New research shows fibre boosts both gut and immune health

Evangelia Kerezoudi has investigated how certain dietary fibres – β-glucans from the oyster mushroom and Rhamnogalacturonan-I (cRG-I) from carrots – influence the intestinal barrier, gut flora, and immune system.

“An important discovery is that β-glucans and cRG-I actively strengthen the intestinal barrier, which is our first line of defence against harmful bacteria and toxins. A weakened intestinal barrier is linked to several chronic diseases, so maintaining its integrity and function is vital,” says Evangelia Kerezoudi.

The protective effect remains evident even during stress or low-grade inflammation, conditions that can impact the gut before any clear signs of disease emerge. According to Evangelia Kerezoudi, the fact that the effect endures even under these circumstances challenges the traditional view of dietary fibre as a passive component of the diet.

“Our results show that certain types of fibre contribute to the gut remaining resilient even at early signs of stress, which suggests that fibre plays a more active role in promoting long-term gut and immune health,” she says.

Actively trains the immune system

Fibres such as β-glucans and cRG-I were also found to have a direct effect on the immune system, both in laboratory models and in a dietary study involving humans. They enhanced the immune response over time, contributing to increased resilience. However, responses varied significantly between individuals. Some people demonstrated clear improvements in both their immune system and intestinal barrier function, while others experienced moderate or no changes at all.

“I was surprised by how differently people reacted to these substances. The same fibre could have a clear effect in one case and very little in another,” says Evangelia Kerezoudi.

A balanced diet contributes to good gut health throughout life

Her thesis also demonstrates that individuals with a more diverse gut flora may benefit more from fibres such as β-glucans and cRG-I.

“Diet is vital for maintaining a resilient gut flora, which in turn is significant for both the functions of the immune system and gut health.”

A fibre-rich diet promotes the diversity of microorganisms in the gut, which can help maintain gut health as we age. Although ageing is often associated with changes in the gut, the results suggest that fibre can assist in preserving a healthy gut as we get older.

"Our results indicate that fibre can help reduce age-related changes in the gut. However, gut health is also influenced by lifestyle, dietary habits, and individual gut flora."

Evangelia Kerezoudi hopes that her research can form the basis for the development of personalised dietary advice that strengthens gut health and immune function.

“By understanding how specific fibres, gut flora and the immune system interact, we can develop dietary strategies that promote long-term health and strengthen the body’s natural defences,” says Evangelia Kerezoudi.