What about ulcerative colitis and fiber?

An email from a friend with ulcerative colitis prompted me to write this post. She referred to my most recent publication:

  • Brotherton CS, Martin CA, Long MD, Kappelman MD, Sandler RS. Avoidance of Fiber Is Associated With Greater Risk of Crohn’s Disease Flare in a 6-Month Period. Clin Gastroenterol Hepatol. 2015 Dec 31. pii: S1542-3565(15)01713-9. doi: 10.1016/j.cgh.2015.12.029. [Epub ahead of print]

She shared her guess as to why we found no association between ulcerative colitis flares and fiber.

My friend’s email triggered me to share here my hypothesis for why our study only found a fiber association in Crohn’s disease, not in ulcerative colitis.

My short explanation…

I believe that for fiber to help people with IBD, the fiber type must match the location of inflammation. Soluble fibers that ferment early in the digestive system produce beneficial short-chain fatty acids that may never reach the distal inflammation of ulcerative colitis. Insoluble fibers that are slower to digest deliver the healing properties of short-chain fatty acids to the more distal digestive system where ulcerative colitis inflammation flares[1,2].

I believe we saw a fiber association in Crohn’s disease and didn’t see a fiber association in ulcerative colitis because there is currently a strong bias against insoluble fiber for IBD. Insoluble fiber (wheat bran) shifts fermentation distally [1,2], delivering short-chain fatty acids further down the digestive tract than the point at which early-fermenting soluble fibers deliver benefits. Because inflammation in ulcerative colitis occurs more distally than inflammation in Crohn’s disease, the bias against insoluble fiber probably hurts patients with ulcerative colitis the most.

Some details…

A little about ulcerative colitis:

Symptoms of Crohn's disease and ulcerative colitis overlap
Symptoms of Crohn’s disease and ulcerative colitis overlap

In ulcerative colitis…

  • patients suffer from symptoms similar to Crohn’s disease:  chronic abdominal pain, chronic diarrhea, and chronic rectal bleeding
  • patients often avoid fiber for the same reasons as people with Crohn’s disease. (See Five Reasons Fiber SEEMS Bad for IBD by clicking HERE.)
  • the pathophysiology of gastrointestinal symptoms overlap with the pathophysiology of Crohn’s disease symptoms

Therefore, it is reasonable that people ask the following question…

Is the effect of fiber the same in ulerative colitis as in Crohn’s disease?

The answer is FAR from simple.

In the above study, we found that Crohn’s disease patients in the highest 25% of fiber intake were ~40% less likely to flare in 6 months. In the highest 10% of fiber intake, Crohn’s patients were ~60% less likely to flare. Crohn’s disease patients who didn’t avoid fiber were ~40% less likely to flare than patients who did avoid fiber.

We didn’t find similar associations in ulcerative colitis… does it mean fiber can’t help people with ulcerative colitis?

NOT NECESSARILY. Diet research is complex. All research studies have limitations… design problems that prevent full discovery of the answers to questions researchers want to investigate. Diet research is especially hard to design — drug studies are easier — one group gets a real drug and the other group gets a placebo. Diet research is different…

The foods people eat are infinitely variable and hard to control in research.

One of the limitations in our study is that we have no way of knowing the specific fibers participants were eating. In particular, we don’t know if the fibers participants were eating were fibers that ferment someplace other than the specific location in which each participant’s inflammation existed. Gathering and analyzing such detailed information would be incredibly informative, but it is not practical to do so at the present state of the science.

To better understand my hypothesis…

First, consider the location of inflammation in Crohn’s disease vs. ulcerative colitis.

In ulcerative colitis, inflammation only occurs in the colon
In ulcerative colitis, inflammation only occurs in the colon


Crohn’s disease inflammation occurs anywhere in the digestive tract, from mouth to anus (mouth, throat, esophagus, stomach, small intestine, colon). The most common site is the small intestine.

Ulcerative colitis inflammation only occurs in the colon.



Next, consider how location of inflammation relates to different fiber types.

The types of fibers eaten make a huge difference — because different fibers deliver benefits to different parts of the gut!

For a food component to have an impact on inflammation in ulcerative colitis, the component has to survive the trip through the whole digestive system — the mouth, throat, esophagus, stomach, and small intestine — before reaching the point of need, which is the colon. Insoluble fiber, specifically wheat bran, does just that. By reaching the colon before fermenting, insoluble fiber/wheat bran helps deliver the healing properties of short-chain fatty acids right to the site of inflammation. (For a little more about short-chain fatty acids, see the webpages entitled, Fiber Feeds Good Gut Bacteria by clicking HERE and Good Bacteria Heal the Gut by clicking HERE.)

Insoluble fiber/wheat bran shifts the site of bacterial fermentation to a later location in the digestive system [1,2]. In contrast, without wheat bran, soluble fibers ferment EARLIER in the digestive system [1,2]. Early fermentation means that the benefits of short-chain fatty acids are more likely to be absorbed in locations affected by Crohn’s disease, but never reach the distal gut affected by ulcerative colitis.

Another benefit of insoluble fiber/wheat bran reaching the distal colon intact is the capacity to soak up and hold excess water [3] present in the DISTAL digestive system of ulcerative colitis patients during a flare. Excess water remains in the lumen of the intestine when the intestinal lining is inflamed and swollen and fails to absorb water normally. Fiber that soaks up and holds excess water slows the rush of intestinal contents [4],  producing soft, comfortably-passed stool.

Finally, consider what IBD patients are being told about insoluble fiber.

There is good reason to assume that IBD patients fail to eat insoluble fiber.

Take a moment to Google the terms “insoluble fiber” and “ulcerative colitis”

Did you see it? Did you see why I think people with ulcerative colitis are purposely avoiding the very fiber type they need most? I will refrain from throwing anyone under the bus, but there is a lot of misinformation out there on the internet — authoritative-sounding statements about insoluble fiber that are not referenced with any scientific research studies. In other words, IBD patients are being told over and over again to avoid insoluble fiber, with no reference to research that supports the recommendation.

Little by little, IBD care providers are understanding the benefits of soluble fiber and SLOWLY starting to gain a little appreciation for the need for soluble fiber in IBD. However, insoluble fiber is still almost unanimously maligned. This attitude toward fiber causes me to get up every morning and do everything I can to educate anyone who cares about gut health and is willing to listen.

If you’ve read the pages of my website, you already know that fewer than 3% of Americans eat the recommended amounts of total fiber [5,6]. Now, considering the repeated warnings against insoluble fiber for IBD, isn’t it reasonable to assume that IBD patients are failing to eat much insoluble fiber? The fiber our IBD participants DID eat was probably solubledoesn’t it make sense that a lack of insoluble fiber in our study might have kept us from seeing a benefit from fiber in ulcerative colitis?

Half a cup of Kellogg's All-Bran Bran Buds cereal
Half a cup of Kellogg’s All-Bran Bran Buds cereal (wheat bran containing 19.5 grams fiber, mostly insoluble)

You can read about how our published article has been received by clicking HERE.

Also, a short YouTube Video Abstract for the article will be uploaded by the American Gastroenterological Association soon, and I will add a link to the video here when the video is posted.

In the future, I will add a review of research studies that have shown some favorable effects from research related to the question of fiber and ulcerative colitis.


  1. Pryde SE, Duncan SH, Hold GL, et al. The microbiology of butyrate formation in the human colon. FEMS Microbiol Lett 2002;217:133-139. Read the full article by clicking HERE.
  2. Muir JG, Yeow EGW, Keogh J, et al. Combining wheat bran with resistant starch has more beneficial effects on fecal indexes than does wheat bran alone. American Journal of Clinical Nutrition 2004;79:1020.      Read the full article by clicking HERE.
  3. Fine KD, Schiller LR. AGA technical review on the evaluation and management of chronic diarrhea. Gastroenterology 1999;116:1464-1486. Read the full article by clicking HERE.
  4. Harvey RF, Pomare EW, Heaton KW. Effects of increased dietary fibre on intestinal transit. The Lancet 1973;301:1278-1280. Read the abstract by clicking HERE.
  5. Clemens R, Kranz S, Mobley AR, et al. Filling America’s fiber intake gap: summary of a roundtable to probe realistic solutions with a focus on grain-based foods. J Nutr 2012;142:1390S-1401S.    Read the full article by clicking HERE.
  6. Agricultural Research Service, U. S. Department of Agriculture. Dietary fiber (g): Usual intakes from food and water, 2003-2006, compared to adequate intakes. What we eat in America, NHANES 2003-2006. Volume 2013, 2010.



Enjoying the “permanence” of a website

Ok, ok, I know websites aren’t exactly permanent. Technology changes – who knows what might come along to replace websites.
But my website kind of feels permanent to me!

I just spent some time (hours, actually!), adding one of my scientific papers…

“Testing the Effects of a High Fiber Instruction”

Now it is there for the world to see anytime. A static page. Sort of permanent. Just two more papers to go, then on to the mountain of relevant research I need to add.

I must press forward. Hardly a day goes by that I don’t run into someone who needs this information. It’s not always someone with Crohn’s disease or ulcerative colitis. There are so many others… people with digestive systems, feeling the effects of our industrialized foods.

I used to spend hours on the phone, explaining to one person

…what they needed to understand about fiber and the gut. Now I can offer a web address where they can read the information and go back over it as many times as they need to, to absorb complex concepts.

I’m thankful for the developers of the Internet, the people at WordPress, the people at Bluehost, and Jocelyn, my website mentor – all of whom have made this website possible.


Why I prefer prebiotics to probiotics

I woke up this morning thinking about probiotics…

Probiotics are a HOT topic right now!

A chain of emails yesterday between me and a good friend sparked my thoughts. She wanted to know my advice on her current GI issues.  Our conversation reminded me of why I am totally committed to prebiotics, instead of  probiotics.

First, for people  who have great success with probiotics… I support the intervention 100% for them.

For me, prebiotics are much better than probiotics, and here’s why…


It all goes back to how I collected my microbiome!

My microbiome is the total combined genetic material that composes the microorganisms native to my gut. Surely you know I’m unique because of my own human DNA.

But do you know the microorganisms at home in me make me 100X as unique as I already am?

There are at least 100 trillion microbial cells in me,1 which is 10X the number of my human cells!2

My microbial cells contain 100X the number of genes that my human cells contain — so that makes me 100X as unique as I would be if I only had my human DNA!

An estimated 1,000 species (and even more sub-species) may or may not be present in my gut — some of my personal species and sub-species are good for me and some can harm me. Certain factors determined which species and sub-species became native to my gut.  Other factors determine which of my native microorganisms flourish now. Factors include my route of birth (C-section or vaginal), breast or bottle fed (and for how long), diet, and antibiotic use.

The sobering truth is… by the time I was about 2-3 years old, my native microorganisms were permanently established — in other words, the neighborhood gangs in my gut will inhabit their niches throughout my lifetime. The composition of my microbial communities is difficult if not impossible to change. Happily, genes in the microbes can be changed (harmless organisms can become harmful versions and harmful organisms can become harmless versions)… but that’s a happy topic for another day!3

So what?

“So what,” you say? I think it’s a big “so what?”

Probiotics are pharmaceutical supplements based on loads of research. About 8 years ago, probiotics were estimated to be a $7 billion worldwide industry. I’ve read many of the research reports that lead corporations to formulate their supplements, and I appreciate the work that goes into this area of science. My hat is off to the men and women who have pushed scientific knowledge forward regarding the human gut ecosystem.

However,  at this point in time, probiotic supplements still involve some guesswork. Decisions have to be made on what species/sub-species are most common and likely to help the most people. But I am not like anyone else…

I am me. Or at least we (my microorganisms and I) are we. LOL

If I take a probiotic supplement containing microorganisms that are not native in me, my natives will do their best to fight off the foreign invaders — it’s what they do!  I may still experience benefit if I take enough of the supplement, but benefits will only last as long as I take the supplement.

Half a cup of Kellogg's All-Bran Bran Buds cereal
Half a cup of Kellogg’s All-Bran Bran Buds cereal

Prebiotics (wheat bran cereal) are food for beneficial microorganisms. Instead of paying a lot of money for expensive pharmaceutical products, I use my food to feed my own personal beneficial microorganisms and help them thrive. Thus, my native beneficial microorganisms succeed in taking up all the real estate in my gut and crowd out the harmful ones.

True, I will have to continue with this therapy for the rest of my life.

But it’s cheap and easy, and 100% tailored to the needs of my unique inner ecosystem.

Also, eating a bowl of cereal doesn’t make me feel like a patient. I  just feel like an informed person making healthy choices for me!

By the way, pharmaceutical companies are moving away from simple probiotics alone. Instead,pharmaceutically-prepared prebiotics are coming into vogue, as well as synbiotics (preparations that combine probitoics and prebiotics). For related information, please see my page entitled “Diet vs. Probiotics? Prebiotics? Synbiotics?” under the “Filling in the Blanks” tab. Or click HERE.



  1.  Clemente, J.C., Unsell, L.K., Parfrey, L.W., and Knight, R. (2012) Impact of the Gut Microbiota on Human Health: An Integrative View. Cell 148:1259-1270.
  2.  Turnbaugh, P.J., Ley, R.E., Hamady, M., Faser-Liggett, C.M., Knight, R., and Gordon, J.I. (2007) The Human MIcrobiome Project. Nature 449:804-810.
  3.  Goldsmith, J.R., and Sartor, R.B. (2014) The Role of Diet on Intestinal Microbiota Metabolism: Downstream Impacts on Host Immune Function and Health, and Therapeutic Implications. J Gastroenterol 49:785-798.

More new evidence for the benefit of fiber in the diet for IBD

I love the way IBD diet research results are becoming easier to obtain and at the same time easier to share…
Researcher canstockphoto5436240-1
Photo credit: http://www.canstockphoto.com”>(c) Can Stock Photo

First thing I saw at my desk this morning — an email alert about a new IBD diet study in China.

Because I select what publications generate an email alert to me,


this article reports a research study smack dab in the middle of my passionate interest…

dietary fiber and gut inflammation in mice!

Of course, I get extra excited when one more study so clearly demonstrates one more time a mechanism that helps explain my amazing success with diet alone for Crohn’s disease.

This article is another one of a host of research studies that I must review and include under the “Relevant Research” tab.

For now, you can see the abstract of the article by clicking HERE

As you read the abstract, it will help if you understand these terms:

  • dietary non-digestible polysaccharides = dietary fiber
  • ameliorate = to make better
  • intestinal epithelial barrier = the lining of the intestines (the barrier must let just the right substances through to maintain a healthy gut)
  • dysfunction = one of the problems in Crohn’s disease is that the intestinal barrier is leaky – it lets substances through that should be kept out of the body
  • IL-10 knockout mice = specially bred laboratory mice with a genetic mutation that causes them to develop gut inflammation

So… hooray for the technology that helped me read about this exciting study done in China.

Double-yay that it took me about 2 minutes to

share it on Twitter!

By tweeting, I connect with other people with IBD, researchers who study IBD, health care providers who treat IBD, and dietitians who advise people with IBD…

all around the world!
Credit: Canstock photo
Credit: Canstock photo


IBD Diet: Hello World Here I Come

This is it… Day 1 is dawning for me.

Sunrise 4

Today, I am finally launching my website… ready or not, I can’t wait any longer! My mind is bursting with ideas for sharing the lessons I’ve learned about eating for a healthy gut.

I have already loaded some pages with basic information about dietary fiber and about me. Come back often, though, because there is MUCH more to come.

I am grateful for the internet and the explosion of social media! I can’t wait to help more people gain better understanding of dietary fiber science. I wake up thinking about microbiome and diet research, I go to bed thinking about it, and I think about it all day in between.

Onwards and upwards!