Those eating just wheat said they felt more tired and bloated as a result

whole grains went to the toilet twice as often

It's perhaps an unwelcome side-effect but flatulence can be a sign you're eating healthily.

People who eat whole grains have from more of a gas build up than those who don't, a study has found.

Those who switched to whole grain versions of foods - including bread, cereal, pasta and rice - noticed their food took longer to pass through their intestines than those limited to wheat.

They made more frequent trips to the toilet and passed wind more often than they used to.

People who eat whole grains - including brown bread, wholewheat pasta, rice and cereals - suffer from more flatulence than those who don't, a study has found

But while flatulence may be embarrassing, experts said it is actually a sign of good health as passing air prevents bloating.

Moreover, those eating just wheat said they felt more bloated and tired as a result.

A whole grain food means that it contains all the essential parts and naturally-occurring nutrients of the entire grain seed.

In non-whole-grain foods, the husk and other parts of the grain, which contain fibre and vitamins, are removed.

Previous research has shown eating whole grains can lower the risk of heart disease, stroke, type 2 diabetes and can help manage weight.

As part of their study, Danish researchers recruited 75 participants to analyse the effects of wholegrains on the gut.

Some replaced grain products with whole grain versions, and were compared against a control group who ate no whole grains.

Lead author Stine Vuholm, research assistant at the Institute of Sports Science and Nutrition at the University of Copenhagen, Denmark, said 'We saw that those who ate whole grains were more flatulent and had several departures of air during the day.

'Those who didn’t eat whole grains, felt more bloated and tired during the same period.'

Those who ate whole grains noticed that their food took longer to pass through the intestines than those limited to wheat.

WHITE BREAD AND PASTA 'MAY INCREASE THE RISK OF DEPRESSION' A diet of white bread and rice could increase the risk of depression in older women, research suggests. But whole grain foods, roughage and vegetables could reduce it. Refined foods cause blood sugar levels to spike rapidly – prompting the body to pump out the hormone insulin, which helps break down the sugar. But this process can cause symptoms of depression, according to the study. The findings, published in The American Journal of Clinical Nutrition, could pave the way for depression being treated and prevented using nutrition. Advertisement

She also noticed a 'moderate' increase in them visiting the toilet - going around twice as often.

'Many of the components in the diet are broken down by the enzymes in the intestine', Ms Vulholm explained.

'However, dietary fibre cannot be degraded, and it ends up in the large intestine where it becomes fermented by the intestinal bacteria.

'Here it forms gas, and this may be one explanation as to why the participants had more air in their stomachs.'

She added that more frequent trips to the toilet might not sound enticing but it’s actually a sign of good health.

She said: 'It may be socially inconvenient, but it's good to get rid of this air.

'If you can’t get rid of gas in the intestine it can cause abdominal pain and make you feel bloated.'

The control group reported not eating whole grains made them more bloated and tired than they used to be, however Ms Vuholm says this could be psychological.

While a lack of whole foods could destabilise blood sugar levels, it could also simply be a matter of perception.

They may associate eating unhealthy foods with such symptoms, she said.

However, given the vitamins and fibre in whole grains, it makes sense people who forgo them feel worse, she added.

"When you refine grains, you remove the husk and many other parts, and this removes vitamins and other beneficial substances.

'So it’s no wonder that people who eat whole grains feel better,' she says.

People eating just processed wheat rather than whole grains said they felt more tired and bloated as a result

In addition to asking the subjects how they felt, the researchers examined over 100 bacteria from the gut and found no changes in gut bacteria.

Ms Vulholm said she was 'surprised' by this but added that intestinal microbes require a lot to change.

'It may not be enough to change just one part of the diet,' she said.

Tine Rask Licht, professor at the National Food Institute, Denmark, who was not involved in the new study but also studies intestinal bacteria, said similar studies have also failed to observe any major changes in intestinal flora.

However, this may be due to researchers not using sensitive enough methods to detect changes in bacteria, she said.

She said: 'Although the composition of the intestinal flora may not have changed, you can see that the activity of intestinal flora has.