By: Churan Chang, dietetic student-volunteer University of British Columbia, reviewed by Lyndsay Hall, Registered Dietitian and the JM Nutrition Team
Does fibre play a role in more than digestion?
When most people hear the word fibre, they think about preventing constipation or adding bran cereal to their breakfast. While fibre certainly plays an important role in digestive health, its benefits extend far beyond regular bowel movements.
Research over the past several decades has shown that dietary fibre supports cardiovascular health, blood sugar regulation, weight management, immune function, and gut health. Emerging evidence even suggests that it may influence brain function through its effects on the gut microbiome.
Despite these benefits, most adults do not consume enough of it to meet recommended intake levels. If you’ve ever wondered whether all fibres are the same, whether fibre supplements are worthwhile, or whether a high-fibre food is automatically healthy, you’re not alone.
Let’s explore what fibre is, why it matters, and how to incorporate more of it into your diet.
What is fibre?
Fibre is a type of carbohydrate found in plant foods. Unlike other carbohydrates, it cannot be fully digested or absorbed by the body. Instead, it passes through the digestive tract relatively intact. It also performs a variety of important functions along the way.
There are two main types of fibre
Soluble fibre
Soluble fibre dissolves in water and forms a gel-like substance in the digestive tract. It may help lower LDL cholesterol, improve blood sugar control, and promote feelings of fullness.
Insoluble fibre
Insoluble fibre does not dissolve in water. It adds bulk to stool and helps food move through the digestive tract. This, in turn, supports regularity.
Most plant foods contain a combination of both types, which is why consuming a variety of fibre-rich foods is generally recommended.
Health Canada recommends an Adequate Intake (AI) of approximately 25 grams of fibre per day for adult women and 38 grams per day for adult men (ages 19–50) (Health Canada, 2023). However, most adults consume considerably less.
Fibre’s impact beyond digestion
Although fibre is often associated with digestive health, its effects extend throughout the body.
One of the primary reasons is its relationship with the gut microbiome, the trillions of microorganisms that reside in the digestive tract. Certain fibres act as food for beneficial bacteria in the colon. When these bacteria ferment fibre, they produce compounds known as short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate (Alahmari, 2024).
These compounds do far more than support digestion. SCFAs help maintain the intestinal barrier, regulate inflammation, support immune function, and contribute to metabolic health. Researchers believe many of the health benefits are mediated through these interactions between dietary fibre and the gut microbiome.
Fibre and the gut-brain axis
In recent years, scientists have become increasingly interested in the gut-brain axis, the two-way connection between the digestive system and the brain.
This relationship is mediated through several pathways, including the nervous system, immune system, hormones, and metabolites produced by gut bacteria. Because fibre shapes the composition and activity of the gut microbiome, it may also influence these biological processes.
Emerging evidence suggests that short-chain fatty acids (SCFAs) produced during fibre fermentation can affect immune responses, regulate inflammation, and contribute to signalling pathways that help connect the gut and brain (La Torre et al., 2021).
Researchers have also proposed that dietary fibre may influence levels of brain-derived neurotrophic factor (BDNF), a protein involved in learning, memory, and the maintenance of healthy brain cells. While this area of research is still developing, these findings highlight a fascinating connection between dietary fibre, gut health, and brain function (La Torre et al., 2021).
Fibre and whole-body health
Higher fibre intake has been associated with improved blood sugar control, better insulin sensitivity, lower LDL cholesterol levels, and optimal blood pressure (Fu et al., 2022). These effects help explain why diets rich in it are consistently associated with a lower risk of cardiovascular disease and other chronic health conditions (Veronese et al., 2025).
Research has also shown that fibre promote satiety. This, in turn, may support healthy weight management by helping people feel full longer after eating (Alahmari, 2024).
When examined collectively, these findings suggest that it is far more than a digestive aid. It is a key component of overall health.
Are most people getting enough fibre?
Despite widespread awareness of fibre’s benefits, most people consume far less than recommended.
Research suggests that more than 90% of adults fail to meet recommended intake levels (Veronese et al., 2025). This is a staggering statistic.
Modern dietary patterns often emphasize refined grains and highly processed foods while providing fewer fruits, vegetables, legumes, and whole grains.
The result is a substantial “fibre gap” between the recommended intake and actual intake.
Fortunately, it’s not that difficult to increase fibre intake as it does not require a complete dietary overhaul. Small, sustainable changes can make a meaningful difference over time.
Examples include:
- Choose whole grain bread instead of white bread.
- Add beans or lentils to soups, salads, and grain bowls.
- Include fruit with breakfast.
- Select vegetables as part of lunch and dinner.
- Snack on nuts and seeds.
These seemingly small habits can significantly increase daily intake.
Are fibre supplements worth taking?
While whole foods should remain the primary source of dietary fibre, supplements may be beneficial for some individuals.
For example, people who struggle to meet their needs through food alone, have certain dietary restrictions, or experience digestive concerns may benefit from targeted supplementation can benefit from supplements. Psyllium supplementation has been shown to help manage constipation and may improve symptoms in some individuals with IBS.
Related: dietitian’s support for supplementation
Certain soluble fibres may also help lower LDL cholesterol levels and improve cardiovascular risk factors (Lambeau & McRorie, 2017; Fu et al., 2022).
However, not all supplements provide the same benefits.
The effectiveness of a supplement depends largely on the type of fibre it contains.
Common examples include psyllium husk, beta-glucan, inulin, methylcellulose, and wheat dextrin.
Gel-forming fibres such as psyllium and beta-glucan have been shown to support digestive health, improve blood sugar control, and lower LDL cholesterol levels (Lambeau & McRorie, 2017; Fu et al., 2022).
Inulin, a prebiotic fibre, may help support the growth of beneficial gut bacteria, while other supplements may primarily be used to increase stool bulk or promote regularity (Lambeau & McRorie, 2017).
As a result, the most appropriate supplement depends on an individual’s health goals and needs.
Importantly, supplements are not a replacement for a fibre-rich diet. Whole foods provide it alongside vitamins, minerals, antioxidants, and a wide range of bioactive plant compounds that supplements cannot fully replicate.
For most people, a food-first approach remains the best strategy. Supplements serve as a targeted tool when additional support is needed.
Is more fibre always better?
Although fibre offers many health benefits, more is not always better.
Increasing fibre intake too quickly can lead to bloating, gas, abdominal discomfort, and changes in bowel habits.
This is particularly common with certain fibres that are rapidly fermented by gut bacteria, including inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS), resistant starch, and pectin. While these help support gut health by promoting the production of beneficial short-chain fatty acids (La Torre et al., 2021), they may also cause temporary digestive symptoms as the body adapts to a higher fibre intake (Daley & Shreenath, 2025).
The solution is not to avoid fibre, but rather to increase intake gradually while ensuring adequate fluid consumption. Allow the digestive system time to adjust because doing so can help minimize unwanted side effects and improve long-term tolerance.
If a food is high in fibre, is it automatically healthy?
Not necessarily. Let us explain.
Many packaged foods prominently advertise their fibre content, but it alone does not determine the overall nutritional quality of a product.
Some foods contain added fibres such as inulin, resistant starch, beta-glucan, or psyllium.
These ingredients can increase fibre content and may provide benefits related to cholesterol management, blood sugar control, digestive health, and satiety (Daley & Shreenath, 2025).
However, a product can still be high in added sugars, sodium, or saturated fat while also being high in fibre.
When evaluating any food product, consider the overall nutrition profile rather than focusing on a single nutrient claim.
Fibre-rich foods to include more often:
- Fruits such as apples, pears, berries, and oranges
- Vegetables such as broccoli, Brussels sprouts, carrots, and sweet potatoes
- Legumes such as lentils, chickpeas, black beans, and kidney beans
- Whole grains such as oats, barley, whole wheat, and quinoa
- Nuts and seeds such as almonds, pistachios, chia seeds, and flaxseeds
For decades, fibre has been largely associated with digestive health.
While supporting regular bowel movements remains one of its important functions, research now shows that fibre influences many aspects of health, including cardiovascular health, blood sugar regulation, immune function, and the gut microbiome.
Emerging evidence also suggests that fibre may play a role in gut-brain communication, highlighting just how interconnected our dietary choices are with overall wellbeing.
The good news is that increasing fibre intake does not require dramatic changes. Small, consistent habits such as eating more fruits, vegetables, legumes, whole grains, nuts, and seeds can add up over time.
Rather than thinking of fibre as simply a remedy for constipation, it may be more useful to view it as one of the foundational building blocks of long-term well-being.
Conclusion
Should you feel you require personalized nutritional sessions and support to help ensure adequate fibre intake or another related health matter, book a free consultation or contact us for an appointment. As always if you have comments or questions, we encourage you to let us know.
References
Alahmari, L. A. (2024). Dietary fiber influence on overall health, with an emphasis on CVD, diabetes, obesity, colon cancer, and inflammation. Frontiers in Nutrition, 11.
Daley, S. F., & Shreenath, A. P. (2025). The Role of Dietary Fiber in Health Promotion and Disease Prevention: A Practical Guide for Clinicians.
Fu, L., Zhang, G., Qian, S., Zhang, Q., & Tan, M. (2022). Associations between dietary fiber intake and cardiovascular risk factors: An umbrella review of meta-analyses of randomized controlled trials. Frontiers in Nutrition, 9.
Health Canada. (2023, November 30). Dietary fibre. Government of Canada. Health Canada Dietary Fibre
Lambeau, K. V., & McRorie, J. W., Jr. (2017). Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy. Journal of the American Association of Nurse Practitioners, 29(4), 216–223. https://doi.org/10.1002/2327-6924.12447
La Torre, D., Verbeke, K., & Dalile, B. (2021). Dietary fibre and the gut–brain axis: Microbiota-dependent and independent mechanisms of action. Gut Microbiome, 2, e3, 1–26. https://doi.org/10.1017/gmb.2021.3
Veronese, N., Gianfredi, V., Solmi, M., et al. (2025). The impact of dietary fiber consumption on human health: An umbrella review of evidence from 17,155,277 individuals. Clinical Nutrition, 51, 325–333.
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About Author:
Lyndsay Hall is a Mississauga and Toronto-area based dietitian who provides personalized support for weight loss, various digestive health concerns, prenatal nutrition and more. Lyndsay is registered with the College of Dietitians of Ontario.
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