4 Evidence-Based Benefits of Soluble Fibre for Intestinal and Overall Health
Microorganisms in the intestine can easily access and process dietary soluble fibre into beneficial products. These products help improve intestinal health and may reduce the risk of gastrointestinal diseases and heart disease.
Highlights
- Soluble fibre dissolves in water. It feeds the “friendly” bacteria and helps improve the intestinal environment.
- Certain soluble fibre can work for both diarrhoea and constipation. Besides, it lowers the risk of heart disease, helps control blood sugar, and aids weight loss.
- Most fruits, vegetables, and whole grains contain soluble fibre, though the amount varies. It is also present in generous amounts in oats, apples, citrus fruits, carrots, and sweet potatoes.
Let’s start with the cliché “we are what we eat.”
Diet is a critical factor for health and disease prevention. When we think of a diet, we often focus on vitamins, minerals, and proteins. While doing so, we are missing the critical nutrient, fibre.
Thankfully, in the last few years, we have seen a surge in information about gut health and fibre. But questions still linger:
- Are all fibres created equal?
- Is gut health the same as intestinal health?
- What makes soluble fibre unique compared to other fibres for intestinal health and digestion?
In this article, we answer these questions, based on the latest evidence.
What Is Soluble Fibre?
As the name suggests, this type of fibre is soluble in water (or other fluids in the digestive tract). It means soluble fibre dissolves in water to a gel-like material. Soluble fibre slows the movement of food through the digestive tract and keeps us fuller for longer.
In contrast, insoluble fibre doesn’t dissolve in water. It helps add bulk to stool and can help people with constipation.
What Are the Sources of Soluble Fibre in the UK Diet?
Soluble fibre is present in most fruits, vegetables, and whole grains. But certain foods are the cream of the crop.
According to the NHS, good sources of soluble fibre include: (1)
- Oats
- Apples
- Citrus fruits
- Carrots
- Brussels sprouts
- Sweet potato
- Turnip
- Aubergine
- Peas
- Green beans
- Barley
- Psyllium
Are All Fibres Created Equal?
The short answer is NO.
Soluble and insoluble fibres act and benefit differently. The insoluble type has a better laxative effect than soluble fibre.
Interestingly, recent evidence suggests that differences may also exist among different types of soluble fibres.
For example, according to a 2017 review, high viscosity fibres such as, β-glucan and psyllium, may be superior to nonviscous soluble fibre like inulin for: (2)
- Lowering cholesterol
- Improving blood sugar
Note: Good sources of beta glucan include oats, barley, rye, maize, and durum wheat. Foods rich in inulin are chicory root, dandelion greens, garlic, leeks, asparagus, and wheat bran.
Gut Health Vs. Intestinal Health: Is There A Difference?
Many of us might use these terms interchangeably. However, they are not the same.
Let’s break down the differences:
Gut health
It refers to the well-being of the digestive tract, which comprises the stomach, small intestine, and large intestine (colon).
Gut health relates to:
- Functions of each component of the digestive tract
- Role of microorganisms in the tract (gut microbiome)
- Influence on gut microbiome on immunity, digestion, nervous system, and disease like diabetes and heart disease
Intestinal health
It focuses on the intestines (small and large), their role in nutrient absorption, waste removal, and intestinal barrier maintenance.
For everyday health, improving intestinal health is one of the most effective ways to support overall gut health.
What Are the Health Benefits of Soluble Fibre?
Both soluble and insoluble fibre are crucial for our health, and many foods contain both types. However, soluble fibre may have benefits beyond digestion.
1. Soluble fibre for intestinal health
Soluble fibre can work for both diarrhoea and constipation.
As the main energy source for the intestinal microbiome, it helps improve the intestinal environment by feeding the “friendly” bacteria. (3)
Besides, soluble fibre stimulates mucus production and secretion, which is essential for protecting the intestine against harmful bacteria.
Bacteria in the intestine can easily break down soluble fibre into beneficial products. These products help relieve constipation and offer other health benefits.
2. Soluble fibre for heart health
Unlike other nutrients, soluble fibre is not absorbed in the small intestine. This unique property enables soluble fibre to attach to cholesterol particles and remove them from the body.
Consequently, this helps reduce cholesterol levels, lowering the risk of heart disease. According to the National Lipid Association, we might be able to lower total and LDL-cholesterol by 5 to 11 units by consuming 5 to 10 grams of soluble fibre daily. (4)
3. Soluble fibre for blood sugar control
Our intestine doesn’t absorb soluble fibre. Therefore, it doesn’t cause blood sugar spikes, which may increase our risk of getting type 2 diabetes and heart disease. For individuals with type 1 or type 2 diabetes, soluble fibre can help keep blood sugar under control.
4. Soluble fibre for weight loss
Soluble fibre keeps us fuller for longer, which can aid weight loss.
In a 2023 study, participants received dietary fibre supplements containing different dietary fibres and energy-restricted diets for 8 weeks.
At the end of the study, the researchers found that the participants had significantly reduced body weight, body mass index (BMI), fat mass, and visceral fat. Besides, they had improved lipid profile and inflammation. (5)
Also Read: Chronic Inflammation Is Widespread In the UK. Here’s What You Can Do to Keep It At Bay
According to the researchers, glucomannan, inulin, psyllium, and apple fibre were most effective at reducing body weight, BMI, and inflammation.
How Much Fibre Should We Take Daily?
According to the NHS, an adult should get 18 to 21 grams of fibre daily and gradually increase to 30 grams daily. (6) Sadly, the average fibre intake in the UK is about 12 grams a day.
The guideline doesn’t specify the daily recommended intake for soluble or insoluble fibre. However, it focuses on eating a diet that has a balance of both forms of fibre.
Also, staying consistent with our daily fibre intake is more important than reaching the numbers.
What Are the Side Effects of Soluble Fibre?
Side effects can include:
- Flatulence
- Bloating
- Diarrhoea
- Cramping
To avoid or reduce the risk of side effects, we should gradually increase fibre intake over a few weeks. Besides, we should drink enough fluid while taking fibre or a fibre supplement to prevent choking and intestinal obstruction.
Expert-Recommended Tips to Increase Fibre Intake
We should aim to get our daily fibre from a variety of sources. To get more fibre, we could include the following in our diet:
- Higher-fibre breakfast cereal, plain shredded whole grain, or porridge
- Wholemeal or granary breads, or higher fibre white bread
- Wholewheat pasta, bulgur wheat or brown rice
- Potatoes with skins on (baked potato or boiled new potatoes)
- Beans, lentils or chickpeas
- Vegetables and fruits
Also Read: Why Leafy and Green Vegetables Should Be on Every Plate
Explore UK-friendly soluble fibre recipes.
Who May Benefit Most With Increased Soluble Fibre Intake
An average person in the UK gets only about 60% of the recommended daily fibre intake. It means increasing daily fibre intake is good for most of us.
Our diet, which typically comprises ultraprocessed foods, is low in fibre. A low-fibre diet has been linked to many medical conditions, such as: (7)
- Constipation
- Haemorrhoids
- Diverticulitis
- Heart disease
- Overweight and obesity
- Diabetes
- Bowel cancer
- Breast cancer
Further Reading: How food processing starves our bodies of nutrients, leaving us feeling run down and tired
Soluble Fibre and Intestinal Health: Frequently Asked Questions
- Is soluble fibre good for digestion?
Soluble fibre supports digestion by feeding “friendly” bacteria in the gut, improving absorption of nutrients, and facilitating removal of waste products from the body.
- Does soluble fibre help with bowel regularity?
Soluble fibre softens the stools and makes bowel movements easier and comfortable.
- Can you have too much soluble fibre?
It is unlikely to get too much soluble fibre only from the diet. However, if we add a fibre supplement to our fibre-rich diet, there may be a problem. Besides, eating a large amount of fibre too quickly can cause gas, bloating and cramping.
- Is soluble fibre better than insoluble fibre for intestinal health?
Insoluble fibre may be better for constipation. However, our body needs both types and each has their role in maintaining intestinal health.
Bringing More Soluble Fibre Into Everyday Life
The evidence is clear: increasing soluble fibre intake is one of the simplest and most effective ways to support intestinal health and protect long-term wellbeing. Rather than focusing on supplements or targets alone, the most sustainable approach is to regularly include foods naturally rich in soluble fibre.
Oats are an excellent place to start, whether as porridge or overnight oats, providing beta-glucan fibre that supports both cholesterol balance and blood sugar control. Fruits such as apples, citrus fruits and pears add soluble fibre in a convenient, whole-food form, while vegetables like carrots, Brussels sprouts and sweet potatoes contribute to both digestive comfort and microbial diversity. Barley, beans and lentils further strengthen fibre intake while supporting satiety and metabolic health.
For intestinal health, soluble fibre feeds beneficial gut bacteria, supports the protective mucus layer of the intestine and helps regulate bowel function. For heart health, its benefits are largely driven by its ability to bind bile acids and cholesterol in the gut, reducing LDL cholesterol levels and lowering cardiovascular risk over time.
Small, consistent changes such as choosing oats over refined cereals or adding an extra piece of fruit each day can make a meaningful difference. By gradually increasing soluble fibre intake through a variety of whole foods, we support not just our digestion, but the health of our heart, metabolism and overall resilience for years to come.
References:
- Dietary fibre (pp. 1–7). https://www.stgeorges.nhs.uk/wp-content/uploads/2022/05/NDI_DF.pdf
- McRorie, Johnson W., et al. “Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber.” Journal of the Academy of Nutrition and Dietetics, vol. 117, no. 2, 2017, pp. 251–264.
- Guan, Zhi-Wei et al. “Soluble Dietary Fiber, One of the Most Important Nutrients for the Gut Microbiota.” Molecules (Basel, Switzerland) vol. 26,22 6802. 11 Nov. 2021, doi:10.3390/molecules26226802
- National Lipid Association. Adding Soluble Fiber to Lower Your Cholesterol: Advice from the National Lipid Association Clinician’s Lifestyle Modification Toolbox. National Lipid Association, 2018, https://www.lipid.org/sites/default/files/adding_soluble_fiber_final_0.pdf
- Jenko Pražnikar, Zala et al. “Effects of Four Different Dietary Fibre Supplements on Weight Loss and Lipid and Glucose Serum Profiles during Energy Restriction in Patients with Traits of Metabolic Syndrome: A Comparative, Randomized, Placebo-Controlled Study.” Foods (Basel, Switzerland) vol. 12,11 2122. 24 May. 2023, doi:10.3390/foods12112122
- Irvine, P. (2022). Physiotherapy service. https://www.uhd.nhs.uk/uploads/about/docs/our_publications/patient_information_leaflets/physiotherapy/fibre.pdf
- https://www.betterhealth.vic.gov.au/health/healthyliving/dietary-fibre#conditions-linked-to-low-fibre-diets
