Irritable bowel syndrome and diet – NHS – NICE

What is irritable bowel syndrome (IBS)?

IBS is a very common condition. It describes a wide range of symptoms that vary from one person to another and can be worse for some people than others.

The most common symptoms are:
wind and/or bloating
• diarrhoea or constipation, or both
• low abdominal pain, which may ease after opening the bowels or be accompanied by a change in bowel habit or stool appearance
• passing mucus
• feeling the need to open the bowels even after having just been to the toilet
• a feeling of urgency
• feeling that your symptoms are worse after eating.

If you have any of the following symptoms consult your doctor immediately:
unintentional and unexplained weight loss; rectal bleeding; a family history of bowel or ovarian cancer; if you are over 60 years old, a change in bowel habit to looser and/or more frequent stools for more than 6 weeks. Before attempting to manage symptoms via your diet, it is important to rule our other medical conditions, and to have a diagnosis established by your doctor or healthcare professional.

Ensure that you:
• eat regular meals
• do not skip meals or eat late at night
• take your time when eating meals
• sit down to eat and chew your food well
• take regular exercise – for example, walking, cycling or swimming
• make time to relax.

Helpful hints:
• keep a food and symptom diary to see if diet affects your symptoms. Remember symptoms may not be caused by the food you have just eaten, but what you ate earlier that day or the day before.
• give your bowels time to adjust to any changes that you make.

Make changes according to your current symptoms

For symptoms of wind and bloating
• Limit fruit to 3 portions a day (including up to 1 portion of dried fruit if wanted) and fruit juice to 1 small glass a day. Remember to make up the recommended ‘5 a day’ with vegetables.
• Try reducing your intake of resistant starches (see below). • Oats and golden linseeds may also help with symptoms of wind and bloating. • If you wish to try ‘probiotics’ the information under ‘symptoms of diarrhoea’ overleaf may be useful.

Fresh fruit = 80 g
How much is 1 portion of fruit or vegetables?
• 1 apple, banana, pear, orange or similar sized fruit,
• 1⁄2 grapefruit, 1 slice of large fruit (melon, pineapple)
• 2 plums
• a handful of grapes, cherries, berries
• 3 heaped tablespoons fruit salad (fresh, tinned, stewed)

Dried fruit = 25 g

• 1 heaped tablespoon raisins, figs, apricots

Vegetables = 80 g

• 3 heaped tablespoons raw, cooked, frozen or tinned vegetables
• a dessert bowl of salad

Resistant starches

These are the starches in foods that are not completely digested by the body. They enter the bowel where they ferment and produce gas. Try reducing your intake of the following foods:
• pulses, whole grains, sweetcorn, green bananas and muesli that contains bran
• undercooked or reheated potato or maize/corn – instead eat them freshly cooked and still hot
• oven chips, crisps, potato waffles, fried rice – choose baked potatoes or boiled rice
• part-baked and reheated breads, such as garlic bread, pizza base – choose fresh breads
• processed food such as potato or pasta salad, or manufactured biscuits and cakes
• ready meals containing pasta or potato, such as lasagne, shepherd’s pie, macaroni cheese • dried pasta – use fresh pasta instead.

For symptoms of diarrhoea
• Replace lost fluids by drinking plenty – at least 8 cups a day. Choose water or non­ caffeinated drinks – for example, herbal teas or sugar-free squash.
• Limit fizzy drinks.
• Try not to have alcohol every day and then have no more than 2 units a day.
• Restrict intake of caffeinated drinks (for example, tea, coffee or cola) to 3 cups a day.
• Limit insoluble fibre intake from wholegrain breads, bran, cereals, nuts and seeds (except golden linseeds).
• Avoid skin, pips and pith from fruit and vegetables.
• Limit fresh and dried fruit to 3 portions a day and fruit juice to 1 small glass a day.*
*Remember to make up the recommended ‘5 a day’ with vegetables.
• Limit intake of foods high in resistant starches (see box overleaf).
• Avoid sugar-free sweets (such as mints and gum) and food products containing sorbitol.
• Live ‘probiotic’ yoghurts, supplements or fermented milk drinks: if you choose to try them you will need to take them daily for at least one month at the dose recommended by the manufacturer to see if they are likely to help. Monitor the effect on your symptoms. If a product does not appear effective, you could consider another brand as the types of bacteria used vary between products.
• Diarrhoea may also be caused by a high intake of fatty foods. Avoid foods high in fat, such as chips, fast foods, burgers and sausages, crisps and cakes. Try low fat versions.

For symptoms of constipation
• Dietary fibre may help with constipation but tends to generate gas, stimulate contractions and make pain, bloating, flatulence and diarrhoea worse. NICE clinical guideline 61 advises that fibre intake should be adjusted according to its effect and reduced if necessary. If you do increase your fibre intake, do so gradually, because any sudden increase may make symptoms worse.
• For symptoms of constipation only, you could try whole grains, along with fruit and vegetables, introducing no more than 1 extra portion over a 2 day period.
• Oats and golden linseeds are good sources of soluble fibre, which help to soften the stool and make it easier to pass; they may also help with symptoms of wind and bloating.
• Ensure a good fluid intake – at least 8 cups of non-caffeinated fluid a day.
• If you wish to try ‘probiotics’ the notes under ‘symptoms of diarrhoea’ may be useful.

Golden linseeds
Can be added to foods such as breakfast cereal, yoghurts or soups. If necessary, take up to 1 tablespoon a day. Give your bowels a few days to adjust to the effect. Remember to wash down the linseeds with plenty of non-caffeinated fluid, and to drink up to 8 cups of fluid a day

Could my symptoms be due to food allergy or intolerance?
Because IBS symptoms are often worse after eating, it is not surprising that food is blamed. True food allergies are rare and are unlikely to cause IBS. However, IBS symptoms could be caused by food intolerance. There is no convincing evidence to support any of the commercially available food intolerance tests. If you feel your symptoms are due to food intolerance, ask your doctor to refer you to a registered dietitian.

Useful contacts:
The Gut Trust. Helpline: 0114 272 3253
BDA website:
NICE website:
Authors: Liane Reeves and Miranda Lomer (2008). Revision of: Bravin and Reeves (2007) Irritable bowel syndrome and diet, BDA, UK.