (like the above post) instead.

  2. rod tucker 24 May 2011 at 6:07 pm #

    I think the risks of colorectal cancer (CRC) need to be put into context. The Centre for Disease control have provided estimates for the 10 year risk of CRC at
    http://www.cdc.gov/cancer/colorectal/statistics/age.htm
    For a 60 year old man, the 10 year risk is 1.46%. Even if red meat consumption increased this risk by 50% (i.e. Relative risk of 1.5) this would only increase the risk to 2.19% (i.e. 50% increase on 1.46) – hardly worth losing any sleep over!
    Also, I think it is worth poiting out that in the study by keys et al (reference 2), the average meat consumption was only 78g/d which is actually less than the average red meat consumption for the UK. (90g/day).
    My final point is that the same authors (reference 1) have also produced a review on the effects of processed meats on CRC which comes to the same conclusion (Alexander et al Processed meat and colorectal cancer: a quantitative review of prospective epidemiological studies. European Journal of Cancer Prevention 2010; 19:328-341)
    So enjoy your red meat – I do!

  3. DoctorM 24 May 2011 at 6:25 pm #

    I agree there is no PROOF that red meat is dangerous. However much red meat is fed on unnatural diets – not paleolithic. And bacon and other pork products are highly processed, ultra modern and certainly not paleo. Wild meat and fish are surely OK as these are pretty paleo. No PROOF but significant RISK in consuming modern red meats particularly processed meats

  4. simona 25 May 2011 at 11:20 am #

    Thank you Dr. Briffa for writing about this. (However, colon cancer doesn’t seem to be that rare, it’s the third most common cancer for both sexes http://info.cancerresearchuk.org/cancerstats/types/bowel/incidence/.)

  5. Soul 25 May 2011 at 6:53 pm #

    I stock up with a large purchase of red meats last week, and then reports come out on bowel cancer associated with beef! Maybe I should have purchased pork, then maybe there would be reports on the disease of out of control political spending. : )

  6. Jon 25 May 2011 at 10:09 pm #

    Dr Briffa

    Did the report distinguish between red and processed meat or class red and processed meats together? There is obviously a big difference between red meat (grass or grain fed) and processed meat (i.e laden with pottasium and sodium nitrates, smoked, high in sodium, and generally having other chemicals etc added to them)

    Jon

  7. Megan 26 May 2011 at 3:34 pm #

    @ Jon – if it’s based on the same ‘evidence’ as their dire warning a year ago, then it not only doesn’t differentiate, but includes cheeseburgers with buns, chicken korma, steak and kidney pie, etc., as ‘red meat’.
    See http://lowcarbjottings.blogspot.com/2009/02/friday-and-promised-email.html

  8. John Walker 27 May 2011 at 6:38 am #

    Strange that we rarely hear of any research into the effects of wheat and other cereal crops on our bodies. or is it so strange?

    I believe many of these anti-meat studies are commissioned by the powerful grains lobby. The growers and marketeers have a huge share of world markets. Any truths about the damage starches and sugars can do that become widely known would not be in their interests. They have the money and therefore the power to ‘swing’ the results in their favour. It’s obvious that any steering away from bread and cereals (The staff of death?) would weaken their grip on the world’s markets, and therefore weaken their wallets.
    I eat meat, and I like it.

    JW

  9. helen 27 May 2011 at 6:58 am #

    I can’t even be bothered reading the utter rubbish they put out about red meat. big difference between a steak and a bit of processed sausage loaded with soy and other additives with the meat waved over the top.
    The only thing that gives people cancer is the stress incurred by trying to do all the stupid things the health profession tells you to do to avoid it!!! Eat red meat to your hearts content literally!!!

  10. DoctorM 27 May 2011 at 11:35 am #

    Helen
    I quite agree. Wild and naturally (grass fed) red meat (venison, lamb, beef etc)the perfect food. Processed meat products, including sausages, salami and bacon junk.
    My only additional observation is that meat in the wild is not high in fat and what fat there is has a natural ‘paleo’ lipid profile. It is only animals which have been fed unnaturally, by man, on grain and soy which have high amounts of fat – fat which does not have a paleo lipid profile. I am therefore doubtful about modern pork as well as grain fed lamb and beef. It is difficult enough, as a consumer, to find out how animals used for food have been fed and I doubt if it was possible to take animal feed into account in the study. Another factor is level of cooking – meat should be lightly cooked to preserve its health benefits – I also doubt whether this was taken into account in the study. So I think the results of the study are likely to have been influenced by unnatural feeds and overcooking – hence wild and naturally fed foods ‘should not be tarred with the same brush’ and should be regarded as safe and beneficial in spite of the study conclusions.

  11. Martin Levac 27 May 2011 at 1:32 pm #

    That’s right Dr Briffa. Science requires three steps:

    1. Observation
    2. Hypothesis
    3. Test

    If any step is omitted, especially step #3, it’s not science. Epidemiology only does at most the first two steps and thus cannot be considered science because of that. At best, even the largest observational studies can be considered as big giant opinion pieces; I saw this and that’s what I think about it. Well, everybody and his dog can have an opinion. And between theirs and mine, mine is eminently more reliable.

  12. ValerieH 27 May 2011 at 1:35 pm #

    “they are more likely to engage in other ‘risky’ behaviours like smoking and being sedentary? ”

    Being sedentary is lumped in with smoking. That is quite interesting. Modern society is sedentary. I drive to my office job and when I get home I am mentally exhausted which also leads to more sedentary behavior. It’s weird. I’m sitting but the job and driving is stressful and there’s no way to relieve that stress. If I create that belief inside, that being sedentary is “risky behavior”, maybe it will help me move more in general. Thanks for the food for thought.

  13. tom scott 27 May 2011 at 2:59 pm #

    First, this is speculation on my part. Every bit as unreliable as an epidemiological study.
    I think that politicians and other world leaders are concerned about food shortages and costs. When people become upset over food shortages and rising prices they become agitated, just as in Egypt. Grain shortages are upon us now. Prices will rise and anger will rise. The politicians, in seeking lower prices and increasing productivity, are very interested in pushing grains and other cheap carbs. Of course, as John Walker mentioned, the huge grain industries are only too happy to finance the attack on meat and to promote grains. They are supported by many that believe it is too expensive to use acreage for feeding cattle when they could be using that land for growing grains to feed the masses much more cheaply.
    Gary Taubes describes President Nixon’s reactions to growing food prices in GCBC.

  14. Daniel Cooley 31 May 2011 at 7:02 pm #

    Does anybody realize that this same argument was used for decades by stooge doctors of the American Tobacco Industry to deny a causative relationship between smoking and lung cancer.

    ‘Look at 95-year-old Norma Smith here; she’s smoked all her life and SHE doesn’t have lung cancer.’ Briffa is saying the same thing. Red meat is ASSOCIATED with certain diseases but that doesn’t mean it CAUSES those diseases (of course it does…it’s the saturated fat in red meat). His ignorance of the scientific method is abysmal.

    Is there a British Cattlemen’s Association? If there is, guess who’s on its payroll.

  15. John Briffa 31 May 2011 at 7:32 pm #

    Daniel

    Red meat is ASSOCIATED with certain diseases but that doesn’t mean it CAUSES those diseases (of course it does…it’s the saturated fat in red meat). His ignorance of the scientific method is abysmal.

    Oh dear, Daniel, time for you to go and learn some basics regarding the scientific method, I think.

    I have never been paid by any organisations that have links with the meat industry. Even if I had, it wouldn’t change the facts…

  16. Matt 10 September 2012 at 9:09 am #

    I disagree. The World Cancer Research Fund and American Institute for Cancer Research conclusions are based on over 7000 studies, analysed by 150+ scientists. This article insinuates that the only evidence demonstrating the link between red meat consumption and cancer is epidemiological – what about the mechanistic research? Surely you’re not unaware of this…

    If you want to eat red meat, that’s one thing…Trying to distort the scientific consensus in favour of your behavioural dispositions is another. Cognitive dissonance anyone?

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