High leafy and root vegetables and high rice dietary patterns were associated with primary and secondary bile acid levels in the feces.

Colorectal cancer has the second highest mortality among cancer sites worldwide, with increasing morbidity, high recurrence rates, and even poorer postoperative quality of life. Therefore, preventive strategies for colorectal cancer should be established. This study aimed to cross-sectionally explore dietary patterns affecting the intestinal metabolism of bile acids (BAs), a risk factor for colorectal cancer, in young Japanese women. We collected fecal samples for intestinal microbiota and BA analysis. We used the Bristol scale to determine 1-week defecation status. Moreover, the brief-type self-administered diet history questionnaire was used for habitual dietary intake status. Reduced-rank regression analysis revealed dietary patterns related to fecal BA levels. The relationship between dietary patterns and fecal BA levels was adjusted for defecation status and intestinal microbiota variables using analysis of covariance. Reduced-rank regression analysis generated two dietary pattern scores related to fecal BA levels. First, the score was associated with a greater intake of leafy and root vegetables, and higher values were associated with greater fecal cholic and chenodeoxycholic acid levels and lower deoxycholic and lithocholic acid levels. Second, the score was associated with greater rice intake and lower Western sweets, pork, beef, and egg intake, and higher values were associated with lower deoxycholic and lithocholic acid levels. These relationships remained after adjusting for intestinal microbiota and defecation status variables.