Laureate Professor Nick Talley said the soldier microbes would be "measured in sophisticated ways".

This will involve examining how microbes affect the soldiers' thinking and functioning.

"We hope to identify microbes that may improve thinking performance, which would be very exciting," Professor Talley said.

"That may have implications for all sorts of things in future, potentially including diseases like dementia.

"So we're very excited about the work."

Soldiers face challenges that affect gut microbes such as infections and differences in drinking water and available food.

"When you go out and fight on any kind of mission and you change your diet, there are all sorts of environmental exposures," Professor Talley said.

"There's increasing evidence from animal models and other work that microbes probably play a role in how we think and behave.

"It's quite amazing really. These microbes talk to the brain through working with the immune system and nervous system."

The research has just begun and there's much to understand.

"We don't really know what the key microbes are yet, particularly those under very severe stress like the military experience," Professor Talley said.

"So the work here is to work out what microbes are present and whether they change with the kinds of stresses that happen with military activities."

The research is aimed at "optimising the cognobiome".

The term cognobiome was coined by the research team to describe the human, microbial and environmental interactions that affect cognitive performance.

As well as the University of Newcastle, the work involves Hunter Medical Research Institute, Queensland universities and biotechnology company Microba.

Professor Talley said this company does "a lot of elegant work in the microbes in the gut".

The researchers will seek to pinpoint the microbes in great detail.

University of Newcastle Professor Scott Brown said the gut-brain axis was now known to be an important part of human health.

"The soldiers suffer because, right at the moment when you want them to be the sharpest, they're eating most poorly and they're the most stressed," Professor Brown said.

"They might want to eat clean, but they have no choice. If you're out, you eat whatever you're given.

"Everyone knows it's a problem, but no one knows how big a problem it is. And no one's quite sure exactly how to deal with it."

He said it was too easy to simply say "eat clean".

"That's not going to work if you're out in the middle of nowhere," he said.

Professor Brown's expertise is in the field of psychology.

"Our job is about measuring the deficits in cognition for these soldiers," he said.

This would determine "exactly where they are weak, how weak they are and why they are lapsing".

Another issue was soldiers who had not lapsed, but were "processing everything a bit slower".

"There are only so many things you can process at once before you start screwing up."

Soldier limits in these areas may drop "when you get this deficit from not eating well, or gut-brain problems".

"There are all these different ways that the problems might manifest," he said.

Professor Brown and his colleague Associate Professor Ami Eidels have "a range of measurement methods and techniques to get the microscope out on the soldiers' cognition".

They can use these methods to "see how and where they're suffering individually".

It is considered important to know how soldiers suffer in different ways, so individual treatments can be prescribed to boost their performance.

Over the next few years, the researchers will work with the Australian Defence Force.

"We'll be testing different groups of soldiers and using that data to work out what microbes may be really important for performance and thinking abilities," Professor Talley said.

The research will examine a range of ways to improve individual soldier performance.

"We'll look at diets. If we change someone's diet in the right way, could that improve performance?

"That'd be pretty exciting because the microbes change when you change diet. That'll be one aspect of this.

"We'll also be looking at things that make functioning worse. And whether we can mitigate that by, for example, changing the diet."

New drugs are part of the plan.

"We'll be looking at whether we can isolate and actually grow some microbes that we could develop into new drugs that can potentially be used for treatments," Professor Talley said.

"That's the hope in the future."

Militaries have previously used drugs such as amphetamines, modafinil and sleeping pills. Supplements such as nootropics have been tested in a bid to improve performance, but more research is needed in this area.

"Medications that soldiers have used to help keep them awake or function have been pretty general drugs with potential side effects," he said.

The researchers were focusing on personalised medicine that could be used to "help people in a safe and effective way to help performance".

"That's at least what we believe should be possible."

Professor Talley's medical experience in the RAAF reserves more than 20 years ago has fuelled his interest in the project.

"This is an exciting area of science now that has a lot of potential. We don't know what the results will be and whether this will all work. We'll have to wait and see."

Asked if the concept could be applied to sport, he said: "I don't know how the sporting bodies would feel about it, but I think it's possible".

"It's not quite the same as taking a performance-enhancing drug if you change your diet, for example, to improve your performance.

"If you were to take probiotics, which are live organisms, I think they might think twice about that."

The research into soldiers will examine the use of probiotics and prebiotics.

"Probiotics would make a lot of sense, if we can find the right one that can change performance in a positive way. That's the holy grail.

"Changing the diet is a way of changing the gut microbes. Supplements can change the microbes as well, so maybe they'll be the answer in some people.

"But that's a long way off as well. There's a long way to go."

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