Soluble Fibre: what it is, foods list and dietary impact

Soluble fibre is an essential part of a healthy diet, and has been linked to several health benefits such as good digestion, better blood sugar control, decreased cholesterol levels and decreased risk of heart disease¹.

Found mostly in fruits and vegetables², soluble fibres are easily broken down by the bacteria in your large intestine³. In this guide, we’ll explore what soluble fibre is, why it matters for your health, and highlight foods that are rich in it.

What is soluble fibre?

Soluble fibre is a type of dietary fibre which, when mixed with water, slows digestion¹. Dietary fibre is important for maintaining a healthy gut and supporting overall wellness, with studies indicating that it may also contribute to several aspects of digestive and general health such as:

• Regulating blood sugar levels

• Regulating bowel movements

• Balancing cholesterol levels

• Reducing colon and systemic inflammation

• Managing body weight

• Regulating your body’s satiation signals, which signal when you’re full.

For most foods, the small intestine usually digests what you eat, but your body takes a very different direction with fibre. Instead, the bacteria that live in your large intestine can either break down dietary fibre partially or fully. Soluble fibre can be broken down easily by the bacteria in your large intestine³.

While in the intestines, soluble fibre dissolves in water to form a gel-like substance that helps shape and thicken stool, promoting better bowel movements².

Why is soluble fibre important?

Soluble fibre plays a key role in supporting various aspects of your health.

For example, it:

Supports regular bowel movements

Soluble fibre absorbs water in the gut, forming a gel-like substance that helps soften and bulk up stools. This can make it easier to pass waste and promote more consistent bowel movements, though staying hydrated is essential for fibre to work effectively³. Some studies also suggest that getting enough fibre in your diet may help relieve chronic diarrhoea² . If you are experiencing persistent, chronic diarrhoea, you should consult your GP.

Promotes better digestive health

Soluble fibre serves as fuel for beneficial gut bacteria, supporting a diverse and balanced microbiome. A healthy gut environment may reduce inflammation and lower the risk of digestive issues, such as diverticulitis³.

Contributes to heart health

Food sources such as barley and oats contain beta-glucan, a type of soluble fibre known for lowering cholesterol. It binds to cholesterol in the digestive tract and helps prevent its absorption, which may contribute to healthier blood lipid levels³.

Helps regulate blood sugar

Eating foods rich in fibre may help control your blood sugar. This is because fibre-rich foods don’t elevate your blood sugar levels as much as low-fibre alternatives. Some studies have even demonstrated that people who consume wholegrains have a lower risk of type 2 diabetes, compared to those who eat processed carbs like white bread³.

Supports healthy weight management

Although more research is ongoing, current evidence suggests that soluble fibre may help with appetite control – as high-fibre foods keep you feeling ‘fuller’ for longer. This can make it easier to manage portion sizes and maintain a healthy weight over time³.

How much dietary fibre do you need?

A high-fibre diet is often linked to a reduced risk of developing type 2 diabetes and heart disease. At the same time, cutting down on added sugars can further support your overall health⁴.

Government guidelines recommend that adults aim for 30g of fibre each day as part of a well-balanced diet. However, most adults are averaging only 20g daily, meaning we need to find ways to increase our intake.

Children also require fibre, though their requirements vary with age⁴:

• 2-5 years old; roughly 15g per day

• 5-11 years old: about 20g per day

• 11-16 years old: around 25g per day.

Encouraging plenty of vegetables, fruits and wholegrain versions of starchy foods can help your child eat more fibre⁴.

While upping your fibre intake is great for your health, however, eating too much too soon can leave you feeling gassy and bloated. To avoid discomfort, increase your fibre intake gradually, drink plenty of water throughout the day, and stay active for good digestive health³.

Foods high in soluble fibre

While soluble fibres are mostly found in fruits and vegetables², they can also be found in other food sources such as these:

Soluble fibre foods list

• Oats – Oats are a great source of beta-glucan, a type of soluble fibre⁵.

• Barley – While often associated with brewing, barley is a wholesome grain that works well in stews, soups and risottos. Much like oats, barley is rich in beta-glucan, a soluble fibre that makes up about 5% of the grain⁵.

• Black beans – Black beans add a rich, hearty texture to meals and are loaded with fibre - about 15g of fibre per 172g of beans. They’re especially high in pectin, a soluble fibre that slows digestion, helping you feel fuller for longer⁵

• Sweet potatoes – Sweet potatoes are rich in potassium, B vitamins and beta carotene. In fact, one medium potato provides more than 400% of your daily vitamin A needs. They also provide around 4g of fibre, nearly half of which is soluble. This makes them a healthy and delicious way to support your fibre intake⁵.

• Brussels sprouts – Brussels sprouts may divide opinions, but there’s no denying their health benefits. Rich in nutrients, they also provide 4g of fibre per cup⁵.

• Carrots – Carrots are a versatile, nutrient-rich vegetable packed with beta carotene, some of which the body converts into vitamin A. They also provide a good amount of soluble fibre, with a bowl (approx. 128g) containing 2.4g of soluble fibre⁵.

• Bananas – Bananas are naturally high in soluble fibre, which forms a gel in the gut and slows digestion. Unripe bananas also offer resistant starch, a fibre that isn’t digested⁶.

Insoluble fibre foods list

• Nuts. Nuts are packed with insoluble fibres like hemicellulose and cellulose to help support digestive health⁷.

• Flax (Linseed) – Linseed or flax is high in lignin, an insoluble fibre. This can be a great addition to a balanced diet⁷.

• Whole-wheat flour – Whole-wheat flour contains complex carbohydrates like amylopectin, amylose and a good amount of fibre. This fibre is mostly cellulose, an insoluble fibre. Cellulose is made up of glucose units linked in a way that our bodies cannot break down⁸.

How to increase sources of soluble fibre in your diet

To get the greatest benefit from fibre, it’s important to include soluble fibre from a variety of sources, which can support heart and gut health. Here are some practical ways to add more to your daily routine⁴:

• Try breakfast options like Weetabix, porridge, oats, or shredded whole grain are particularly high in soluble fibre

• Consider wholegrains like brown rice, bulgur wheat or wholewheat pasta

• Eat potatoes with their skins on, whether baked, boiled or roasted, to retain more fibre

• Add chickpeas, lentils and beans to soups, stews, salads and curries. These are great plant-based sources of soluble fibre

• Add vegetables to meals as a side dish or add to curries, stews or sauces⁴.

Quick summary

• Soluble fibre is a type of dietary fibre that dissolves in water to form a gel-like substance, helping to slow digestion and support various aspects of health²

• It’s linked to good digestion, lower cholesterol, better blood sugar control, and a lower risk of heart disease¹

• Good sources of soluble fibre include oats, barley, black beans, bananas, sweet potatoes, carrots and Brussels sprouts⁵

• Insoluble fibre, like that found in nuts, linseed, and whole wheat flour complements soluble fibre by adding bulk and helping with regular bowel movements⁷

• Most UK adults only get around 20g of fibre daily, but the recommended amount is 30g per day⁴

• Increase your fibre intake slowly and drink plenty of water to avoid gas and bloating³.

Soluble fibres FAQs

What fruits are high in soluble fibre?

Avocados, pears, apricots, apples and guavas are some popular fruits that contain a high amount of soluble fibre⁵.

What are the best sources of soluble fibre?

Different seeds, fruits and grains can be a great source of soluble fibre. These can include oats, barley, black beans, Brussels sprouts, bananas and carrots just to mention a few⁵.