Mental health and the gut

Medical Academic (MA): Hi Dr Barrow. What is the use of peppermint oil, and how does one take it?

Dr Peter Barrow (PB): Peppermint oil is widely recognised for its efficacy in managing symptoms of irritable bowel syndrome (IBS), particularly bloating, abdominal pain, and spasms. Its active component, menthol, acts as a smooth muscle relaxant, reducing colonic contractions.

For optimal results, enteric-coated capsules (typically 0.2–0.4 ml per dose) are recommended to prevent premature dissolution in the stomach, which can cause reflux. Patients should take it 30–60 minutes before meals, up to three times daily. However, it may exacerbate gastroesophageal reflux disease (GERD), so caution is advised in such cases.

MA: How do you test for gluten intolerance?

PB: Gluten-related disorders include coeliac disease, wheat allergy, and non-coeliac gluten sensitivity (NCGS). Testing for coeliac disease involves IgA tissue transglutaminase (tTG) antibody testing, along with total IgA to exclude deficiency. If positive, a duodenal biopsy confirms villous atrophy.

For wheat allergy, skin prick tests or IgE blood tests are used. Non-coeliac gluten sensitivity is a diagnosis of exclusion, made after ruling out coeliac disease and wheat allergy. A gluten-free trial with symptom monitoring may be helpful. Importantly, patients should not start a gluten-free diet before testing, as it can lead to false-negative results.

MA: How long can one use a chlordiazepoxide and clidinium bromide combination?

PB: This combination is used for short-term management of IBS-related anxiety and spasms. Due to the risk of dependence (chlordiazepoxide is a benzodiazepine) and anticholinergic side effects (from clidinium), treatment should not exceed 2 to 4 weeks. Long-term use can lead to tolerance, cognitive impairment, and constipation.

However, the medication can be safely used intermittently, as long as you keep in mind that it is recommended to reduce the usage and only use it for flare-ups of symptoms.

MA: Any research on the use of EMDR therapy and IBS?

PB: Emerging evidence suggests that psychological trauma may contribute to IBS. Eye Movement Desensitisation and Reprocessing (EMDR), a therapy for post-traumatic stress disorder (PTSD), has been explored for IBS patients with a history of trauma.

A 2020 pilot study found that EMDR reduced visceral hypersensitivity and improved IBS symptoms in some patients. While promising, larger randomised trials are needed before widespread recommendation.

MA: Medical aids are forcing us to do colonoscopies even though we can reach a diagnosis by calprotectin. Why is this?

PB: While faecal calprotectin is an excellent non-invasive marker for intestinal inflammation (helping distinguish IBS from inflammatory bowel disease, IBD), insurers often mandate colonoscopies for definitive exclusion of malignancy, especially in older patients or those with red-flag symptoms (e.g., weight loss, bleeding).

Colonoscopy also allows for histological confirmation and therapeutic intervention (e.g., polypectomy). Until calprotectin is universally accepted as sufficient for exclusion of serious pathology, this discrepancy will likely persist.

MA: Is probiotic use long-term not recommended because there is no evidence of long-term efficacy?

PB: Probiotics are generally safe, but their long-term efficacy remains uncertain. Most studies focus on short-term use (4–12 weeks) for conditions like antibiotic-associated diarrhoea or IBS. Concerns include strain-specific effects, potential gut microbiome disruption with prolonged use, and a lack of robust long-term safety data. Intermittent use or targeted courses may be preferable until further evidence emerges.

Some studies suggest that blood group O may be associated with a higher risk of H. pylori infection and peptic ulcers, while blood group A may have an increased susceptibility to IBD

MA: What is your opinion on the slow gastric emptying caused by GLP-1 treatment?

PB: GLP-1 receptor agonists (semaglutide, liraglutide, etc) delay gastric emptying as part of their glucose-lowering and satiety-enhancing effects. While beneficial for weight loss and diabetes, this can cause gastroparesis-like symptoms (nausea, bloating, constipation).

Most patients adapt over weeks, but those with pre-existing motility disorders may struggle. Dose reduction or slower titration can help. Long-term implications are still under investigation.

MA: How do we help children with autism spectrum disorder who struggle with chronic constipation?

PB: Management involves dietary adjustments such as increased fibre, fluids, and probiotics. Behavioural strategies, including regular toilet schedules and visual aids, can be helpful. Laxatives, particularly osmotic agents like polyethylene glycol, are first-line, while stimulants such as senna may be used short-term. Sensory support to address tactile sensitivities around toileting is also important. A multidisciplinary approach involving a paediatrician, dietitian, and occupational therapist is often necessary.

MA: Please comment on amitriptyline dosage and duration of use.

PB: In functional GI disorders such as IBS, low-dose amitriptyline (10–50 mg nocte) is used for its neuromodulatory and analgesic effects. It can be used long-term if effective, with periodic review. However, anticholinergic side effects (dry mouth, drowsiness) and cardiac risks in older adults must be considered. Alternatives such as nortriptyline may be better tolerated in some patients.

MA: Any association between blood group and bowel problems?

PB: Some studies suggest that blood group O may be associated with a higher risk of H. pylori infection and peptic ulcers, while blood group A may have an increased susceptibility to IBD. However, evidence is inconsistent, and clinical relevance remains limited.

MA: How common is lactose intolerance, and can it mimic symptoms of IBS?

PB: Lactose intolerance affects approximately 65% of adults globally, with higher prevalence in Asian and African populations. Symptoms such as bloating, diarrhoea, and cramps overlap with IBS. Diagnosis involves a lactose hydrogen breath test or an elimination diet followed by rechallenge.

Many IBS patients wrongly attribute symptoms to lactose, so formal testing helps avoid unnecessary dietary restrictions.

MA: Why do people have a 33% increase in suicidal depression after a gastric bypass operation?

PB: Potential factors include nutrient deficiencies (vitamin D, B12, etc) affecting mood, psychosocial stressors such as body image adjustment and unrealistic expectations, and gut-brain axis disruption due to altered ghrelin/leptin signalling. Pre- and post-operative psychological support is crucial to mitigate these risks.

Has any association been found between baby colic and IBS in later life? Some studies suggest infant colic may predict functional GI disorders such as IBS due to early gut-brain dysregulation. However, confounding factors, including maternal anxiety, complicate this link, and further research is needed.

MA: Any role for low-dose GLP-1s in terms of anti-inflammatory action?

PB: Preclinical data indicate that GLP-1 agonists may reduce inflammation, such as in IBD or NAFLD, via modulation of immune cells. Human trials are ongoing, but anti-inflammatory benefits are not yet a licensed indication.

MA: How can I make an IBS diagnosis without definitively excluding all other GIT pathology?

PB: The Rome IV criteria allow IBS diagnosis based on symptom patterns, such as recurrent abdominal pain with altered bowel habits for at least six months. Limited testing (FBC, CRP, calprotectin, coeliac serology) often suffices in young patients without red flags. Colonoscopy is not mandatory unless risk factors exist, and shared decision-making with the patient is key.

Dr Peter Barrow is an experienced gastroenterologist with an interest in inflammatory bowel disease and interventional endoscopy including endoscopic ultrasound. He practices at Wits Donald Gordon Medical Centre in Johannesburg.

'To watch a CPD-accredited recording of a webinar presented by Dr Barrow and Dr Frans Korb, entitled 'An update on the brain the gut interplay, please click here: https://bit.ly/4mqDkqE.