Significance of vitamin B12 and its analogs as determinants of colonic microbiota diversity.

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K11576
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 59040:Nutrition science and health science-related
• Research Institution: Shizuoka University
• Principal Investigator: Nishimura Naomichi 静岡大学, 農学部, 教授 (10341679)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ビタミンB12 / 大腸発酵 / プロピオン酸 / コハク酸 / 腸内細菌叢 / コバルト / 難消化性糖質

Outline of Final Research Achievements

In this study, we investigated whether VB12 deficiency in the colon is responsible for the impaired colonic propionate production and decreased diversity of the colonic microbiota caused by high amylose cornstarch (HACS), a non-digestible saccharides. The results revealed that it is caused by a deficiency of VB12, a cofactor in the propionate production pathway of colonic bacteria, and suggested that the propionate production pathway can be normalized if VB12 is supplied to the colon to maintain a colonic VB12 concentration of 63 pmol/g or higher. It was also found that VB12 administration restores the reduced diversity of the colonic microbiota that occurs in HACS intake. Furthermore, we showed that supplying Co to the large intestine increased VB12 and its analog synthesis by colonic bacteria and normalized propionate production in the large intestine.

Free Research Field

栄養化学

Academic Significance and Societal Importance of the Research Achievements

潰瘍性大腸炎を患った人の大腸ではコハク酸蓄積が認められる。また、コハク酸が消化管粘膜における炎症を誘導することが知られている。そのため、本研究成果はコハク酸による炎症誘導を抑える上で重要な基礎知見となりうると考えられる。
また、難消化性糖質のみを大腸にデリバリーし、大腸発酵を誘導することがこれまでに多く研究されているが、そのときに必要な因子を適切に供給することが大腸発酵の正常化に欠かせないことを示したものであり、今後さまざまな因子による大腸発酵の制御について研究が進むと考える。