The Role of Probiotics and Prebiotics in IBS – What is the Current Evidence?
Options of IBS symptom management
Whilst science based evidence has suggested that a low FODMAP diet can alleviate symptoms of Irritable Bowel Syndrome (IBS) in up to 70% of patients; pharmacologic, psychologic, and complementary approaches are also considered as good therapeutic options for IBS patients.
Prebiotics and probiotics have been getting a lot of attention in the media. So what are they and do they help with IBS symptoms?
What are probiotics?
Probiotics are live microorganisms that have been demonstrated to exhibit potential health benefits particularly in gut health when eaten in food (such as yoghurts and fermented milk) or as a supplement. Our gut microbiome is thought to contain up to 1000 different species of bacteria, which can be further categorised into individual strains. Probiotics are made up of a single or mixed-culture of bacteria species and strains in specific doses. Common strains include bifidobacteria and lactobacilli. There are a number of beneficial roles of probiotics in gut health such as inhibiting the growth of ‘bad’ bacteria, maintaining a healthy immune system and potentially helping improve mild inflammation of the gut.
Probiotics and IBS
Although a number of meta-analyses and systemic reviews demonstrate potential benefits of probiotics in improvement of the severity of IBS symptoms in comparison with placebo, their conclusions vary due to the diversity in the study designs, patient populations, bacterial strains and dosages used of the reviewed studies. In addition, the precise mechanism of action of probiotics is still unclear. Hence, there is still no definitive answer as to how effective probiotics supplementation is to improve IBS symptoms, whether IBS patients should take probiotics and what strains they should be taking. More research needs to be done with more participants with IBS over longer periods of time to develop concrete evidence regarding the use of probiotics in the symptoms management of IBS.
If a person decides to trial a probiotics supplement, it is recommended to avoid it in the Elimination or Challenge phase of the low FODMAP diet because it can skew the body’s reactions to the ‘challenge FODMAPs’. Under the guidance of an Accredited Practising Dietitian or a Registered Dietitian, probiotics can be trialled for up to 4 weeks during the Maintenance Phase of the low FODMAP diet or without following a low FODMAP diet.
What are prebiotics?
A prebiotic is a food substance that nourishes good bacteria in the gut. It passes through the small intestine undigested and stimulates the growth and activity of certain ‘good’ bacteria in the large intestine.
Prebiotics and IBS
The gut bacteria ferment prebiotics and create gas, which can cause gastrointestinal symptoms like bloating, excessive wind and cramping in IBS patients. Hence, a low FODMAP diet restricts foods that are high in prebiotics such as wheat, onion, garlic, cabbage, nuts and legumes due to their potential to trigger IBS type symptoms in certain individuals.
The low FODMAP diet is only recommended to be trialed for 2 to 6 weeks because it restricts the food sources of the gut bacteria. In the long run, a personalised low FODMAP diet with adequate amount of prebiotic-containing foods should be developed together with your dietitian to maintain the health of your gut bacteria.
While studies have shown a beneficial effect of prebiotic supplementation in different pathological conditions, such as infections and gastrointestinal diseases including cirrhosis, IBD and chronic constipation, only few studies have evaluated the efficacy of prebiotics in IBS and existing results are conflicting. Similar to probiotics, the clinical efficacy of prebiotics depends on the type and dose. Low doses may be ineffective and high doses can stimulate excessive gas production and other unwanted side effects.
Probiotics and prebiotics are both important to our gut health. Whilst both can provide health benefits in certain conditions, current scientific evidence does not support or not support the supplementation of probiotics and prebiotics in symptom management of IBS. The best way to manage IBS symptoms is to get in touch with an IBS specialist or a specialised dietitian to discuss your personalised IBS management plan.
Written by: Flora Cheung (APD, AN)
Edited By: Atlanta Miall-Shorten (APD, AN, AccSD)
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Joanna Baker. Probiotics, Prebiotics & IBS [Internet]. Melbourne: Everyday Nutrition; 2018 [updated 2018 Jan 13; cited 2018 Jun 21]. Available from: https://www.everydaynutrition.com.au/blog/probiotics-prebiotics-ibs