Stress giving you the runs? UK surgeon explains how disrupted gut-brain signaling can trigger anxiety and bloating

The gut and the brain are intricately connected through the gut-brain axis. Dr Rajan explains why anxiety can lead to digestive discomfort and vice versa.

Ever felt the sudden urge to rush to the loo before a stressful meeting? Or noticed your anxiety spike when your stomach feels bloated or unsettled? You are not imagining it. The gut and the brain are in constant communication, and when one is out of balance, the other often follows. This two-way relationship explains why emotional stress can trigger digestive symptoms - and why ongoing gut issues can quietly heighten feelings of anxiety.

Dr Karan Rajan, a UK-based surgeon and popular health content creator, is shedding light on why digestive issues can sometimes trigger anxiety - and how stress, in turn, can upset your stomach. In an Instagram video shared on February 28, he explains the intricate connection between the gut and the brain, and how disrupted signalling along this pathway can create a vicious cycle of stress and gastrointestinal discomfort.

Your gut can mess with your brain

According to Dr Rajan, the gut and brain are closely connected through the gut-brain axis, allowing them to constantly influence one another. He notes that a significant portion of the body’s serotonin is produced in the gut, where it helps regulate motility, pain signalling and nausea via the vagus nerve. When gut serotonin signalling is disrupted, it can amplify stress responses and contribute to heightened anxiety, while the physiological reaction can manifest as bloating.

The surgeon explains, “Your brain can influence your gut, but your gut can mess with your brain too. About 90 percent of your serotonin is produced in the guts and here it regulates gut motility, pain signaling, and nausea via the vagus nerve. Whilst gut serotonin doesn't directly enter the brain, disrupted gut serotonin signaling, like you might see in IBS, changes how the gut moves. "

“It also increases visceral sensitivity, i.e. how sensitive your gut is to pain. The brain interprets these abnormal gut signals as threats, thus heightening your anxiety. And when gut movement is impaired, gas and distension increase. Sensory nerves fire more intensely and activate anxiety related brain regions like the anterior cingulate cortex. So bloating isn't always just bloating. It's an amplified neural input that raises your baseline stress levels,” he notes.

The microbiome also shapes anxiety

Dr Rajan highlights that the gut microbiome also plays a key role in regulating anxiety. He explains that when dietary fibre is fermented by gut bacteria, it produces short-chain fatty acids (SCFAs), which help modulate inflammatory signals and influence neurotransmitter balance. As a result, low-fibre diets may reduce SCFA production, heighten inflammatory signalling and potentially amplify stress responses.

He further breaks down, “Microbiome disturbances can increase gut permeability allowing inflammatory molecules to leak into blood circulation, thus affecting mood. This creates a self-inforcing loop. Stress leads to gut disruption, which then causes inflammation and eventually anxiety and then more stress. This cycle is perfectly illustrated by IBS - higher anxiety rates, altered brain responses to gut stimuli and improvement in mood when gut symptoms improve. Which is why low dose anti-depressants are often used in IBS. Not necessarily for the brain, but for the gut brain, and improving gut symptoms.’

Tips to improve symptoms

Dr Rajan outlines three practical ways to support brain health by nurturing your gut. These include:

• Increased fibre intake: Increasing your fibre intake can boost short-chain fatty acid production, which helps reduce inflammation, thereby regulating stress signals.
• Adequate sleep: Prioritising at least seven to eight hours of sleep helps regulate gut circadian rhythm, keeping cortisol levels at bay.
• Movement: Regular physical activity enhances vagal tone, thus improving pain signaling and digestive discomfort.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. It is based on user-generated content from social media. HT.com has not independently verified the claims and does not endorse them.