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Bowel movements: the scoop on poop

September 29, 2011 by Michael Greger M.D. in News with 16 Comments

 Years ago we learned that those eating plant-based diets are just “regular” people. In a study comparing omnivores, vegetarians, and vegans profiled in my Bowel Movement Frequency video, researchers found a “very clear trend towards an increasing number of bowel movements with a more rigorous degree of vegetarianism.” For example, even meat-eating women who piled on the fruits and veggies and ate the same amount of fiber had only a quarter the odds of having a daily bowel movement compared to women eating vegan. But does this translate to decreased disease risk?

 This year marks the 40th anniversary of the publication of Painter and Burkitt’s landmark paper “Diverticular Disease of the Colon: A Deficiency Disease of Western Civilization” (PDF here). Just as scurvy is a vitamin C deficiency disease, they argued, diverticulosis is a fiber deficiency disease, the result of not eating whole plant foods. No surprise, then, that the majority of older Americans are afflicted with this condition.

As I explain in my diverticulosis video, a lifetime of straining to pass stools that aren’t softened and bulked up by fiber can eventually balloon pockets out through the weakest points in the wall of our colons. These bulging outpouchings can get inflamed, infected, and even lead to a life-threatening rupture of our intestines. More than 100,000 Americans are hospitalized every year for this preventable condition.

This summer, a team of scientists at Oxford released the results of a study (PDF here) in which 15,000 vegetarians and vegans were followed for nearly a dozen years. Compared to meat eaters, vegetarians had 35% less risk of being hospitalized or dying from diverticulitis, and those eating vegan appeared to eliminate 78% of the risk.

What’s most surprising is that even after controlling for fiber intake, those on plant-based diets still had significantly lower risk, leading the researchers to suggest that meat itself may increase the risk of diverticular disease “by altering the metabolism of bacteria in the colon, which could lead to a weakening of the colon wall….”

In addition to enhanced regularity, vegetarians and vegans also get points for achieving the preferred stool size and shape. The bigger the better. For example, one reason why women eating vegetarian may have lower breast cancer rates is because they have larger bowel movements, the topic explored in last Friday’s video, Relieving Yourself of Excess Estrogen.

On Monday, Stool Size Matters offered a tip on how to use beets to measure one’s intestinal transit time, and Tuesday’s Food Mass Transit revealed that it may take an average of four days for food to get from one end to the other in women eating a standard American diet, too slow to meet the target half-pound-minimum fecal output for optimal cancer prevention.

Yesterday’s Bowels of the Earth contest revealed which country has the largest average stool size (i.e. who’s #1 at number 2), and which population has the smallest (New Yorkers!).

Check out my other 23 videos on colon health, everything from a Toxic Megacolon Superbug to Greasy Orange Rectal Leakage.

-Michael Greger, M.D.

Image credit: theogeo / Flickr

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Dr. Michael Greger

About Michael Greger M.D.

Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

View all videos by Michael Greger M.D.

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  • http://nutritionfacts.org/members/mgreger/ Michael Greger M.D.

    Please feel free to leave any questions you may have about this entry below, and feel free to check out all the videos on fiber as well

    • http://nutritionfacts.org/members/jack-forrest/ Jack Forrest

      I’m a retired physician who has heard you speak a couple of times and enjoy your material and approach but I’m a fast reader and would like to read your material. How can I do this.

    • Nicole G.

      Hi Dr. Gregor, I suffer from pelvic floor dysfunction (I think) and have no issue with transit time as per a recent Sitz marker test. What I do experience though is an intense pain over my right eye when I cannot have a bowel movement. Also, I have virtually no sensation in my rectum. Might you know what is causing my difficulties or what I can do to help? I am vegan and have been for over 3 years.

  • http://nutritionfacts.org/members/DavidSchmidt/ David Schmidt

    Off topic I know Doctor, but I wanted to know if you can help offer direction on getting off of my Blood pressure medicine. I only take a low dose, but when I stop, my blood pressure does go up into a borderline range. I am Vegan, and do regularly eat red lentils.
    Thanks in advance!

  • http://nutritionfacts.org/members/AmberRogers/ Amber Rogers

    Hi David, I’d have to know a little more about your diet and exercise habits to give you a more detailed answer, but off the top of my head: are you watching your sodium intake http://nutritionfacts.org/videos/salt-ok-if-blood-pressure-is-ok Processed foods are one of the worst offenders as far as sneaking sodium into your diet. Vegan cheeses and meat substitutes are loaded with the stuff.
    Regular exercise is also one of your best weapons against high blood pressure.

  • http://nutritionfacts.org/members/earthgypsy/ earthgypsy

    Any opinions on aloe vera juice?

    • http://nutritionfacts.org/members/mgreger/ Michael Greger M.D.

      A recent randomized, cross-over, placebo-controlled study failed to find any benefit of aloe vera over placebo in the treatment of irritable bowel syndrome. There is, however, evidence that peppermint oil may help. In general, the available science suggests that the purported benefits of aloe are overblown, and given recent reports of aloe-induced hepatitis, I would recommend against ingesting it. Applied topically, though, to second degree (blistering) burns, aloe vera does seem to accelerate healing. Thank you so much for your question–I’m always happy to look things up for folks.

  • Zeph

    This is all very interesting!  What about personal “experience” of the TMI kind?  My personal experiences differ from the results of these studies.

    Ready for a little TMI?  Ok, a lot of TMI?  :)

    A few years ago, I decided to head toward vegetarianism.  I also started eating very healthy–organic, local, fresh, homemade, etc.– and quit smoking.  I took up a “flexitarian” diet, consisting of no meat on most days and small amounts of meat once or twice a week.

    At some point during that time, I also developed a rectocele (unbeknownst to me until a few months ago).  The last year and a half, I was  feeling increasingly constipated, stools were difficult to pass and yet rather thin.  Of course, cancer was my fear. 

    Then I discovered the rectocele.  I decided to up the fiber even more, via grains, veg and inulin.  Things became even more difficult.  I was having the urge to defaecate every day, several times a day, but it was far from easy.

    This past month, I had two house guests back to back.  They are both meatetarians, To keep them happy, I cooked meat, just like back in my olden days when it was a slab of meat as the main and the rest as sides.

    And wouldn’t you know it, regular bowel movements ever since.  No splinting, no straining.  They are the right color, larger in size, etc.

    I really hate to cave to this and leave my dreams of being a vegetarian in the dust, but…. if I can avoid surgery for the rectocele I will. 

    Incidentally, wasn’t there a study recently revealed about the rather marked increase in colon cancer risk among vegetarians, perhaps due to the large amount of fiber and therefore the scraping of the intestines (scraping releasing mucous, thus requiring healing followed by possible DNA replication mistakes ergo cancer)?

    • http://www.DonForresterMD.com/ Don Forrester MD

       Sorry to hear about the rectocele. There are many factors that go into the development of a rectocele as I’m sure you are aware. It is not unusual for the symptoms to be made worse by the increase in fiber and bulk of the stool. Given your history it appears that you have two choices. The first to continue what you are doing to minimize the problems caused by the rectocele or to have the rectocele surgically repaired and to resume a whole food plant based diet. Given the risks of the standard american diet as it relates to arterial disease, cancer, autoimmune disorders, obesity, diabetes, osteoporosis and neurological disorders it would be easy to argue for the surgical repair with improved nutrition. I haven’t seen the study that you are referring to but all the studies I have seen and the current best hypothesis is that fiber reduces the risk of colon cancer when all the other variables are taken into consideration. As each case is unique it is important to work with your physician(s) to help you make the right decision for yourself. Good luck.

  • MarilouGaron

    About 6 months ago, I switched to a plant-based diet but am having terrible diarrhea. I cannot eat anything “healthy” (especially legumes, green leafy vegetables and berries) without almost immediate diarrhea. I sometimes go on a bread/cheese/meat diet for a day or two, just to obtain relief of the diarrhea! Is this something normal, in your experience? Even after eating essentially plant-based for 6 months, the diarrhea does not seem to want to disappear. I have had stool tests and blood tests, all of which are normal. I’m so sad and confused… it seems like the world’s best diet, is turning out to be my worst nigthmare! If you have any thoughts, I woudl be thrilled to read them. Many, many thanks for your blog and videos which are truly fantastic, and very much appreciated.

    • Brian Humphrey

      Hey MarilouGarson, Sorry to read about your diarrhea aka “mudd butt”. I know it sucks, literally. Thanks for sharing with all of us. Sounds like you might me getting too much fiber. I would be interested to know what your diet was on a typical plant-based day. Also try consuming some probiotics (no yogurt) to boost your healthy gut bacteria. I’ve used GOL (Garden Of Life) Raw Probiotics and they did a fantastic job with regulating my digesting and relieving diarrhea constipation after a round of antibiotics or stomach bug

  • Yvette

    Great article!!!! I’ve been vegan 3 weeks and notice the difference in many aspects of my health.

  • John

    Dear Dr Greger,

    I have been vegetarian for about 25+ years and virtually vegan for about 5 years. I contracted prostate cancer some years ago (I think) although it was diagnosed Dec 2012 (Gleason 3+4). I have had a prostatectomy in March and am about to have radiation therapy BUT the medics have had me on the CT scanner four different times (4 hour round trip) to set up the scanner and mark my pelvis area, but my bowel is never correct – too much gas or faeces. I used a de-gas pill and now they gave me laxatives (2 x 2 times a day) which I took 1 x 2 times a day. I think the problem is timing because my bowel is very efficient and healthy, 1-2 movements every day, but they think I need laxatives.

    Is a vegan bowel more likely than the average one to move waste in a continuing kind of process? I had an enema last trip but they waited an hour before I went on the CT again. They told me the scan was fine on the day but now they rang to say there was too much faeces in it.
    I just want to get the scan right but I’m not sure laxatives are going to make any difference.
    Any suggestions?

  • Smash

    What about frequency? I only go once a day and I would say it is large. Just wondering if what people say about going after every meal is correct.

  • Adirel

    Hi dr. Greger. I was diagnosed with stage 4 breast cancer metastatic to the liver. I am on a vegan diet and I go very often (about 3-5) on bad days. My bowel is loose and sometimes I don’t feel complete evacuation. What can I do? I have lost a lot of pounds and can’t gain weight on a vegan diet (is that possible, I’m pooping more than I need to?

    • Thea

      Adirel: I’m so sorry to hear about your cancer. Not only your cancer, but your other problems too.

      I’m not a doctor nor an expert, but I have seen some articles that address people who want to gain weight on a vegan diet. These articles suggested eating lots of calorie-dense, whole foods such as: nuts, seeds, avocados and maybe even olives. You can make all sorts of sauces and dips out of these foods. Or even just load up on nut butters like peanut and almond butter. Whether or not something counts as calorie dense or not might depend on a lot on your existing diet. If you are eating a lot of low-fat or fat-free salads and raw veggies, then just about anything would be higher calorie density – including say tofu.

      While you may not be a teen and/or an athlete, the following page may interest you. Not all of the recommendations on the page are whole foods, but there are some good ideas that may help and it is a site (Vegetarian Resource Group) that I trust.
      http://www.vrg.org/teen/veg_athlete_weight_gain.php

      Since I am not a doctor, I do not know if these suggestions are a good idea for your situation. I just thought you might find these ideas helpful.

      Good luck.

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