Why do meat eaters get colon cancer more often?

Not the best for your colon?

Not the best for your colon?

This post may be controversial – like swearing in the church of low-carb.

Is it unsafe to eat meat? Despite the scare propaganda the answer seems to be no. Meat is a nutritious and great food that humans have always eaten.

Warnings in the media are usually based on extremely uncertain studies – statistics from food questionnaires, where people who eat more meat also smoke more, eat more junk food, exercise less and so forth. Even with this unfair comparison the differences between meat eaters and non-meat eaters are usually small – and sometimes they point in the opposite direction.

In Asia, for example a review of all studies has shown that Asian meat eaters are healthier than non-meat eaters. Asians with a vegetarian orientation seem to get more heart disease and more cancer.

In summary, meat seems to be generally healthy, nutritious and great food. But there’s one exception.

The Exception

The exception, the area that deserves to be taken quite seriously – is the risk of colorectal cancer. For some reason studies repeatedly show that people who eat red – mainly processed – meat specifically get more colon cancer.

The increase in risk for colorectal cancer in people who eat a lot of meat is generally low, around 20%. This can be compared with a massive 1,000% increase of risk for lung cancer for smokers. But even if the increase in risk is small, it’s been shown so often and so consistently that it probably is real.

Two days ago another study was published showing a slightly smaller risk for colorectal cancer in vegetarians. Why does red (processed) meat seem to slightly increase the risk of colorectal cancer?

The Probable Cause

People who eat a lot of chicken or a lot of fish don’t seem to have an increased risk of colorectal cancer. There have been many attempts to explain why red meat is different, but probably the simplest explanation is closest to the truth. Heating. Excessive heat gives rise to many different new substances, some of which are potentially carcinogenic.

The best example is again smoking. It’s not the tobacco or the nicotine that increase the risk of cancer – it’s allowing the tobacco to burn and inhale all the new substances formed during combustion.

Similarly, we tend to cook red meat on high heat. Barbecuing is a good example. Inhaling the smoke can be harmful to the lungs. Eating charred meat may be harmful, where the strongly heat-treated meat is in prolonged contact with the body’s mucous membranes… And where’s that? Exactly, the colon and rectum.

What You Can Do

So what can you do? Some experts advise eating a lot less meat. I don’t think it’s necessarily a good choice. Moderation is often best. Meat is a nutritious and hearty food. To completely avoid it isn’t only boring for many, it also makes it harder to become full and satisfied.

The risk is that you eat more of other things, such as bad carbohydrates instead… with a long-term risk of weight gain, diabetes and thus all common cancer forms throughout the body. It’s like out of the frying pan and into the fire. From a minimal increase in risk of colorectal cancer to an increased risk of all cancers, diabetes, obesity and heart disease.

It’s possible to eat healthily as a vegetarian or even a vegan – without refined carbs – but it’s harder. It requires more knowledge and determination.

An easier and tastier way could be to prepare meat with some caution. Avoid making it well-done, avoid eating charred, blackened parts. Trim them away. Prepare the meat rare or medium instead. Or choose chicken and seafood more often.

Finally, it’s wise to fry meat in stable fats like butter, coconut oil or lard. When cooking with high heat avoid like the plague polyunsaturated fats like sunflower oil, corn oil, rapeseed oil or margarines. These unstable polyunsaturated fats can’t withstand heat without lots of potentially toxic substances being formed.

The old fear of natural saturated fats could be the cause of not only an obesity and diabetes epidemic, but also an enormous amount of unnecessary cancer-causing substances from heated vegetable oils.


Charred, dry meat fried overdone in vegetable oils or margarine is hardly good, and it doesn’t seem to be healthful for the bowel either. Try to choose better and healthier ways to cook red meat, when you want to eat it.

Also remember to keep in perspective the size of different risks. This is a small health risk, and trying too hard to avoid it can easily expose you to worse risks.

What do you think about it? Leave a comment below.


Asian Meat Eaters Are Healthier!

Do Unhealthy Meat Eaters Live Shorter Lives?

The Big Fat Surprise – Nina Teicholz
Can Red Meat Kill You? – Nina Teicholz
The Myth of Vegetable Oils – Nina Teicholz
Is It Dangerous to Eat Meat Before Age 65?

Statistics for Beginners


  1. Raz
    As long as I boil (not fry) and not over cook I don't think that should limit consumption. 1-2g/kg of ideal body weight.
    Reply: #56
  2. John Myers
    Processed meat will always correlate with cancer because it is always accompanied by bread. So is it the the hot dog or the hot dog bun that is the problem? There are populations that eat a lot of cured meat (or traditionally did so) and they have excellent lifespans. Andorra comes to mind. The CIA factbook in recent showed them to live to 90s. Lots of cured meat and they grow tobacco.
    If smoke is inherently bad, why doesn't marijuana seem to show any ill effects? I'm sure smoke of any kind isn't beneficial but if the theory is that we started to become human when we cooked our food thereby making the nutrients more bio-available, then smoke and cooking and charred meat is part of our story for how we got to modernity. In America a lot of people like their beef pink and fairly rare. I don't know anyone who eats rare chicken. That stuff is cooked to death on the grill for good reason.
  3. Tuck
    "But even if the increase in risk is small, it’s been shown so often and so consistently that it probably is real."

    That's not how it works, though. You need a mechanism to prove cause and effect, not weak, poorly constructed epidemiological studies. There's no mechanism present for why a food that we seem to have evolved to eat can be harmful.

    "Red meat and colon cancer: should we become vegetarians, or can we make meat safer?"

    Significant as used in these studies is a statistical term, not one meaning it's cause and effect. And relative risks as small as those found are not meaningful.

    "Eating charred meat may be harmful, where the strongly heat-treated meat is in prolonged contact with the body’s mucous membranes… And where’s that? Exactly, the colon and rectum."

    Very little, if any, meat gets to the colon and the rectum. See this experience of a man who had most of his intestinal tract removed.

    "Can Humans Digest Meat?"

    Additionally, one of the most interesting anti-cancer substances found in recent times is conjugated linoleic acid. This is a fat that is found in ruminants, it comes along with red meat, in other words.

    So eat the fat with your red meat, and don't worry about it.

    Reply: #23
  4. Alec
    I'm with Tuck.
  5. Zepp
    Im altso with Tuck!

    Other small studies shows that vegetarian get more colon cancer!

    "Vegetarians Have Fewer Cancers But Higher Risk Of Colorectal Cancer"


    Other big studies shows that red meat eaters drink more, smoke more and excersise less!

    One have to put up some good explanation!

  6. Annie
    Thank you for tackling this issue, it's something that is always in the back of my mind as my father died at the young age of 52 from Bowel cancer and he did enjoy meat and tried the Atkins diet in its infancy ...... However as a young man he was also a heavy smoker......
    I think you are right, moderation is key
    Perhaps for those of us following this way of eating the fact that we are not eating sugar will help. I think it was Gary Taubes ( ?) forgive me if I have the wrong name who gave a speech at the recent conference about feeding cancer with sugar ?( so a possible treatment being to starve cancer ) I have over simplified this I know.
    Thank you for raising this issue
  7. Soul
    I've often though that if there is a connection to red meat eating and cancer, bowel cancer in particular, not only would the cooking method be a concern, but also and maybe more so, the method used to raise the animal. Personally, I've often thought in my mind of common commercially factory raised cattle almost as synthetic meat. I'm hopeful that grass fed meats are less of a problem, possible even protective.
  8. Charles Grashow
    No problem - I eat 1/2 lb of raw grass fed/finished ground beef a day. No need to worry about cooking. Lately I've been eating Scottish Highland beef - very, very good.
  9. Simon
    Consumption of poultry and fish is not correlated with an increased risk of colon cancer, although they contain the same compounds when heated (polycyclic aromatic hydrocarbons and heterocyclic amines) that are supposed to be the causative agents. This makes the meat-colon cancer correlation rather dubious. Who eats red meat if it is supposed to give you colon cancer? Nobody who believes to be health-conscious. Red meat consumption becomes a marker for health-conscious behavior.

    Do you really believe it is the meat itself causing anything if it is healthy to eat it in Asia but not in other places? Absent significant and consistent differences in animal husbandry (pasture vs. feed lot) I don't find it plausible that geography would modulate the health effects of meat consumption.

    In addition, in the Women's Health Initiative "the intervention group decreased their intake of red meat by 10%, whereas the control group increased their intake by 10% (mean difference 20%; 95% CI 15–25). Despite this marked difference, there was no effect on colorectal adenomas or cancers during 8 years." Lindeberg (2009): Food and Western Disease. p. 189

  10. T33CH
    This British study showed that vegetarians had a higher risk of colon cancer....


    "The vegetarians in the group in fact had a slightly higher rate of cancers of the colon and the rectum, although not significantly so."

    I would posit that vegetarians have healthier lifestyle and thats why they tend to show better health outcomes.

  11. Mark
    No problem - I eat 1/2 lb of raw grass fed/finished ground beef a day. No need to worry about cooking. Lately I've been eating Scottish Highland beef - very, very good.

    Where do you buy such meat?

    Reply: #13
  12. Jules
    What about the effects on colon health from sitting and not squatting?


    Reply: #14
  13. Charles Grashow
    My wife and I live in an area with several local family owned farms so getting it isn't a problem.
  14. Zepp
    Its a bad idea.. one cant use ones smartphone when squatting!
  15. Paul D.
    Another speculative possibility might be the presence of a virus in cattle that could cause cancer. If so, eliminating the virus from herds would solve the problem.


  16. Lorraine
    It would be interesting to see if grass fed beef gave a different result to grain fed beef.
    Reply: #55
  17. Janknitz
    We lived along the southern edge of the town of Salinas, California, where much of the nation's lettuce, broccoli, cabbage, and cauliflower are grown. Many members of our religious community and social-economic group lived along this corridor--our homes were built on former lettuce fields and directly across a 4 lane highway behind our homes the lettuce fields stretched south for miles. Almost all of the people of my parents' generation died of digestive cancers--my dad died of colon cancer at the age of 67. They were all red meat eaters in those days, but we also lived on and under (by way of crop dusters that made their turns over our homes) and breathed in loads of pesticides used to treat the lettuce fields. So was it the meat or the pesticides or something else entirely (they were all heavy smokers, too)? The problem with epidemiological studies is that it's very hard to account for all the variables.

    You mentioned "processed meat" often, so I doubt very much these studies involved organic and grass-fed meat, which is what I'm eating these days. Grass fed meat does not do well with high temperature cooking--it is too lean. So I'm not terribly worried, despite my supposed genetic pre-disposition because of my first degree relative with colon cancer.

  18. Joanne
    A number of years ago I read articles on the Maillard Reaction that causes our foods to brown during cooking. This primarily affects the cooking of carbohydrates, but occurs in the cooking of meat as well. Since then I've tried to avoid and to minimize the reaction when I cook. Cooking slower with lower temps and adding water to the cooking process. Your idea that the way we prefer to cook our red-meat might be producing more chemicals reminds me of the Maillard issue.


  19. Jay Wortman
    Remember that all the studies that suggest red meat is a problem were conducted in populations who were eating a high carb diet full of sugar and seed oil. A LCHF diet that avoids these foods is such a metabolic game-changer that you can't really extrapolate. You would have to repeat the study in a LCHF population to determine if the effect still appeared. While I'm waiting for that to happen, I am going to enjoy my nice fatty rib eye on the BBQ.
  20. MarkO
    I will posit that the way in which they conduct these studies leads to false conclusions. I think that the aggregate of the foods one consumes (and also genetic predisposition related to those foods) probably has a far more powerful correlation to the onset of Colon Cancer than simply if they ate a lot of red meat. Did they eat a lot of red meat with lots of vegetables or was it the fast food variety consumed with milkshakes and french fries?

    Regardless, I don't see how you could ever conduct a study linking the "doneness" of red meat either. How many people honestly, really, seriously consume an expensive ribeye they have charred to death? It does not seem plausible that the red meat eating alone is the factor causing that type of cancer at least from anything other than an anecdotal perspective. There would have to be many other co-factors involved IMHO.

  21. tony
    At the last annual meeting of cancer researchers, the participants agreed there was little evidence that a certain diet could cause or prevent diet:


  22. Jim Anderson
    I read the study in JAMA Internal Medicine that claimed vegetarians had 22% less risk for getting colon cancer relative to meat-eaters. The actual numbers of cancers for each group were buried in a table, and told a far less alarming story, as I blogged about here: http://www.lifeaftercarbs.com/2015/03/red-meat-and-colon-cancer-whats...
    Reply: #34
  23. Murray
    It seems the data are too inconclusive to get concerned. Any food that has a reputation as not being healthy should correlate more strongly to poor health outcome because more health conscious people will avoid that food. The ones who eat more correlate to greater health indifference. Call it a reverse placebo effect.

    It would be strange if cooking meat were a serious problem. The anthropological evidence (Wrangham, Catching Fire) shows cooking of meat for definitely over 200,000 years and likely over a million years. Further, the work of Weston Price suggests cancer was largely absent before flour and processed sugar were added to traditional diets.

  24. Apicius
    Thank goodness the studies didn't say anything bad about bacon.

    Just kidding. Seriously, though. I don't think there is sufficient evidence to draw a conclusion on red meat. Meanwhile, I will continue eating my fatty, grass fed beef, fried in butter or bacon grease!!

  25. Andy T
    The recent study that Andreas refers to shows pescovegetarians having a significantly lower hazard ratio than other types of vegetarians, including vegans. So presumably this means that eating fish actually prevents cancer to some degree. Omega 3 perhaps? Just as long as we don't overcook it!
  26. Gaui Ella
    My opinion is.
    When our life stock became corn eaters, instead of being grass fed, the balance between the omega fatty acids were tempered with in favour of the omega 6 at the cost of omega 3.
    Fact is, that too much omega 6 cause inflammation. This balance became further disrupted when we started to throw away the fat, and eat only the meat. Omega 3 is mainly in the fat and omega 6 in the meat.
    One of the most favourite environment for cancer, apart from high blood sugar and too much acid is inflammation.
  27. Justin
    I think your conclusion addresses every concern here.

    "Charred, dry meat fried overdone in vegetable oils or margarine is hardly good, and it doesn’t seem to be healthful for the bowel either. Try to choose better and healthier ways to cook red meat, when you want to eat it."

    Even if a large(ish) RCT trial showed any proof regarding this idea, it would still most likely be performed using grain-fed meat cooked in seed oil, at least at first. These are 2 of the bigger things that people who eat real food tend to avoid, so its not just trying to find an excuse not to believe the results. Once that study happens, with all of the confounding variables accounted for, I would be happy to believe it, but until then, the association seems weak at best.

  28. Ash Simmonds
    I think it's pretty clear by now that epidemiology causes cancer.

    -> http://highsteaks.com/forum/health-nutrition-and-science/epidemiology...

  29. palmonal
    Is red meat roasted in crock pot everyday okay? Or boiling it would be better?
    Reply: #30
  30. Zepp
    In any way.. as long as it dont make you smoke, drink and quite excersise!

    They have to explain how red meat make us do all that bad things first!

  31. Lissa
    Dang ... now I am craving a nice, juicy ribeye.
  32. Soul
    Aflatoxin found in cured tobacco is my pick for cancer causing substance in smoking. Figured with the grains fed to commercially raised cattle along with antibiotics given, sometimes similar could occur.
  33. Jennifer Snow
    "It’s not the tobacco or the nicotine that increase the risk of cancer – it’s allowing the tobacco to burn and inhale all the new substances formed during combustion."

    Yeah, and this TOTALLY explains why people who CHEW tobacco have an enormously higher risk of mouth and throat cancer . . .

    Oh wait.

    Reply: #58
  34. BobM
    Nice points made in your blog, Jim. This illustrates a problem with using these types of percentages (relative risk, not actual risk). The actual risk is tiny, but blown up to relative risk, it sounds high. The other great point you made is that the study's chief author admitted there were other differences between the two groups. Once that happens, and red meat is selected as the culprit (instead of "sweets, snack foods, refined grains and caloric beverages" and red meat), you know you're looking at a case of bias.
  35. Zepp
    Now Im all in whit Ash.. it seams that the more epidimological studies done.. the more cancer!

    Could we get some taxes on epidimiological studies.. please!

  36. Mark.
    Increasingly I'm cooking beef at low temperatures for long periods: beef brisket for a day around 85 degrees C or less. Using an oven and sometimes smoke flavoring (yes, might be some carcinogens in there, but I'd expect relatively few) yields tender, tasty meat, though the relatively cheap brisket I buy is very fatty and probably has more omega-6 than omega-3 fatty acids. Seems to have a lot of saturated fat, too. I've tried sous vide with a slow-cooker and external controller, but I have not been impressed with the flavor.
  37. DonnaE
    I avoid cooking meats using dry heat methods (I'm surprised Andreas didn't mention stewing). This issue is not at all new; we've been warned about carcinogenic heterocyclic amines in grilled meats for years! The other big question about meat and cancer is Neu5gc. Tuck wants a "mechanism that proves cause and effect." I just cited two possibilities I think we'll be hearing more about in the coming years. Meanwhile, I'll keep eating meat, but in moderation and stewed.
    Reply: #39
  38. Mats Granvik
  39. Zepp
    Yes we have been warned about those frome cooking but not frome those that is internaly, frome high glucose levels!

    Im more worried of those that comes frome internaly sources like elevated glucose levels.. I dont seen anything that those maked externaly could pass our digestion?

    Could be those that have leaking gut syndrome then.. but they are not healty. they should avoid a lot of things.

    And at the end.. one dont like burned food or overcooked.. its like those highly prossesed and highly prepacked fastfood!

  40. Wade Henderson
    The final sentence....

    "What do you think about the associations?"

    I think you answered it quite directly. That the meat causes a increase in colon cancer.
    All the rest of the stuff is like tap dancing around the topic with "what about's" and "ifs, ands, and buts"

    Again, the meat was found to increase colon cancer.

    Amazing what humans do in their heads to deflect the direct and simple truth.

    Reply: #47
  41. looking
    Instead of blindly accepting a study, maybe ask more critical questions such as what kind of meat was used and how was it prepared. It wasn't that long ago fat studies said saturated fat made you obese, increased cholesterol, and promoted heart disease. These studies failed to mention what kind of fat was used and how it was prepared. Now we know trans fat (like Crisco and margarine) is harmful in any amount in the human body and real fats (lard and butter) is good for you and can help you loose weight effortlessly.

    Many commenters here are right on but missed one vital secret: eat meat with plenty of land/sea plants. Preferably, all from trusted sources that won't expose you to harmful chemicals and raised responsibly.

  42. protisystem
    Great ....I usually take .Good for health and provides all nutrients to our body.Please suggest me how many quantity to eat in a week for healthier life.
    Weight loss tips
  43. BJML
    I think that the source of the meat is extremely important. When you look at these big epidemiological studies, especially since it specifically mentioned processed meat, there is never any mention of source. I have to guess that it is standard and probably commercially raised meat. This means antibiotics and GMO corn, alfalfa and soy. So the meat is in my opinion contaminated from the start. Additionally my husband is allergic to soy and we haven't had processed meat anything in years aside from Applegate meats and those only occasionally. I have also seen lots of other info on the dangers of browned meat and so we eat most of ours braised. I think if you buy grass fed and finished beef, and braise it- the risk is nonexistent in differing from poultry and fish. Certainly the risk of overeating carbs by avoiding meat is significant.
  44. Darag Rennie
    I'm with Jay Wortman on this. Those observational studies have way too many variables to extrapolate causation.

    I went vegetarian in medical school and continued that way for 35 years, including 10 years as a wheat free vegan. Even though on the outside I looked healthy and my weight was better controlled than my parents (only child so no siblings to compare), in my early-mid 50's all sorts of signs of internal inflammation appeared - blepharitis, rosacea, testicular cancer and bad blood lipids. I also have another long term vegetarian friend who had colorectal cancer. So on our trial of n=2 that got me thinking. Over the last few years I transitioned to paleo then LCHF. Got my blood fats back to normal by doing the opposite of what my GP suggested - less red meat-more whole grain:)! If that diet got me in trouble, how was it going to get me out? Took a while to get my taste back for it as I could only stomach chicken and fish for a while but when I felt like having a steak and actually had it, I felt like I'd been transported to heaven:). It amazes me how much we use our philosophy/beliefs to limit our choices and how long our body can take to get back to giving us good cues about what's good for it. And yes I cook it in butter or coconut oil, in NZ we're fortunate that grass fed abounds. But home kill, well taken care of animals are still a touch above supermarket options. And my daughter who we brought up in our wheat free vegan phase now enjoys her steak more rare than I do.

    Reply: #46
  45. Steve M
    Oh no! I like nothing more than charred meat from a big fire....
  46. Paul the rat
    How many times I heard this: " I am a vegan, and you are telling me I have a cancer ?!, how is it possible ?!"
  47. Paul the rat
    Wade, we went through this topic at least twice within the last 3 years on this blog, in details, with your fervent involvement. If you can not recall it - go LCHF.
  48. George Henderson
    The study was in Seventh Day Adventists, like a lot of these studies, they are the go-to vegetarian population, but they are not like the vegetarians and vegans you and I know.
    They have a lot of other practices that should reduce disease risk, and the ones that are less strict vegetarians are either less strict in other ways, or have health needs or a social position that means they can't avoid meat.
  49. Noah
    According to this study, QxMD.com/r/25773851, the ketogenic diet delays the growth of colon cancer cells. Apparently cancer cells can't use ketones for energy. Perhaps red meat causes colon cancer in conjunction with a high carbohydrate diet.
  50. John
    When roasting meats, I always set the oven on a very low number (2 or 3) and cook the joints for at least three hours in mid-oven. Not only is the meat much more juicy, it is cooked through, whilst retaining its tenderness; esp lamb. Few meats are as delicious as a slow-cooked, boned and rolled, shoulder of lamb. Yummmm! :)
  51. Nina
    Anyone interested in more accurate and reliable research please read:


    Reply: #52
  52. erdoke
    If it comes to worthless observational studies, I rather suggest that this one is checked out:
    At least they are talking about 1.45-2.01 HR when a high GI/GL diet is followed. According to the father of modern epidemiology, anything below 2 is negligible...
  53. Dr. Sergio Castorena
    Hi Dr. Andreas,
    It´s known that red meat consumption lowers melatonin levels, and high carb diets lower it as well. And if we recall the effects of melatonin as a super antioxidant, maybe it could be linked.
    Excellent blog btw :)
  54. Marty
    well, were the people studied just eating the processed meats? Or did their diet contain other processed foods as well, Maybe it was not the meat at all.. I would like to know "everything" these people were eating for this study..
  55. Kelly
    The nutrition in grass fed beef is considerably different / better. Large amounts of grains do the same thing to cows as they do to humans, they add fat more weight on cows equals more money for the rancher. Additional fat also makes the meat more tender when cooked. When you compare a grass finished beef to the standard supermarket beef the taste difference is very noticeable.
  56. Kelly
    I agree with you but I have been trying to go ketogenic which requires your limited protein amount to only what your body needs to maintain muscle. It is about half the protein I was going through before dieting. The standard American diet consumes way too much protein in general.
  57. Richard Curtin
    I found this site while looking up "secondary bile acids" and colon cancer. It seems most commentators here "circled the wagons" on this one. It appears that even the Dr himself refuses to acknowledge the severity of the risk. I don't know about you but 20% increase is big in my book. Trying to compare or sell 1000% chance increase with cigarette while downplaying 20%.....doesn't cut it in my book.
  58. Richard Curtin

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