Clinical study investigating the impact of dietary fibre on type-2 diabetes

“We’re looking to identify possible links between the clinical benefits of increased dietary fibre intake to changes in immune cell activity and metabolism,” says Malaghan Institute Senior Research Fellow Dr David O’Sullivan, who is running the study with Dr Olivier Gasser in collaboration with Professor Jeremy Krebs at the Centre for Endocrine, Diabetes and Obesity Research in Wellington. The study is funded by the High Value Nutrition National Science Challenge, Ko Ngā Kai Whai Painga.

“By increasing our understanding of how specific immune cells respond to diet and how this impacts a disease like diabetes, in the future we may be able to tailor therapies to achieve better outcomes,” says Dr O’Sullivan.

Around a quarter of a million Kiwis are affected by diabetes, with type-2 diabetes the most common, and rates for Māori and Pasifika people 2-3 times higher than people of European ethnicity according to the Manatū Hauora Ministry of Health. The disease is characterised by a combination of impaired insulin secretion and insulin insensitivity leading to an inability to properly regulate blood glucose levels. Elevated glucose levels substantially increases the risk of secondary diseases such as heart attacks and stroke.

At the immune system level, people living with type-2 diabetes typically display chronic low-grade inflammation and an increased inflammatory response, markers that are thought to contribute to the progression of this disease.

Unlike type-1 diabetes, environmental factors such as obesity, unhealthy diet and inactivity can play a role in the development of type-2 diabetes, and contribute to the worsening of symptoms. However, healthy dietary changes can both reduce the risk of disease onset and help regulate blood glucose level fluctuation to a safer range. Diets high in fibre are thought to have a greater effect.

The study will compare participants with type-2 diabetes while on their regular diet over the course of 14 weeks, before and after natural fibre supplementation, to explore how increased fibre intake impacts their immune cells and gut microbiota. The study will also assess blood glucose levels and whether the increase in fibre consistently lowers these levels.

“Dietary fibre has a multitude of effects from improving gut health to supporting a beneficial microbiome and influencing immune responses” say Dr O’Sullivan.

Fibre is digested by the bacteria that live in our gut into smaller components known as short-chain fatty acids. These molecules then pass through the lining of the gut to be taken up by waiting immune cells and used for various functions – including metabolism.

“Increased dietary fibre and the subsequent production of short chain fatty acids by gut microbiota is known to influence immune cell function and metabolic activity,” says Dr O’Sullivan.

“High fibre diets correlate with a decrease in inflammatory markers and we’ve seen in preclinical models that dietary fibre can modulate immune cell metabolism, leading to a rebalancing away from pro-inflammatory responses, which we hope translates to better outcomes for people with type-2 diabetes.”

If you are interested in taking part in this clinical study, are diagnosed with type-2 diabetes and live in the Wellington region, contact [email protected] for more information.