The Gut Microbiome

In discussing probiotics last week, I was struck with a novel concept: when it comes to fiber, there's more to the story than just providing bulk for our system to be able to process things more efficiently and get rid of waste quicker. Whereas the research behind probiotics just does not exist yet, the research behind fiber and its benefit is sufficient to draw positive conclusions relating to overall health.

Short chain fatty acids, a by-product of gut microbial metabolism upon digesting fiber, appear to play a tremendous role in terms of maintaining health through a healthy gut micrbial population in the large intestine. Research has shown the bacteria taking up residence in our large intestine, the final portion of our digestive tracts,  actually have quite complex relationships with the human cells and receptors of the gastrointestinal tract (the gut). It has been demonstrated that healthy gut bacteria utilize soluble fiber, found in fruits and vegetables, inulin, fructo-oligosaccharides, resistant starches, such as those found in green (under-ripe) bananas, to fuel their own metabolism and produce by-products like acetic acid, propionic acid, and butyric acid (all short-chain fatty acids) which in turn signal multiple receptors of the cells lining the intestinal tract. The receptors targeted include those indicating satiety, or fullness communicated directly to the brain, indicating it is time for the gut to get things moving through, AKA peristalsis, indicating to the immune cells it is time to down-regulate cytokines, thereby reducing inflammation, and indicating to the colonic cells it is a good time to proliferate and differentiate, allowing for a healthy gut to continue producing healthy gut cells.

This was the first time I was presented with the idea that fiber did something more than adding bulk to the food you eat, and I hope I can share this exciting information with others. Well, it's exciting to me. Hopefully someone else out there will find this topic exciting as well :). It is now obvious that these incredible gut bacteria are providing us with benefits of healthier digestive systems all because of their need to feed on fiber.

So, now that you, too, know just how much of an impact fiber has on your body, eat your vegetables and fruits at every meal! Lots of leafy greens and cruciferous veggies should always be on the menu :).

Reference:
Thank you Dr. Bizeau for bringing this topic to our class!

For further reading, check out these research articles:
http://www.bpgastro.com/article/S1521-6918(13)00060-7/abstract
http://www.bpgastro.com/article/S1521-6918(13)00076-0/abstract
http://www.annualreviews.org/doi/abs/10.1146/annurev-med-010312-133513