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.