If a person is told that a medicine might cause side effects like nausea or headaches, they might start feeling those symptoms – even if the medicine doesn’t actually cause them. This is called the nocebo effect, where what we believe or expect can affect how our body feels. For people with irritable bowel syndrome (IBS), a condition already linked to stress and gut-brain interaction, the nocebo effect can make symptoms worse and complicate treatment.
Understanding the ‘nocebo effect’
While the placebo effect improves symptoms through positive expectations, the nocebo effect worsens them due to negative beliefs. Studies show that expectation alone can trigger the nocebo effect, particularly in people with IBS. Research from The Lancet found that the expectation of consuming gluten caused symptoms like abdominal pain, bloating, and altered stool patterns – even more than actually eating gluten. For some, even strict gluten-free diets failed to ease symptoms, suggesting other triggers like FODMAPs play a role. However, cutting out gluten without proper guidance risks nutrient deficiencies and an unbalanced diet. Wheat, a staple food in many Western diets, provides vital nutrients like fiber, vitamins, and minerals. Whole-grain wheat may lower risks of obesity, heart disease, and type 2 diabetes.
How to spot the nocebo effect in IBS
The nocebo effect in IBS can be challenging to recognise. It occurs when negative expectations or beliefs about a treatment or food trigger symptoms, even if there’s no direct cause. Here’s how to spot it and what to do about it.
- Fear and worry: People with IBS may feel anxiety or fear about certain foods or treatments, even before trying them. If this anticipation leads to increased symptoms, it could be a sign of the nocebo effect.
- No clear trigger: Sometimes, IBS symptoms flare up without a clear dietary or lifestyle cause, especially when you’re anxious about a treatment or food. This is often linked to negative beliefs influencing your gut.
What you can do about the nocebo effect
How diet plays a role
While it’s tempting to cut out certain foods like gluten in hopes of relief, strict diets without proper guidance can lead to nutrient imbalances. Instead, focus on identifying your triggers using a symptom tracker or try a low-FODMAP diet, which has been shown to reduce IBS symptoms by limiting fermentable carbohydrates like fructans, lactose, and polyols that irritate the gut. These compounds are common in trigger foods and may worsen IBS symptoms for some people.
The low-FODMAP diet should not be a long-term solution, but it can help identify which foods trigger the symptoms. Ideally, you should be able to reintroduce more foods into your diet over time, which is why it’s best to follow this approach with the guidance of a nutritionist to avoid unnecessary restrictions.
Mind-body interventions
Psychological therapies like cognitive-behavioral therapy, mindfulness meditation, yoga, and gut-directed hypnotherapy can help patients manage anxiety and reframe negative thoughts about IBS symptoms, reducing the nocebo effect and IBS symptoms. These approaches target the gut-brain connection, which plays a crucial role in IBS.
Cognitive-behavioral therapy (CBT)
CBT helps patients identify and challenge negative thought patterns that contribute to stress and symptom anticipation. For example, patients learn to reframe thoughts like “This meal will cause pain” into more neutral or positive beliefs, breaking the cycle of fear and discomfort. CBT also reduces stress, which directly influences gut motility and sensitivity, improving symptoms over time.
Yoga
Yoga combines gentle physical activity with mindfulness and deep breathing, which lowers stress and supports relaxation. These practices activate the parasympathetic nervous system, also known as the “rest and digest” system, helping to regulate gut function and reduce IBS symptoms. Regular yoga practice can also improve mood, enhance sleep, and build resilience against stressors that may otherwise worsen IBS.
Gut-directed hypnotherapy
Gut-directed hypnotherapy uses hypnosis to help normalise bowel function by suggesting control over digestive processes. Weekly sessions with a trained therapist for 6–12 weeks have been shown to reduce IBS symptoms and alleviate anxiety and depression.
The success of mind-body interventions lies in their ability to address the brain-gut connection. Negative expectations and stress activate the brain’s threat response, increasing gut sensitivity, motility, and inflammation – all of which worsen IBS symptoms. By calming the mind and reframing thoughts, therapies like CBT and yoga reduce this overactivation, allowing the gut to function more smoothly.
Conclusion
The nocebo effect is a powerful yet underappreciated phenomenon in the management of IBS. By influencing the gut-brain connection, negative expectations can significantly worsen symptoms and complicate treatment. However, with greater awareness and intentional strategies, both patients and clinicians can minimise the impact of the nocebo effect, ultimately reducing IBS symptoms and improving your overall quality of life.