DIARRHOEA

Causes

When food is swallowed, it passes from the stomach into the small intestine. Waves of muscular contractions move it along the gut as nutrients are taken up for the body to use. It then passes into the large intestine (the bowel), where most of the remaining water is absorbed, and from there into the rectum. The moist faeces then pass out of the body via the anus, which is controlled by a ring of muscle called the anal sphincter. When the normal digestive process is disturbed and the bowel becomes irritated, the faeces remain liquid and are therefore expelled quickly, resulting in diarrhoea.

This can happen for a number of reasons. For example, certain drinks can upset the digestive system and prevent it from working normally. Also, eating spicy foods such as curry can irritate the lining of the gut, which then speeds up its action to get rid of the irritation. Problems are even more likely to arise from eating infected food or contaminated water.

The holiday myth

Although it is commonly assumed that diarrhoea usually only occurs on holidays abroad, it can be just as much of a problem in this country, and for just the same reasons. Heavy drinking sessions, sudden changes of diet, and poor standards of food hygiene at home or when eating out, can all result in diarrhoea - with predictable consequences.

Associated problems

Everyone knows the embarrassment of having to rush to the toilet to answer an urgent call of nature, especially in a work situation. On a social level, diarrhoea can make it necessary to cancel outings without notice, or to cut short an evening out.

Diarrhoea also causes physical discomfort, such as stomach cramp. This happens when infected food is eaten, because the gut's natural reaction is to protect the body from infection by expelling the food from the system as quickly as possible. This means that the bowels are working much faster and more strongly than normal in order to get rid of their contents. However, they may continue doing this for a while even when there is no more food to process, resulting in abdominal pain.

As foodstuffs and fluid have not been absorbed properly, a bout of diarrhoea may lead to dehydration and loss of essential salts and minerals. Children are particularly vulnerable, as their bodies are less able to tolerate the effects of diarrhoea.

It should also be borne in mind that diarrhoea can interfere with the effectiveness of any medications which need to be taken regularly, such as the contraceptive pill. For advice on this, or if diarrhoea lasts longer than 24 hours, consult a doctor. A GP should certainly be consulted as soon as possible if at any time there is blood in the faeces.

Avoiding dietary upsets

Working out which types of food irritate the digestive system is largely a matter of trial and error. Each individual reacts differently to the food he or she eats, and even foods which form a normal part of the diet can cause problems on some occasions. Age can also influence whether or not the body reacts badly to certain ingredients. Some older people may not be as able to digest certain foods as they were when they were younger.

In general, however, it is best to avoid eating large, spicy meals (such as curries) if unused to them. Alternatively, combine a small portion with something more bland, such as rice, pasta or a cooling side-order of plain yoghurt. Also try doing this when eating rich food, for example sauces or red meats. Fruit is good because it contains a lot of fibre, which encourages the gut to work harder, but eating too much, too quickly, may also result in diarrhoea.

If prone to occasional bouts of diarrhoea, it is worth keeping a diary of what is eaten in order to identify the "trigger" foods. Most meals take about 24 hours to be digested, but this speeds up considerably in the case of diarrhoea. If several different types of processed food have the same effect, they may well contain a common ingredient which causes the problem. Check the label to see if this is the case.

Choosing the right drinks

Different drinks contain a wide variety of nutrients and/or irritants, which can also have different effects on the body. Neat spirits can inflame the lining of the stomach. This may then lead to over-activity of the bowel, resulting in diarrhoea. Because of this, it is best to limit intake of spirits and to avoid drinking on an empty stomach. Because drinks such as stout or real ale contain a high proportion of hops, digestive problems are likely to occur if large quantities are drunk. Alternating each drink with a glass of water and simply drinking more slowly can also aid digestion.

Fruit juices, particularly those containing pulp, can stimulate the digestion (due to their fibre content). While this is useful in the case of constipation or simply as part of a healthy diet, large amounts can lead to diarrhoea.

Squash and canned drinks often contain a lot of sugar, which can again encourage the expulsion of waste products. Check the label on bottles or cans to see how much sugar they contain, and if necessary switch to a different brand.

Milk and water are unlikely to irritate the stomach or bowel, but as with any other beverage, it is best not to drink large amounts of cold liquids very quickly.

Checking standards of food hygiene

One of the most common ways of getting diarrhoea is through infection by salmonella or staphylococcus bacteria. These tiny organisms are easily transferred from one person to another by poor hygiene practices, most of which can easily be avoided.

Eating out

Restaurants, fast food outlets, sandwich shops and delicatessens are obliged to follow strict regulations of food preparation and service. If they do not follow these, the local Environmental Health Inspector can take steps to close them down. But there are a number of ways to safeguard one's own health by deciding whether or not to eat there.

People handling food should be neat and tidy, with short, clean fingernails and hair tied back to prevent it falling on the food. Their cuffs should not fall over their hands, and they should change their aprons if these become dirty. Avoid places where the staff wipe their hands on their aprons rather than regularly washing and drying them with a disposable towel, or where somebody who handles food also handles money.

Take a look at the way that food in a shop is stored, weighed, and served. Cooked meats should be stored separately from uncooked meats and kept under refrigeration. Fresh food should be stored in new containers, rather than being added to the food currently on display. Ideally, slices of meat and cheese should be handled with tongs or picked up with a piece of plastic film wrapping to avoid contamination from hands. When weighing goods, staff should first place plastic film underneath them to keep the scales clean. If this kind of care is not taken, any infection can quickly spread to other foods.

In a restaurant, it may be possible to take a quick glance at the kitchen if it opens off the dining area. If not, the standards of hygiene can be assessed to some extent by the appearance of the waiters and the cleanliness of the table.

At home

When buying chilled or frozen food, pack it together to keep the temperature low until reaching home. In a car, use a coolbox with frozen ice-packs to keep the shopping cold in summer. Because bacteria grow so quickly under warm conditions, make it a priority to get food home and into the refrigerator or freezer as soon as possible.

Before storing fresh items, check what is already in the refrigerator and rotate it if necessary. Keep an eye on the "Best Before" dates marked, and be prepared to throw food away if the date has passed. Even freezer food will not keep longer than a few months at the most, so check the star rating on the packet.

Also check the temperature of the refrigerator regularly with a thermometer, bearing in mind that the amount of food stored, the closeness of heat sources in the kitchen, and the effectiveness of refrigerator door seals can all affect this.

To avoid the risk of cross-infection, store cooked and raw meats separately, and ensure that meat juices cannot drip onto the shelf below. Eggs should be kept in the refrigerator, and eaten within two weeks to ensure freshness. Wipe refrigerator surfaces with a disinfectant cloth each week, and clear up any spills quickly.

Make sure that frozen food, especially chicken, is thoroughly defrosted before it is cooked, and do not re-heat it unless able to keep it at a sufficiently high temperature for long enough to kill any bacteria which may be present. And, of course, always wash the hands before and after handling food.

By following these simple precautions, you will safeguard your own and your family's health.