Your "gut brain"
mentioned in chapter 3, your belly is home to a major portion of the nervous system
the enteric nervous system, or ENS that lines your entire gastrointestinal
tract, beginning with your esophagus.
Your "gut brain" and
the brain that's up top in your skull, the "cranial brain," are derived
from the same embryological tissues and produce the same biochemicals, called
neurotransmitters, which turn nerve impulses into physiological action. One such
biochemical, which plays a major role in relieving depression, is serotonin. Popular
antidepressant drugs, such as Prozac, likely work by maintaining a generous supply
of serotonin in the cranial brain.
Your enteric nervous system not only produces serotonin it produces
a lot of it. In fact, your gut produces and stores 95 percent of your body's total
supply of serotonin. The serotonin in your gut plays many roles in managing your
digestion. It starts the process by stimulating the secretion of enzymes from
the pancreas. And it orchestrates the pace and rhythm of peristalsis, the wavelike
muscular contractions that move food through your digestive tract.
may already be aware of the action of serotonin in your belly. Too much or too
little of this biochemical speeds up or slows down peristalsis. The result? Diarrhea
Your gut brain doesn't share its abundant supply of
serotonin with your cranial brain, but its serotonin does influence the cranial
brain by stimulating the tenth cranial nerve (also known as the vagus nerve).
This nerve descends from the cranial brainstem through the neck to the abdomen,
allowing for two-way talk between the gut and cranial brains. The gut is the chatty
one, sending up nine nerve impulses for every one it receives in return. Even
with all this checking in, the enteric nervous system in the gut can operate largely
independently of the cranial brain making its own measurements and assessments,
initiating its own decisions, and learning its own lessons.
The enteric nervous system also comes into play in conjunction with an immune
response that the cranial brain initiates. Here's one possible scenario: When
substances threaten to breach the gut's lining substances including stress
hormones, as well as natural and industrial pathogens the cranial brain
activates the immune system's special agents, its mast cells, and appoints them
to guard the gut wall. Doing their job, the mast cells secrete biochemicals, such
as histamines, that induce inflammation. The inflamed tissues make the enteric
nerves overly sensitive and overactive, deregulating the production of serotonin.
Chronic inflammation gets on the gut's nerves. It would make anyone irritable.
Although the causes of irritable bowel syndrome (IBS) may not be well understood,
many women are familiar with the signs of this functional bowel disorder. Common
symptoms include abdominal bloating, cramping, and pain, and sometimes constipation
alternating with diarrhea. According to the International Foundation for Functional
Gastrointestinal Disorders, this particular kind of misery affects as many as
one out of five adults, mostly women. Colitis, Crohn's disease, and other forms
of inflammatory bowel disease (IBD) affect many more.
The connection between your mood and how your bowels are moving extends to
anxiety and depression. As Dr.
Emeran Mayer, Director of the Center for Neurovisceral Sciences & Women's
Health at the University of California, Los Angeles, asserts, "The majority
of patients with anxiety and depression will also have alterations of their GI
function." He goes on to reveal that nearly three-quarters of those he has
treated for chronic gastrointestinal disorders have suffered severe stresses as
children. They've witnessed their parents divorcing, for example. Or they've endured
a parent's death. Such events can disrupt the sense of security and connection
the sense of being mothered, being nurtured that a child needs to
digest experience and absorb nourishment throughout her life.
body awareness, movement, and breath might contribute to healing gastrointestinal
distress. How? Since your belly is home to your entire digestive tract except
for your esophagus, your belly also encompasses the major portion of your enteric
nervous system. When you're energizing your belly, you're interacting with this
system of nerves.
As Dr. Michael Gershon, a leading investigator in the
expanding field of neurogastroenterology and author of The
says, "The gut monitors pressure." Here's what I suspect: When you breathe
deeply, rhythmically contracting and expanding your belly, you're sending soothing
signals to your enteric nerves. You're reducing their arousal....
2006 Self-Health Education