Fiber & Constipation: The Dirty Truth?

Since 19th century health nut Sylvester Graham (the “prophet of bran bread”) began espousing the nutritional and moral superiority of whole vs refined grains, Fiber has assumed a central role in medical lore as essential for healthy digestion and elimination.

Today, whenever issues of constipation come up, one of the first questions you get asked is "Are you eating enough fiber?" Ironically, often, the answer is "Yes!" Many people suffering from irregularity eat extremely high fiber diets. (As a former raw foodist, I myself was an excellent example of this unfortunate phenomenon.) In such cases, adding more fiber is rarely a solution. On the contrary, experience leads many people with bloating symptoms to develop a near mortal fear of fiber (think of the incredible expanding psyllium seed, and other "bulking" agents that threaten to blow your intestines up to monstrous proportions).

At any rate, in response to anecdotal evidence challenging the value of fiber for bowel health, investigators have begun asking: What if fiber isn't the constipation cure-all it's promoted to be? Research designed to answer this question, ended up with remarkable results, as evidenced by the following title:

Stopping or reducing dietary fiber intake reduces constipation and its associated symptoms.

[Ho K-S, et al. World J Gastroenterol. 2012 Sep 7; 18(33): 4593–4596]

Here's the scoop on what went down.

Sixty-three constipated adults between the ages of 20 and 80 (median age 47) were enrolled in the study referenced above. All subjects went on a 2-week fiber-free diet. Afterwards, if they had found the fiberless plan to be beneficial in terms of constipation relief (which all of them did), they were asked to remain on as low a fiber diet as possible.

Six months later, a follow-up was performed. 41 of the patients had remained on a no fiber diet, 16 on a reduced fiber diet, and 6 had resumed their high fiber diet for religious or personal reasons. And guess what? Those in the first two groups reported significant improvement in their symptoms, while the few who went back to a high fiber diet remained as constipated as ever.

A classic "zero-fiber" meal: Roast Chicken

Patients on the zero fiber diet got the best results, improving from an average of 3.75 days between bowel movements (sound familiar?) to just 1 day (the dream!) Results for the 16 low-fiber dieters were mixed, but most people in that group also started having daily poops.

To read the entire study, click here. Below are some of my favorite quotes from the paper:

"This study has confirmed that the previous strongly-held belief that the application of dietary fiber to help constipation is but a myth."

"Constipation is often mistaken by the layman as the state of not passing stool, with the subsequent false notion that making more feces will allow easier defecation. In truth, constipation refers to the difficulty in evacuating a rectum packed with feces, and easier defecation cannot possibly be affected by increasing dietary fiber which increases bulky feces."

"It is well known that increasing dietary fiber increases fecal bulk and volume. Therefore in patients where there is already difficulty in expelling large fecal boluses through the anal sphincter, it is illogical to actually expect that bigger or more feces will ameliorate this problem. More and bulkier fecal matter can only aggravate the difficulty by making the stools even bigger and bulkier. Several reviews and a meta-analysis had already shown that dietary fiber does not improve constipation in patients with irritable bowel diseases."

"The role of dietary fiber in constipation is analogous to cars in traffic congestion. The only way to alleviate slow traffic would be to decrease the number of cars and to evacuate the remaining cars quickly. Should we add more cars, the congestion would only be worsened. Similarly, in patients with idiopathic constipation and a colon packed with feces, reduction in dietary fiber would reduce fecal bulk and volume and make evacuation of the smaller and thinner feces easier. Adding dietary fiber would only add to the bulk and volume and thus make evacuation even more difficult."

  

All this is GREAT news for those of us C types following a SIBO-safe diet! (Since fiber is the Great Fermenter, there is very little of it in a good SIBO protocol.) However, everyone has a different body, and a different response to food. I get terrible bloating from whole grains, but do find that a little "bulk" can sometimes push a stool through. However, I always try to keep it in the realm of the less-fermentable starchy vegetables (carrots, winter squash), sometimes Jasmine rice, and occasionally, Lundberg rice cakes.

What's your experience been with fiber and constipation. I'd love to hear about it in the comments below!


NOTE: Thanks to Dr. Norm Robillard for pointing me in the direction of this groundbreaking study. To learn about Dr. Robillard's work, visit his digestivehealthinstitute.com.