Change Your Life: Living Skillfully

Wouldn’t it be great to have a second brain to take care of some routine tasks?

photo credit: *madalena-pestana*

Well, actually, we already do. I’m studying anatomy and physiology as part of my Health Science course, and I’ve just been learning about the “enteric nervous system” – the brain in your gut.

Inside your digestive system is a complex control mechanism which contains more neurons than your spinal cord and uses many of the same neurotransmitters as the brain in your head. The process of digestion involves a lot of complicated chemistry, rather like running a sophisticated chemical plant, and of course must adapt to a wide range of different foods with different chemical compositions and to different amounts of food at different, sometimes unpredictable times. It also needs to protect itself against infection. No wonder it needs its own brain.

photo credit: euthman

The thing is, because the two brains are linked (through the vagus nerve and prevertebral ganglia as well as by chemical messengers), what affects one affects the other. If you’re emotionally upset, you can get an “upset stomach”, ranging from “butterflies” to diarrhea or even vomiting. Antidepressants can affect the digestion – they both affect serotonin, a neurochemical which the gut uses even more than the brain. And the connection goes both ways, as anyone who pays attention to how they feel emotionally after different meals will know.

The brain-gut link is well accepted now, and there’s a field known as “neurogastroenterology” which studies the interactions between the two. My anatomy and physiology textbook (Marieb and Hoehn) even includes emotional distress as a factor in one of its diagrams about digestion.

And yet, many medical professionals don’t consider the link. An overseas-based friend of mine had a very stressful and unrewarding job for several years, and was suffering from irritable bowel syndrome. He went to a gastroenterologist, who didn’t even ask him about his stress levels – yet when he was laid off from the job, his problems vanished almost immediately.

photo credit: Arturo J. Paniagua

The brain-gut link is through the autonomic (“self-governing”) nervous system. Textbooks will tell you that we don’t voluntarily or consciously control the autonomic nervous system, and while this is true, it’s a bit like saying that the government doesn’t control the economy. While we can’t control our digestive system the way we can, for example, wiggle our fingers, there are things that we can do consciously and deliberately to improve our digestive functioning through the brain-gut link.

A 2004 article in Neurogastroenterology and Motility, for example, reports that patients can learn to use biofeedback to affect the electrical activity of their gastric muscles. The gut functions best when this activity is rhythmic and at approximately 3 cycles per second, and the study taught the participants to use relaxation methods together with a monitoring device to increase the amount of time that their gut was behaving in this way.

Actually, relaxation practices in general can improve gut function, as Herbert Benson and his colleagues have been finding for decades. Engaging the parasympathetic branch of the autonomic nervous system – which is a technical way of saying “relaxing” – enhances blood flow and nerve and chemical signals to the gut and puts it into an improved state for carrying out its functions. Stress, on the other hand, moves us into the sympathetic nervous system response, which takes priority away from digestion in order to focus on fighting or running away. This is why prolonged stress often has a negative impact on digestive function.

photo credit: maessive

I have a number of posts on relaxation here in the Living Skillfully blog, which will give you some tools and techniques to use if more relaxation would be a benefit in your life. Hypnotherapy is known to be one of the more effective treatments for irritable bowel syndrome and similar issues. And in a future post, I’ll talk about the concept of a “blue prescription” and why doctors should start giving them.

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