01/11/2015
Red Meat Causes Cancer? Let’s Talk About That…
On Oct. 26, The World Health Organization released a report stating that eating red meat is “probably carcinogenic to humans.”
It also said processed meat (bacon, sausage, hot dogs, and the like) is “carcinogenic to humans.”
The media went bonkers. As of today, Googling “meat” and “cancer” garners 39 million hits on Google News.
Yet as usual, sensationalist media articles bear little resemblance to what the report actually says -- and does not say.
Upon closer examination, rest assured, there is no need to back away from the barbecue.
Here’s the overarching premise.
Human beings and their hominid forebears have eaten “red” meat -- that is, the meat of four-legged ruminants including cattle and their ancestors -- for well over a million years. In some inland indigenous cultures, it was eaten almost exclusively.
And natural “processing” techniques (for example, preservation via salting) have been around for millennia.1
Yet cancers in these cultures -- including colon cancers, which the report states are the main meat-based cancer threat -- were virtually unknown until their diets became Westernized.2
That red meat, in particular, is intrinsically carcinogenic simply beggars belief. As Peter Cleave, the late former surgeon captain of the U.S., once put it, “For a modern disease to be related to an old-fashioned food is one of the most ludicrous things I have ever heard in my life.”
Beyond that, here are four reasons to be skeptical:
1. The report’s conclusion is based on inferior studies. The best way to figure out whether a food is healthy, neutral or dangerous is to collect randomized controlled trials. In other words, you combine studies where Group A was fed some amount of a given food and Group B was not and compare their health after some period of time.
No study, as least that I can find, has ever been done where Group A was fed 50 grams of processed meat or 100 grams of red meat daily (the amounts the report deemed the danger cutoff) and Group B was not.
The report’s conclusion was based on observational studies -- hands down, the worst kind of study if you want accurate information. This is because they rely on questionnaires that ask the participant to remember what he or she ate over the last week, month, or even year.
As you might expect, this kind of study is notoriously unreliable and full of potential pitfalls.3
2. Confounded confounders. There’s a vast difference between an overweight fast-food addict who gets his burger patty or hot dog in a white-flour bun along with fries and a Coke while binging on Game of Thrones and a paleo devotee who eats grass-fed, grass-finished steak after his daily hour in the gym.
Observational studies attempt to filter out such “confounders,” but this is absolutely impossible -- there are too many.
The fact is, red and processed meats have been so thoroughly demonized in the public’s mind that the people who still eat them are, quite often, people who ignore health advice generally.
They smoke, drink to excess, are sedentary and overweight, and have many other health-destructive habits.
It can’t be said often enough: Association is not causation. Even if red and processed meat has a weak association with cancer (more on how weak below), it is also associated with a constellation of truly awful lifestyle habits.
Parsing which of these caused the cancer is far from straightforward.
3. Many kinds of meat. The report defined processed meat as “meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.”
Human beings have preserved meat via natural means such as salting and smoking for millennia, while chemical preservatives are new. The report made no effort to distinguish between these.
More to the point, the report made no effort to sort out two kinds of red meat. Grass-fed, grass-finished meat rich in Omega-3 fatty acids was lumped in with GMO corn-fed, antibiotic-laden meat from crowded feedlots in which cattle stand knee-deep in excrement, gushing stress hormones into their tissues.
The nutrient profiles of these two kinds of meat are so different they might as well be from separate species.4 No study that fails to acknowledge the distinction can be called definitive.
4. Two kinds of risk. The report’s press release states that “each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18 percent.”
Sounds terrifying. But this 18 percent figure is the “relative risk,” not the “absolute risk.”
It’s a key distinction.
Absolute risk is a number that tells you the chance of something happening. Relative risk is a number that results from comparing two types of absolute risk.
In the U.S., the average absolute risk of getting colon cancer is relatively low: roughly 45 people out of 1,000. Put another way, an average American’s risk of developing colon cancer is about 4.5 percent.
What this study is saying, then, is that with each extra 50 gram portion of processed meat an average American eats, their relative risk of getting colon cancer increases by 18 percent.
So the math on that looks like this: 4.5 percent (i.e. absolute risk) × .18 (i.e. increase in relative risk) = .81 (increase in absolute risk).
In other words, even if you were to totally disregard this study and eat an extra 50 grams daily of processed meat -- enough to raise your relative risk by 18 percent -- your absolute risk of getting colon cancer will rise only by less than one percent (i.e. 4.5 percent + .81 percent = 5.31 percent) .
As you can see, absolute risk is the far more useful number, but it’s nearly always low and boring. Relative risk, on the other hand, is nearly always high and scary.
No wonder online news outlets -- whose advertiser-driven business models depends on accumulating pageviews -- have all the reason to conflate these two kinds of risk to produce more sensationalist headlines!
If you really want to know how a food or habit affects your level of risk, though, you must know the absolute risk number.
Considering the previous three points, I’d argue that the “less than one percent” increase in absolute risk fades to less than zero.
So…
I generally steer clear of processed meat. It’s simply too difficult to know whether it’s come from animals raised in healthful, sustainable ways, and whether the preservation method used was free of potentially harmful chemicals.
But red meat is a different story. As I explore here, beef provides an array of nutrients that are in short supply in modern diets.
I get grass-fed, grass-finished beef from a rancher north of Phoenix. But I’ve noticed that Trader Joe’s now sells such beef from New Zealand -- and for a relatively affordable price, too.
It would be tragic if the report scared anyone away from eating a health-sustaining, grass-fed, grass-finished, sustainably raised animal product.
Bottom line: Ignore the press misinformation about the WHO report. One of the best things you can do for your own and your family’s health is to visit LocalHarvest.com, search for suppliers of grass-fed, grass-finished beef in your area, and make these products a regular part of your diet.
Brad Lemley
Brad Lemley
Editor, Natural Health Solutions
