Author
Behall, Kay | |
Howe, Juliette |
Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/9/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Changing the type of starch typically consumed in the diet from amylopectin to amylose has been shown to favorably decrease insulin response and lipid levels. This may result in increased intake of starch that is poorly digested in the small intestine, termed resistant starch. Amylose starch is resistant to enzyme digestion in the laboratory. To investigate the digestion of high amylose starch, diets containing 70% amylose or amylopectin corn starches were fed for 14 weeks each to 24 men, half hyperinsulinemic, in a crossover design. Fasting breath samples and hourly samples up to 7 hours post ingestion were analyzed for hydrogen during a nibbling pattern and acute load after each diet. Breath hydrogen was significantly increased on the amylose diet, especially in the hyperinsulinemic subjects after both the nibbling and acute loads. Increased breath hydrogen production indicates that amylose is more available for colonic bacterial digestion, particularly in hyperinsulinemi men. Colonic starch digestion produces short chain fatty acids in addition to hydrogen. These fatty acids are beneficial to colonic cells and may aid in reducing blood lipids. Individuals at risk for heart disease or colon cancer may benefit by consuming a high amylose diet. Technical Abstract: Recommendations made to increase carbohydrate and fiber intake in the U.S. diet may result in increased intake of poorly digested fiber or starch. Under in vitro conditions, high amylose starch appears to resist digestion. To investigate the in vivo effect of high amylose starch, diets containing 70% amylose or amylopectin corn starches were fed for 14 weeks each to 24 men, half hyperinsulinemic, in a crossover design. Fasting breath samples and hourly samples up to 7 hours post ingestion were analyzed for hydrogen during weeks 12 (a nibbling pattern) and 14 (acute load) of each diet phase. Breath hydrogen was significantly increased on the amylose diet, especially in the hyperinsulinemic subjects after both the nibbling (P < 0.025) and acute (P < 0.001) loads. Following 3 days of overfeed at 125% of maintenance energy, breath hydrogen after amylose was still significantly greater than after amylopectin (P < 0.001). Increased breath hhydrogen production indicates that amylose is more available for bacterial digestion, suggesting amylose may be less well digested than amylopectin, particularly in hyperinsulinemic men. |