Airing on ABC’s catalyst series last month, Gut Revolution was a two-part feature seeking to sort the facts from the faeces. Hosted by Dr Joanna McMillan, we followed the path of two people with debilitating gut issues, on their quests for better health. Food and Mood Centre director, Professor Felice Jacka, featured and provided her expertise on the role of the gut and diet, to mental wellbeing. In this two-part recap, we describe the science that has made poo trendy and how we may be one step closer to understanding two rampant health conditions  – irritable bowel syndrome and obesity.

Part 1: Irritable Bowel Syndrome (Melissa’s story)
By Dr Amy Loughman

In Part 1 of The Gut Revolution: A Catalyst special, we met Melissa, a 26 year-old mum of two, whose severe IBS symptoms of cramps and diarrhoea were getting in the way of a normal life. We saw that Melissa’s gut microbiome profile at the start showed some unusual features that may have explained some of her symptoms. These included a high proportion of Actinobacteria and low counts of bacteria involved in breaking down dietary fibre. After following the low-FODMAP diet 6-weeks, those Acintobacteria had reduced, and her gut symptoms had settled down. Let’s take a deeper dive into the science behind the IBS story.

Getting to the guts of IBS

Irritable bowel syndrome, or IBS, is characterised by recurring abdominal pain or discomfort, and irregular or altered bowel movements (such as constipation or diarrhoea). It is one of the most common gut conditions, affecting 10-15% of the population worldwide! There is no known single cause of IBS, and there is often no sign of any abnormality in the bowel seen on tests such as colonoscopy.

One of the interesting things about IBS, and a key to managing the condition, is its direct association with stress. IBS symptoms often start, or flare up, after periods of major psychological stress. It is truly a ‘brain-gut disorder’.

There are a few things that strongly support this idea that IBS and mental health (stress, depression, anxiety) are linked in both directions. Firstly, a large, long-term follow-up study of adults in Newcastle, NSW, found that people who were experiencing IBS at the start of the study were much more likely to experience depression or anxiety 12 years later. This may not be such a surprise: IBS can be a challenging condition to live with. However, they also found that people who had depression or anxiety at the start of the study were much more likely to develop IBS when they followed them up 12 years later!

Secondly, stress is a well-known trigger for IBS symptoms, which can come and go at different times in a person’s life. Melissa had a lot on her plate and the stress in her life at the time of filming may have made things particularly worse.

Finally, psychological therapies such as gut-directed hypnotherapy and cognitive behaviour therapy have been found to be as effective as diet-based therapies for reducing gut symptoms of IBS. The exact physical mechanisms for these therapies, as for IBS more generally, remain a bit of a mystery.

So where does the microbiome fit in this ‘brain-gut disorder’?  The gut-brain axis, a highway of communication in both directions, between the gut and the brain, is highly mediated by microbiome. Gut bacteria are involved in signalling information about the gut to the brain and central nervous system. This means that the gut itself, and its bacteria, receives plenty of information about brain states such as stress and anxiety. Studies from rodents show us that the microbiome is changed as a result of early life stress, and similar findings have been shown in humans to. So managing stress is one way to keep the gut bugs happy, and to keep IBS symptoms at bay.

Evidence for microbiota-based solutions

Diet-based therapies can also be effective for IBS, and this is likely to be at least in part, due to their effects on the microbiota. Short-term adherence to the low-FODMAP diet, as Melissa did, is one of the most evidence-based therapies for IBS. FODMAPs are a group of fermentable carbohydrates found in particularly high quantities in foods such as apples, pears, onions, milk and lentils. FODMAPs are prebiotic fibres that can exacerbate IBS symptoms in some people, however they also feed the microbiota. For this reason, a low FODMAP diet is considered a short-term treatment to reduce symptoms, with gradual reintroduction of FODMAPs into the diet really important to ensure that the microbiota is in balance again. It is best to consult a professional to do any kind of specialised diet to ensure that potential side-effects are managed.

Without getting fancy with specialised diets though, there are a number of dietary triggers that can change the microbiota and cause gut symptoms. These include sorbitol and mannitol found in artificial sweeteners, emulsifiers and other food chemicals (including those often found in highly processed food). It may be worth starting with reducing these common culprits by limiting the amount of processed and packaged food in your diet, if you are experiencing recurrent gut symptoms (and indeed for good overall health).

In short

If you suffer from IBS symptoms, or get the occasional pain in your guts, remember there are some little bacteria in there just trying to make things work.  Tummy troubles may often be a sign of more serious health conditions so it is important to speak to your doctor to rule these out, and receive a formal diagnosis of IBS, before starting any diet.

How can you best support your bacterial friends down there? A balanced and varied diet is always a good idea. While gut bugs are fed primarily by indigestible carbohydrates (FODMAPs), a short-term low FODMAP diet can help some people to get symptoms under control. You can read about it here, but its best to talk to your doctor or an Accredited Practising Dietitian before jumping in.

Remember the gut-brain axis: the brain can affect the gut too. Is there anything you can do to reduce stress in your life? It is common to experience anxiety alongside IBS symptoms, and getting help for the anxiety can reduce the IBS too. Reducing your stress and anxiety might be as simple as finding some regular time-out to active outdoors, do some breathing exercises or meditation, or perhaps you may benefit from talking things through with a trained professional. Your gut will thank you for it.

Dr Amy Loughman is a post-doctoral research fellow at the Food & Mood Centre specialising in gut microbiome research