Epidemiological research for elucidating the combined effects of diet, gut microbiota, and metabolites on colorectal carcinogenesis

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19680
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 58:Society medicine, nursing, and related fields
• Research Institution: National Cancer Center Japan
• Principal Investigator: Iwasaki Motoki 国立研究開発法人国立がん研究センター, がん対策研究所, 部長 (60392338)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: 大腸 / 腸内細菌叢 / 代謝物 / 食事因子 / 疫学研究

Outline of Final Research Achievements

As a representative example where the combined effects of diet, gut microbiota, and metabolites are hypothesized, we conducted an epidemiological research focusing on meat and fatty acid intake, primary bile acids, and secondary bile acids produced by gut microbiota metabolism. The results showed no significant association between the intake of red meats and saturated fatty acids and the risk of colorectal tumors. However, the analysis of gut microbiota revealed that the abundance of Romboutsia was significantly higher in the case group. Additionally, in this study, a comprehensive metabolomic analysis was performed using plasma 303 samples collected prior to cancer screening, obtaining the concentrations of 14 types of bile acid metabolites. Regarding the association with colorectal tumor risk, a positive association was suggested with glycocholic acid, a conjugated primary bile acid, but no associations were found with other bile acid metabolites, including secondary bile acids.

Free Research Field

がんの疫学

Academic Significance and Societal Importance of the Research Achievements

日本人を対象として食事因子・腸内細菌・代謝物の複合的作用が検討可能な疫学研究基盤は非常に限られている中で、既存のアンケート情報から食品・栄養素摂取量の評価、便検体由来DNAを用いた16S rRNA解析による腸内細菌叢データの整備、さらに一部の対象者の血漿検体を用いて新規に代謝物濃度の測定を実施し、大腸腫瘍リスクとの関連が検討できる研究基盤が構築された点は、当該分野の研究推進の面で貢献は大きい。さらに代謝物濃度の測定を行う対象者を増やし、食事因子・腸内細菌・代謝物の複合的作用の検討を進めて行くことが期待される。