Fibre and Inflammatory Bowel Disease
Should I avoid fibre if I have IBD?
This is one of the most common questions my clients ask and there is so much conflicting information.
If you have ever been advised to:
Avoid raw fruit and vegetables
Follow a low residue diet
Only eat white foods
Never eat nuts and seeds
Then this blog is for you. Let's look at why fibre is not the enemy in IBD.
What is fibre?
Fibre is the part of plants you don’t digest in your small bowel and is broken down (fully or partially) by gut bacteria in the large bowel.
Not all dietary fibre is the same. You may have heard of soluble and insoluble fibre, but there are more than just these two types. Fibre is split into different categories depending on:
Solubility: Does it dissolve in water?
Viscosity: Does it thicken?
Fermentation: Is it digested by gut bacteria?
These properties determine the effect on the gut. Foods contain a mixture of fibres, so variety is key. Soluble fibre draws in water, softening stools, whereas insoluble fibre adds bulk and increases the speed stools move though the bowel. High viscosity fibre create a gel-like substance, forms stools and slows the movement through the bowel, while fermentable fibre breaks down to feed the gut bacteria.
What does this mean for IBD?
In IBD, knowing which types of fibre to include in your diet can help your gut symptoms and benefit your gut health by promoting bacteria diversity and a strong gut barrier.
The fermentable fibre found in oats, when broken down produces short-chain fatty acids (SCFA’s), including butyrate, which may help to reduce inflammation.
Onion and garlic are good sources of prebiotic fibre which feed beneficial gut bacteria associated with good gut health.
Foods containing high viscosity soluble fibre, such as chia seeds, can be helpful if you struggle with diarrhoea, constipation, bowel urgency and incomplete evacuation by forming soft stools and slowing digestion.
Does fibre cause flares?
There is no evidence eating fibre causes flares - in fact, the opposite may be true. More fibre in your diet could protect against flares and keep you in remission for longer.
You may have symptoms when eating fibre foods, but symptoms do not always mean inflammation. Fibre foods can cause symptoms if you:
Do not usually eat fibre and have too much at once - however, your bowel can adapt to fibre and in time you may be able to tolerate fibre more easily.
Are already in a flare - eating large amounts of insoluble fibre may exacerbate your symptoms, but this is not worsening the inflammation in your bowel.
Have a stricture (narrowing) in your bowel - insoluble fibre may cause bulky stools which could lead to an obstruction (blockage). Adapting foods containing insoluble fibre, such as by peeling, cooking and blending, can help you tolerate them and reduce the risk of developing a blockage.
A note about FODMAPs
FODMAPs (Fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are fermentable carbohydrates. In remission, these can cause IBS-like symptoms in some people such as bloating, abdominal pain, diarrhoea and wind. Although symptoms may resemble those you experience in a flare, they are not related to inflammation.
Take aways:
Fibre is not ‘bad’ for IBD
Eating more fibre might benefit your gut health and subsequently your IBD
Symptoms from eating fibre are not related to inflammation or causing a flare
Eating a variety of fibre and adapting fibre foods can help you tolerate these foods better
If you are struggling to eat fibre or eat to increase your intake of fibre, work with an IBD Dietitian like me for support.
