• Encourage people with irritable bowel syndrome (IBS) to try to identify sources of stress, and discuss ways to create relaxation time.
• Give general advice regarding diet.
• High fibre diets are not recommended for people with IBS.
• Advise the person to adjust their fibre intake according to their symptoms:
• Fibre intake often needs to be reduced in people with IBS. Advise people to reduce their intake of insoluble fibre, such as wholemeal or high fibre flour and breads, cereals high in bran, and whole grains such as brown rice.
• If more fibre is needed, recommend soluble fibre supplements (e.g. ispaghula) or foods high in soluble fibre (e.g. oats).
• Consider a trial of wheat or lactose exclusion — seek advice from a registered dietitian before starting single food avoidance and exclusion diets.
• Give people with low physical activity levels brief advice and counselling to increase their activity levels.
• Adults should aim to do 30 minutes of moderate intensity physical activity on at least 5 days of the week.
• This can be achieved either by doing all the daily activity in one session, or by doing several sessions of at least 10 minutes.
• The activity can be lifestyle-based (e.g. climbing stairs, walking, or cycling), structured exercise (e.g. attending a dance class or fitness training session), sport, or a combination of these.
• Increased physical activity may not be appropriate for people with diarrhoea-predominant IBS, and people with certain medical conditions.
• Discuss the use of probiotics where appropriate. Advise people who wish to try probiotics to choose one brand and:
• Take them for at least 4 weeks while monitoring the effect.
• Take them at the dose recommended by the manufacturer.

There is a lack of good quality evidence on the role of lifestyle modification in the management of irritable bowel syndrome.

• These recommendations are consistent with the National Institute for Health and Clinical Excellence guidance Irritable bowel syndrome in adults [National Collaborating Centre for Nursing and Supportive Care, 2008; NICE, 2008].

Basis for encouraging people to create relaxation time

• Stress commonly aggravates irritable bowel syndrome (IBS). Around half of IBS outpatients attribute the onset of symptoms to a stressful event [National Collaborating Centre for Nursing and Supportive Care, 2008].

Basis for not recommending a high fibre diet

• Based on their clinical experience of adverse effects of a high fibre diet in people with IBS, the Guideline Development Group (GDG) unanimously agreed that the practice in primary care of recommending high fibre diets to people with IBS should stop [National Collaborating Centre for Nursing and Supportive Care, 2008].

Basis for modifying fibre intake

• Evidence from nine RCTs (n = 545) shows that significantly more people have improved global symptoms of IBS when taking fibre compared with placebo.
• Subgroup analysis suggests that soluble fibre is more effective than insoluble fibre.
• Evidence from several small RCTs suggests that fibre does not significantly improve pain or bowel habit compared with placebo.
• Evidence from one RCT (n = 80) suggests that fibre increases bloating compared with placebo.
• Evidence from two RCTs (n = 281) shows that significantly more people have improved global symptoms of IBS when taking soluble fibre compared with insoluble fibre; however there is no significant difference in pain or in improvement in bowel habits.
• The consensus of the GDG was that insoluble fibre should not be recommended for people with IBS as it is ineffective in the management of symptoms and may even increase symptoms in some people [National Collaborating Centre for Nursing and Supportive Care, 2008].
• The GDG suggested that GPs should investigate the person's usual fibre intake with a view to modifying fibre levels to suit the symptom profile and they should monitor the person's response to dietary modification [National Collaborating Centre for Nursing and Supportive Care, 2008].
• It may be preferable for the dietary fibre intake to be closer to 12 grams per day than 18 grams per day.

Basis for considering a trial of wheat or lactose exclusion

• The role of dietary modification in the management of IBS is uncertain. Some experts recommend a trial of wheat or lactose exclusion [Spiller, 2007; Spiller et al, 2007], although there is little evidence to support this.
• Approximately 10% of people with IBS have lactose intolerance [Spiller et al, 2007]. There is weak evidence from one RCT (n = 70) that a lactose restricted diet produces a significant difference in symptom score in people with lactose intolerance, but not in those who are tolerant of lactose [Bohmer and Tuynman, 1996].
• In people with IBS, wheat consumption is often associated with increased symptoms which may be due to the content of fibre, fructans, or resistant starch. Increasing the variety of other cereals and reducing, but not necessarily excluding, wheat may be beneficial [National Collaborating Centre for Nursing and Supportive Care, 2008].

Basis for recommending that exclusion diets only be undertaken under supervision of a registered dietitian

• The GDG was concerned that excluding individual foods or complete food groups without appropriate supervision can readily lead to inadequate nutrient intakes and ultimately malnutrition. In addition, symptoms often remain unresolved leading to further inappropriate dietary restriction [National Collaborating Centre for Nursing and Supportive Care, 2008].

Basis for recommending an increase in physical activity in people with IBS

• This recommendation is based on limited indirect evidence and evidence from epidemiological studies.
• Evidence suggests that regular physical activity can improve gastric emptying and colon transit time, however, CKS found no direct evidence on the effect of regular physical activity on symptoms of people with irritable bowel syndrome.
• Evidence regarding the association between physical activity and IBS in the general population is inconclusive.
• The GDG also took into account the NICE public health intervention guidance [NICE, 2006] and the Chief Medical Officer's report on physical activity [DH, 2004].
• There is evidence that a programme of physical activity reduces the percentage of hard and incomplete stools in constipated people without IBS.

Basis for considering the use of probiotics

• Probiotics are microbial food supplements which, when administered in adequate amounts, have a beneficial effect on the host.
• These recommendations are based on evidence from 13 RCTs. However, 11 of these studies included fewer than 100 people, the majority were undertaken in secondary care, and there was significant heterogeneity between the studies.
• The consensus of the GDG was that [National Collaborating Centre for Nursing and Supportive Care, 2008]:
• Probiotics were not harmful, were widely available, and may benefit some people with IBS as part of their diet.
• Although there is some evidence from single trials, it was not sufficient to recommend named bacteria or probiotic products.