Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
11 Mar

Dear Mark: Is Meat Going to Kill Me (Again)?

Red MeatThere’s another “meat is bad” study making the rounds, featuring such stellar prose as:

“Although causality cannot be established…”

“…further research is recommended.”

“…should still strive to reduce intake of red and processed meat, which tend to contain high amounts of saturated fat and sodium.”

And so on.

By now, we see these lines, roll our eyes, and keep on moving down the path that seems to be helping us. But that’s us, people who pay attention to nutrition news and stay abreast of the literature. We may be able to write off these breathless articles without thinking we’re going to die because we ate that bunless burger the other day, but our parents, our friends, our colleagues may not be so well-equipped. They’re worried about our health, and who can blame them? If you take mainstream health articles at face value, articles which confirm what your doctor is probably telling you, you would do the same.

Hi Mark,

Have you heard about the latest study saying that we’re all killing ourselves? I’m personally not that worried, but I’ve been getting a ton of frantic and/or smug emails from concerned and/or smug friends and loved ones. I’d love to be able to point them toward something to explain the results. Think you could tackle it?

Thanks,

Matt

This is another in a long line of observational studies that find associations between processed meat intake and early death so that journalists can feel superior about something while writing easy articles (with lots of copy and pasting from the last one). I mean, aren’t they all the same? “Regardless, [name of expert] is quick to urge consumers to cut back on [delicious, Primal food that has supposedly been killing us humans, bite by bite, for tens of thousands of years] and reduce the overall percentage of [saturated fat or cholesterol or sodium] in their diets.” If you’ve read one, you’ve read ‘em all.

I feel like I’ve done all this before. I’m experiencing the distinct sensation of deja vu, kinda like when you have a dream and it feels like you’ve had it before, but when you wake up and try to piece it all together with a clearer mind, you realize that it was a totally unique vision and just an artifact of the nature of dreamscape. This may not involve showing up late to the big exam in the nude or falling from a cliff and waking up right before you hit ground, but it’s strangely familiar, isn’t it?

Being hit with one of these studies every couple months like clockwork wears down a man. It boggles me how people can grapple with the same questions (oftentimes using the same datasets), never coming to a conclusion, never even getting any closer to the truth, always dancing around on the edges. I get that this is how science works – you can’t leap to conclusions that aren’t actually there – but why not ask some different questions? It’s the same thing over and over again.

And yet it will be thrown in your face, so let’s go over it.

The study used data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which collected complete information on diet, smoking status, physical activity, and BMI from almost a half million men and women without stroke, cancer, or heart disease. They grabbed a decade’s worth of data along with “clinical endpoints” (death from various causes), and have since been running the numbers to see the effect of various factors – usually a particular category of food or nutrient – on mortality. Today’s study was about the effect of red meat and processed meat on all-cause mortality.

What did they find?

The highest intake of processed meat was associated with a 44% increase in all-cause mortality. That could be death from bladder cancer, myocardial infarction, or car accident. Anything goes. This association was reduced to 24% after adjusting for smoking, but it wasn’t eliminated. Adjusting for other confounders, like energy intake, alcohol intake, body weight, activity levels, and produce intake, was also unable to totally make up the difference. Doing all the right things and avoiding all the wrong things still didn’t remove the association. Interestingly, the lowest intake of processed meat (none) was associated with more mortality than low or moderate consumption of it. Perhaps some meat-based nutrients are so vital that getting them via Lunchables is better than nothing?

Intake of unprocessed red meat was barely associated with increased all-cause mortality until adjusting for other confounding factors, after which point the association vanished completely. These confounding factors included overall energy intake, alcohol intake, smoking, body weight, activity levels, and produce intake.

There’s a definite healthy user bias when it comes to processed meat. People who ate the most processed meat also ate the least amount of fruits and vegetables. They also smoked and (the men, at least) drank a lot and tended to avoid the gym. Red meat eaters, too. As I said, they tried to account for these confounding variables, but I’m skeptical they can do so completely.

I’m just happy they’ve actually started differentiating between red and processed meat. It used to be that “red meat” was cautioned against on the strength of studies which lumped fresh rare rib-eyes and braised short ribs with Oscar Meyer hotdogs, bologna, and ham Lunchables, but some of the latest ones have realized there’s a difference between the two. Next, it’d be nice to see what happens if they start accounting for what people eat alongside processed meat; I’m pretty sure white bread buns, strange goopy seed oil sauces, and french fries all play their role, too.

Another pleasant thing about this study is that the articles it’s spawned have generally been high quality. Confounding variables, the difference between causation and correlation, and the fact that fresh red meat had no significant associations with mortality were all mentioned and addressed in most of the articles I came across.

So, to sum up: This was an observational study that only showed correlations. It did not establish causation.

Assuming the correlations indicated causation (which, you know, we have no way of knowing), fresh red meat has no effect on mortality. Processed meat does, but this effect is lessened when you account for the fact that processed meat eaters also lead generally unhealthy lifestyles bereft of exercise and produce and replete with smoking, overeating, and, for men, drinking. Even so, those adjustments were purely mathematical. Even the authors of the study “could not exclude residual confounding,” the general unhealthy lifestyle effect. You can’t quantify general unhealthiness, recklessness, psychological stress, and all the other factors that affect our health and mortality. They didn’t track things like checkups at the doctor, either.

All that said, this research isn’t saying anything we’re not already aware of.

Real red meat, fresh cuts of cow, pig, and lamb, are nutritious foods. There’s no evidence that they’re killing us en masse.

Don’t make processed meat your major source of animal products. Eat steak, not those weird processed meat sticks they sell at gas stations. I’ve said this before.

And yes, bacon is delicious, but it shouldn’t replace real, actual meat in your diet. A pound of bacon for breakfast is a fun thing to have when your vegetarian friends stay over, though – I’ll admit that.

Eat your produce, folks. It’s good for you, and it may even reduce the formation of carcinogenic compounds when co-ingested with meat (steak and salad, anyone?). That could explain the relative reduction in mortality among people who ate lots of fruits and vegetables with their processed meat.

Don’t overcook your meat. The authors speculate that high-heat processing and the subsequent formation of heterocyclic amines (HCA) could explain the association between processed meat and mortality. Other studies have certainly found a connection between high-heat cooking, HCA, and prostate cancer, so I wouldn’t be surprised if there was a mechanism there.

Your Primal way of eating may kill you, kill you even deadergive you diabetes, give you diabetes againgive you breast cancer, be worse for you than smoking, and give you heart disease, but none of these studies actually say it.

Hope this helps, everyone. Thanks for reading and be sure to leave a comment!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Joy from FRIENDS is not the smartest guy on the planet, but he’s got a good point about meat:
    “It is natural for humans to eat meat, okay? We eat the cows, the cows eat the grass, we mow the grass, which makes us hungry for more cows.”

    :D

    Hanne wrote on March 12th, 2013
  2. You mention “high temperature” as a possible culprit in cooking. In your opinion, is using a pressure saucepan ok? I like to plunk my frozen lamb chops in there and cook them to glorious tenderness.

    Yolanda Breidenbaugh wrote on March 12th, 2013
  3. Hi
    I am glad I read this post it cleared a big issue up for me. The main one being that it is not the processed meat that probably increases mortality it is that the mor e processed meat you eat correlates with a whole load of other factors that increase your mortality.

    Great post lee

    Lee wrote on March 12th, 2013
  4. I continually find it amazing that the other interesting finding out of these studies is almost always ignored.

    As Mark mentioned, those that ate no meat had worse health outcomes than those with low/moderate consumption.

    I find this particularly interesting as most read meat avoiders do so for “health” reasons – i.e. they are consciously trying to lead what they consider a “healthy” lifestyle. They might get more exercise, eat less processed foods, more fresh fruit/veg etc.
    In other words, the health bias should be in their favour, yet they had worse outcomes. That seems like an interesting finding that is definitely worth pursuing.

    But I’m not holding my breath for that…

    Paul N wrote on March 12th, 2013
  5. My grandfather used to keep hogs. I have never been able to find bacon or sausage anywhere that tasted like what he made on the farm. Well, except for what his friend’s farm produced.

    I think they kept the good stuff and sold the rest to the grocery stores.

    Curtis wrote on March 12th, 2013
  6. So what exactly is considered ‘high temperature’? If it’s not charred, but browned, is that okay? Braising and slow cooking aren’t always options when I need to throw a quick meal together…

    Katie wrote on March 12th, 2013
  7. Good source of fresh meat products is very important. Cooking also affects the meat and it is also important to eat meat along with other nutritious food especially vegetables. Meat is still a very important source of various nutrients that our body need to function properly.

    Pat Cobb wrote on March 12th, 2013
  8. I can’t stand most processed meats. They gross me out. We try to always buy fresh cuts whenever possible. Thanks for the interesting article.

    Mike wrote on March 12th, 2013
  9. Just thought I’d point out that this study didn’t take into account how much sugar or refined carbs each subject was eating. Which on its own more or less invalidates this study. These guys aren’t stupid – even if they don’t agree with Gary Taubes, Robert Lustig etc about sugar and refined carbs, they know about their theories. So to completely ignore sugar/refined carb consumption suggests at best bad science, and at worst a suspicion that the authors of this study set out to incriminate processed meat, and didn’t want anything getting in the way of that goal.

    Andy T wrote on March 13th, 2013
  10. “The risk associated with specific red meat subtypes depended on the animal of origin and cancer subsite; thus, the risk for colon cancer was significantly elevated for higher intake of lamb [IRR(per 5g/d) = 1.07 (95% CI: 1.02-1.13)], whereas the risk for rectal cancer was elevated for higher intake of pork [IRR(per 25g/d) = 1.18 (95% CI: 1.02-1.36)]. Substitution of fish for red meat was associated with a significantly lower risk for colon cancer [IRR(per 25g/d) = 0.89 (95% CI: 0.80-0.99)] but not rectal cancer. Substitution of poultry for red meat did not reduce either risk. This study suggests that the risks for colon cancer and potentially for rectal cancer differ according to the specific red meat subtype consumed.” – From the highly respected Journal of Nutrition, February 20, 2013: Associations between Red Meat and Risks for Colon and Rectal Cancer Depend on the Type of Red Meat Consumed.
    http://jn.nutrition.org/content/early/2013/02/18/jn.112.168799.abstract

    Apocryphon wrote on March 15th, 2013
  11. It was an interesting study. Personally, I always try to buy fresh meat I don’t trust what they put into the processed meats.

    Sarah J wrote on March 15th, 2013
  12. I agree with you Isabel. There is tons of empirical evidence to support your position as well. The “China Study” lays this case out exquisitely. Very objectively, the study draws comparisons between the Western diet and long term degenerative diseases. The meat lobby is so strong, they’ve got us all convinced. We forget we were all peasants at one point, and meat was scarce. It was not as central to our diet as it is today, but merely an intermittent, special form of protein we enjoyed when mature pasture animals were slaughtered or we hunted.

    Jackson wrote on March 19th, 2013

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