Only fibres promoting a stable butyrate producing colonic ecosystem decrease the rate of aberrant crypt foci in rats

Area of Science:

• Gastroenterology
• Nutritional Science
• Oncology

Background:

• Dietary fibers are investigated for their potential role in colon cancer prevention, but existing research yields inconclusive results.
• The protective effects of dietary fibers may be specifically linked to their ability to produce butyrate.

Purpose of the Study:

• To investigate the factors necessary for sustained, stable butyrate production in the colon.
• To examine the relationship between stable butyrate production and susceptibility to colon cancer.

Main Methods:

• A two-part randomized blinded study in rats was conducted using a control diet and three high-fiber diets: wheat bran (WB), resistant starch (RS), and fructo-oligosaccharides (FOS).
• Rats were fed diets for varying durations (2-44 days) to assess adaptation, fermentation, and colonic effects, including mucosal proliferation.
• A subsequent experiment involved carcinogen injection (azoxymethane) to evaluate aberrant crypt foci formation.

Main Results:

• After 44 days, resistant starch (RS) and fructo-oligosaccharides (FOS) diets resulted in significant butyrate production and a trophic effect in the large intestine.
• No significant differences in mucosal proliferation were observed among diets at 44 days.
• Rats fed high butyrate-producing diets (RS and FOS) exhibited significantly fewer aberrant crypt foci, indicating reduced colon cancer susceptibility.

Conclusions:

• A stable colonic ecosystem that produces butyrate, fostered by specific fibers like RS and FOS, appears to inhibit colon carcinogenesis.
• These findings support the hypothesis that butyrate-producing fibers play a crucial role in colon cancer prevention.