Biochemical epidemiology of colon cancer: effect of types of dietary fiber on colonic diacylglycerols in women.

BACKGROUND/AIMS: In view of the potential significance of dietary fat and fiber in colon cancer and the possible indirect involvement of diacylglycerols (DAGs) in the pathogenesis of colon cancer, the effect of types of dietary fiber on fecal DAG in premenopausal women was investigated.

METHODS

Forty-eight women consuming a typical western diet provided two 24-hour stool specimens and two sets of preintervention 4-day food records. They were randomly assigned to one of the fiber groups, namely, a wheat, oat, or corn bran supplement. They consumed their control diet plus 13-15 g of dietary fiber from each source for 8 weeks. At the end of the fiber period, each subject provided two 24-hour stool specimens and 4-day food records. Stool samples collected during the two periods were analyzed for total fat and DAG fatty acids.

RESULTS

All sources of dietary fiber increased the amount of fecal fat excreted. Dietary wheat bran decreased the concentrations of total DAG and DAG containing lauric acid, myristic acid, palmitic acid, stearic acid, and linoleic acid, whereas oat bran increased the DAG composed of oleic acid and linoleic acid compared with the control diet. Corn bran decreased the DAG containing stearic acid.

CONCLUSIONS

These results show that the modifying effect of dietary fiber on DAG depends on the type of fiber consumed.