Abdominal pain, cramping, bloating, sudden diarrhoea, chronic constipation: the symptoms of irritable bowel syndrome (IBS) are unpleasant and can have a severe impact on quality of life. Nevertheless, many sufferers soldier on for years, managing symptoms by strictly controlling the foods they eat.
What is often recommended for IBS is a low Fodmap diet. This stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are short-chain carbohydrates (sugars). The diet was developed by researchers at Australia’s Monash University and involves identifying which high Fodmap foods are causing digestive distress and eliminating them. The problem is, says Sharon Erdrich of the Auckland Gut Clinic, many of those foods – which include high-fibre fruits, vegetables and pulses – are a key part of a healthy diet.
“I’ve seen patients who have been on a low Fodmap diet for five or 10 years and that’s not good for the gut microbiome, which needs those fermentable substances,” says Erdrich, a registered nutritionist with a long interest in digestive disorders. “One sufferer had reached the point where they were consuming only five or six foods.”
A healthy gut microbiome is important for regulating the immune system and also plays a role in brain health. Too restrictive a diet can disrupt the balance of gut bacteria, which may lead to further problems down the track. For that reason, eliminating trigger foods should be only a short-term fix, says Erdrich, with the aim of returning to a normal diet in time.
The gastrointestinal system is complex, so finding out what is causing an individual’s digestive symptoms and treating them won’t be straightforward, either. Blood tests and imaging will only rule out other conditions, not make a diagnosis.
A more tailored approach to identifying any food intolerances is to take a hydrogen/methane breath test. This is a noninvasive way to measure levels of the gases in the breath you exhale and will diagnose digestive problems, including lactose intolerance and small intestinal bacterial overgrowth – which is helpful bacteria from the colon that have moved to the small intestine where they don’t belong. The test involves overnight fasting then challenging the body by drinking different sugar solutions.
For some sufferers, a course of antibiotics will be an effective treatment. Rifaximin has been shown to be helpful, though in New Zealand it isn’t funded for digestive disorders so patients will have to pay. There is also some science to suggest that certain herbal therapies may be just as useful.
Ultimately, the aim is to restore a healthier balance of bacteria in the gut so higher Fodmap foods are processed properly and can be reintroduced. This is a highly personalised process. “No two human microbiomes are identical so, understandably, the same approaches may have different outcomes in different people,” says Erdrich.
One therapy that has been trialled is faecal microbiota transplantation, although at this stage that seems more beneficial as a treatment for infections caused by the bacteria Clostridium difficile and for ulcerative colitis than for IBS.
Along with a gradual tweaking of the diet, methods used by Erdrich might include sending patients for physical therapy to help restore normal gastrointestinal flow or addressing any chronic stress levels which may be impairing digestive function.
“You’re trying to restore an ecosystem and that takes time,” she cautions. “The hardest people to treat in my experience are those patients who have had a digestive problem for a very long time.”
Some IBS sufferers are prescribed antidepressants by their doctor to help reduce the pain of symptoms. Others have been told there is nothing to be done and they will just have to live with it. Erdrich prefers to offer hope.
“There’s a personal and economic cost to having a digestive disorder,” she points out. “Not only are people limited in what they can do socially, they’re often having to take time off work for medical appointments and pay for special foods. But if your digestion was good once and nothing got broken in terms of the actual anatomy of your body, then I strongly believe there is a pretty good chance that you can get it back to a healthy, well-functioning process.”
