SIBO & the MMC – Part 1: Background & Overview

This is part one of a five-part series. The parts are:
1. What is the MMC and why should we care
2. What Influences the MMC
3. When things go bad with the MMC
4. Healing with drugs and herbs (no I did not say dealing drugs and herbs – focus!)
5. Healing with lifestyle


Why do we care about our MMC?

MMC stands for Migrating Motor Complex. The MMC is key in preventing and managing Small Intestine Bacterial Overgrowth (SIBO) which you can read all about here.

The MMC is also implicated in a host of other illnesses e.g. diabetes, gastroparesis, Chagas disease (horrible parasite based thingamy).

I have SIBO.

If you have IBS you probably have SIBO too, and then probably issues with your MMC.

If your guts and poops are in order, return to the main page and find something more up-your-alley (look right to the category search) or send on ‘with love’ to a friend who is all up-the-poop.

If you are up-the-poo too, read on my friend as 4,281 words (and counting) await you over the coming weeks.

What is MMC? Is it sexually transmitted?

The MMC is the ‘housekeeper’ of your gastrointestinal tract (Deloose and Tack 2016). It cleans up the stuff that should not be there, moving stuff along when it is time for it to move along. I see it like a bouncer at a teenage party “Oui you – the hairy ugly one! OUT. Now. And don’t come back!”

The MMC has three phases (or maybe four depending on who you trust):



  • Phase I: No contractions … kind of a non-phase, phase.
  • Phase II: Irregular contractions
  • Phase III: Regular contractions (2-3 per minute in your stomach and 11-12 per minute in your small intestine).
  • PHASE IV: The rapid decrease of contractions.

Phase III is the most famous bit of the whole affair and can start in the stomach or the small intestine.

The process is cyclical – i.e. at the end it goes back to the beginning.

The length of the process is different for different people (and at different times), it varies from 113 to 230 minutes (Deloose and Tack 2016).  How long it lasts seems linked to where it starts.

Honestly now, the sexually transmitted bit was a (bad) joke to get your attention, because I know this stuff is pretty dry.

Your MMC and your QoL

Even scientists say …. and I quote “The MMC is important for maintaining Quality of Life(QoL)” (Miyano, Sakata et al. 2013).  For the record, it was not me that turned it into a TLA* (as if there weren’t already enough of those bastards in this series).

Why the QoL issue?

Mostly when the MMC breaks you are likely to end up with complications such as SIBO (here are just some of the symptoms you might expect if you are one of these unlucky sods).

Say Thank You (to your tummy noises)

Stomach rumbling might be embarrassing in work meetings or on a first date.  However, it is an active sign that your MMC is working effectively. So next time your tummy rumbles don’t look shy and apologize for your hungry stomach ….. whatever you do don’t go eat!

I’m not sure about people with Irritable Bowel Syndrome (IBS) where the noises are unnaturally often and loud.  This makes no sense as the majority of IBS-ers probably have SIBO, so you might expect less noise. I am sure some scientist off in a lab somewhere could explain this to us but I have not found an explanation in my reading so far.

Are you ready?

We are going to move together through quite a journey of detail on the old MMC.
Now is the time to post questions while the rest of the series is still in draft format.

Meanwhile, charge on with your gurgly tummy in the direction of your dreams!

Yours as ever,

The WellbeingatWork(nearly)Dr.


I am not a doctor, I am a spoonie* and one of my challenges is SIBO. SIBO tends to reoccur after treatment.  So I am putting my research skills (I am a middle aged PhD student) into finding out what I can do to help improve my MMC and sharing with others who also might have an unhappy MMC. However, given my area is not medical research some of this is pretty tough going (because academics never learnt the ‘write for a 10 year old’ thing, actually some of them never learnt the ‘write for anyone at all’ thing). …so be nice to me.


*Spoonie = Poor sod living with chronic illness(es).
*TLA = Three Letter Acronym = Horrible little beast used by people to exclude other people, especially in corporate life.


Deloose, E. and J. Tack (2016). “Redefining the functional roles of the gastrointestinal migrating motor complex and motilin in small bacterial overgrowth and hunger signaling.” American Journal of Physiology-Gastrointestinal and Liver Physiology 310(4): G228-G233.

Miyano, Y., et al. (2013). “The role of the vagus nerve in the migrating motor complex and ghrelin-and motilin-induced gastric contraction in suncus.” PloS one 8(5): e64777.








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