Effective Management for IBS Sufferers: The FODMAP Diet
Irritable Bowel Syndrome (IBS) is a functional disorder characterised by chronically recurring abdominal discomfort or pain combined with altered bowel habits. Other symptoms include bloating, feelings of incomplete evacuation, presence of mucus in the stool, straining or increased urgency and increased GI distress associated with psychological distress¹.
IBS is one of the most common disorders seen by gastroenterologists with 10 – 20% of adults meeting the diagnosis. These sufferers are often left with inadequate treatment strategies achieving insufficient symptom relief²´³. IBS prevalence is 1.5 times greater amongst females compared to males, is usually diagnosed before 50 years of age and is more commonly seen in lower socioeconomic individuals⁴´⁵. IBS creates a substantial economic burden and poorly impacts on patients’ quality of life, often causing isolation due to symptoms preventing patients from leaving their home⁴´⁶.
Diagnosis is made using the Rome criteria after other medical conditions are ruled out¹. Diagnosis can also be categorised as shown below⁷.
The pathogenesis of IBS is thought to be a combination of a number of factors including visceral hypersensitivity, altered gastrointestinal motility, stress/psychological influences and altered intestinal immune responses. These factors adversely affect motility and sensation and the ability to cope with illness².
When considering treatment options for individuals with IBS, dietary modification is an important and effective option. There are a range of other options available, including hypnotherapy, psychological therapy including cognitive behavioural therapy and pharmacotherapy with antispasmodics, anticholinergics and antidepressants.
A particular dietary approach which is used at an increasing rate, and with good affect, is the FODMAP diet. Approximately 74% of patients respond positively to the diet⁸. The diet involves restricting fermentable short-chain carbohydrates, fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs). The theory is that these poorly absorbed carbohydrates lead to distention of the small and/or large bowel due to their osmotic action and rapid fermentability. Visceral hypersensitivity and or abnormal motility responses to luminal distention lead to the common symptoms reported amongst IBS sufferers⁹.
The FODMAP diet involves restricting high FODMAP foods for a 2-6-week period, until the patient reports they are symptom free. At this point, the patient undergoes a number of “challenges” which involves reintroducing one food from each FODMAP subgroup and monitoring the body’s response. Between each “challenge” the patient has a few days back on the complete low FODMAP diet. This is a time-consuming process which requires effort from both the health professional and patient. This process allows the patient to identify which particular FODMAP groups they are sensitive to and allows liberalisation of the diet. Thorough education and monitoring from a dietitian is important throughout the length of the diet. This is important to reduce unnecessary restriction in the diet which could be putting the patient at an increased risk of nutrient deficiencies¹⁰.
There is also ongoing research to determine the potential role of the FODMAP diet in other population groups, including those with Irritable Bowel Disease, coeliac disease¹¹ and patients with an ileal pouch or colorectal anastomosis¹². However, further clinical trials are needed amongst these population groups.
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