Fibre – friend or foe for IBS sufferers?

Fibre – friend or foe for IBS sufferers?

If you have IBS, navigating mealtimes can feel a bit like a digestive minefield. Many people with IBS end up restricting their diet, keeping the same few foods on rotation as they are simply too anxious to eat much of anything for fear of flare-ups.

Not only can limiting what you put on your plate lead to a less than joyous meal, it also gets in the way of getting the nutrients you actually need – especially fibre. High-fibre diets are linked to improving gut health, as well as lower cholesterol levels, improved metabolism and longevity. This study shows that there are clear associations between dietary fibre intake and multiple pathologies that include cardiovascular disease, colonic health, gut motility and risk for colo-rectal cancer. Dietary fibre intake also correlates with mortality.

Of course if you have IBS, where one of the predominant symptoms is loose stools, or frequent/urgent need to empty your bowels, it might seem counter-intuitive to eat more of a nutrient that’s known for helping you poo. It’s important to work with a specialist to heal your gut, and a nutritionist or dietitian who can help you craft meal plans that won’t upset your stomach. Still, there are some general rules that are helpful to keep in mind when looking to improve your fibre intake.

Fibre is both simple and quite complicated. At a basic level, fibre is a part of some foods (fruits, vegetables, grains, beans, nuts, seeds) that you do not digest and therefore ends up in your large bowel. It can make your stool bigger and softer and sometimes also looser. It can produce gas. You might have heard that the bacteria in your gut can digest fibre and that generally this is a good thing. You might have also read somewhere that there are different types of fibre and the different types can have different effects on your gut. You probably know fibre can be given in pills or powder as a laxative. Fibre can also be used in food processing as gels or thickeners to make food look and feel smoother. The more we learn about fibre, the more complicated it looks!

Despite this apparent complexity, the recommendations around fibre have not changed much over the years. Organisations and healthcare professionals have been saying for decades that we need to eat more fibre, obtained from a wide variety of foods, and preferably unprocessed.

Fibre helps to stay fit and healthy

Fibre can contribute to a long and healthy life and most of us should increase the amount we eat. However, people who suffer from digestive diseases sometimes have a tricky relationship with fibre. Arguably you should only cut back on foods containing fibre if a certified health professional tells you to do so, and you should be told how, why and for how long you need to do this.

Unlike other nutrients, the effect of fibre on our body can be remarkably quick. However, it is not easy to control those changes. Part of the reason for this is that fibre actually comes in different shapes and sizes and the various types have different effects on the gut. Those different effects are particularly important for people with digestive disorders.

So what are these different effects, or functions, of fibre?

Some fibre types absorb water from the large bowel making the stool bigger but also softer and easier to move along the gut. These types of fibre are sometimes referred to as soluble fibre. Some fibre types do not absorb water themselves but can actually stimulate the bowel to secrete more water, as well as secrete mucus, a smooth substance that also helps speed the stool along. These types of fibre are sometimes referred to as insoluble fibre.

fibre rich food


Oats, rye, barley, onions, leeks, root vegetables, apples and bananas contain soluble fibre while wholegrain bread and cereals, nuts and seeds, leafy vegetables, green beans, and potatoes with their skin on are higher in insoluble fibre. Beans and pulses contain both types. Even though fibre is now known to be more complex than just being soluble or insoluble, it is useful to be aware of these terms as they are often used by health professionals and the general public.

However here lies one of the first distinctions in the function of fibre. Insoluble fibre can help with constipation though it is important to increase fibre intake slowly and drink plenty of water (this applies to all fibre types). The role of soluble fibre in constipation is more complex. Some types of soluble fibre might help with constipation, but some other types will have little effect and if consumed in excess could make matters worse. It is also important to note that soluble fibre can produce gas, and this might cause discomfort and bloating in some people. On the other hand, soluble fibre can be useful if you have loose stools or diarrhoea, as it absorbs water. Insoluble fibre, on the other hand, might worsen diarrhoea by making the bowel secrete more water. As you can see, it is not straightforward.

There are two added complications. One is that as most foods high in fibre tend to contain a mixture of types, manipulating the type (as opposed to just the total amount) of fibre in your diet can be challenging. The second complication is that you are not alone. Your large bowel is full of bacteria and they have a say in the matter. Most bacteria are fussy eaters and will consume only certain types of fibre. They struggle with insoluble fibre but they are keen on the more soluble types. When soluble fibres reach the bowel, they soak up water, swell up and soften. Bacteria find this irresistible and start to digest the fibre rapidly. This has two effects. On one hand, it means our stools lose some of the fibre that helps keep them soft, as it is eaten by our bacteria. The bacteria are also responsible for the gas that is sometimes produced in our guts. After they digest our fibre, the bacteria produce substances that are beneficial to our gut. These substances are very small fat molecules (called short-chain fatty acids) that serve as nourishment for the cells that line our bowel and can be turned into fat and sugar molecules by our liver. Bacteria also produce some vitamins. We feed our bacteria and in turn our bacteria feed us.

Knowing a little about the complexities of fibre may help explain why fibre tolerance in IBS is very variable – we know fibre is essential for good health, but as with anything, too much of a good thing can be bad. While people have different food triggers, fibrous foods are one of the most common. Fibre can certainly be a trigger for some IBS sufferers, but it can also be a great help to others. It varies from person to person. When you understand the differences, you can then find a diet that eases your symptoms.

Where Fibre supplementation comes into its own

fibre supplement

If remembering all of the above is complicated (and it is!), but you know that you need to eat more fibre, then one of the best ways is to try taking two of our gentle Just For Tummies Fibre tablets half hour before lunch and repeat at dinner with a large glass of water.

However, if you have IBS, then supplementing with Fibre tablets will not be enough, depending upon your symptoms. Whether you have IBS (C), (D), Mixed, or Post-Infectious, there are other supplements you need to take to help reduce your symptoms. For individualised advice, please reply to this email.

If you have any questions about a digestive and gut health issue, and would like to know how our products might be able to help, then please get in touch.