Fibre supplements create a healthy gut microbiota and in turn reduce airway inflammation in asthmatics, a new HMRI study has shown.

A University of Newcastle/HMRI study has shown fibre supplements create a healthy gut microbiota and in turn reduce airway inflammation in asthmatics.

The research, presented at the Thoracic Society of Australia and New Zealand (TSANZ) Annual Scientific Meeting in Canberra, adds to a growing body of evidence that shows what you eat not only affects your waistline but your lungs too.

More importantly the research offers hope to the estimated one million Australians struggling to control their asthma with an additional drug-free intervention, says Professor Peter Gibson, co-director of the HMRI VIVA Program.

“This is the first time anyone has looked at the impact of altering the gut microbiome on asthma control in humans. We’re at the tip of a new paradigm for how diet can be used to treat asthma,” Professor Gibson said.

By including soluble fibre in the diet you can potentially reduce the reliance on medications such as inhaled preventers to try to control the inflammation, he added.

“The treatment of asthma is focused on things that we breathe in, avoiding irritants that we breathe in and giving drugs that we breathe in and so here we take a completely different approach and focus on the persons’ diet and how we can modify their diet to improve their asthma.”

As part of the study, 17 patients with poorly controlled asthma despite the use of inhaled steroid medication were given 12 grams of daily inulin – a soluble fibre supplement.

Lead researcher Professor Lisa Wood says all patients had a reduction in airway inflammation and an improvement in their asthma control, so improved lung function and fewer symptoms such as wheezing.

The fibre works by suppressing the overactive immune system that exists in people with asthma.

“Soluble fibre doesn’t get digested until it reaches the large intestine and then the bacteria that are present in the large intestine breakdown the fibre to produce metabolites called short-chain fatty acids and they can go back into the bloodstream and they affect immune cells which control inflammation,” Professor Wood said.

While soluble fibre in the diet can help manage asthma a diet high in fat can worsen it.

Another study, also presented at the TSANZ meeting, has shown the consumption of saturated fats temporarily narrow the airways that carry oxygen to the lungs, leading to coughing, wheezing and shortness of breath.

Professor Wood and her team are now hoping to secure funding from the National Health and Medical Research Council (NHMRC) so they can conduct a large clinical trial to prove the efficacy of soluble fibre as an asthma treatment.

“There is a lot of interest from people with asthma in alternative ways to treat their disease other than just traditional asthma medications so we really do want to push this work forward.”