Irish study finds a high-fibre diet can reduce stress and change your mood

3 Nov 2022

Image: © sewcream/

APC Microbiome researchers found a link between a ‘psychobiotic’ diet and reduced levels of perceived stress.

Irish scientists have found a new link between diet and mood, suggesting that what you eat could help with stress management.

Researchers at APC Microbiome, the Science Foundation Ireland research centre based at University College Cork, found in a recent study that a ‘psychobiotic’ diet high in prebiotic and fermented foods could reduce stress and depressive symptoms in healthy individuals.

“Although the microbiome has been linked to stress and behaviour previously, it was unclear if by feeding these microbes demonstratable effects could be seen,” said Prof John Cryan, one of the study’s lead authors and principal investigator at APC Microbiome Ireland.

“Our study provides one of the first data in the interaction between diet, microbiota and feelings of stress and mood.”

Dr Kirsten Berding, a nutritionist and Irish Research Council postdoctoral fellow, collaborated with Cryan and Prof Ted Dinan to design a diet for the study, which was published in Molecular Psychiatry last week.

The researchers studied participants with relatively low-fibre diets and measured their perceived levels of stress. Participants were then split into two groups for a period of four weeks.

One group consumed food based on a psychobiotic diet including fruits and vegetables high in prebiotic fibres, grains and legumes, as well as fermented foods such as sauerkraut, kefir and kombucha. The control group received general dietary advice based on the food pyramid.

It was found that those following the psychobiotic diet experienced a reduction in perceived stress at the end of four weeks, with those who most closely followed the psychobiotic diet experiencing stronger decreases in perceived stress.

There were also significant changes in the level of 40 chemicals, while only subtle changes in microbial composition and function were observed. Quality of sleep improved in both the groups.

“Using microbiota-targeted diets to positively modulate gut-brain communication holds possibilities for the reduction of stress and stress-associated disorders, but additional research is warranted to investigate underlying mechanisms,” added Cryan.

Dinan, who is a principal investigator at APC Microbiome and was co-lead author on the study, said that psychiatrists “rarely” give patients dietary advice – a trend he hopes this study will change.

“Our research in recent years provides evidence that an appropriate diet is essential in managing stress-related disorders. Hopefully, the current paper will encourage psychiatrists to include nutritional advice as part of holistic patient management.”

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Vish Gain is a journalist with Silicon Republic