Irritable bowel syndrome cannot be considered a disease; rather, it is a common syndrome (a group of symptoms) made up of: altered bowel movements, increased sensitivity of the digestive tract and increased reactivity of the gut to external and internal stimuli. Irritable bowel syndrome does not cause indigestion or malabsorption of nutrients. In IBS there is no clear inflammation or tissue damage.
In everyone with the condition, the nerve–gut system is sensitive to the presence of food, its chemical components and its quantity. Irritable bowel syndrome causes regular contractions of the large intestine. In a person with irritable bowel syndrome (IBS), the strong urge to open the bowels may come sooner and may be accompanied by abdominal pain, cramps and diarrhoea.
Prevalence: symptoms first appear between adolescence and the fourth decade of life, but many people do not discuss their problem with a doctor. The syndrome has been reported in 15 per cent of women and 10 per cent of men. Signs and symptoms: irritable bowel syndrome usually has one of three symptoms: diarrhoea, constipation or abdominal pain. However, patients may have a combination of all of them.
Bloating, a feeling of incomplete emptying and mucus in the stool may also occur. Stressful factors can trigger the syndrome or make its symptoms worse.
Contributing factors: in addition to dietary patterns and stress, factors that may make symptoms worse include: heavy use of laxatives or antibiotics, caffeine, a history of stomach or bowel disease, and disturbed regulation of sleep, rest and fluid intake. Treatment: irritable bowel syndrome is a functional disorder, which means it relates to how the bowel works, not to a structural defect.
Therefore, treating the symptoms is the key to reducing pain and discomfort. Education, medication, counselling and diet all play an effective role in treatment. The important point is that people should follow a diet that ensures an adequate intake of nutrients while also preventing digestive symptoms as far as possible. Diet: many people say that their symptoms start after eating certain foods.
As a result, the foods that trigger symptoms should be identified and avoided. Compared with healthy people, these people react more strongly to careless eating and to psychosocial factors. Healthy people may also experience mild stomach and bowel upset in response to all of the factors mentioned.
Stressful life events, such as a change of job, travel, moving home or uncomfortable social situations, may trigger symptoms or make them worse, and may overshadow many treatment efforts.
Increasing dietary fibre may help normal bowel movements to some extent. If the patient cannot get enough fibre from food, fibre powder supplements can be used, and they must be taken with adequate amounts of fluid.
In these patients, excess dietary fat, caffeine (coffee and tea), sugars such as lactose and fructose (milk and dairy products and some fruits) and heavy meals are tolerated less well than in healthy people. In patients with a family history of allergy, sensitivity to particular foods may be the cause of IBS. In this situation, an elimination test (removing foods and checking the result) may help identify the main food trigger.
Dietary recommendations
- Drink 6 to 8 glasses of water a day. This is especially helpful if you have diarrhoea. Fizzy (carbonated) drinks can increase discomfort because of the gas they contain.
- Eating more fibre is helpful. Dietary fibre often helps to reduce IBS symptoms both in patients with diarrhoea and in those with constipation. Wholegrain cereals and bran bread, fruit and vegetables are rich sources of fibre. Eating large amounts of wheat bran over a long period is not recommended, as it may make symptoms worse in some people with IBS. Starting a high-fibre diet can increase gas and bloating for a few weeks, so it is recommended that you add fibre to your diet gradually.
- Try to eat smaller meals more often. Large amounts of food can cause cramps and diarrhoea.
- Eating foods that contain beneficial bacteria, such as yoghurt, or taking a probiotic supplement is helpful: increasing beneficial bacteria can help return the gut's microbial balance to normal or prevent disease-causing bacteria from attaching to the bowel wall.
- Avoid foods that cause you problems. Alcohol, chocolate, caffeine and sugar-free sweeteners such as sorbitol and mannitol can trigger symptoms. High-fat foods can also make symptoms worse. Eating dried fruit, commercial fruit juices or large amounts of fruit – especially plums, peaches and nectarines, mango, watermelon, apples, apricots, cherries, black mulberries and persimmons – or vegetables such as okra, garlic, onions and Persian shallots (musir), cabbage, mushrooms and beetroot, as well as pistachios, honey and wheat products, may also cause bowel discomfort.
- Eat at regular intervals. Eating at regular times can improve how your bowels work.
- Antidiarrhoeal medicines and laxatives are not made for heavy or long-term use. Talk to your doctor.
- Low-fat foods reduce bowel contractions after eating, which means they reduce abdominal pain.
- Do not eat foods that cause gas and bloating. These include: all kinds of cabbage, onions, spring onions, green peppers, lentils, chickpeas, beans and fizzy drinks.
- Do not chew gum, because it makes you swallow a lot of air.
- If you get diarrhoea after eating dairy products, you probably have lactose intolerance and should avoid dairy products.
If you would like to have dairy products, you can add them to your diet gradually in small amounts, or use lactose-free products. Reducing stress and anxiety: avoid stressful situations. Helpful ways to reduce stress include counselling, concentration exercises, regular exercise, muscle relaxation, deep breathing, and so on. Physical activity and exercise: exercise regularly.
Many patients report that their symptoms improve simply by walking for half an hour a day. Exercise is also effective in reducing stress.
Prepared and compiled by: Fereshteh Nakhaei, Nutrition and Diet Therapy Specialist – Education Unit
Document code: NSH-NU-BR-37