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Improving soldier cognitive performance through nutrition

14 February 2018

When the Army was looking for guidance on ways to maintain and potentially improve the cognitive performance and resilience of our soldiers, they came to DST for advice.

"One option is through nutrition and supplementation," says Defence scientist Dr Diane Pomeroy.

"Research till now has largely been directed to their impact of nutrition on physical performance, or in improving cognition in a clinical population."

DST has now developed a research program, aimed at identifying dietary supplements capable of enhancing cognitive performance and examining their effectiveness.

University collaboration

"We extended the collaboration to include Professor Eva Kemp and her team at Flinders University, Eva is a recognised expert in eating behaviours," explains Pomeroy.

"Our collective knowledge provides us with the breadth and depth to evaluate and understand published research related to identifying the effect of dietary supplements on cognitive performance, and specific aspects of cognition that may or may not be enhanced."

There's a lot of hype surrounding the multi-billion dollar nutritional supplement industry, but where's the evidence? The team began by conducting a systematic literature review on the efficacy of dietary supplements as a means of cognitive enhancement.

The literature survey results, presented at the recent Defence Human Sciences Symposium, reinforced what the team already knew.

"Namely, that caffeine is very good if you are sleep-deprived, and also if you are stressed," explains Pomeroy.

"And there's a little bit of evidence, that we need to look at further, that it might be beneficial for well-rested individuals, but dosage is important; too much is detrimental and can be harmful."

There are several other supplements that warrant a closer examination for military personnel working in stressful environments.

So, can ingesting bacteria improve our thinking?

Probiotics are beneficial gut bacteria commonly found in yoghurt, sauerkraut and kefir (fermented milk drink). These bacteria can nurture the naturally occurring gut microbiota.

Prebiotics are non-digestible carbohydrate fibres, commonly found in fruits, vegetables and legumes. Prebiotics promote the growth and survival of probiotics. There's increasing evidence that they are helpful for maintaining a healthy human gut, but does ingesting sufficient quantities have a beneficial effect on cognitive function, well-being or mood?

The answer could lie in synbiotics, a combination of pre and probiotics that improve the survival of the probiotics, helping them to remain embedded in the gut and enhancing the changes to the gut microbiota.

"Our study was, to our knowledge, the first to investigate the direct effects of prebiotic and probiotic supplements on human cognition and mood," Pomeroy says.

First study to demonstrate benefits

Preliminary results show a significant improvement in those participants who had taken supplements, in terms of short-term memory and long-term memory, compared to those who had taken the placebo.

"Taken together, this was the first study to demonstrate that prebiotic and probiotic supplements do improve immediate and delayed memory in healthy, young adults," explains Pomeroy.

"Our study has implications for the influence of synbiotics on gut to brain access, as a potential mechanism by which cognition can be enhanced.

"Such supplements could be particularly useful for workers prone to high levels of stress including Army personnel.

"We believe we've come up with promising first steps into discovering the potential, and further investigation is warranted."