IBS and Diet
Irritable bowel syndrome (IBS) is a functional gut disorder with multiple contributing factors. Research on IBS shows that what we eat plays a big part in symptoms.
Other factors involved in IBS include the gut-brain connection, exercise, genetics, and even the immune system. Needless to say, IBS is a complex condition with lots of different management strategies.
Today, we’re going to focus on diet. I’m Marlee Hamilton, from Ignite Nutrition Inc. – a dietitian practice that specializes in digestive disorders. As a digestive health dietitian, I personally specialize in working with those who have IBS. Let’s review the best diet options for IBS and specific strategies for success when changing your diet.
The Low FODMAP Diet for IBS
At this time, the most well-recognized diet to support IBS is the low FODMAP diet. This is an elimination-style diet. The goal is to reduce intake of specific types of fermentable carbohydrates found in a variety of foods.
The low FODMAP diet is implemented in 3 phases – the elimination phase, reintroduction phase, and maintenance phase. Although many foods contain FODMAPs, the point of this diet is not to be perfect. There’s a reason it’s called a low FODMAP diet, not a “No-FODMAP” diet. Think of your ability to tolerate FODMAPs like a bucket – the size of your bucket may be smaller than someone else’s, meaning you can’t eat quite as many FODMAP-rich foods without getting noticeable symptoms.
Potential Cons of the Low FODMAP Diet:
- This diet is restrictive and may not be appropriate for everyone, particularly if there is a history of disordered eating/eating disorders. It also may not be suitable for children, elderly people, pregnant people, or those who are at increased risk of malnutrition.
- There is a lot of planning involved, which can be difficult for those with busy lifestyles.
- You may find that following this diet increases some food costs, as certain alternatives can be more expensive than their counterparts – such as lactose-free dairy products, gluten-free bread, or low FODMAP branded foods.
Who Should Follow a Low FODMAP Diet?
While a restrictive diet like this may not be for everyone, many people do feel better. Studies estimate that about 50-75% of people with IBS may benefit from a low FODMAP diet. It has been shown to help with improvement in symptoms such as cramping, bloating, gas, constipation, abdominal pain, and diarrhea.1
If you experience any of those symptoms, you may benefit from a low FODMAP diet. However, it is important to be assessed by a doctor or gastroenterologist to first rule out other possible diagnoses such as celiac disease or inflammatory bowel disease.
Some other important questions to ask yourself prior to starting a low FODMAP diet:
- Have I already tried to manage symptoms with positive health habits such as quality sleep, regular exercise, stress management, adequate fiber, and adequate fluid intake?
- Do I feel I am able to physically, mentally, and emotionally limit my diet for a period of time without endangering my health?
If you can’t confidently say yes to these questions, consider a less restrictive diet change to manage your symptoms of IBS. For many IBS patients, pulling in some more basic nutrition principles can still improve symptoms.
Nutrition Basics for IBS
In 2008, the National Institute of Clinical Excellence (NICE) released IBS management guidelines that are different from the low FODMAP diet2. Instead of a phased dietary elimination, these guidelines focus on both diet and lifestyle factors that in general are more simple and sustainable. Since they were created, these guidelines have been reviewed again and updated as new research emerges. Ultimately, they continue to be an excellent first line approach for patients prior to moving toward a more strict elimination, such as the low FODMAP diet.
While the NICE guidelines also provide advice for mindfulness, exercise, and pharmacological therapies, we’ll focus mainly on the dietary guidelines here.
Diet and Nutrition Recommendations
The NICE guidelines recommend limiting components in foods that can be irritating to the gut, leading to changes in digestion. This means potentially limiting intake of the following types of foods/drinks:
- Caffeine – particularly in those with IBS-D (but can potentially help with motility in those with constipation)
- Carbonated drinks
- High fat foods
- Sorbitol and other sugar alcohols
Although this provides an excellent start point, individuals can have very different tolerance levels to these common triggers. Use the philosophy “cut back, not cut out” when attempting to change your diet with IBS. A full restriction of these food items may not be required. Instead, consider keeping a food journal and monitoring how you feel after intake of caffeine, fat, carbonated drinks, alcohol, etc.
In addition to the food items to limit, there are some other nutrition basics that can improve IBS symptoms. For instance, how much fluid you should drink each day – for most, it’s recommended to have at least 8 cups of water or other non-caffeinated drinks.
Fibre is also an important consideration. Not only should you consider how much to consume, but also which types are best for specific GI symptoms. In particular, with IBS, we generally try to limit insoluble fibre and increase foods high in soluble fibre, such as oats or psyllium husk. However, these recommendations can vary depending on the person. It’s best to review your fibre intake with a dietitian before making changes.
Lastly, a core ‘dietary basic’ that can really make a difference with IBS is how we eat – specifically slowing down, chewing our food, and eating regular meals and snacks. It’s best to avoid missing meals or having long gaps between eating times. Setting aside time to eat without distraction and noticing how your body feels can greatly reduce IBS symptoms.
Ultimately, IBS care doesn’t have to start with the low FODMAP diet. Starting with more simple strategies may be as far as you need to go to see symptom improvement. However, for those whose symptoms are still difficult to manage, a low FODMAP diet may be worthwhile. It’s best to work with a registered dietitian to determine which diet changes are right for your IBS.
Looking for more information on treatment options for IBS? Check out more resources:
- IBS Toolkit for the Newly Diagnosed
- Cognitive Behavioural Therapy for IBS
- IBS and Stress
- Medications & Supplements for IBS
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- Ford AC et al, American College of Gastroenterology Monograph on Management of Irritable Bowel Syndrome. Am J Gastro 2018; 113:1-18)
- National Institute for Health and Care Excellence. (2008). Irritable bowel syndrome in adults: Diagnosis and management (NICE Guideline CG61). Last updated 2017. https://www.nice.org.uk/guidance/cg61