Lindsay Kent, Master Trainer

By Lindsay Kent

Your stomach begins to growl and you instinctively decide that you must be hungry.  It’s a common association we make in decoding our body’s hunger signals. In fact, a growling stomach does not signal that your body needs nutrients but, rather, that your migrating motor complex, or MMC, is busy at work.

The MMC is electromechanical activity in the gastrointestinal smooth muscle that takes place between meals or any time you eat. It is commonly referred to as the “housekeeper” of the digestive tract, as its primary job is to sweep residual, undigested material through the digestive tube and out of the body. Many common issues can inhibit this important process, leading to gastric problems. Understanding the basics of it will help you take preventative measures to keep your gut functioning optimally.

Four Phases

There are four primary phases of the MMC, with the cycle recurring every 1 1/2 to 2 hours. During Phase I, the smooth muscle is quiescent, or dormant. Only rare action potentials and contractions may take place. Otherwise, all is quiet; this phase lasts approximately 45 to 60 minutes.

Phase II is where the peristaltic contractions begin, becoming increasingly more frequently. Peristaltic contractions originate in the stomach and move to the small intestine; this phase lasts about 30 minutes.

In Phase III, the peristaltic contractions are rapid and evenly spaced, and the pylorus (the opening from the stomach into the small intestine) remains open as the undigested material passes through the stomach; this phase lasts 5 to 15 minutes.

The final phase, Phase IV, is very rapid. It’s the transition between the heavy activity of Phase III and the inactivity of Phase I. Phase IV also creates an increase in gastric, biliary, and pancreatic secretions, all of which aid the MMC’s cleansing process by preventing bacteria from accumulating in the digestive tubes.

When Problems Occur

If the MMC becomes inhibited, the gastric contents and organisms will sit around in your gut, creating a prime environment for any number of bacteria to take up residence in the small intestine; this condition is called small-intestinal bowel overgrowth, or SIBO. Numerous problems can be related to SIBO.

Dyspepsia, which is a collection of intestinal symptoms, including abdominal distention, bloating, pain, early satiety, and nausea, develops from an overgrowth of bacteria in the digestive system. As well, there is a correlation between h.pylori bacteria overgrowth and the MMC, although studies have not yet concluded what causes it. The point is the importance of keeping everything moving.

What Causes MMC Problems

Several factors can affect these kinds of gut problems. The MMC is thought to be run by the central nervous system and the hormone motilin. It can be easily “overridden” by other processes; for example, if you eat something, which stops the MMC and kicks in the digestive pattern of motility.

Tips for Keeping Your Gut Happy

The MMC keeps your body free from debris that can cause bacteria and dysfunction. By following a few simple rules, you can keep things moving smoothly and learn to read your body’s physiological hunger cues.

1) Eat less frequently and avoid grazing all day.

2) Try not to eat after 7:30 pm.

3) Avoid stress (easier said than done sometimes).

4) Take medications as directed.


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