Features

Lifting the lid on farting and flatulence

by Cathy Johnson

Love the idea of a healthy high-fibre diet but not so keen on its after effects? Fear not. There's more to farting than meets the eye (or even the nose).



[Image source: iStockPhoto | lucielang ]

Does eating a chickpea curry make you fearful of sharing a confined space like a car, office or elevator with others?

Or perhaps you steer clear of cabbage, onions and baked beans to avoid 'trouser coughs'.

All these high-fibre foods get the nutritionist's tick of approval. But they also have a well-deserved reputation for generating intestinal gas, says Gut Foundation president Dr Terry Bolin, who confesses to a strong personal interest in farting, flatulence and bloating.

Why farts smell (or don't)

While we all pass wind  no-one is immune  incredibly, as many as 60 per cent of us never produce smelly farts because we don't have the particular bacteria responsible for the bad odours living in our guts, Bolin says.

"About 40 per cent of the population produce smelly gas, others don't."

If you've got the smell-producing bugs  and it shouldn't be hard to tell  it pays to know they love sulphites, which are present in large amounts in foods like cabbage, broccoli, onions, brussel sprouts, peas, leeks and garlic. There are also lesser amounts in eggs, milk, nuts, seafood and meat. Sulphites are also added to some processed foods during manufacturing, for example long life fruit juices and dried fruit as well as deli meats and wine.

Spices can also contribute to the bouquet of your gas so a curry of any type may be a valid reason to avoid those shared confined spaces. When the curry contains chickpeas, there's double the reason to seek time alone.

But it's the fibre in foods that's the biggest trigger for farting and yes, if you increase your fibre intake, you will produce more gas. But Bolin says it's a small price to pay for the benefits a high fibre diet brings. It wards off constipation and also generates fatty acids that nourish the lining of colon and help prevent diseases like bowel cancer.

Excessive sugar, especially artificial sweeteners, can also give you flatulence, however  even fruit can be problematic if you eat a lot  as can large amounts of milk and ice cream if you're lactose intolerant.

But the idea swallowed air from things like carbonated drinks could increase farting doesn't wash with Bolin. "I don't think there's much truth to that. I don't believe it anyway."

Why do we fart? Most of the gas we pass is produced in the colon (part of the large intestine) by bacteria which feed on dietary fibre and some types of starches and sugars. Some of the gases the bacteria make are absorbed in the blood and eventually expired on our breath, others are used as energy by the bugs themselves. The rest, about 1500 millilitres a day, is passed out through the anus as "flatus". (Any associated noise is dependent on factors including the volume of gas and your anus size; with a relaxed, large, anus giving a lower pitch than a smaller tight one.) There's a huge range of what's considered normal; it can range from  "some people say nothing, but that's hard to believe, to up to 50 times a day," Bolin says. "Women do pass less gas than men, but whether that's social responsibility or less gas, no-one knows." Women average seven farts a day and men about 12, he says. (Yes, it's actually been counted. He and nutritionist Rosemary Stanton once did a landmark study in which participants were given hand held metal counters to click each time they broke wind.)

Should you worry about your farting?

Farting is perfectly normal and certainly never life-threatening  although those around you may at times feel otherwise. But if you want to reduce it, you need to know that each of us responds differently to different foods.

So you probably need to experiment with cutting out potential offenders and reintroducing them one at a time to see which ones affect you.

The same advice applies to those whose problem is not so much the gas that gets out, but rather the gas that stays in, making them feel bloated and uncomfortable. (Holding farts back for social reasons can sometimes cause this problem, Bolin says.)

Any reintroduction of fart-inducing foods, or indeed any attempt to eat more fibre generally, should be gradual  over a period of weeks or months as this helps your body learn to tolerate it better.

You don't need to switch to a poor diet, just to eat foods you find problematic in moderation; "beans, chickpeas and lentils are notorious," Bolin says (although soaking them for long periods and throwing away the soaking water before cooking helps).

You could try changing your bread to those made from grains such as spelt (an ancient form of wheat) or rye as these are still high in fibre, but for some reason seem to generate less gas in most people, he says.

"You've got to eat enough fibre to overcome constipation, but avoid fibre that's going to give you symptoms of bloating and pain [or excessive farting]. You have to match your fibre to your stool [poo] output. The aim of everyone is to produce a sausage a day at least  preferably a kransky rather than a chipolata."