484 Our Complex Gut [13 August 2018]

In grade school health we were taught that our digestive system was a fairly simple “food processing machine” comprised of a handful of organs. Food entered at one end, a variety of digestive juices were added along the way, nutrients were extracted, and the leftover waste expelled out the other end. Scientists are just now discovering how complex our digestive system really is.

Dr. Emeran Mayer in his 2016 book “The Mind-Gut Connection – how the hidden conversation in our bodies impacts our mood, our choices, and our overall health” shares what cutting-edge science has learned about the connections between our gut, our brain, and our microbiome. This adds to previous articles I wrote about the brain-gut axis: #320 in May 2015 and #422 in May 2017.

First, the gut has its own nervous system, sometimes called the “second brain”. The enteric nervous system (ENS), as it is properly named, rivals the spinal cord for number of nerve cells – some 50-100 million. The ENS makes the gut the largest sensory organ of the body – covering an area the size of a basketball court.

The gut contains more immune cells than in all the rest of the body. There is a good reason for this – the gut is exposed to more pathogenic microbes than any other system. It can identify and destroy a pathogenic species out of the approximately 1,000 species that may exist in our gut.

The gut contains more endocrine cells than in all the other endocrine glands put together – adrenals, thyroid, pituitary, etc. The gut produces and stores 95% of the body’s serotonin, the neurotransmitter that controls our mood, sleep, appetite, and pain sensitivity.

Then there is the microbiome. Technological advances in DNA testing over the past few decades has allowed us to identify the thousands of microbial species that typically inhabit our body. There are about as many microbial cells in and on our body as there are human cells (if you include the red blood cells). By weight our microbiome is more massive than our brain. And since there are over 1,000 species, their collective genes outnumber our own a hundred fold.

These gut systems communicate with the brain in different ways. The large vagus nerve directly connects the gut and the brain. The hormones and neurotransmitters produced by the cells in the gut wall, and the metabolites produced by the microbes, can travel by the bloodstream to the brain. Mayer calls this complex three-way communication system the “Gut-Microbiome-Brain Axis”.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner. Find this article on my website for links to sources and further reading.