Rethinking Fibre Classification for Better Nutrition
A team of Australian food scientists from RMIT University has proposed a new way of classifying dietary fibres, moving beyond the traditional “soluble” and “insoluble” labels. Their research seeks to enhance the understanding of fibre intake, paving the way for targeted fibre diets that offer clearer guidance to consumers, dietitians, and food manufacturers in developing tailored nutritional strategies.
Dietary fibres found in fruits, vegetables, legumes, and whole grains play a crucial role in human health, benefiting digestion, weight management, blood sugar control, heart health, and even cancer prevention. However, according to Professor Raj Eri, a food scientist at RMIT University, current consumer advice on fibre intake is too general.
“Just as different medicines target different conditions, different fibres serve different functions,” Eri explained. “For instance, the dietary fibre in apples works differently from that in bananas. Our research is helping to determine which types of fibre are most beneficial for specific health conditions.”
A New Model for Tailored Diets
The researchers have introduced a more detailed classification system based on five key fibre characteristics: backbone structure, water-holding capacity, structural charge, fibre matrix, and fermentation rate. This refined approach enhances the understanding needed to create targeted fibre diets and their impact on overall health.
Dr. Ben Opperman, a co-researcher on the project, explained how this method provides a scientific foundation for tailoring fibre intake to specific health goals. “If you want to improve colon health, you can identify fibres based on fermentation rate, ensuring you consume the right type,” Opperman said.
The RMIT team has already examined 20 different types of fibres, studying their interactions with the gut microbiome. “Until now, these specific interactions have been understudied, but our framework is paving the way for a more detailed and beneficial understanding of dietary fibres,” Opperman added.
Addressing the Global Fibre Deficiency
Despite the well-documented health benefits of fibre, studies show that people worldwide are consuming far less than the recommended amount. According to Professor Eri, fibre intake is alarmingly low in surveyed regions, including Europe and the USA.
“The recommended daily intake of fibre is between 28 and 42 grams, yet Americans consume only 12 to 14 grams on average, while Europeans get between 18 and 24 grams,” he said. “Given how essential fibre is to our health, this widespread deficiency is a serious concern.”
The traditional classification of fibres as either soluble or insoluble is based on whether they dissolve in water. Insoluble fibres primarily aid digestion and bowel movements, while soluble fibres are more readily fermented and can help reduce cholesterol and glucose absorption. However, Eri pointed out that this classification oversimplifies the complex ways in which fibres interact with the human body.
“Some insoluble fibres can also ferment rapidly and influence glucose absorption,” he explained. “Despite our growing knowledge of how fibre supports gut health, our classification system remains outdated. Our new framework is an essential step toward understanding fibre’s diverse structures and functions.”
The research team aims to investigate how different fibre types affect the gut microbiota, using these insights to advance targeted fibre diets for health applications. Their work could help shape the future of dietary guidelines and improve fibre intake worldwide.
