Eating high-fibre foods may reduce the effects of stress on our gut and behaviour, it has emerged.
Interest has been growing in recent years in the link between gut bacteria and stress-related disorders including anxiety, depression and irritable bowel syndrome. Bacteria in the gut produce short-chain fatty acids the main source of nutrition for cells in this part of the body. Foods such as grains, pulses, and vegetables contain high levels of fibres and will stimulate the production of these short-chain fatty acids.
The study, conducted by scientists at APC Microbiome Ireland at University College Cork and Teagasc food Research Centre, found there was decreased levels of stress and anxiety-like behaviour when short-chain fatty acids were produced.
Stress experienced over a long period can affect the bowel by making the barrier between inside the gut and the rest of the body less effective and leaky.
This means that undigested food particles, bacteria, and germs will pass through the leaky gut wall into the blood and cause persistent inflammation.
Treating with short-chain fatty acids can reverse this leakiness. Developing dietary treatments that target the bacteria will be important for treating stress-related disorders.
The study was published in The Journal of Physiology. It involved feeding mice the main short-chain fatty acids normally produced by gut bacteria and then subjecting them to stress.
Using behavioural tests, the mice were assessed for anxiety and depressive-like behaviour, stress-responsiveness, cognition, and sociability, as well as how easily material passes through the gut.
The exact mechanisms by which short-chain fatty acids facilitate their effect remains undetermined.
Senior research author John Cryan said they had been showing for some time that microbes in the gut were really important for brain health and stress.
Scientists have started testing short-chain fatty acids in humans to see if they can be delivered in different ways. A recent British study showed how they were getting to the brain.