Wednesday, August 14, 2013

The Anatomy Of A Bowel Movement (And How To Cure Constipation)

Many of us take for granted our trip(s) to the porcelain throne each day as we rid ourselves of built up toxins and waste products via nature's evacuation system. Or to put it more candidly, I'm talking about pooping. Everybody does it, but not everybody does it well.

We've all been in this second group of folks, at least at some point in our life, straining and struggling to get those rock hard miniature boulders out of our bottom end to finally provide us some relief. Ultimately, many of us still find ourselves falling short of the call of "duty". This is no fun by any means, so what now? A pill? A powder? An extra gallon of water? A trip to the doctor's office?

I'm going to outline the ins and outs of constipation, as well as what you can do about it, to help you navigate the human plumbing system in hopes of providing you with some much needed relief. After all, everybody deserves to feel good. As an added bonus, you'll get the bragging rights of becoming a super pooper. Now how can you turn down that deal?!

Constipation - Definition and Prevalence

Constipation is officially defined as less than 3 stools per week using the Rome III criteria. The presence of hard stools, straining, and incomplete defecation is present 25% or more of the time. Constipation does tend to be a very subjective disease, however, as lack of agreement between patient and physician can occur when defining what exactly constipation means to each individual. Nonetheless, nobody wants to be constipated regardless of how many or what kind of stools are taking place so no sense in squabbling over diagnosis details.

Constipation is very common in the North America occurring in anywhere from 1.9% to 27.2% of the population, according to a systemic review of the literature [1]. The same holds true for our European counterparts where the reported median rate of constipation was 19.8% [2]. In the United States, all this backed up human stool translates into 2.5 million physician visits per year at an average annual cost of $7,522 per patient in direct health care costs to diagnose and treat it [3]. That's some expensive clean up!

In contrast, the incidence of chronic constipation in poorer, less developed countries is very low. Reports from Asian and Eastern developing nations show prevalence rates for constipation anywhere from 2.6% to 3.9% [4,5,6]. It is important to note that these countries traditionally consume a diet high in fiber, unlike westernized cultures. This plays a huge role in the etiology of constipation as you will soon find out.

Other notable factors regarding the prevalence of constipation include the following [1]:
  • Women are affected more than men - upwards of 3.77 times more
  • Patients with irritable bowel syndrome (IBS) are more prone to constipation
  • Elderly (> 65 yrs) have a prevalence rate upwards of 30%
  • Individuals with lower education and lower socioeconomic status have higher rates of constipation (most likely due to poorer nutrition from lack of availability and/or higher cost of healthier food options)

The Anatomy of a Bowel Movement or Lack There Of

So what is a "normal" bowel movement suppose to look and feel like? Or better yet, what happens during an "abnormal" or constipated bowel movement?

As described in the Journal of the American Board of Family Medicine - "Normal defecation requires a series of orchestrated actions, starting with relaxation of the puborectalis muscles, descent of the pelvic floor with straightening of the anorectal angle, inhibition of segmental colonic peristalsis, contraction of the abdominal wall muscles, and finally, relaxation of the external anal sphincter with expulsion of feces."

Say again please!? In English this means...

Ideally, large amounts of dietary fiber [7] (via fruits, vegetables, legumes, and whole grains) will combine with other bodily waste products and toxins to make up a fresh batch of stool. This newly formed concoction of stool will fill up the rectum (causing this area to distend) creating pressure on the rectal walls. The brain detects this pressure and relaxes the muscles of the anal, rectal, and pelvis regions (the basement of our torso). At the same time, the muscles in our abdomen will tense up and contract forcing the stool downward and out. For illustration purposes see image below.
Stages of a Bowel Movement

For those individuals eating a high-fiber (30-80 grams/day), whole foods, plant-based diet—consisting entirely of fruits, vegetables, legumes, whole grains, and nuts/seeds—this normal bowel movement is not a problem. One gentle push with the abdominal muscles can easily empty out the bowels. However, for those on the Standard American Diet (SAD)—based heavily on meat, dairy, eggs, and refined/processed foods—a "normal" bowel movement typically involves straining, grunting, and multiple pushes to try and force out hard, tiny, marble-like pebbles that make up the woefully puny stool. The lack of fiber is obvious in this latter instance as the typical western diet lends itself to a measly 15-16 grams of fiber per day at best [8]. This is hardly enough to form soft, consistent stools from a fiber-rich, plant-based diet. Or as my father would always say, "That ain't enough to make a turd!"

The Bristol Stool chart below gives us a wonderful graphic version of various stool samples. Developed by Dr. Ken Heaton (University of Bristol) in the late 1990's it is used primarily as a clinical communication aid in categorizing stool types [23]. It is not an official classification system (just in case you were wondering). Stool types 1 and 2 are typical of a constipated individual. Stool type 3 is bordering on the grounds of normal, while stool type 4 is the gold standard for the perfect stool. If you're a 4 then stand proud soldier! Stool type 5 is heading in the direction of diarrhea. And stool types 6 and 7 reflect an individual in diarrhea distress. So there you have it. Don't ever say I never taught you anything now. You've just been stooled!

Constipation - Causes, Contributing Factors, and Potential Fixes

1)  Lack of Fiber
This is by far the single largest contributing factor leading to constipation. Dietary fiber is simply the nonndigestible carbohydrates and lignins found in plant foods [9]. It makes up the bulk of stools. Fiber is NOT  found in animal foods (beef, chicken, pork, fish, dairy, or eggs). Only plant foods have fiber, and unrefined plant foods are the best source (fruit, vegetables, legumes, and whole grains). Refined grains (white rice, white bread, white pasta, etc.) and other processed plant foods have had most of their fiber removed and are poor choices when looking to increase your fiber intake.

Fiber does not get broken down by the body's digestive enzymes and, consequently, passes all the way through the digestive tract forming the bulk of stools. Hence, the reason for its effectiveness in treating constipation [10]. There are two types of fiber - insoluble fiber and soluble fiber. Insoluble fiber does not dissolve in water and provides most of the bulk to your stools. Soluble fiber does dissolve in water forming a gel like substance, which, among other things, slows the absorption of sugar into the body, thereby helping to regulate blood sugar levels [11].

How about fiber in a pill or a powder? While it is always best to obtain fiber directly from fiber-rich plant foods there are commercially available fiber laxatives available too. These are considered bulk-forming agents. Examples include psyllium (Metamucil), calcium polycarbophil (Fibercon), methylcellulose (Citrucel), wheat bran, and glucomannan (Japanese Konjac plant). Of these, psyllium and wheat bran have been noted to be of superior efficacy [12]. As a word of caution - don't expect the same results from fiber supplements as you would from consuming more dietary fiber in whole, plant-based foods. Eating health-promoting natural foods is always a better option that popping a pill or mixing up a powder. You simply can't replicate Mother Nature in a pill or powder.

For a more information on fiber click here.

2)  Inadequate Hydration
A lack of fluids may contribute to constipation as well. However, it has been shown that increasing fluid intake, in the absence of dehydration, will not by itself improve constipation [13]. Instead, a combination of more fiber (25 grams/day) and 1.5 to 2 extra liters of fluid intake per day was needed to improve chronic constipation [14].

3)  Dairy Consumption
Many people do not even consider the fact that the cow's milk they're drinking or the ice cream or cheese they're eating is the cause of their constipation, but dairy protein should be a prime suspect in causing constipated bowels. Multiple studies in children have proven the link between cow's milk consumption and constipation [15, 16]. In both studies, children with chronic constipation were put on a diet that eliminated cow's milk. Twenty four of 52 children (46%) on the first study and 44 of 65 children (68%) in the second study experienced the complete relief of their constipation when taken off cow's milk. Their constipation returned when cow's milk was reintroduced to their diet.

4)  Lack of Physical Exercise
While it is often sited by many healthcare practitioners that adding regular physical exercise to an individual's constipation treatment regimen may be helpful, the keyword is "may". Studies have shown both no improvement after exercise was added to relieve constipation [17] and significant improvement in self-reported symptoms by women who added exercise to their treatment regimen [18]. Of course there is no negative effects from adding exercise into your overall lifestyle, so it is well worth doing so.

5)  Other Less Common Causes of Constipation
Several other secondary causes can be at fault for chronic constipation which are listed below [12,19,20]. This is by no means an all-inclusive list:
  • Pelvic-floor dysfunction
  • Slow colon transit time
  • Hemorrhoids
  • Anal fissure (trauma and sudden tear of anal mucosa occurring when passing of hard stools)
  • Pregnancy (typically worsening in later trimesters)
  • Electrolyte disturbances (hypercalcemia, hypokalemia, hypermagnesemia)
  • Endocrine and metabolic disorders (diabetes mellitis, hyperparathyroidism, hypothyroidism, chronic renal failure)
  • Neurological disorders (Parkinson's disease, dementia, neuropathies, multiple sclerosis, spinal cord injuries, cauda equine syndrome)
  • Psychological comorbidities (depression, distress, personality disorders, history of abuse)
  • Medications (Opioid narcotics, iron supplements, tricyclic antidepressants, calcium channel blockers, antacids, antihistamines, anticholinergic drugs, and many other medications)
  • Nicotine withdrawal from smoking cessation

Constipation - Medical Treatments

Most patients and physicians quickly turn to pharmacological treatments or other medical procedures to rectify the situation (no pun intended). However, have I mentioned that increasing dietary fiber by adopting a whole foods, plant-based diet should be the first line treatment of choice?! Ok, good! Now that we've gotten this out of the way, it is worth noting that medications, manual disimpaction, or even surgery may be required if all else fails, including diet.

Drug Therapy

1)  Bulk-forming Agents - As mentioned before, these include psyllium (Metamucil), calcium polycarbophil (Fibercon), methylcellulose (Citrucel), wheat bran, and glucomannan (Japanese Konjac plant). Bulk-forming agents are probably your safest bet for drug treatment options. They work by adding fiber (bulk) to the stool which expands as water enters the stool.

2)  Stool Softeners and Emollients - These include the stool softener docusate sodium (Colace) and emollient mineral oil. Evidence to their effectiveness is moderate at best [12]. These items are considered second line treatment options behind bulk-forming agents.

3)  Osmotic Agents - These include polyethylene glycol (Miralax), lactulose, sorbitol, and magnesium hydroxide. They work by absorbing and retaining water in the stool. They are recommended if bulk-forming agents and stool softeners do not work.

4)  Stimulant Laxatives - These include senna, bisacodyl (Dulcolax), and castor oil. They work by forcing muscle contractions of the colon wall and increasing peristalsis. While shown to be effective, stimulant laxatives should only be used as a last resort because over time with chronic use the bowel becomes dependent on them to function under normal conditions.

5)  Chloride Channel Activator - Lubiprostone (Amitiza) is a prescription drug. It works by increasing intestinal fluid secretion and increasing transit time [21]. A meta-analysis of lubiprostone revealed the number needed to treat (NNT) was 4. In other words, 4 individuals needed to be treated with lubiprostone for 1 person to realize a benefit from treatment. Nausea and diarrhea were significantly higher in the treatment group compared to placebo group. The cost is approximately $200-$300 per month.

6)  Guanylate Cyclase-c Receptor Agonist - Linaclotide (Linzess) is a prescription drug. It works the same way Amitiza works [21]. The NNT was 6 for linaclotide. Diarrhea is the most common side effect. The cost of linaclotide is approximately $200 per month.

7) 5-HT 4 Receptor - Prucalopride (Resolor) is a prescription drug only available in Europe at this time. It works by increasing gut motility and transit time [21]. The NNT was 6 for prucalopride. Headache, nausea, and diarrhea were all common side effects with this medication. In addition, one episode of a severe cardiovascular event (supraventricular tachycardia) occurred during trials with prucalopride. Zelnorm, a similar drug in this class, was withdrawn from the market in 2008 due to similar severe cardiovascular events.


Biofeedback therapy is used in cases where pelvic-floor dysfunction is the cause of chronic constipation. This form of treatment works by retraining the individual to coordinate the contraction and relaxation of abdominal and pelvic floor muscles to effectively defecate stools. In essence, it is a form of psychological therapy used to attain smoother flowing bowel movements. And it works! With success rates ranging from 70%-81.5% and no reported adverse effects, biofeedback is certainly a safe and efficacious treatment to consider in the presence of pelvic-floor dysfunction [22].

Summary and Final Thoughts

Constipation is widespread in affluent nations eating a rich, Western diet and rare in cultures where they eat a traditional whole foods, plant-based diet. Adequate fiber intake is of primary importance when treating chronic constipation and should remain the mainstay of treatment. The addition of 1 to 2 liters of fluid per day and regular physical exercise can also help. An individual's bowel movements should return to normal within 1-3 days of adopting a fiber-rich, plant-based diet. Adopting this same diet as a permanent lifestyle change should result in 1-3 bowel movements per day on average. And you get the added benefit of preventing and reversing a number of other chronic diseases on a plant-based diet including heart disease, type 2 diabetes, cancer, etc.

Should a change in diet and lifestyle not be enough to alleviate chronic constipation there are pharmacological and medical treatments available if needed. These should be used sparingly and for short periods of time, if at all possible. Stimulant laxatives should not be used on a long term basis as these agents have been known to cause the bowels to become dependent upon their use, making it difficult for the bowels to return to their normal functioning state when constipation is relieved.

The only thing left for you to do now is to put this new found knowledge into action. May the porcelain Gods be kind to your bodily needs in the days and weeks to come as you embark on becoming a member of the super pooper club. Yes, we plant-based people are proud of our stools!

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by Dustin Rudolph, PharmD
Clinical Pharmacist

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Photo credit: Process of a Bowel Movement (Spinal Cord Medicine: Principals and Practice)
Photo credit: Person on Toilet (


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  1. Thanks Dustin Rudolph for sharing healthy note about constipation. Yeah fiber plays a major role to reduce the constipation problem and fights against to constipation. The fiber should consume according to your age and sex consult to your dietitian he/she suggests you. I have read complete post I honestly appreciate you efforts for sharing healthy information probably after reading this blog post everyone will aware of their diet. Thanks a lot.

  2. Hello... Really I appreciate your efforts to make such kind of valuable info regarding constipation issues. It's worthy, the anatomy of a bowel movement and 5 causes of constipation are awesome which you have delivered here. Instead of medical treatment for constipation, it sounds good with natural remedies to avoid the constipation.

  3. Well kudos for your decent work. Well explained and elaborated piece of work. Though everyone constipates some or the other time in their life, most people think it is chronic. Truth is it is just applies to very minute percentage of people. These days if we are constipated regularly, I can say the fault lies from our side. The fast pace of life we follow, fast and processed foods which are zero of nutrients and necessary things are consumed by most of us. Also we drink less water and mostly depending on caffeinated and alcoholic drinks satisfying the thirst and the result are these health issues. Often I disobey with the posts but with your timing and elaboration, I can say this is a perfect post for constipation. Keeping posting such wonderful and informative stuff on board

  4. You certainly covered all bases. A very thorough article on an important subject we tend to never discuss.

  5. Very informative and wonderfully presented. We should be sharing this with our youth to establish early healthy eating and bowel habits.


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