You need to fart but you're teaching. Do you let go and blame the pong on the chemistry department or hold it in, asks Phil Hammond. Is it possible to control your farting? It's an interesting question and perhaps not one you'd expect to find in an education magazine, but there are few things guaranteed to cause class merriment more than a windy teacher. Healthy men let one go between 14 and 25 times a day and women half as often, although women tend to produce a stronger smell.
In socially embarrassing situations (class 7Z), it is possible for some of the wind to be absorbed through the gut wall, into the bloodstream and out via the lungs. Indeed, one study found that people who hold their wind in exhale more hydrogen. Others, particularly the older teacher and mother of four, are slacker down below and find it hard to hold on.
So, how does the wind get there? Every time we swallow, we gulp in air, and fizzy drinks compound this. Bicarbonate in the saliva and pancreatic juices react with stomach acid to produce carbon dioxide and many of our gut bacteria react with whatever is passing through to produce methane, hydrogen and more CO2. All of these cause wind, but it is the tiny amounts of sulphur-containing gases that make it smell.
Farting and belching in the absence of other symptoms are entirely healthy. The Dutch Liver Foundation once launched a publicity campaign encouraging people to break wind 15 times a day. Other studies have shown that a forceful, moist fart can spread gut and skin bacteria over a Petri dish some distance away.
A happy medium would be to go easy on foods with a high proportion of unabsorbable carbohydrate, which provide a feeding frenzy for the lower gut bacteria. These include beans, peas, broccoli, cauliflower, Jerusalem artichokes, root vegetables, raisins, prunes, apples and fruit juice. You'll note that all of these are supposed to be very good for you and wind is the price you pay for a healthy diet and bowel.
A lot of slimming products contain sorbitol and fructose, which also cause wind. Fizzy drinks, gulping, eating too fast and overeating stack up the gut with wind that will escape either up or down, as does smoking, chewing gum and sucking on pen tops. Tight clothing and "hold in" underwear also give your bowel gas fewer options.
A brisk walk before a lesson is a great way of relieving the pressure and a charcoal biscuit or tablet can minimise the smell. Chemists have other anti-flatulence products and in extreme cases, Under-Tec pants have a carbon filter gusset or you can buy a cushion called a Flatulence Filter to absorb the smell. If you're desperate, you can blame it on a pupil or the dog. If you're like me, you'll put on an Australian accent and proclaim: "Better out than in". Merry Christmas, pass the sprouts.
Phil Hammond is a GP, school governor and author.