Did you know there is a ‘second brain’ in our gut? Hidden in the walls of our digestive system, it’s the source of our feelings which we describe as ‘going with our gut’ when making a decision, or feeling ‘butterflies in our stomach’ when nervous, among others. Called the enteric nervous system (ENS), its study is drawing up exciting new links between digestion, mood, health and the way we think.
What is the ENS?
The ENS is made up of two thin layers of more than 100 million nerve cells. These layers line the gastrointestinal tract from the oesophagus to the rectum. The gastrointestinal tract is sensitive to emotion. When we feel anger, anxiety, sadness, elation, and other emotions, they can trigger symptoms in the gut.
Role of the ENS
The main role of the ENS is controlling digestion. It controls the entire process, from swallowing to the release of enzymes that break down food, to the control of blood flow that helps absorb nutrients, and finally elimination. While the ENS doesn’t seem capable of thought (like our big brain), it communicates back and forth with the big brain.
The brain and the gastrointestinal (GI) system are closely connected. The brain has a direct effect on the stomach and intestines – and vice versa. Thinking of food, for instance, can release the stomach’s juices even before food gets there. In the same way, a troubled intestine also sends signals to the brain. It is a connection that works both ways. Thus, it is possible that a person’s tummy or intestinal distress can either be the cause or the result of anxiety, stress, or depression. When a person experiences gastrointestinal upset with no obvious physical cause, it is important to consider the role of stress and emotion when trying to heal a distressed gut.
The ENS can trigger emotional changes experienced by people with irritable bowel syndrome (IBS) and functional bowel problems such as constipation, diarrhoea, bloating, pain and stomach upset. Now researchers are finding evidence that irritation in the gastrointestinal system may send signals to the central nervous system (CNS) that trigger mood changes.
The gut/ brain/ microbiome axis
The gut microbiome indicates the microorganisms and their combined genetic material in a particular environment. The gut microbiome, which is home to approximately 100 trillion microorganisms, plays a key role in the development of both health and disease. The gut microbiome is made up of a vast ecology of commensal bacteria, archaea, fungi, and viruses. A healthy adult gut microbial profile exhibits both diversity and stability. The microbiota modulates various vital physiological activities and shapes and maintains the immune system. The brain modulates gut function and, in turn, the gut modulates the function of the central nervous system. These pathways are called the microbiota-gut-brain axis (MGBA). The gut microbiota has considerable potential for new therapeutic opportunities, which can target and impact the microbiota-gut-brain axis for treating many challenging diseases.
The link between gut health and anxiety
There is a close interaction between the gut and the brain. It’s the reason why, when under stress, we feel nauseous or experience intestinal pain. The physiology of the gut is influenced by psychosocial factors. Thus, stress, depression or other psychosocial factors can affect the movement and contractions of the GI tract. Some people with functional GI disorders can experience pain more severely than other people do, as their brain responds with more sensitivity to pain signals from the GI tract. What’s more, the existing pain is made worse due to stress. New research findings could help explain why more people with IBS and functional bowel problems also develop depression and anxiety.
The gut-brain connection
It is important to observe whether your tummy or intestinal problems are related to stress. Whether heartburn, abdominal cramps, loose stools or other common symptoms of stress, do keep a track of your experiences and discuss them with your medical expert. This would help arrive at strategies to help deal with the stressors in your life, as well as ease digestive discomforts.
Benefits of therapy and treatment
With therapy to reduce stress or treatment to treat anxiety or depression, the symptoms of some patients with functional GI conditions can improve. Studies find that psychologically based approaches can have better results in treating digestive symptoms as compared to conventional medical treatment alone. Gastroenterologists (doctors specializing in digestive conditions) serve as counsellors, who look for ways to soothe the second brain. They may prescribe antidepressants for IBS, as these medications may calm symptoms in some cases as they act on nerve cells in the gut. As the two brains ‘talk’ to each other, therapies that help one may also help the other.
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