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Hungry for health knowledge

Raj Eri

This year we launched our online series Explore, which provides opportunities for advancement and inspiration.

Our most recent webinar ‘How to keep your gut happy’ presented by University of Tasmania alumnus and Associate Professor Dr Raj Eri, proved to be a particularly popular topic.

Alumni tuned in from all over the world to watch him discuss the current research into the human microbiome (the combined genetic material of all the microorganisms living in and on the body) and its impact on our overall health.

Given the huge amount of interest in the topic and the unprecedented number of questions we received before, during, and after the presentation, Dr Eri has kindly provided us with answers to several of the most commonly asked questions.

To learn more, watch Dr Eri’s full presentation on the Alumni Explore YouTube Channel

Five common gut health questions answered by Associate Professor Dr Raj Eri

What is the impact of fasting on the microbiome? Are there any fasting routines you would recommend?

“It is well-established that diet (and changes to diet) reproducibly and sometimes rapidly alter the gut microbiota. Fasting, especially intermittent fasting, produces significant changes to our gut microbiome.

Latest research indicates that brown fat (the type of fat that burns energy compared to white fat that stores energy) is activated during intermittent fasting, apart from the well-known benefits such as increased ketones, autophagy (refreshing our body cells) and reducing inflammation. In fact, animal model studies indicate that the white fat can be turned brown by intermittent fasting.

But remember, the food you eat during non-fasting periods is also important to maintain a healthy microbiota. At the moment, we have the most research data from intermittent fasting, but more research is needed to assess the effect of microbiota on long-term fasting methods.”

What foods or probiotics and/or prebiotics can be taken to counteract the effects of antibiotics and other medications on gut health? Is it beneficial to take probiotics consistently and not just while on antibiotics?

“Not every probiotic is for everybody. I can’t say all probiotics work, but we know from a number of clinical studies probiotics are extremely important and they make a lot of difference to keeping the gut happy.

Taking yoghurt probiotics might help reduce symptoms such as diarrhoea that appear when you are on antibiotics (as evidenced by our clinical trial in children on antibiotics), but evidence is lacking with respect to how quickly probiotics re-establish microbiota post-antibiotic treatment. The major problem in this type of research is also how one defines the health human gut microbiome.”

How does a high-fibre diet help with the healthy maintenance of microbiomes? Are there certain times, such as if you have Irritable Bowel Syndrome (IBS) or Diverticulitis, when it is better to avoid a high-fibre diet?

“Fibres add bulk to the diet and makes you feel fuller, hence they can reduce the appetite. They lower the LDL cholesterol, regulate blood pressure, alleviates constipation, and reduce the risk of colorectal cancer.

Fibres can be classified as soluble and insoluble fibres, as I discussed in my talk. In IBS, soluble fibres are more beneficial, because they have a capacity to hold water and form a gel-like consistency in the gut. I do agree insoluble fibres (coarse in nature) may aggravate bowel movements.”

What is the gut-brain axis? Can you tell us a bit more about what the research is showing about how microbiome can affect mental health, particularly anxiety?

“A close relation between the gut and the brain is referred to as gut-brain axis. In fact, gut is also called by some as the “second brain”. The main connection between gut and brain is mediated by the vagus nerve, as a bi-directional highway of traffic in gut-brain axis.

Dysbiotic (disrupted ecosystem) microbiota in the gut seems to influence mood, anxiety and sleeping patterns. There is a term ‘mind-altering bugs’ that refer to altered microbiota that can secrete neuro-transmitters with a potential to cause systemic inflammation, weakened immune system or alter important stress hormones such as serotonin, and cause mood disorders and anxiety.

A recent systematic review on modulating microbiota for anxiety-like symptoms suggests that in patients who are not suited to the administration of psychiatric drugs, probiotics/prebiotics might be considered in addition to other dietary modifications such as low FODMAP. One caution in all these findings is that most of the studies emanate from animal models and hence need more human clinical studies.”


Can you recommend a good source for further information about microbiome health research?

A couple of excellent books written by top notch scientists are:

  • Follow Your Gut: How the Ecosystem in Your Gut Determines Your Health, Mood, and More by Rob Knight with Brendan Buhler
  • The Good Gut: Taking Control of Your Weight, Your Mood and Your Long-term Health by Justin Sonnenburg.
Published on: 14 Oct 2020 12:29pm