The Call, Column 34 – Don’t Avoid Meat, Just Eat Your Vegetables!

22 11 2015

(November 22, 2015)

The Urban Farmer

Don’t Avoid Meat, Just Eat Your Vegetables!

Part 2

Two weeks ago, we began our criticism of modern nutritional science, in the context of that ridiculous claim from the World Health Organization that “meat causes cancer”, and hopefully made a solid case that much of what we’re told about nutrition is probably just wrong.

Today, I want us to set our now well-honed sights on this specific claim, and figure out what it may actually mean for our health. Spoiler: we should still eat meat.

Before anything else, it’s important to reiterate that the nutritional studies on which the WHO based their claim are generally questionable at best – with the research bias, unscientific methods, overdramatized conclusions, and misreporting, we should be skeptical. One thing that I’ve found in my own reading is that correlations between diseases and the consumption of animal products, cholesterol, and saturated fat vanish when we look at a study that has removed those imperfections we discussed last time. As the research gets closer to being actual science…it no longer concludes that animal products are unhealthy!

But from a much broader perspective, we need to question why it is that eating meat has (supposedly) only just begun to cause cancer and the other health problems often blamed on it, when we’ve healthfully eaten it for at least 2.6 million years.

I will talk more about the idea of the ideal human diet in the near future, but the central point is this: like every other animal on this planet, we were healthy eating a diet natural to our species, which included lots of vegetables and about half of daily Calories from animal products (mostly red meat); the further we’ve strayed from this, the less healthy we’ve become.

So how should we look at statements of “x causes cancer” or any other disease? We have to ask the question: what change(s) have we made that open the door for cancer and other diseases to develop? In the case of meat, the answer is clear: we’ve swapped vegetables for grains and sugar! This proposal, that a reduction in vegetable consumption is the cause of disease, allows there to be some truth in the WHO’s report about a meat-cancer link without that link actually being because of the meat. Let me explain.

This idea came from Dr. Sarah Ballantyne. You should check out her blog post on this topic, and The Paleo View podcast #167 for a more thorough discussion than my quick reiteration below.

As we discussed last time, people who care about their health tend to eat less meat because they’ve been told that it is healthier to do so (though this is not true). So in observational nutritional studies, what tends to happen is those people who eat more meat (against nutritional advice) also eat fewer vegetables (against nutritional advice). What this means is that meat and vegetable consumption are negatively correlated – more of one, less of the other – and therefore, anything that can be blamed on one variable (an increase in meat consumption) can equally be blamed on the other (a decrease in vegetable consumption). And yet, meat is blamed.

And here’s the fun part. When studies actually account for this effect (the WHO report did not), when they only compare meat consumption amongst people who all eat, say, 5 servings of vegetables per day, the link between meat and cancer disappears.

Dr. Ballantyne introduces this interesting concept of a “conditional carcinogen” – a particular chemical (say, one present in meat) that is involved in the formation of cancer cells only when some other chemical (say, one in vegetables) is not present, or only when some other chemical (say, one in grains) is present. Our natural diet included the regular consumption of huge amounts of vegetables (mostly dark, leafy greens) and no grains, so a fairer assessment than “meat causes cancer” is that “in the absence of a huge amount of dark, leafy greens and the presence of a large amount of grains, cancer is allowed to form from otherwise healthy foods like meat”.

There are three such chemicals related to meat consumption, as discussed in her blog post: heme iron, TMAO, and heterocyclic amines; and a fourth, Neu5GC, is tangentially related.

Heme iron, a chemical found in red meat, can form carcinogenic compounds in the intestines when it is present there without chlorophyll, the chemical that gives plants their green color. But heme is necessary for good health, and this carcinogenic effect does not occur when one eats both meat and vegetables. Check one.

TMAO is created by the liver from L-carnitine, an amino acid in meat, and is linked with cancer formation. But this effect is driven by bacteria that only exist in the gut when one eats a diet high in grains. So the cancer link disappears when one replaces grains with vegetables. Check two.

Heterocyclic amines are chemicals formed when meat is cooked at high temperatures, and they are considered carcinogenic (though some, like niacin, are necessary for human health). The obvious solution is not to overcook meat – another glaring confounding variable that the WHO report admits that they were unable to account for. But even so, when overcooked meat is eaten with vegetables (like broccoli), spices (rosemary and thyme), and even a healthy-fat-based marinade (olive oil, lemon juice, and garlic) – this effect diminishes. Check three.

There is the fourth compound, Neu5GC, which is found in red meat, and can sometimes be mistaken by our immune systems as a threat, causing inflammation and a slightly increased risk of cancer. This effect seems only to occur when our immune systems are already in a hyper-active state of chronic inflammation (the boogeyman that is related to most diseases), which is brought on by stress and an unhealthy diet, deficient in vegetables and full of processed foods. Check four.

Do you see a pattern here? Where a compound in meat is linked to cancer, it is often one that is necessary for human health, and only carcinogenic when eaten while simultaneously 1) not eating vegetables, 2) eating lots of grains, or 3) coupled with stress and inflammation, which are associated with (1) and (2).

With that said, most of that small increase in risk (from 5% to 5.9%) can be attributed to chemicals added to processed meat that we already know to cause cancer. The high concentrations of nitrates and nitrites that are used to preserve processed meat, certain molds that can develop during aging when low-quality ingredients are used, and the added refined sugars have all been proven unhealthy. These are likely responsible for a big part of the measured effect, and do not implicate the meat itself.

In case you are skeptical of my logic (which I encourage, because blindly trusting reports on nutrition is what got us into this mess), here’s a good analogy: carbohydrates. It is well-documented that digestible carbohydrates (sugars and starches), whether “natural” or refined, have unhealthy effects on our bodies. And yet vegetables, whose Calories come mainly from sugars, are healthy. How is that?

The answer: context! When those sugars are wrapped up with all that vegetable-y, or fruity or nutty, goodness – the fiber, micronutrients, healthy fats, and antioxidants – or come alongside protective enzymes and micronutrients like in honey, the negative effect that the actual sugars may have on our metabolism is completely outweighed by the positive effects of everything else.

In the same way, compounds which are sometimes present in meat, and can be associated with carcinogenesis, are harmless or beneficial when in the context of also eating vegetables (and low-sugar fruits); they may even be outweighed by the many healthy things that we get from eating animal products. That’s another important point: healthy fats (omega-3 in particular), complete and easily-digestible proteins, Vitamin A, Vitamin B12, Vitamin K2, heme iron, and zinc are all mainly or exclusively available in animal products. Ask yourself: how often have medical professionals recommended eating fish oil (an animal product) for all of its awesome benefits?

So, as has become my tradition in these nutrition columns, here’s my third rule for eating more healthfully: fill your plate with as many vegetables (cooked and raw) and low-sugar fruits as you can eat, and add enough animal products (meat, eggs, cultured/full-fat dairy) and healthy fats (olives, avocados, nuts, coconuts, butter) to build, maintain, and fuel your body. As fellow urban farmers, I know I don’t need to tell you this: eat your vegetables!

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.

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.