The Call, Column 33 – “Meat Causes Cancer” – the Folly of Mainline Nutritional Science

8 11 2015

(November 8, 2015)

The Urban Farmer

“Meat Causes Cancer” – the Folly of Mainline Nutritional Science
Part 1

Last week, the World Health Organization released a statement that classified processed meat as “carcinogenic to humans”, and red meat as “probably carcinogenic”. I hope that, like me, you took this statement with a grain of salt (or maybe a strip of salted, pasture-raised bacon). I don’t say this because we shouldn’t aim for the best health through diet, nor because we should generally doubt the validity of scientific research – quite the opposite. To put it in the nicest words possible, modern nutrition science is in a sad state of disarray, having made quite a few unjustifiably definitive statements based more in preexisting biases, politics, and industry lobbying than in fact. This is unacceptable, and to be brutally honest, we would likely be healthier by simply ignoring the conclusions of this research.

Today and in the next column, we’re going to discuss some of the central weaknesses in nutrition research, guided by example of the WHO’s recent statement about meat. As urban farmers, it is important for us to understand how our diets affect our health, and to know when it is more prudent to trust in the wisdom embedded in 4.5 billion years of geological evolution, and 7 million years of human evolution, than in 2-week-long studies funded by the processed food industry. That is why I need to write this column.

The group of 22 researchers at the WHO considered the results of meat-cancer studies (no original research was conducted), and voted, not unanimously, that eating 50 grams of processed meat – 2 slices of ham or 6 slices of bacon – per day increases relative risk of colorectal cancer by 18%. Considering the average person’s risk is around 5%, this conclusion means that actual risk is increased from 5% to 5.9%. In full recognition of the seriousness of cancer, I can’t help but point out that this increase is almost statistically insignificant in comparison to smoking, which increases risk by 2500%.

Let’s consider the first big weakness – nutritional research bias. Unsurprisingly, much of nutritional research is funded by the processed food industry and the government. When continued funding depends on certain conclusions, namely that it is meat, not sugar which is responsible for chronic disease, and that existing governmental (grain-heavy) dietary recommendations and subsidies to grain and legume (processed food) agriculture are nutritionally-responsible, the research conclusions must be of a certain…slant. In addition, the average bias among nutritional scientists is that saturated fat, cholesterol, and animal products are generally unhealthy (though this has not been proven), which affects their conclusions – including whether a study gets published at all if it doesn’t show the desired result. These biases are usually unintentional, but are often present nonetheless.

Next, consider the unscientific methods used in nutritional research. In general, the methods used in nutrition are much less scientifically-rigorous than those used in the hard sciences like physics. For example, the statement that “a solar panel captures sunlight with x% efficiency” is actual scientific fact, the result of a lot of testing and direct observations in order to make a very small, simple assessment on a well-understood system; whereas the statement that “saturated fat is unhealthy” is not comparatively definitive, and is based on weak trends in a system (the human body) where millions of chemical reactions, many not-well-understood, are happening simultaneously, and where there are so many things that simply cannot be accounted for.

The accuracy of science relies on two perfect systems to be compared – one “control group”, where nothing is changed, and one “experimental group”, where a single variable (characteristic) is different from the control – in order to understand the effect that changing this single variable has on the system. Variables that are not kept constant between the two study groups, characteristics which simply cannot be accounted for, are called uncontrolled confounding variables – in nutrition, these include the quality of the food (i.e. organic/grass-fed vs. CAFO meat) and whether the person smokes, exercises, sleeps enough, drinks alcohol, drinks enough water, has a stressful life, has pre-existing conditions, etc, all qualities which affect their health completely independently of whatever variable is being studied (i.e. meat consumption).

The most common nutritional study – observational studies – allow the people being studied to live their lives, sometimes with specific dietary recommendations, and then every few weeks/months/years write down the things they ate, drank, etc. The researchers then attempt to account for all of the confounding variables above, and assume that the peoples’ bodies behave exactly the same way, in order to make a conclusion about the effect that (for example) the amount of meat consumed has on their health. Can you see where this probably doesn’t produce the most accurate results?

While I was learning about this, the first alarm that went off in my head was this: for 40 years, we have been told to eat less animal products, less fat, and less cholesterol by the government. The people who otherwise care about their health – who don’t smoke, don’t drink, exercise regularly, get regular physicals, sleep, avoid stress, eat little sugar, etc – also eat somewhat less of these things. They eat less meat because they’re told it’ll make them healthier, whereas the people who care less about their health probably don’t heed that recommendation.

Not smoking, for example, positively affects one’s health so much more than any particular dietary choice, positive or negative. So what we find is that the people who eat less of these things are generally healthier – not because they eat less animal products, but because they do everything else right. And yet, the animal products are wrongly accused as being the cause of ill health.

Finally, there is the issue of overdramatized and frankly incorrect conclusions, reported both by the nutritional research organizations themselves and the national media reporting on the research. First and foremost, it’s important to understand what the data that nutritional researchers collect actually means. By its very nature, this science is one of “correlations” – the data says that when a certain thing (X) happens more, a certain other thing (Y) happens more, or less, or whatever. This does not – I repeat, does not at all – imply that X causes Y. This is a statement central to statistics – “correlation doesn’t prove causation”. If you want to laugh, search that statement in Google – apparently (by the logic used in nutrition), an increase in Facebook users resulted in the Greek debt crisis, and the decrease in the pirate population is the primary cause of climate change. All kidding aside, I hope it’s obvious now that “meat causes cancer” is a simply unscientific statement, given the little honest evidence they had available.

To make matters worse, the whole “landscape” of nutritional science is simply misreported. Many studies find no link between saturated fat, cholesterol, and animal product consumption and health defects, but the general narrative of the government, nutritional organizations, and the global media is that these things are unhealthy. As a result, only those studies that agree with their preconceived notions are reported as fact (called confirmation bias).

What’s more, the actual conclusions of the research get completely blown out of proportion, being overstated in order to drum up reader interest. This declaration by the WHO is a perfect example – where their statement suggested a tiny increase in cancer incidence, the overall media firestorm was that “meat will kill you!”, period, end of story, eat more healthy whole grains and sugar. Given that nutrition is the most centrally important science to us as individuals, this “loss-in-translation” has very dramatic effects.

I hope I’ve given you a good idea of why the conclusions of nutritional research, including the declaration by the WHO, leave something to be desired. As people intimately involved in food production, it is important for us to know how to critically analyze the conclusions of nutritional research, putting them through a skeptical filter of “this is probably not true or nearly as definitive as the reports say”, and find whatever scientific accuracy might actually be buried in the headlines

Next time, we’ll directly discuss why the “meat causes cancer” headlines probably mean very little to our health. We will discuss whether there may be some grains of truth (spoiler: there are, but not in the way that you think), and I’ll give some personal recommendations for a healthy diet.


My column appears every other Sunday in The Woonsocket Call (also in areas where The Pawtucket Times is available). The above article is the property of The Woonsocket Call and The Pawtucket Times, and is reprinted here with permission from these publications. These are excellent newspapers, covering important local news topics with voices out of our own communities, and skillfully addressing statewide and national news. Click these links to subscribe to The Woonsocket Call or to The Pawtucket Times. To subscribe to the online editions, click here for The Call and here for The Times. They can also be found on Twitter, @WoonsocketCall and @Pawtuckettimes.




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