Think Twice: How the Gut’s “Second Brain” Influences Mood and Well-Being
The emerging and surprising view of how the enteric nervous system in our bellies goes far beyond just processing the food we eat.
As Olympians go for the gold in Vancouver, eventhe steeliest are likely to experience that familiar feeling of “butterflies” in the stomach. Underlying this sensation is an often-overlooked network of neurons lining our guts that is so extensive some scientists have nicknamed it our “second brain”. A deeper understanding of this mass of neural tissue, filled with important neurotransmitters, is revealing that it does much more than merely handle digestion or inflict the occasional nervous pang. The little brain in our innards, in connection with the big one in our skulls, partly determines our mental state and plays key roles in certain diseases throughout the body. . . .
“The second brain doesn’t help with the great thought processes…religion, philosophy and poetry is left to the brain in the head,” says Michael Gershon, chairman of the Department of Anatomy and Cell Biology at New York–Presbyterian Hospital/Columbia University Medical Center, an expert in the nascent field of neurogastroenterology and author of the 1998 book The Second Brain(HarperCollins). . . .
The second brain informs our state of mind in other more obscure ways, as well. “A big part of our emotions are probably influenced by the nerves in our gut,” Mayer says. Butterflies in the stomach—signaling in the gut as part of our physiological stress response, Gershon says—is but one example. Although gastrointestinal (GI) turmoil can sour one’s moods, everyday emotional well-being may rely on messages from the brain below to the brain above. For example, electrical stimulation of the vagus nerve—a useful treatment for depression—may mimic these signals, Gershon says. Given the two brains’ commonalities, other depression treatments that target the mind can unintentionally impact the gut.
The enteric nervous system uses more than 30 neurotransmitters, just like the brain, and in fact 95 percent of the body’s serotonin is found in the bowels. Because antidepressant medications called selective serotonin reuptake inhibitors (SSRIs) increase serotonin levels, it’s little wonder that meds meant to cause chemical changes in the mind often provoke GI issues as a side effect. Irritable bowel syndrome—which afflicts more than two million Americans—also arises in part from too much serotonin in our entrails, and could perhaps be regarded as a “mental illness” of the second brain.
Scientists are learning that the serotonin made by the enteric nervous system might also play a role in more surprising diseases: In a new Nature Medicine study published online February 7, a drug that inhibited the release of serotonin from the gut counteracted the bone-deteriorating disease osteoporosis in postmenopausal rodents. (Scientific American is part of Nature Publishing Group.) “It was totally unexpected that the gut would regulate bone mass to the extent that one could use this regulation to cure—at least in rodents—osteoporosis,” says Gerard Karsenty, lead author of the study and chair of the Department of Genetics and Development at Columbia University Medical Center.
Serotonin seeping from the second brain might even play some part in autism, the developmental disorder often first noticed in early childhood. Gershon has discovered that the same genes involved in synapse formation between neurons in the brain are involved in the alimentary synapse formation. “If these genes are affected in autism,” he says, “it could explain why so many kids with autism have GI motor abnormalities” in addition to elevated levels of gut-produced serotonin in their blood.
This may give us a new appreciation and meaningful insight into the adage “Listen to your gut feeling.” This article leaves little doubt about the importance of a healthy gut flora. There are numerous health products out there to help clean up your alimentary canal and keep it well supplied with friendly bacteria. Fasting is one way to give the gut a reprieve from its primary duty of digesting the seventy tons of food we pass through it over an average lifespan.
Dr. Depak Chopra recommends a one-day fast every week to foster the production of growth hormones and thereby add years to one’s life. I haven’t personally heeded his advice, but I have fasted for as much as seven days, and I can attest to the incredible impact fasting has on one’s mental and visual acuity and function.
Fasting is safer under the supervision of a health practitioner or physician and should not be done without proper preparation and professional guidance. I’m not going to spend time here on all the ways to help keep a healthy intestinal tract. That is readily available on the web and in health related books. I will only tout and highly recommend the 21-day total body cleanse put out by Standard Process Labs in their Purification Kit at a moderate cost of $250. That I make my readers aware of the gut-brain connection in mental health and illness issues, such as depression, is sufficient for this post. Until my next post in this series,
Here’s to your mental health and healing,
Anthony Palombo, DC
Visit my second blog at HealingTones.org for inspired writing on the spiritual and energetic aspects of health and life.