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How To Start Working Out When You Don’t Like To Exercise
Focus More on Your Brain and Less on Your Diet if You’re Serious About Losing Weight
Home Court Habits: The Secret to Effortless Weight Control
10 Reasons You Aren’t Losing Weight When You Think You’re Doing Everything Right
How To Burn More Calories Without Breaking A Sweat
The 7 Habits of Highly Effective Foodists
Red Meat Is Killing Us All! Or not…
Photo by Irwin-Scott
I’ve had about a zillion people ask me about a new study that came out in the Archives of Internal Medicine this week linking red meat consumption to increased mortality.
Naturally some people are afraid their carne asada habit may be dooming them to an early death, and who could blame them with headlines like these?
On the other hand, I suspect many of you have dismissed the study out of hand because it conflicts with your world view that animal foods only make good things happen.
But in the interest of science and being grown ups, let’s take a look at the study and see what we can learn.
First, it is worth mentioning that the study was fairly well-designed and conducted by a respectable team of scientists at Harvard. They reanalyzed data from two large prospective cohort studies: The Health Professionals Follow-Up Study (HPFS, 1986-2008) and the Nurses Health Study (NHS, 1980-2008).
Both cohorts were large groups of health care professionals, which would presumably limit differences in education and income that can often confound health studies. The participants filled out regular food frequency questionnaires that have been previously validated as decently reliable (though food frequency questionnaires are notoriously unreliable).
Importantly, all the participants were eating Western diets during what have come to be known as the least healthy decades in US history. Also important, during the course of the study both red and processed meat consumption declined in both men and women.
“The mean daily intake of unprocessed red meat dropped from 0.75 to 0.63 servings from 1986 to 2006 in men and from 1.10 to 0.55 servings from 1980 to 2006 in women.”
The authors never comment on what this reduced consumption means for their analysis, however, since they “created cumulative averages of food intake from baseline to death from the repeated food frequency questionnaires.”
According to the report, people who ate the most red meat were more likely to smoke, drink, eat far more calories and be overweight. They were also less likely to exercise and eat healthy foods like fruits, vegetables, whole grains and fish. Basically they were less healthy people with less healthy habits.
The authors claim to have controlled for such lifestyle factors by doing statistical corrections for these variables, which is the industry standard for this type of analysis. They also performed a sensitivity analysis to see if any other dietary variable (including glycemic load) may have impacted their results. They did not detect any significant differences when controlling for these factors, which I admittedly find surprising.
To their credit, the authors made an effort to distinguish between processed and unprocessed meats. Given the time during which the study took place, however, it’s unlikely that any of the participants were eating non-industrial, grass-fed and pastured meat. I think this is an important point, particularly when considering cancer mortality, since toxic compounds tend to accumulate in the fat of animals.
In their analysis the authors estimated that for every one serving of red meat per day (defined as 3 oz), total mortality risk increased by 12% (20% for processed red meat alone, 13% for unprocessed). Heart disease risk increased by 16% for total red meat (21% for processed red meat, 18% for processed), and cancer risk increased 10% for total red meat (16% for processed, 10% unprocessed).
To help put this in perspective, in the Nurses Health Study (the larger of the two) the group that ate the least meat consumed about a 1.5 oz (half a deck of cards) of meat per day and the group that ate the most consumed around 6.5 oz of meat per day (here’s the data I’m pulling from, using the 3 oz serving size for conversion).
Remember, these numbers are for daily consumption. For the highest group, that’s nearly 3 pounds per week (45.5 oz). For the lowest group, under 1 pound (10.5 oz). Realistically, the lowest group probably ate red meat 1-2 times per week, while the highest group ate it once or twice a day. How we got from here to “all red meat will kill you” isn’t exactly clear.
Interestingly, when they did an analysis to see the specific effect of saturated fat in meat it accounted for only 4% of the 16% estimated risk. This is fairly low considering that saturated fat is supposedly what makes meat so bad for us by raising cholesterol. But since the authors say that saturated fat could account for some of the increased risk, can we at least assume that those eating the most meat were more likely to have higher cholesterol? Not so fast. It turns out that in both cohorts, those in the lowest group of meat consumption were the most likely to have high cholesterol. (Thanks Denise Minger for making this astute observation).
So what about the meat is killing us exactly? In addition to saturated fat, the authors also estimated that heme iron in meat (assumed to be a risk factor for some diseases) can account for another 5% of the risk, but they do not elaborate on how this might work. It is unclear what else about red meat may be increasing mortality risk, though preservation methods are suspected for the higher risk associated with processed meats.
The authors also used some fancy statistical magic to estimate what would happen if the participants theoretically replaced one “daily” meat serving with an equal portion of either fish, poultry, nuts, legumes, low-fat dairy or whole grains and determined that mortality risk would decline 7%, 14%, 19%, 10%, 10% and 14%, respectively. It is important to remember though that *ahem* these are not real experiments but merely estimations based on the numbers and statistical models used in this study. At best an analysis like this can generate a hypothesis that could then be tested in a controlled trial.
Fortunately controlled studies replacing meats (oh, and all the other crap in the Western diet) with other nutritious, whole foods have already been done. For example, in the Lyon Diet Heart Study (1988) a group of patients who had already had a heart attack were instructed to change their diets. One group went on the low-fat American Heart Association diet, the other group adopted a Mediterranean style diet that included lots of green and root vegetables, fruits, legumes, more fish and poultry, less red meat, olive oil and no cream. After only 3 years the study was stopped by the ethics and safety committee because the Mediterranean diet group had a 70% reduced risk of death compared to those on the low-fat diet.
Studies have consistently shown that replacing some dietary meat with fish and other sources of omega-3 fatty acids reduces the risk of heart disease. However, replacing red meat with anything else (even olive oil) seems to be pointless. For this reason I’ve always been skeptical that red meat is uniquely bad when the simpler explanation would be that eating more fish is uniquely good. I don’t see how this new analysis of old studies changes anything.
Lastly, although the authors included controls for lifestyle factors I’m highly suspicious that people with so many unhealthy habits are at an increased risk of death primarily because of meat consumption. Consequently, all that I’d feel comfortable concluding from the new analysis is that in the context of a Western diet, eating something other than meat every once in awhile is probably a good idea. Outside of the Western diet? It’s much harder to say.
What are your thoughts on the study?
Very good review of this study.
On the heme iron being a risk factor for various diseases, most of the studies on the link you provide appear to be epidemiological, again. The CDC website lists only hemochromatosis as an actual disease implicating iron. And that’s a genetic condition. Are there any other diseases that have been shown to be caused by iron by means other than statistics?
I’m very, very skeptical of any of these “red meat’s gonna kill you” studies, given that the evolutionary evidence indicates that we’re predators of animals with red meat. Do lions, one of our competitors in Africa for ruminant prey, die of meat overdoses?
Thanks for the great work.
Hi Tuck,
Early Humans didn’t just hunt animals, they were also practiced cannibalism..If Tribe (A) was faced with famine they would go and raid tribe (B), stealing food killing and eating men and children but also raping women or taking women slaves so that tribe (A) could flourish….. we have documented evidence of this in the Bible
So you’re suggesting we should indulge in a little long pork?
hi Tuck,
No i am not suggesting we should indulge in some long pork…i know i was a little off topic, but what i was trying to say was that humans have always had access to meat even if it involved hunting and killing other humanoids.
“and eating men and children” “… we have documented evidence of this in the Bible” This is new to me. Reference please?
Not that I really take much in the Bible as literal truth or evidence, but since you asked about references to cannibalism there: http://www.rationalchristianity.net/cannibal.html
Hi Michael,
Agree …the site you posted is full of references .
I am researching cannibalism and religion, Aztecs, Polynesians, even native Carribean Indians practiced some form of cannibalism, but i was suprised to find it in the Christain faith….the Holy Communion is symbolic in gesture but what is implies goes back thousands of years.
Thank you Michael C! Interesting read…
Oh, and here’s the CDC link for Iron:
http://www.cdc.gov/nutrition/everyone/basics/vitamins/iron.html
Hi Darya,
Red Meat,(or any other Mammal meat) is not very good for humans, living in a modern urban environment,. The problem with meat is that is too similar to human tissue cells.
Our bodies efficiently recycle a lot of the nutrients we need, and one important function of recycling of nutrients, is so that the bad gut fora cant flourish.
Once the meat tissue reaches the intestine, the bad gut bacteria find themselves with a food source that has no active immunity. Bacteria being Bacteria don’t have teeth, but what they do have are enzymes that break the cell walls of the meat, these enzymes also attack the walls of the intestine . Bacterial digestive enzymes work more efficiently in an acid environment, so eating meat changes the acidity of the intestine causing cancer etc etc.
So its a good idea to eat a lot of green vegetables with meat …so that it is passed through the digestive tract quickly. About 80% of your immune systems resources are employed in keeping your gut flora in check.
i Have also read about the Inuit Paradox, the pre 1930s Inuit diet consisted of high meat and fat intake with not apparent ill affects. However I believe that humans are no different to Darwin’s Galapagos Finches which have adapted to the Biological and Environmental factors.
Read meat is bad. Red meat isn’t bad. Red meat is bad. Well, maybe it’s not as bad as we thought. No, it’s totally bad again and you’re going to die if you eat it. Honestly, it gets tiring tracking all the new studies that prove that whatever we thought for the last ten years was wrong. But in reality, like most things, it’s probably true that most things are okay in moderation. The problem is that we’ve got a lot of people in our society that don’t know what the word “moderation” means. Logically, a steak for dinner every night is probably not a good idea (for my health or my wallet). This study does nothing to change my habits.
This issue is definitely contentious that’s for sure. Personally I think that the quality of the meat you eat has a direct bearing on health outcomes. Factory produced meat is not equal to pasture raised. Also everyone is different so while some people thrive on a diet that includes meat every day other people do not. Balance (and exercise) is key.
Thanks for addressing this, Darya! I was one of the people who sent you the LA Times article because while I knew they were glossing over things for the sake of headlines, I wasn’t quite sure how to wrap my mind around the facts. Seems like we’ve already established that a diet high in saturated fats is bad, but there didn’t seem to be those conclusions being drawn. Excellent take, as usual. 🙂
“Seems like we’ve already established that a diet high in saturated fats is bad…”
You’ll be happy to know that saturated fats have been vindicated. The whole thing was a false alarm. (So long as we’re talking natural saturated fats, not synthetic trans-fats.)
All very good points. Guess I will have to lower my own consumption from that ammonia story that broke big a few days ago.
And here is DrG’s video on this study too:
http://www.facebook.com/NutritionFacts.org/posts/410809725602209 3/12/2012
His latest volume is out
http://tinyurl.com/drgvolume8 from 3/1/2012
Hi and thanks for the review. Why would respected scientists do this study with unheathy habit people and not with the ones with good healthy habits?….
Health professionals (high education, high income) are among the healthiest people in America. Problem is that for the past 50+ years, no Americans were shunning processed foods. Many of these packaged foods were viewed as healthier than natural foods for a long time. Even now there are very few of us eating mostly natural, unprocessed food sources for most of our meals. The scientists didn’t do a bad job, they just only tested something in the context of a Western diet.
Just want to add my thanks for another (great as always) analysis debunking the hype.
hi,
Just to add….it is important that we understand the biological consequences of meat digestion..the bacterial digestion of meat proteins results in the production of biological free radicles , namely nitrogen oxide and hydrogen sulfide. It seems that minced meat or reconstituted meat products such as burgers and sausages once digested allow a greater surface are for bacterial digestive enzymes to break down. Eating processed meat increases your chances of colon cancer by as much as 25%.
Interesting study and thoughtful commentary. I personally quit eating any kind of meat about 2 years ago and am currently easing out of dairy. My initial motivation was more environmental than health, because I thought even as an omnivore, I ate in a fairly healthy fashion – little to no processed food, fruits, veg and when I did eat meat, it usually came from small scale farmer at the farmer’s market. While I wish people would adopt a more healthy (heavier on veg, little to no industrial meat) diet, I don’t think limited amounts of sustainable, small scale, pasture raised meat is going to kill you. All things in moderation. However, once you read about environmental devastation and even worse, treatment of animals on factory farms, red meat holds far less appeal.
Ok. There is need of the same kind of study focused on unprocessed diet groups not processed.
I’m a scientist by NO stretch of the imagination, but I think that unless you are getting your beef from a local source (on the hoof), it has ALL been bathed or at least exposed to ammonia (as a cleanser and/or disinfectant) whether ground or sliced commercially. Darya, ammonia is toxic to humans, so wouldn’t constant low level exposure over years have a negative effect regarding health issues and mortality?
Absolutely. Industrial meat is really scary for a lot of reasons. But industrial vegetables can be scary too. I’m sure the participants in the study consumed lots of both.
Denise Minger does a great analysis of the data used in this study. It is worth a read to help us understand the bias of the “scientist”.
http://www.marksdailyapple.com/will-eating-red-meat-kill-you/#axzz1p95nqTb4
Yup, linked it in the post.
Thanks so much for this article. I really appreciate your careful dissection of the issue. Why can’t the media even be 1% as thorough and fair???
I’ve been super cranky the last few days as I see RED MEAT=DEATH popping up everywhere. Man, people will do anything to work themselves into a panic. I’m constantly amazed.
That’s why I get the big bucks! Oh wait…. 😉
Good things come to those who “wait”
Thank you Daria for digging into the topic and spending the time to share your analysis. There is so much junk science out there and even if the data are sound, It can be manipulated to prove whatever point wants to be made. Your blog is great service for pointing out that there is still so much that the “experts” don’t know or are paid not to tell us. I think it is safe to say having a burger out at a chain joint every other day is bad for us. However, splurging on a grass fed Angus filet or Delmonico steak that one selects from a reputable butcher and prepares it at home a few times a month is not going to hurt us.
Thanks for covering this topic. I’m curious about the benefits of red meat as an iron source vs. the cholesterol dangers for heart patients. My dad had bypass surgery 15 years ago and recently had 6 stents installed. He also just found out he is anemic, so he needs a lot of iron.
Can he get enough iron from plants (kale? legumes?), chicken, and fish; or would you recommend that he incorporates some grass-fed red meat to really optimize his iron intake? And does lamb provide as much iron as beef?
Good post. I think red meat is fine in moderation and its the quality of the meat that really counts (living conditions and feed). How the animal was treated also at another level may have something to do with what gets transferred “energetically” to your body. I can see eating local grass fed as a solution, but I think Salmon is a better choice (ethically and for the oils). Dr. Colin Campbell (The China Study, Forks over knives) has done a good job in researching the links to protein as it affects heart disease and cancer. Here is his presentation with his findings. http://youtu.be/yfsT-qYeqGM
Ok thanks Darya…. Let me see ….My strategy with red meat would be to eat small quantity 2-3oz , once per month, with copious servings of green leafy vegs! Lets see how it goes..
Good luck! Though I’d say even as often as 1x/week is conservatively safe.
Here’s this month’s Men’s Health talking about prostate cancer and red meat
Charred meat 160F max (full screen window to maximize image):
http://imageshack.us/f/23/49455400.png/
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And Silverhydra’s post http://www.reddit.com/r/Fitness/comments/sgw6a/is_eating_grilled_hamburger_every_day_going_to/
I thought the study was better structured than most I’ve read about but there is still a blind spot that is not being addressed. Since we have listened to the mantra for over 30 years that red meat is bad, there is a stronger tendency for people who eat a healthy diet with lots of fruit, veg, and non-processed food to also not eat much red meat. And conversely folks that don’t bother with a healthy diet and eat larger amounts of white flour, sugar, and processed foods tend also to eat more red meat. I’d like to see a study in which the various groups all ate a balanced diet of unprocessed fruit, veg and whole grains and then vary the protein by the different study groups eating either factory farmed red meat, grass fed red meat, or mostly fish. To make a statement about red meat you need to nail down the rest of the diet and vary the red meat. I think the only thing they managed to prove is that if you eat a lot of red meat you tend to have a Standard American Diet (SAD) and are therefore at higher risk of dying. Don’t think I needed a study to know that.
I feel that red meat is healthy in moderation when it is from a clean source such as pastured-raised animals. When from this source, the omega-3 to omega-6 fat profile is much better (higher healthy omega-3 to less healthy omega-6). Also they do not accumulate as much toxins, hormone, and antibotics in their fat as the fed-lot animals that are feed on unnatural corn diets.
Red meat becomes unhealthy only if you are eating so much of it that they are crowding out all your vegetables off your plates. Your plate should have more vegetables than meat.
It also is unhealthy if cooked in vegetable oil or is burned or charred. It is the oxidized polyunsaturated oil that is bad and the carcinogenic black burn parts.
I eat pastured-rasied beef and lamb on a regular basis and I eat their saturated fat. And I prefer to cook it healthly with coconut oil rather than have restaurants do it. Saturated fat is not unhealthy if from natural source (meat and butter from pastured-raised animals, coconuts).