How an apple a day could keep the stress away

IN TIMES of stress, many of us turn to comfort food – but it seems high-fibre snacks could help us calm down, a study by Irish researchers suggests.

Fruit, vegetables and wholegrains are a prime source of substances called short-chain fatty acids.

Eating high-fibre foods reduces stress levels in the body and may prevent food and bacteria leaking from the gut into the blood, a study shows.

The link between the bacteria in our bodies and our behaviour – particularly anxiety and stress – is a growing area of scientific research.

High-fibre foods – the roughage found in fruit, vegetables and in wholegrains – are the prime source in the body of substances called short-chain fatty acids (SCFAs).

Researchers at University College Cork and others found that over a long period of time, low levels of SCFAs cause the gut to become less effective and ‘leaky’. The researchers said the leaky gut wall allows undigested food particles, bacteria and germs to pass into the blood and cause persistent inflammation.

Studies in mice found that those whose diet was supplemented with SCFAs showed less anxiety and depressive-like behaviour, were more sociable and had better cognitive skills.

The researchers suggest that the SCFAs have an effect in the brain in reducing feelings of anxiety as well as in preventing the gut from ‘leaking’.

The inside of the bowel is lined by a single layer of cells that make up the mucosal barrier between the inside of the gut and the rest of the body.

This barrier is effective at absorbing nutrients, but prevents most large molecules and germs from passing from inside the bowel into the bloodstream, where they could potentially cause inflammation.

Professor John Cryan, the corresponding author on the research, commented on the findings: ‘There is a growing recognition of the role of gut bacteria and the chemicals they make in the regulation of physiology and behaviour.

‘The role of short-chain fatty acids in this process is poorly understood up until now.

‘It will be crucial that we look at whether short-chain fatty acids can ameliorate symptoms of stress-related disorders in humans.’

Certain substances, such as alcohol, aspirin and painkillers such as ibuprofen can irritate the gut lining, damaging the seal between cells which allow some substances pass through the gaps and into the blood.

Previous research has found that short-chain fatty acids can play a key role in the prevention and treatment of certain cancers, mainly colon cancer. One SCFA, butyrate, has been found to keep colon cells healthy and prevents tumours from growing.

Diets high in fibre reduced anxiety