FIBRE. The story goes beyond poop.

Another aspect to how fibre can help prevent disease is the ability of some fibres (soluble fibre like those found in oats) to lower cholesterol by removing it from our digestive tract. Soluble fibre forms a gel in our colon and the bile acids, which help digest fat, get trapped in the gel. Bile acids are made in our liver with cholesterol, so when we lose the bile acids in our poop, the liver has to use up additional cholesterol to make more.

There are other ways fibre helps improve our health over the long run and protect us from disease, like improved blood sugars and prevention of constipation, but there are also factors that may have nothing to do with the fibre itself. When it comes to nutrition the story is never about one single food or nutrient, and fiber is no different.

Foods that are high in fibre also tend to be high in important phytochemicals. Phytochemicals are compounds naturally found in foods that provide a possible health benefit but are different from a nutrient (like protein or vitamins). Some research has also shown that people who purposefully incorporate high fibre foods into their diet are also consciously pursuing other healthful choices like joyful movement, not smoking, low alcohol intake, good sleep habits, etc.

What about increasing our fibre intake in the short-term, can that also be beneficial?

Ideally, you want to maintain a high fibre diet through your lifetime to see the benefits (plus more) that are discussed above, but there are instances where increasing or even reducing your fibre intake temporarily may be necessary.

I think the most obvious case would be when treating constipation. Increasing your fibre intake when you experience constipation is a good tactic along with increasing fluid intake (always a good idea when increasing fibre), finding more time for joyful movement, reducing stress, and many other strategies.

Some cases where reducing your fibre intake would be beneficial are:

• Flare up of IBD

• Acute diverticulitis

• Prolonged episodes of diarrhea, depending on the cause

• In preparation for or recovery from certain medical tests, surgeries, or treatments

• Other GI conditions like dumping or short-bowel syndrome

The story of fibre is long, complicated, and like a lot of aspects of nutrition, not 100% known. But considering what we do know about it, striving for a diet that is high in fibre while still being sustainable (that’s the most important part) can be helpful for more than just pooping regularly.

Disclaimer: Fibre is often co-opted by diet culture as a means to lose weight instead of improving health. I am not recommending a high fibre diet for weight loss as I do not recommend the pursuit of weight loss to anyone. If long-term health is your goal, weight loss does not need to be a part of it as weight or body size does not predict health. One of my sources listed below (marked by *) makes some bold statements on weight that are based on fatphobia not science, I do not endorse or agree with these statements.

Sources:

Ananthakrishnan, A. N., Khalili, H., Konijeti, G. G., Higuchi, L. M., de Silva, P., Korzenik, J. R., Fuchs, C. S., Willett, W. C., Richter, J. M., & Chan, A. T. (2013). A Prospective Study of Long-term Intake of Dietary Fiber and Risk of Crohn's Disease and Ulcerative Colitis. Gastroenterology, 145(5), 970–977. https://doi.org/10.1053/j.gastro.2013.07.050

Dahl, C., Crichton, M., Jenkins, J., Nucera, R., Mahoney, S., Marx, W., & Marshall, S. (2018). Evidence for Dietary Fibre Modification in the Recovery and Prevention of Reoccurrence of Acute, Uncomplicated Diverticulitis: A Systematic Literature Review. Nutrients, 10(2), 137. https://doi.org/10.3390/nu10020137

* Rubin, R. (2019). High-Fiber Diet Might Protect Against Range of Conditions. JAMA, 321(17), 1653. https://doi.org/10.1001/jama.2019.2539