CONDITIONS & DISORDERS
IRRITABLE BOWEL SYNDROME This article will be outlining current and potential treatment approaches of IBS, including genetic links in its aetiology. Irritable bowel syndrome (IBS) is the most common functional gastro-intestinal disorder, characterised by abdominal pain and changes to stool frequency, form or both. It is reported to effect on average 11% of the worldwide population.1 Whilst symptoms are not likely to be indicative of physical damage, they can have a significant detrimental effect on quality of life. Global prevalence rates of IBS are estimated to be around 7-21%,4 although the actual incidence may be much higher, as many people may not seek medical help for their symptoms. Twice as many women as men are thought to be affected and symptoms of IBS may cross-over into gender-specific conditions such as endometriosis in some of these women. As a functional gastrointestinal disorder, a diagnosis is made once other medical causes for symptoms have been ruled out. Rome IV criteria may be used to inform a diagnosis of IBS subtype according to stool type: • Diarrhoea predominant (IBS-D), which is the commonest subtype. • Constipation predominant (IBS-C). • Mixed, fluctuating between diarrhoea and constipation (IBS-M). • Unclassified (IBS-U)2. These subtypes are no longer distinct, but are recognised as being on a spectrum, depending on ‘the person’s quantity, intensity and severity of different symptoms’.2 As the diagnosis of IBS is based on exclusion of other medical causes, clinical investigations carried out by a patient’s GP may include: • full blood count (FBC) to assess for anaemia; a raised platelet count may suggest active inflammation as an alternative cause for symptoms; • inflammatory markers, such as
erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), may be raised if there is active inflammation or infection; • coeliac serology to exclude coeliac disease, particularly if there is diarrhoea-predominant IBS or mixed symptoms.3 WHAT CAUSES IT?
The exact cause of IBS remains unclear, as symptoms and pathology differ case to case. Suggested causes of symptoms are: • increased gut sensitivity; • increased or reduced gut motility; • psychological factors, ie, stress and anxiety; • post-infective (following a gastrointestinal infection). As genetic research techniques advance, there has been an interest in identifying factors that may be linked to IBS development. A recent large scale study looked at genetic data from over 346,000 participants in the UK Biobank and from further centres in Europe and the US. A significant association was found between chromosome 9q31.2 and 13 other loci. Variants at locus 9q31.2 were associated with the risk of IBS in women, but not shown in men.5 Whilst the study was well-powered, there was no way to confirm clinical diagnosis of IBS in participants, as donors in the Biobank self-report this data. The identification of this significant risk locus for IBS may help to highlight a link between sex hormones and autonomic nervous dysfunction in people with IBS – interesting insight of the higher incidence of IBS in women – and potentially leading to novel treatments following further research. Early childhood development may also be of importance, with a recent
Jessica English RD Freelance Dietitian, founder at Level Up Nutrition Jess runs Level Up Nutrition, working with individuals on a one-to-one basis in Brighton and online UK-wide. Jess has a special interest in health communications and global public health nutrition.
REFERENCES Please visit the Subscriber zone at NHDmag.com
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CONDITIONS & DISORDERS research paper linking stress in early childhood to the development of IBS at a later age. The study looked at induced stress in rodents using neonatal maternal separation, identifying potential areas for research into the underlying mechanisms of action.6 DIETARY MODIFICATION
IBS is notoriously difficult to treat. Current guidelines recommend diet and lifestyle modifications that patients may struggle to implement and maintain without structured support, and this may be difficult to provide under the NHS. Healthcare providers are encouraged to give as much information, guidance and support as possible to patients. Many people resort to dietary modification to help manage their IBS, with 90% of people reporting that their symptoms are affected by certain foods.7,8 The most common dietary modifications followed by healthcare professionals in the UK include basic NICE guidelines3 and a low-FODMAP diet. NICE guidelines include: • regular mealtimes; • adjusting fibre intake according to symptoms; • adjusting intact caffeine, alcohol, spicy and fatty foods and fizzy drinks; • trial probiotics, if desired, for up to four weeks (no specific probiotic recommended) to determine adequacy. If first-line dietary and lifestyle advice isn’t effective, NICE and the BDA recommend the use of single-food avoidance and a low-FODMAP diet under the guidance of a healthcare professional. The low-FODMAP diet Certain fermentable carbohydrates have been shown to worsen symptoms of bloating, pain, stool form and frequency in people with IBS. The low-FODMAP diet is designed to initially reduce the overall intake of these foods; they are then reintroduced as ‘challenges’, with the overall aim being to develop a personalised tolerable level of FODMAPs whilst maintaining a balanced diet. The low-FODMAP diet has been shown to be effective for many people, although, as it is a very restrictive diet, attrition rates in studies have been high. The diet may also be less effective in people with mainly constipation-predominant IBS symptoms.9 28
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Whilst still in the early stages of development, new research is hopeful of an an assessment to identify suitability for this diet.10 If found to be effective, this could mean a simple and non-invasive faecal analysis to assess suitability for various interventions. This method is, however, limited by the high potential for stool variability dependent on many factors, which may change daily. LIFESTYLE INTERVENTIONS
Although evidence is limited, NICE guidelines recommend that increasing physical activity can have a positive effect on IBS symptoms, potentially due to the stress-reducing effect of such activities, or an associated increase in gut motility. Research into the effect of physical activity has shown that not only could regular physical activity be helpful in reducing symptoms, but a lack of physical activity may even worsen them.12 A small study from 2015 highlighted the longer-term benefits of exercise in those with IBS, with exercises primarily being aerobics, cycling and walking.13 In 2017, a small study also demonstrated an equivalent improvement in IBS symptoms for an intervention involving yoga compared with a low-FODMAP diet.14 Conversely, some types of physical activity, such as higher intensity training, may worsen symptoms, with activities such as running, causing heartburn, diarrhoea and nausea in some people. PHARMACOLOGICAL
There’s limited evidence to support pharmacological agents in the treatment of IBS, with many studies focusing on the effectiveness of antispasmodic agents, such as mebeverine, in conjunction with lifestyle modifications. Antispasmodics are thought to affect pain caused by spasmodic muscle contractions after eating, in patients with IBS. In patients with IBS-D, in particular, this may be helpful as they may have increased contractility in the bowel.15 As there is some evidence of bile salt malabsorption in some people with IBS,16 bilesalt binders may be effective in this population. However, research into this area is limited and lacking well-designed RCTs.17 Other treatments may include: • selective serotonin reuptake inhibitors (SSRIs); • tricyclic antidepressants (TCAs); • laxatives or anti-motility agents.18
CONDITIONS & DISORDERS THERAPEUTIC INTERVENTIONS
Talking therapies, such as mindfulness-based cognitive behavioural therapy (CBT) and gutfocused hypnotherapy, have been shown to be equally effective as a low-FODMAP diet in treating symptoms of IBS.19,20,21 As the physiological link between the gut and the brain continues to be investigated (the gutbrain axis), it’s becoming apparent that people whose IBS is triggered by stress and anxiety may have enhanced gut-brain communication. This could mean that stress and anxiety could influence gut symptoms, or conversely, that gut symptoms may impact on psychological wellbeing. NICE recommends talking therapies such as CBT to help with symptoms where appropriate and a recent RCT showed that both web and telephone-based CBT could be helpful in improving symptoms,22 although this method won’t be suitable for everyone. PRE- AND PROBIOTICS
Although the research base continues to expand, FEDX no - May specific of probiotics 2019.pdf 1 strains 28/05/2019 16:44:29 are currently recommended for IBS, or for
different IBS-subtypes.23 Patients who wish to trial probiotics are recommended to take one brand for a minimum of four weeks and monitor effectiveness, stopping if there are no improvements.3 Prebiotics may also be beneficial in the treatment of IBS symptoms, with a recent small study showing statistically significant improvements equivalent to a low-FODMAP diet for many outcomes.24 CONCLUSION
Due to the varying nature of the condition, individualised treatment remains the ideal pathway for many people to achieve adequate symptom relief. If first-line treatments are ineffective, second-line interventions include a low- or modified FODMAP approach, if appropriate, or other dietary modification alongside lifestyle modification and psychological therapies if suitable. Research is ongoing into the aetiology of IBS, with genetic factors being investigated and potential for future pharmacological therapies resulting from this.
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Call for Research Reviews from NHD and British Lion eggs Network Health Digest (NHD) and British Lion eggs surveyed readers earlier this year about eggs and found that there’s still much about this nutrient-packed food that healthcare professionals are unclear about. To help educate your peers, we would like your original research reviews on the role of eggs in the diet. We are looking for fully referenced articles discussing two key themes: 1. Understanding the fat content and calories in eggs, as well as additional nutritional benefits they offer. 2. Egg safety, especially in relation to babies and older people, and allergy. The best article will be published in NHD later this year and the winning author will
WIN £500 WORTH OF SHOPPING VOUCHERS.
Emma
Entries will be judged by NHD Editor Emma Coates RD and Dietitian and Health Writer, Dr Carrie Ruxton.
Carrie
For a ‘Contributor template’ and further guidance on submissions please email info@networkhealthgroup.co.uk. We look forward to receiving your entries. For more information on eggs please visit www.egginfo.co.uk For the terms and conditions please email: info@networkhealthgroup.co.uk
Deadline for submission Monday 1st July 2019