Before we get to the fiber, let’s engage in a sort of thought experiment. Let’s assume that way back in the early days of medicine doctors always wanted to see us cough up mucus from our lungs. Since mucus is a kind of breeding ground for all kinds of nasty bacteria, it would make sense in the olden, pre-antibiotic days to want patients to hack up as much of this stuff as possible to get it out of the body where the bacteria could no longer wreak their havoc.
Let’s assume that doctors of old–who didn’t realize that the excess mucus was the body’s way of ridding itself of something foreign, i.e., the bacteria or viruses causing the infection–started equating coughing up ‘healthy’ amounts of mucus with good health. It’s not too far a leap to imagine these doctors supposing that if they could get their patients to cough up stuff all the time, the respiratory system would stay clear of the mucus that harbors all the pathogens that cause lung problems. Druggists might come up with concoctions that would cause people to cough, even if they didn’t need to.
Now let’s imagine that the idea that coughing up large amounts of mucus-laden sputum reaches the point of a national obsession.
People, especially the elderly for whom respiratory infections are much more dangerous, discuss with one another how much sputum they produce and how often. If they don’t cough as much or as productively as they perceive those around them are doing, they go to their doctors who prescribe a sputum inducing medicine for them. People everywhere are obsessed with keeping their respiratory systems clean.
Then someone comes along and says, Hey, world, I’ve got the perfect product to keep everyone coughing productively. Use my product and before you know it you’ll be coughing your head off and ridding your lungs of all kinds of nasty junk. Here, try one of these. It’s called a cigarette.
In today’s modern world we all know what cigarettes do. The irritation of the smoke damages the lining of the tubes that carry air into and out of the lungs. As the damage continues, goblet cells (so called because they resemble little goblets), the cells that produce mucus, increase in size and number, producing more mucus to coat and protect the cells lining the airways. As the smoking continues, so does the damage, and so does the double duty of the goblet cells.
Ultimately, in far too many people, the production of the protective mucus from the goblet cells isn’t able to keep up with the damaging effects of the smoke and cell injury occurs. As these cells are damaged, they cease to function properly, and ultimately die. They are then replaced by new cells, which themselves go through the same cycle. Somewhere along the way one of these cells, due to the damaging effects from the smoke, undergoes a malignant transformation and starts to reproduce itself.
When this happens lung cancer is born.
We know what happens to the lungs with smoking. We know that all the coughing and mucus production isn’t a good thing–it isn’t protecting us from disease; it is the result of disease. But if we lived in a society that worshipped bringing up mucus every day, how long would it take us to figure out that smoking wasn’t particularly good for us?
Into this society of mucus lovers a researcher comes along and writes a paper showing how cigarettes cause an increase in mucus. He talks to the press and tells them about his research, saying, ‘I’ve now figured out how these wonderful cigarettes work to improve our mucus production. They damage the cells, which then make and release more mucus to protect themselves. It’s really wonderful how the body responds thusly. Now that we know how it all works, let’s go out and smoke even more.’
Preposterous, you’re probably thinking. But only if you live in a society that doesn’t worship regular mucus production.
Instead, we live in a society that worships regular bowel movements.
Doctors for the last few hundred years have focused much of their effort in ensuring the regularity of their patients. Many people, the elderly especially, are obsessed with moving their bowels daily. Most people, if asked, would probably reckon that it’s not good to have fecal matter just sitting around in the colon. Get it out of there, they would say. It can’t be healthy. Just as it escaped the notice of our doctors in the scenario I imagined above that animals in the wild don’t bring up copious amounts of mucus daily, it has escaped the notice of doctors today that animals in the wild, especially carnivorous animals, don’t always have daily bowel movements, and that when they do, such BMs aren’t always huge and loose.
Into our bowel-regularity-worshipping society there has come a substance that ensures regularity. It’s called fiber. It is sold everywhere in diverse forms.
All manner of ‘experts’ from our doctors to our grandparents encourage us to consume plenty of fiber. If we can’t get enough from the foods we eat to achieve regularity, we are encouraged to buy supplements. Everyone is on the regularity bandwagon and, by extension, the fiber bandwagon. The much despised Jane Brody has written countless times on the virtues of fiber, WebMD encourages us to get our share, even C. Everett Coop exhorts us to keep the fiber coming. And, despite numerous studies showing that fiber doesn’t really do squat for us health-wise, everyone continues to recommend it.
To paraphrase John Huston: Evidence? We ain’t got no evidence. We don’t need no evidence. We don’t have to show you no stinking evidence.
Into this society of bowel movement lovers a researcher comes along and writes a paper showing how fiber causes an increase in regularity. Our intrepid researcher’s name is Dr. Paul L. McNeil; he is a cell biologist at the Medical College of Georgia. I’ll let him tell how it all works.
When you eat high-fiber foods, they bang up against the cells lining the gastrointestinal tract, rupturing their outer covering. What we are saying is this banging and tearing increases the level of lubricating mucus. It’s a good thing.
It’s a bit of a paradox, but what we are saying is an injury at the cell level can promote health of the GI tract as a whole.
He goes on to explain that even though epithelial cells usually live less than a week, they are regularly bombarded, in most of us at least three times a day, as food passes by.
These cells are a biological boundary that separates the inside world, if you will, from this nasty outside world. On the cellular scale, roughage, such as grains and fibers that can’t be completely digested, are a mechanical challenge for these cells.
But in what he and colleague Dr. Katsuya Miyake view as an adaptive response, most of these cells rapidly repair damage and, in the process, excrete even more mucus, which provides a bit of cell protection as it eases food down the GI tract.
As reported in ScienceDaily
In research published in 2003 in Proceedings of the National Academy of Sciences, Dr. McNeil showed proof of his then decade-old hypothesis that cells with internal membranes use those membranes to repair potentially lethal outer-membrane injuries. A recent paper published in Nature in collaboration with Dr. Kevin Campbell’s laboratory at the University of Iowa showed how human disease, including certain forms of muscular dystrophy, can result from a failure of this mechanism.
An outer membrane tear is like an open door through which calcium just outside the cell rushes in. Too much calcium is lethal but that first taste signals the vulnerable cell it better do something quick. With epithelial cells, several of the internal mucus-filled compartments fuse together within about three seconds, forming a patch to fix the tear. In the process the compartments expel their contents so, almost like a bonus, extra mucus becomes available to lubricate the GI tract.
And a final telling paragraph.
The scientists aren’t certain how many times cells can take a hit, but they suspect turnover is so high because of the constant injury. Potentially caustic substances, such as alcohol and aspirin, can produce so much damage that natural recovery mechanisms can’t keep up. But they doubt a roughage overdose is possible.
(You can click here to read this study in its entirety in PLoS Biology)
So, we have a situation where a product causes damage to the cells lining a tube, causing them to produce a lot of mucus in an attempt to protect themselves. In the process many of these cells die and are replaced by new cells. And this is perceived as a good thing.
My question is: is it really a good thing?
Why aren’t you a scientist, instead of an MD?
You seem to actually care about logic, reasoning, scientific method, et cetera…
…well, OK, that’s probably why you’re not a scientist. I’ve been assured by my scientist friends in DC, where I used to be a consultant, that such things are a bane to fund-grubbing and journal-publishing.
It’s astonishing how many ideas in modern medicine, like the above, are based on the perpetual reinforcement of old inductive reasoning, not hard science.
Of course this is, as I implied, true of science in general. Did you have to study the ideas of http://en.wikipedia.org/wiki/Karl_Popper in college? He really solidified what good scientific reasoning and methodology are, but while good scientists therefore consider him iconic, academics often hate him for that very reason.
Blah, this thing stripped out the hyperlink for Karl Popper.
Words of the Sentient:
The best security for liberty is a nation of well informed men, who have
been taught to know and prize the rights which the Creator has given them.
— Benjamin Franklin
Yahoo Messenger/AIM/AOL: KazVorpal
MSN Messenger: KazVorpal@yahoo.com
Believe it or not I started out as a scientist (a PhD candidate) but switched to medicine.
I have read a lot both by and about Karl Popper. If you want to see an interesting dissection of his work, read David Stove, an Australian philosopher who died 10 or so years ago.
I have long believed that the whole fibre thing was just as stupid as the dangerous saturated fat myth! Since I started on the PP diet 6 years ago I quickly cast aside any such notions and just eat heaps of great meat, fat, and fresh vegetables and berry fruits. I am constantly amazed at all the products promoted to “detoxify”, “cleanse” etc. I always wonder how our ancestors managed to do these things!
PS. love you guys’ blogs.
Thanks for the kind words. When we wrote Protein Power we wrote an entire chapter on how worthless fiber really is. Our editor figured that since the book was already to long, we needed to cut it. Why, she wondered, should we spend an entire chapter talking about something unnecessary for the program. This study gave me the chance to strike back.
Have you ever seen one of those commercials for fiber, where it shows the woman eating a bran muffin at home, broccoli in the car, an apple while working out, and I think maybe other food. The whole premise is, why should you have to eat all this food just to get fiber, when you can just take it in the form of a pill. I was personally amazed by this, that they would basically say eating healthy is too time consuming; just take a pill. What’s even more sad is people buy into it because that’s what a lot of this country is like today. While the bran muffin might be suspect, I’d certainly go for the apple and broccoli any day, and NOT because I’m hoping I’ll get enough fiber.
It is amazing that people are being encouraged to take a pill to replace healthy eating. What’s even more amazing is that in this case the pill is replacing something that has never been shown to have health benefits in the first place.
I read somewhere that the texture of the inside of your stomach and intestines is very similar to that of the inside of your mouth. the notion that constantly cutting and scraping the inside of my mouth could somehow be good for me seems downright absurd!
How true, how true.
That’s an interesting comment about the chapter on fiber that was cut out of your book. Have you every considered making it avalaible on your website?
I would have to find it first. I’ve had a couple of requests, so I’ll see if I can dig it up. Don’t hold your breath, though.
I wonder if there is a difference between soluble and insoluble fiber as far as causing GI damage? I would guess that insoluble fiber which I believe is found much more in grain products, like wheat is more evolutionarily suspect and is what causes the damage. While soluble fiber which I think is more common in the fruits and vegetables would not damage the lining of the gut or at least not to the same degree as the insoluble. Soluble fiber is also much better for the blood sugar than insoluble.
Many of your common grain products also contain gluten or gluten-like proteins which can damage the gut lining causing problems, but this would be an additional problem and not something strictly caused by insoluble fiber as there may be insoluble fiber that is non-gluten that may or may not cause the damage to the GI lining. Did the researchers control for this in their study?
I would recommend reading Sally Fallon’s book, Nourishing Traditions and her organization’s website, http://www.WestonAPrice.org which has similar discussions on this topic and also the value of lactofermented foods such as sauerkraut for GI health. Many primitive peoples who had high fiber diets also had that food as fermented products and not as the modern highly processed foods that are sold in American grocery stores today.
There is also much information at that location on the value of primitive diets including some such as the traditional Eskimos who ate no fiber at all for 9 months of the year and had no gut problems. Sally’s philosophy is quite similar to yours in many senses.
I think deranged blood sugar problems cause nerve damage in people which affects among other things the autonomic nervous system and hence the action of the gut among other things. This is quite common in older people who then are turning to fiber supplements to help their gut function but often in the form of psyillum with a ton of sugar dumped in it to make it palatable, which helps the short term constipation problem but increases the long term blood sugar problems and all the bad things that that causes. See Richard Bernstein’s book which talks about gastoparesis (delayed stomach emptying) being a consequence of chronic high blood glucose levels.
I have just discovered your site and am still working my way through your back issues. But I can see already that I love it. Keep up the good work.
No, the researchers didn’t control for glutens, nor did they differentiate between soluble and insoluble fiber. They damaged the cells mechanically and watched how they repaired themselves, which they did by secreting mucus. The assumption is that fiber causes this same damage.
I know Sally Fallon and I am very familiar with the Weston Price organization, which has a wonderful website. I don’t agree with everything on the site, but I do agree with about 90% of it.
Well, I feel vindicated.
I’ve forwarded this wonderful post to all my friends that think I’m crazy for thinking fiber isn’t very good for you. And that I should be going more than twice a week.
Thanks, Dr. Eades.
My pleasure. Glad I could help.
I am old enough that my grandmother recommended mineral oil, not roughage. Now I just eat fat & never have a problem. The only time I really needed fiber (or wished they made roto-rooters for humans) was when I was following very low-fat high-carb Pritikin & Ornish type diets.
One thing I’ve noticed amoung new immigrants from some countries is they see hoarking on the sidewalk as “normal” & everyone from toddlers to centenarians seems to be doing it, so it is not just smokers or those with lung disease as the second generation born here is doing it too. My city had to resort to enforcing a 150 year old no-spitting bylaw.
But this makes me wonder about how we “civilized” people hold everything in and use cough-suppressants when we have colds so as not to offend anyone or disturb people in school or work. I’ve noticed that I seem to get over colds faster if I take nothing.
Nature provided us with the cough reflex for a reason.
Thanks for posting this. It’s been a major pet peeve of mine. On low carb forums everywhere (including your own), there are a lot of posts about how someone thinks they are constipated because they no longer “go” everyday (or multiple times a day).
When you eat high quality food, there isn’t as much waste to excrete, so you won’t “go” until you need to. Let the system work as intended.
I couldn’t have said it better. Thanks for commenting.
The fiber issue is something that I’ve thought about for a long time, more so since I started LCing. Since high school, I’ve suffered from the constipation form of IBS on and off. The worst bouts were in the recent years before I saw the light and moved to a LC diet. During that time, I was eating copious amounts of whole grains as a high fiber diet was recommended for my condition. The only thing that happened was that I got worse: my small intestines were so blown up with gas that I looked pregnant and combined with the constant constipation, I was beyond miserable. My guts rumbled and cramped constantly. Within a week of eliminating grains from my diet that all disappeared with the exception of the constipation which I still deal with on a regular basis. Psyllium husk really helps with that. Am I doing my intestines harm by using the husk? I don’t have any tummy problems using it. In fact, my theory, such that it is, is that soluable fiber is ok with my digestive system but insoluable fiber is not. I’ve also found that certain veggies like broccoli and cauliflower are much tolerable cooked than raw and that certain fruits, such as apples, need to be cooked, as well.
Looking back on it, the periods of my life when my IBS abated coinside with those times when I was eating very little grains and not whole ones at that. I had ramped up my consumption in recent years as I became interested in eating “healthier” and ironically, trying to loose weight. As for the constipation issues, I belong to a DES daughter listserve and it seems to be a common complaint amongst us which leaves me to wonder if along with screwing up our reproductive systems, the DES did a number on our digestive systems, too.
Thanks for the interesting history. I’m glad things are working better with a low-carb diet, It’s been my experience that they usually do.
I don’t have an answer for your question on DES daughters and constipation. I’ve seen it go both ways.
Just started reading your blog recently and have thoroughly enjoyed it so far. Thanks for taking the time.
PP Lifeplan was what first got me started on the “right track” after sitting through years of “nutrition” classes in naturopathic school. Don’t know where I or my patients would be now had I not read your book, so thanks.
Anyway, do you happen to still have that omitted chapter on fiber from PP lying around? If so, maybe you could post it? Sounds like really interesting reading to me, though I guess I’m not the average reader.
If I can find the chapter, I’ll post it. I wrote the chapter way back in 1995 and have moved several times since then. The computer I used to write it and where it was stored on the hard drive was stolen from my office many years ago. I’m sure I’ve got it saved on a floppy somewhere, but it will take a lot more time than I’ve got right now to track it down.
You are one curious and questioning sumbuck — outstanding post.
One thought; maybe those poor souls afflicted with Morgollons should cut back on the bran flakes and see if those fibers stop popping out of their skin. Sorry, bad and tasteless joke.
Second thought; to build new muscle you need to damage existing muscle cells (via slow burn for instance) in order to promote repair and growth of new cells. Is that correct? If so, the process is similar to what you’ve described above and forces the ignorant of the world (yours truly) to ask why it’s a good thing for muscle cells but maybe not for the goblet and epithelial cells lining. Why wouldn’t the new lung and gut cells come out stronger and better?
Muscle cells are different that epithelial cells. There is a large turnover of epithelial cells. When one is injured and dies, it gets replaced. When this happens more often than normal, the chances increase that there will be a malignant transformation. Muscle cells don’t die and get replaced. They are pretty much permanent. When they get injured by heavy stress, they repair themselves by growing larger in an effort to withstand such stress in the future. Epithelial cells just die and are replaced.
Are we going so far as to say fiber is damamging? Like the low fat diet causing obesity is a high fiber diet possibly a cause of colon cancer? Or is that too much of a jump for right now? Can I quit the afternoon salad and stick with a cheddarworst for lunch? Or should I get the herb salad mix and keep loading it with cheese and bacon bits?
Hanging on every word,
I don’t know that fiber causes cancer, but it can’t be ruled out. This study was done on stomach cells, showing how they are damaged by mechanical effects. In the olden days, i.e., back in the 20s and 30s and before, we ate a lot of fiber, and stomach cancer was one of the most common, if not the most common, cancers afflicting people in the U.S. Since that time fiber consumption has decreased dramatically, and now stomach cancer is almost non-existent. Does that mean that there is a cause and effect operating here? I don’t know. But I do know that multiple studies have been published showing that fiber exerts no positive benefits, so I figure, why take the chance.
If fiber is so dangerous, why recommend anything that (like veggies and fruits) that contain so much?
For me, fiber is pretty much a necessity. I know that when I started low-carb my intake of veggies went WAY up, and for the first time in ages I could poop regularly without the aid of a fiber tablet (before that I felt horrible and couldn’t go at all without the tablets). Now I only use the tablets occasionally, such as when I fall off the wagon and eat a ton of carbs and don’t get my veggies that day.
The magnesium also helps with that. I had to up my dose to three pills to get headache relief, and now it is effecting my bowel movements! Annoying, but I can live with it.
BTW, due to your chapter on iron, I have an appointment tomorrow to give blood. The last time I gave was roughly 20 years ago and I was so scared that I nearly fainted afterwards and then threw up. That scared me off. Now I’m ready to try again.
Be brave at the blood donation place. It’s much better now than it was 20 years ago.
Also, taking the magnesium at bedtime seems to cause less of a tendency toward diarrhea than taking other times of the day.
Hello Dr. Eades,
Am I right in assuming that the 10% you don’t agree with from the Weston Price Foundation has to do with their recommendations to eat grains, and maybe a little of their recommendations for heavy dairy consumption? While the 90% you agree with includes their stress on the importance of high quality animal foods and fat consumption, including saturated fats?
Can you direct me anywhere on your blog where you actually discuss your opinions on fat consumption, especially saturated fat, and how it differs from Cordain’s?
You’re spot on in my disaggreement with the Weston Price Foundation website.
I’ve posted a number of times on my take on the saturated fat issue. Basically, I don’t have a problem with saturated fat at all. It’s a good, natural fat that, as far as I’m concerned, doesn’t cause any problems. The literature showing saturated fat causing heart disease is scanty and practically non-existant, although one wouldn’t know it by the way almost everyone assumes there is a vast literature showing that saturated fat causes heart disease. I’m in the process of reviewing a number of the old papers that purport to show a connection between saturated fat and heart disease, and I will be posting on the subject in the near future.
My position vis a vis Loren Cordain (who is a good friend of mine with whom I debate this issue often) is that Dr, Cordain believes that saturated fat is a risk factor for heart disease. He is convinced that saturated fat makes LDL levels rise (he’s right to an extent about this), and that elevated LDL is a cause of heart disease. I’m not particularly a believer that LDL, certainly not Type A LDL, is a driving force behind the development of heart disease. And I certainly don’t think saturated fats are either.
One thing I have always wondered about is the insistence by promoters of low-fat, high-carb diets that reducing the saturated fats in the diet is a healthy thing when the very fat made by the liver from excess carbs is palmitic acid, a 16-carbon saturated fat. This is especially weird when all the studies that have looked at which types of saturated fat appear to cause an increase in LDL, palmitic acid is at the top of the list.
Hope this helps–
‘I’m not particularly a believer that LDL, certainly not Type A LDL, is a driving force behind the development of heart disease’
Neither am I. As Malcolm Kendrick and Anthony Colpo state in their publication, the idea that LDL causes heart disease is wrong. It is a classical inversion of cause and effect. LDL elevation is a symptom of a dysfunction which leads also to heart disease, but reducing artificially LDL level does not necessarily cure the real cause of the elevation.
It is like killing firemen to combat fires, because we see very often a lot of firemen when there is a fire.
Thanks Dr. Eades, that helps a lot. Have you heard of Anthony Colpo? He used to run an excellent website called Omnivore.com, and has written a book full of good research, called The Cholesterol Con. If you haven’t already, I’d go here:
and purchase his $5 compilation of posts on his omnivore site, which includes a two part debate with Dr. Cordain, on the saturated fat issue. Fascinating stuff.
I’ve been on Anthony Copo’s site and I have his book, although I haven’t read it yet.
I’ve seen the debate with Cordain, which really isn’t a debate with Cordain. It’s a debate with a Cordain surrogate. Some one wrote to Colpo saying Cordain says this, Colpo responds to the guy writing in, the guy obviously emails Cordain to find out what he has to say. Cordain answers the guy, who then writes to Colpo saying what Cordain said. So it’s not really a direct debate. I’ve asked Loren about it; he says he’s never seen the so-called debate and has never been on Colpo’s website. He only knows of it because so many people have told him about it.
Sir you ever noticed or anyone else if one eats too much fat it seems to scupper ones mood.
Same thing anyone else ?
Fat certainly doesn’t ‘scupper’ my mood nor MD’s. I think the opposite happens, however. People who don’t get enough fat seem to have thier moods scuppered. Witness Dean Ornish and Neal Barnard.
One last question on elimination (hopefully). Has anybody studied to see if there a correlation between frequency of defecation and colon cancer? Thanks for an interesting take on an ancient issue. And I need to study Karl Popper, I thought
he played blues harp, alright I didn’t really think that. Thanks for your time.
As far as I know there has never been a study on defecation frequency and the incidence of colon cancer. That’s not to say there isn’t such a study–I just don’t know of one.
If you’re interested in finding out, go to http://www.pubmed.com and run a search. Be sure to let all of us know what you find out. Karl Popper would have approved.
Below are the results of my search in Pub Med using the search terms “defecation frequency and
cancer”. While other factors are at least hypothesized as related to colon cancer, defecation frequency is stated in every case to be unrelated to frequency of colon cancer. In fact at least 1 study concludes that “Although the most common bowel habit was once daily this was a
minority practice in both sexes; a regular 24 hour cycle was apparent in only 40% of men and
33% of women”. The Studies are listed below for the curious. As always thanks for the time and
space (in this case a lot of it).
I’m going to insert my comments here. Skip on down for the actual papers.
So, there isn’t a correlation between colon ca and frequency of defecation. Interesting. And the average person (at least in the groups studied) defecated less often than once per day. No s**t? I couldn’t resist. Anyway, that’s interesting as well.
Thanks for your diligence on this. It’s an interesting fact to know given the focus on daily bowel movements as a protective mechanism against colon cancer.
Prospective study of bowel movement, laxative use, and risk of colorectal cancer among women.
* Dukas L,
* Willett WC,
* Colditz GA,
* Fuchs CS,
* Rosner B,
* Giovannucci EL.
Department of Nutrition, Harvard School of Public Health, Boston, MA, USA.
The authors prospectively examined the association between bowel movement frequency,
laxative use, and the risk of colorectal cancer in 84,577 women of the Nurses’ Health Study
living in the United States, 36-61 years of age and free of cancer in 1982. Between 1984 and
1996, 611 incident cases of colorectal cancer were documented. After controlling for age, body
mass index, fiber intake, postmenopausal status and hormone use, physical activity, and use of
laxatives, the relative risks associated with having bowel movements every third day or less,
compared with those with bowel movements once daily, were 0.94 (95% confidence interval
(CI): 0.69, 1.28) for colorectal cancer, 0.88 (95% CI: 0.62, 1.26) for colon cancer, and 1.18 (95%
CI: 0.63, 2.20) for rectal cancer. Compared with women who never used laxatives, the
multivariate relative risks associated with weekly to daily laxative use were 1.00 (95% CI: 0.72,
1.40) for colorectal cancer, 1.09 (95% CI: 0.76, 1.57) for colon cancer, and 0.68 (95% CI: 0.29,
1.57) for rectal cancer. These findings do not support an association between infrequent bowel
movement, laxative use, and risk of colorectal cancer and indicate that simple questions directed
at bowel movement frequency are unlikely to enhance our ability to predict colorectal cancer
Association of bowel movement frequency and use of laxatives with the occurrence of
symptomatic gallstone disease in a prospective study of women.
* Dukas L,
* Leitzmann MF,
* Willett WC,
* Colditz GA,
* Giovannucci EL.
Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA.
OBJECTIVES: The authors prospectively examined the association between bowel movement
frequency (used as a proxy for intestinal transit), laxative use, and the risk of symptomatic
gallstone disease. METHODS: A total of 79,829 women, aged 36-61 yr, without a history of
symptomatic gallstone disease and free of cancer, responded to a mailed questionnaire in 1982
that assessed bowel movement frequency and use of laxatives. Between 1984 and 1996, 4,443
incident cases of symptomatic gallstone disease were documented. Relative risks (RRs) of
symptomatic gallstone disease and 95% confidence intervals (CIs) were calculated using logistic
regression. RESULTS: After controlling for age and established risk factors, the multivariate
RRs were, compared to women with daily bowel movements, 0.97 (95% CI 0.86-1.08) for
women with bowel movements every third day or less, and 1.00 (95% CI 0.91-11.1) for women
with bowel movement more than once daily. No trend was evident. As compared to women who
never used laxatives in 1982, a significant modest inverse association was seen for monthly
laxative use, with a multivariate RR of 0.84 (95% CI 0.72-0.98), and weekly to daily laxative use
was associated with a RR of 0.88 (95% CI 0.78-1.02). CONCLUSIONS: These findings do not
support an association between infrequent bowel movements and risk of symptomatic gallstone
disease in women, and indicate that simple questions directed at bowel movement frequency are
unlikely to enhance our ability to predict risk of symptomatic gallstone disease. The slightly
inverse association between use of laxatives and risk of symptomatic gallstone disease may be
due to a mechanism that is not related to bowel movement frequency.
PMID: 11280540 [PubMed – indexed for MEDLINE]
Bowel movement, use of laxatives and risk of colorectal adenomatous polyps among women
* Dukas L,
* Platz EA,
* Colditz GA,
* Willet WC,
* Giovannucci EL.
Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA.
BACKGROUND: Infrequent bowel movements and use of laxatives have been hypothesized to
increase risk of colorectal neoplasia. However, the few existing epidemiologic studies in humans
have been inconclusive. PURPOSE: To investigate prospectively the associations of bowel
movement frequency and laxative use with the occurrence of adenomatous colorectal polyps in
women. METHODS: A total of 17,400 women 36-61 years of age, without previous diagnosis of
cancer or polyps, responded to a mailed questionnaire in 1982 that assessed bowel movement
frequency and use of laxatives and had an endoscopy between 1984 and 1996. Between 1984 and
1996, 906 cases of adenomatous polyps (496 classified as small ( or = 1 cm) and 52 unclassified) were documented. Relative risks (RRs) of adenomas and 95%
confidence intervals (CIs) were calculated using logistic regression. RESULTS: After controlling
for adenoma risk factors, the multivariate RRs associated with having bowel movements every
third day or less compared to once daily were 0.9 (95% CI: 0.7-1.2) for total colorectal
adenomas, 1.0 (95% CI: 0.7-1.5) for large adenomas and 1.0 (95% CI: 0.7-1.3) for adenomas of
the colon only. The multivariate RRs associated with weekly to daily laxative use compared to
never use were 0.9 (95% CI: 0.7-1.1) for total colorectal adenomatous polyps, 1.0 (95% CI:
0.7-1.5) for large adenomas and 0.8 (95% CI: 0.6-1.2) for colon adenomatous polyps only.
CONCLUSION: These findings do not support an association between infrequent bowel
movement or laxative use and risk of colorectal adenomas.
Cancer. 1984 Oct 1;54(7):1475-7. Links
Colorectal cancer and bowel habits.
* Nakamura GJ,
* Schneiderman LJ,
* Klauber MR.
In a retrospective case-control study comparing 100 colorectal cancer patients with 100 age-,
race-, and sex-matched hospital controls and 51 spouse controls, no significant differences were
observed in the historical frequency of bowel movements, presence of constipation, or use of
laxatives between cases and controls. There is a suggestion of greater suppository or enema use
in both control groups as compared to patients with colorectal cancer.
PMID: 6467171 [PubMed – indexed for MEDLINE]
S Afr Med J. 1981 Oct 10;60(15):571-3. Links
Cancer of the colon and rectum in the coloured population of Johannesburg. Relationship to
diet and bowel habits.
* Maisto OE,
* Bremner CG.
In the Coloured population of Johannesburg, the incidence of carcinoma of the colon and
rectum estimated over an 11-year period (1970-1980) is 1,33 and 1,08/100 000 respectively per
year. This is lower than the incidence reported in Whites and appears to be even lower than that
reported in South African and Zimbabwean Blacks. A survey of dietary factors in this population
showed a diet which was high in protein, low in fats and high in bulk. The frequency of bowel
action was higher than in both Whites and Blacks. These factors support Burkitt’s hypothesis
which states that races with a high-bulk diet have a lower incidence of large-bowel cancer.
PMID: 7280914 [PubMed – indexed for MEDLINE]
Am J Clin Nutr. 1978 Oct;31(10 Suppl):S239-S242. Links
Diet, transit time, stool weight, and colon cancer in two Scandinavian populations.
* MacLennan R,
* Jensen OM,
* Mosbech J,
* Vuori H.
In samples of adult men from two Scandinavian populations with 4-fold differences in colon
cancer incidence, a comparison was made of estimated food records over 4 days, defecation
habits, mouth-to-anus transit time, and stool weight. The “high incidence” group consumed more
white wheat breads and total meat and beer, but less potatoes and milk than the “low incidence”
group. Defecation habits were similar. Transit time and stool weight had few significant
correlations with diet and defecation habits, but stool weights were higher in the low incidence
group. The results are consistent with a possible protective role of dietary fiber, unrelated to
PMID: 707381 [PubMed – indexed for MEDLINE]
Lancet. 1977 Jul 30;2(8031):207-11. Links
Dietary fibre, transit-time, faecal bacteria, steroids, and colon cancer in two Scandinavian
populations. Report from the International Agency for Research on Cancer Intestinal
* Maclennan R,
* Jensen OM.
A comparison of dietary intake and faecal characteristics in population samples from two areas
of Denmark and Finland with 4-fold variation in colon-cancer incidence suggests that the
aetiology of colon cancer may be multifactorial and is not associated in a simple manner with
dietary fat, neutral steroids, acid steroids, or their bacterial metabolites. However, meat
consumption was greater in the high-incidence areas. Higher intakes of dietary fibre and milk in
the low-incidence area suggest a possible protective effect, unrelated to mouth-anus transit-time.
Further careful dietary and metabolic studies are needed to clarify the relationships between
possible carcinogenic and protective effects of diet.
PMID: 69826 [PubMed – indexed for MEDLINE]
: Lancet. 1977 Jul 16;2(8029):110-1. Links
Bowel transit-time and stool weight in populations with different colon-cancer risks.
* Glober GA,
* Kamiyama S,
* Nomura A,
* Shimada A,
* Abba BC.
It has been suggested that the risk of cancer, polyposis, and diverticulosis of the large bowel
increases with bowel transit-time. Hence, Japanese inhabitants of Hawaii, in whom the risk of
these diseases is high, would be expected to have longer transit-times than Japanese in Japan, in
whom such risks are low. However, bowel transit-times were similar in Japanese groups. Stools
from the Hawaii Japanese did weight significantly less than the specimens from Japan, and this
factor may be indirectly related to the risk of colorectal cancer, polyposis, or diverticulosis in the
1: Gut. 1992 Jun;33(6):818-24. Links
Defecation frequency and timing, and stool form in the general population: a prospective
* Heaton KW,
* Radvan J,
* Cripps H,
* Mountford RA,
* Braddon FE,
* Hughes AO.
University Department of Medicine, Bristol Royal Infirmary.
Because the range of bowel habits and stool types in the community is unknown we
questioned 838 men and 1059 women, comprising 72.2% of a random stratified sample of the
East Bristol population. Most of them kept records of three consecutive defecations, including
stool form on a validated six point scale ranging from hard, round lumps to mushy.
Questionnaire responses agreed moderately well with recorded data. Although the most common
bowel habit was once daily this was a minority practice in both sexes; a regular 24 hour cycle
was apparent in only 40% of men and 33% of women. Another 7% of men and 4% of women
seemed to have a regular twice or thrice daily bowel habit. Thus most people had irregular
bowels. A third of women defecated less often than daily and 1% once a week or less. Stools at
the constipated end of the scale were passed more often by women than men. In women of child
bearing age bowel habit and the spectrum of stool types were shifted towards constipation and
irregularity compared with older women and three cases of severe slow transit constipation were
discovered in young women. Otherwise age had little effect on bowel habit or stool type. Normal
stool types, defined as those least likely to evoke symptoms, accounted for only 56% of all stools
in women and 61% in men. Most defecations occurred in the early morning and earlier in men
than in women. We conclude that conventionally normal bowel function is enjoyed by less than
half the population and that, in this aspect of human physiology, younger women are especially
PMID: 1624166 [PubMed – indexed for MEDLINE]
Hi, Dr. Mike.
A little off the track here, but do you believe in supplementing with acidophilus to boost the healthy flora in the intestine? Also, what’s your opinion on the “yogurt exception” which states that the carbs in yogurt are actually lower than the nutrition label suggests due to the healthy bacteria consuming the lactose?
I don’t supplement myself nor do I have my patients supplement for a couple of reasons. First, I’m not really a bowel-oriented kind of guy, especially where a low-carb diet is concerned. Second, if one eats the right kind of diet, the bacteria in the bowel will respond and grow in the proper proportions. There are a zillion different kinds of bacteria in the GI tract, all in constant warfare and turf battles. If the food coming down the gut has a lot of carbs in it, then those bacteria that flourish on carbs will have a field day and reproduce in much greater numbers than those will that subsist on fat. If fat comes down the tract instead of carbs, the opposite happens. As long as the diet is a proper one (read: whole food, low-carb), then I figure the gut flora will take care of themselves. Second, I’ve never seen (and I’m not saying I’ve seen everything in print; I’m not particularly interested in this topic, so I haven’t spent a lot of time searching) a decent study showing that acidophilus does anything positive for those on low-carb diets.
As to the yogurt question: I don’t know. I don’t really eat yogurt unless forced, so I haven’t paid much attention to anything having to do with it.
>Below are the results of my search in Pub Med using the search terms “defecation frequency and
cancer”. While other factors are at least hypothesized as related to colon cancer, defecation frequency is stated in every case to be unrelated to frequency of colon cancer. In fact at least 1 study concludes that “Although the most common bowel habit was once daily this was a minority practice in both sexes; a regular 24 hour cycle was apparent in only 40% of men and
33% of women”. The Studies are listed below for the curious. As always thanks for the time and
space (in this case a lot of it).<
It’s so weird talking about bathroom habits…
I like to have at least one BM a day just because I *feel* better. Cancer risk or not, I just don’t like going less. I’ve gone less most of my life and hated it the whole time.
I guess it’s a case of different strokes for different folks. Or maybe different poops for different groups. Whatever sets well with your spirit is probably the best thing.
My son has Duchenne Muscular Dystrophy. Are you saying that he should not be having high-fibre foods as his mucous-repair mechanism does not work? So his epithelial cells are not getting repaired?
I’m not saying anything about a mucus-repair mechanism. The study I wrote about simply showed that the way fiber works in the GI tract is by damaging the cells, which then secrete mucus to protect themselves. There mucus producing systems work fine; it’s the chronic damage from the fiber that is problematic.
Hope this helps–
The issue with yogurt is that carbohydrate content on labels is calculated indirectly (total kilocalories minus kilocalories for protein and fat), so the kilocalories of the lactic acid contained within are counted as carbohydrate, massively overstating the carbohydrate count.
There is very little lactose left once yogurt has fermented; indeed, many lactose-intolerant individuals can tolerate yogurt.
If you haven’t liked yogurt in the past, but like dairy products generally, you might try Stonyfield’s organic fullfat “cream on the top” yogurt. IMO, it’s as decadently wonderful as cream cheese or sour cream or marscapone. It is somewhat tart, and I tend to mix in some strawberries or blackberries or even a sugar-free coffee syrup or such to cut the tartness a bit. But it’s wonderfully creamy, yummy stuff.
Yogurt was *always* a good and yummy food when I was growing up. There was only one brand and hardly anyone ate it. Then it became popular or trendy and they started making it lowfat and nonfat and adding all these thickeners and such to it to make up for the cream they removed and started replacing fruit-flavorings with chemical flavorings and all that. *That* crap is not yogurt anymore than any other factory-produced food.
Dear Doctor Eades–
I am reminded of the time a doctor once asked me about how often I went, and at what time…as if TIME had any bearing on my health!
My response to him was that I don’t keep a “potty diary” and I go when I need to. I let the raw vegetation from salads, and the grains from baked goods and sandwiches do their work for me–no measuring, no worries about “getting enough” fiber, and my only bout of constipation came after a cheese-tasting festival.
Just GOING is good enough for me. Time, quantity, size, texture, and all that mean nothing–it’s all just fermented compost anyway.
There has been a suggestion planted in the TV viewer’s mind (from a PBS fundraiser) that the average human needs 35 grams of fiber daily for good health. We’d have to consume an entire tree, a bale of hay, or a bushel of grain to achieve that amount! Of course, the lecture giver DID finish up by pimping various OTC fiber supplements. She should’ve pushed Mexican food instead of pills–the beans, raw onion, raw lettuce, and raw tomato would’ve done the same thing!
Both fiber and frequent bowel movements are highly overrated.
Mike, I’m confused. Am I correct in understanding that you believe the fiber in fruits and vegetables is harmful and to be avoided? Should we be eating a meat and fat only diet since fiber damages the GI tract?
I’ve seen your blog linked to elsewhere on the internet in support of such a diet and was curious if that was really what you support?
No, I don’t think the relatively small amount of fiber that comes in as part of a good, whole-food low-carb diet causes problems. But I do think taking large amounts of fiber supplements, wheat bran, etc. is probably not a great idea.