Nisshin Seifun Group: The Key is “Diverse Fermentable Dietary Fibers” - New Possibilities for High-Fiber Wheat Flour

Nisshin Seifun Group (Nisshin Seifun Group Inc., President & CEO: Kenji Takihara; Nisshin Flour Milling Inc., President & CEO: Toshiaki Yokoyama), in a joint research project with the National Institute of Health and Nutrition (President: Yusuke Nakamura), has identified gut bacteria that utilize the diverse “fermentable dietary fibers” contained in high-fiber wheat flour and elucidated part of the mechanism by which short-chain fatty acids*1 (butyrate) are produced.

This research confirmed the importance of consuming diverse fermentable dietary fibers for improving the gut environment, and the potential effectiveness of using high-fiber wheat flour as a method for their intake. Moving forward, we will continue to promote the creation of value based on scientific evidence and raise awareness for maintaining and promoting health through fermentable dietary fibers that can be consumed as a staple food, thereby contributing to the creation of healthy and prosperous lives.

《Key Research Findings》

① Agathobacter rectalis: A key gut bacterium for producing “short-chain fatty acids (butyrate)”

It was confirmed that the gut bacterium Agathobacter rectalis plays an important role in the production of butyrate using fermentable dietary fibers contained in high-fiber wheat flour.

② Promoting butyrate production with fermentable dietary fiber × Vitamin B5

It was confirmed that Agathobacter rectalis proliferates by utilizing resistant starch*2 contained in high-fiber wheat flour and produces butyrate by utilizing arabinoxylan*3. Furthermore, it was suggested that the addition of vitamin B5 further promotes butyrate production.

*Bread made with high-fiber wheat flour is rich in “fermentable dietary fibers”

High-fiber wheat flour, made from high-fiber wheat rich in dietary fiber in the endosperm, contains approximately five times*4 the amount of dietary fiber as general wheat flour, yet it is easy to process and use in regular cooking. Bread made with high-fiber wheat flour is characterized by its richness in “fermentable dietary fibers” such as resistant starch and arabinoxylan, which are utilized by gut bacteria.

What are fermentable dietary fibers?

Fermentable dietary fibers are dietary fibers that reach the intestines without being digested or absorbed, serving as food for gut bacteria. It is known that when gut bacteria utilize fermentable dietary fibers, beneficial components such as short-chain fatty acids (e.g., acetate and butyrate) are produced, which helps improve the gut environment. Incidentally, May 18th each year has been designated as “Fermentable Dietary Fiber Awareness Day” by the Fermentable Dietary Fiber Promotion Project General Incorporated Association, to promote the spread and increase the intake of fermentable dietary fibers.

■ Research Details

The purpose of this research was to elucidate the mechanism by which multiple fermentable dietary fibers contained in high-fiber wheat flour are utilized by gut bacteria to produce short-chain fatty acids (butyrate).

● Human trials: Analysis of the relationship between butyrate and gut bacteria

Analysis of stool samples from individuals who consumed bread made with high-fiber wheat flour showed a correlation where individuals with a higher occupancy of Agathobacter rectalis before intake also had higher fecal butyrate concentrations after intake. Furthermore, an analysis targeting individuals with a pre-intake Agathobacter rectalis occupancy of 1% or more revealed that the group consuming bread made with high-fiber wheat flour had significantly higher fecal butyrate concentrations compared to the group consuming bread made with general wheat flour (Figure 1).

These results suggest that Agathobacter rectalis plays an important role in butyrate production through the intake of diverse fermentable dietary fibers contained in bread made with high-fiber wheat flour.

● Cultivation trials: Elucidation of fermentable dietary fiber utilization and butyrate production mechanism

The results of cultivation trials using Agathobacter rectalis revealed that: ① Agathobacter rectalis proliferates by utilizing resistant starch, ② butyrate production increases by utilizing arabinoxylan, and ③ butyrate production is further promoted by the addition of vitamin B5 (Figure 2).

These results show that by utilizing multiple fermentable dietary fibers contained in high-fiber wheat flour, short-chain fatty acids (butyrate), which contribute to the improvement of the gut environment, are produced, suggesting the importance of consuming diverse fermentable dietary fibers.

Figure 1: Fecal butyrate concentration in subjects with Agathobacter rectalis occupancy of 1% or more

Figure 2: Butyrate production mechanism using high-fiber wheat flour derived fermentable dietary fibers by Agathobacter rectalis

■ Future Developments

Our group will continue to develop products based on the findings clarified in this research.