Carbs and Bowel Health

May 27/Health & Medicine Week --  According to recent research published in the British Journal of Nutrition, "Dietary non-digestible carbohydrates (NDC) play an important role in large-bowel health and one form of NDC, resistant starch (RS), can promote low levels of DNA damage and other markers of colonic health. The objective of the present study was to determine whether the ability of dietary RS or other NDC to influence colonic health, particularly DNA damage, is dependent on the type of dietary oil."

"We compared the effects of diets containing 10% of NDC from cellulose, wheat bran, high-amylose maize starch (HAS, a rich source of RS type 2) or a retrograded HAS (RHAS, a rich source of RS type 3) on DNA damage, SCFA production and bacterial changes in the large bowel of rats. Each carbohydrate source was combined with 10% fish oil (FO) or Sunola oil (SO; rich in oleic acid). There was a significant interaction between NDC and oil treatments on single-strand DNA breaks in colonocytes isolated from the colon. The damage in rats consuming RHAS was greater for FO consumption than for SO consumption. There was a significant interaction between NDC and oils on caecum weights, and treatment effects of NDC and oils were observed for the weights and lengths of other gut tissues. Significant differences were found in colonic SCFA pools and caecal numbers of lactobacilli, bifidobacteria, Escherichia coli and Bacteroides fragilis with the various NDC and oil treatments," wrote M.A. Conlon and colleagues.

The researchers concluded, "The present results demonstrate that the effects of NDC and oils, particularly on colonic DNA damage, can depend on how they are combined within the diet."

Conlon and colleagues published their study in British Journal of Nutrition (Interactive and Individual Effects of Dietary Non-digestible Carbohydrates and Oils on DNA Damage, SCFA and Bacteria in the Large Bowel of Rats." British Journal of Nutrition, 2009;101(8):1171-1177).

For additional information, contact M.A. Conlon, CSIRO Human Nutrition, POB 10041, Adelaide Bc, SA 5000, Australia.

From the June 8, 2009, Prepared Foods E-dition