Holistic Centre for Body, Mind & Spirit

Gut Instinct

New research has discovered a ‘second brain’ in your stomach – controlling your mood, your health and more.


When Dr Michael Gershon uttered the immortal line, “If you’re chained by bloody diarrhoea to a toilet seat, it can really do you in,” on an American late-night chat show, he was uttering the “I think, therefore I am” of the neurogastroenterology world.

Gershon, professor of anatomy and cell biology at Columbia University, was the first person to expound the existence of what he calls the “second brain”, and independent nervous system that exists in the lining of the oesophagus, stomach and intestines, in the gastrointestinal tract. And his quote illustrates the visceral power our mucky gut has over our lofty mind.

Four decades after Gershon’s theory was laughed off by his colleagues, we now know that his “second brain” theory has legs. Properly known as the “enteric nervous system”, our gastrointestinal tract contains as many neurons as the spinal cord and about 40 neurotransmitters, as many as are found in the brain.

The gut is the only organ that can work independently of the brain. It controls the movement and absorption of food through the intestines without any input from the central nervous system, and continues to function even after brain death. The gut brain sends the big brain signals. These are not like conscious thought, but can influence memory, learning, decision making and emotions such as sadness and stress. My poor gut suffers most when I have a mountain of work to do and not a lot of time to do it. I’m well acquainted with the classic “gut brain” call of anxiety: a tight throat, a leaden stomach and a bolt to the bathroom.

This research has implications for the treatment of diseases such as Parkinson’s, depression, autism and osteoporosis, all of them among the illnesses that display both causes and early symptoms in the gut.

Back in 1965, when Gershon first suggested the gut might use some of the same neurotransmitters as the brain, he was considered an iconoclast and a bit odd. Neurotransmitters were the noble messaging systems of the brain. The gut was a simple, subordinate organ that digested the food we ate. He went on to discover that 95% of the body’s happiness neurotransmitter serotonin (5-HT) is found in the gut. A “misery guts” might be precisely that: too little 5-HT causes depression. Whereas too much causes irritable bowel syndrome. New treatments for IBS are not dissimilar to Prozac. Digestive disorders are a bit like mental illness of the second brain.

Gershon, famously, likes to compare the brain to a CEO “who doesn’t like to micromanage, and leaves the gut to operate the messy, dirty business of digestion on its own... and allows you to think about finer things than the number of enzymes it is going to take to turn that steak you ordered into soup”.

Through what we swallow, the gut processes information from the outside world. It might not write poetry with that information, but it knows the difference between a good oyster and a bad one without having to consult the brain.

This knowledge profoundly affects people with gastrointestinal ailments. “Don’t trivialise GI ailments,” Gershon says. “Worldwide, they are the No 2 cause of hospital admissions, and IBS affects 20% of people in America and Britain.”

Understanding the “second brain” has led to alternative treatments for depression and epilepsy. Implanting something like a pacemaker in the vagus nerve of the gut has proved an effective, and less traumatic, alternative to therapies such as electroconvulsive treatment. This vagus-nerve stimulation could help other chronic conditions such as Alzheimer’s, migraine and tinnitus.

A significant number of reputable studies in humans and animal prove that emotional stress in childhood can cause chronic GI diseases in adults. Emeran Mayer is a professor in the departments of medicine, physiology, psychiatry and biobehavioural sciences at UCLA. He says that the majority of the patients he treats for digestive disorders have experienced trauma, be it emotional or physical illness, as children. “The typical IBS patient often describes having a tummy ache as a kid, or being a colicky baby. Anxiety and increased gut reaction commonly go together.”

Gershon sees political ramifications in his work. “There is a lot of prejudice toward IBS – many patients with IBS are women, and people think it is the hysterical ravings of women and not a good, solid, dependable disease like cancer.”

In some respects, the work coming out of the labs bears out the beliefs in ancient health systems such as traditional Chinese medicine and Ayurveda. Hence Mayer’s academic interest in integrative medicine. “We had a conference that a lot of the ancient medical systems came to talk at,” Mayer says. “The Buddhist monks’ theories of mindfulness-based stress-reduction techniques, simplified and adapted from Zen meditation, linked well with modern neurogastroenterology; it was good for digestive disorders, and there was scientific evidence to support it.”

Mayer, down there in California, is open to examining these approaches. “When the Ayurvedic doctors described emotions being related to different types of food, I laughed. But the more we learn about the gut, the more they start to make scientific sense. The tradition of the cleansing diet, fasting and enemas goes back thousands of years. Fundamentally, all they are about is changing gut flora.”

These friendly bacteria are the welcome resident aliens that live on the walls of the GI tract, and they, too, are constantly exchanging information with the mind through the gut. It has even been suggested, albeit controversially, that certain probiotics may be effective psychiatric treatments. There is research that links a reduction in our ingestion of fermented foods, from real ale to yoghurt, with some of the ailments that define the modern condition.

The specific balance of these bacteria influences us throughout life, but especially in infancy. Some scientists believe we are actually controlled by these resident aliens, which is brilliantly sci-fi. “The gut is host to more good bacteria cells, 100 trillion, than we have cells in our bodies,” Mayer says “We wonder, do patients with anxiety disorders have altered bacteria? Do the internal flora influence health and mind?”

Nutritionists are finding that neurogastroenterology bears out what they see in their patients. “If anxiety and depression are present together with IBS-type symptoms, we will work on the latter, and most often see improvements in the former,” says the nutritionist Ian Marber. “The connections between the functioning of the gut and an individual’s psychological and physiological state are so numerous, one could easily argue that a huge number of the day-to-day health issues or symptoms that can be addressed through diet are about the mind-gut connection.”

The gut can secrete chemicals that make us do things. We are, to an extent, its slave. The urge to eat a fatty snack is not merely psychological, nor a hunger message sent from the stomach, but a search, gut-brain-driven, for fat’s ability to give a sense of wellbeing. Injecting fat directly into the stomach has the same effect as eating it. Comfort eating is self-medication with some logic behind it. The academics at the hard end, watching rats and prodding guts in test tubes, describe unprecedented interest in the field. “We are entranced by the idea of a second brain,” Mayer says. “People in business and economists are interested in what it has to teach about intuitive decision making.”

He believes that as much as 80% of our wellbeing might come from the complicated relationship between the brain and our intestines. You don’t need to be a scientist to know this – it’s gut instinct.

Kate Spicer

The Love Below: What Science Says You Can Do to Keep Your Second Brain Happy


  • Manage stress
  • Meditate – all the evidence points to mindfulness, abdominal breathing, yoga, nidra (psychic sleep) and hypnosis helping to keep the gut relaxed
  • Do not drink heavily
  • Eat a diet rich in fruit and vegetables, but be aware there are no universal ‘good’ foods: when it comes to gut health, one man’s meat, grain or veg can be another man’s poison.  Listen to your body
  • Avoid refined sugars
  • Avoid deep-fried foods
  • Eat fermented foods such as live plain yoghurts, miso and sauerkraut
  • Take a daily probiotic
  • Avoid excessive unfermented dairy produce – adult humans are not generally designed to drink a lot of milk
  • Include fibre in your diet, but be aware of what fibre does for your gut.  Different people handle fibre differently: some guts flourish on heavy roughage such as wheat bran, while others are more comfortable with soluble fibres such as those found in oats

Gut Instinct

While this article talks about cutting edge new information, this is only true in relation to Western medicine’s modern paradigm. It is actually ancient wisdom that has long been known in the East - and also in our own culture prior to the industrial revolution. It is only relatively recently that in the West we have made the false separation of body, mind and spirit, whereas they actually all interact with each other seamlessly and continuously.

There is an intimate link between the body and mind that can make the functionality of the body highly complex, and its consequences for health and wellbeing extensive. Many people do not appreciate just how much their life experiences and feelings can be absorbed and develop into a very real set of physical symptoms.

We have many powerful and intelligent ways to respond to this aspect of health. For a truly holistic and fully integrated diagnosis of body, feelings, mind and spiritual wellbeing, we would draw most from the wisdom and understanding provided by such treatments as Iridology, Herbal Medicine, Acupuncture or Naturopathic Nutrition (with its vast range of associated laboratory tests and supplements). These would be part of a bespoke and in-depth programme of care.

With gut health, the above approaches can often take the initial lead, with other therapies or treatments providing supporting functions. Sometimes the support treatments themselves take over and become the lead applications - such therapies and treatments may include Deep Memory Process, Visualisation, Psychotherapy, Regression Therapy or ‘Mindfulness in Action’ e.g. Yoga, Tai Chi, Shiatsu, stretch or bodywork.

One person’s programme of care will be completely different from another’s even if the symptoms appear the same because the story of those symptoms will be unique to that person. These therapies and treatments help people to tune into what’s going on in their emotional world and therefore in their own body, and to positively influence what happens there.

The protocols we use are based on a thorough analysis of each client’s unique story: their health issues and symptoms; their family medical and dietary history; their emotional, social, lifestyle and exercise history; and the analysis of functional and biochemical tests.