|VAN DER SLUIJS, A|
Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/1997
Publication Date: N/A
Interpretive Summary: Increased fiber intake has been recommended for the U.S. population. Soluble fibers have been shown to be a beneficial factor in decreased glucose response after a meal and blood lipid levels during chronic consumption. 'Oatrim', an oat extract developed at USDA to concentrate the soluble fiber b glucan, was examined as a potential food component for lowering both fat intake and blood lipids. This paper describes the result of two 'Oatrim' studies. In both studies, breath hydrogen and methane responses were determined before and periodically after oral tolerance tests. Study 1 examined the effect of cooking on the oat extract and study 2 examined chronic consumption. Subjects were fed a typical diet containing 35% of the calories from fat to standardize initial intake. Inclusion of oat extract in an acute tolerance resulted in increased breath hydrogen but different cooking methods were not different. During chronic consumption, oat extracts containing 1% b glucan (low, 1.8 g soluble fiber/day) or 10% glucan (high, 7.2 g soluble fiber/day), by weight, replaced 5% of the fat and starch calories in the standard diet (0.8 g soluble fiber/day) for 5 weeks each. Breath hydrogen was significantly higher after both oat extracts; breath methane was not significantly different. These data indicate that bacterial digestion of oat extracts was similar with cooked and uncooked products. Increased breath hydrogen production indicates that some oat extract is available for colonic bacterial digestion which produces short chain fatty acids in addition to hydrogen or methane. These fatty acids are beneficial to colonic cells and may aid in reducing blood lipids. Chronic consumption of diets enriched with the oat extracts show potential benefit for people at risk for heart disease or colon cancer.
Technical Abstract: Soluble fiber consumption has been reported to decrease glucose and lipids but could also increase flatus, breath hydrogen production, or breath methane production. This paper describes the results of two oat-fiber- extract studies. In both studies, breath hydrogen and methane responses were determined before and periodically after oral tolerance tests providing 1 g carbohydrate/kg body weight. Study 1: While consuming a maintenance diet, 24 subjects ingested uncooked, baked, or boiled pudding containing oat extract (10% beta-glucan by weight). Overall hydrogen but not methane expiration after all tolerance tests with the pudding containing the oat extract, regardless of cooking method, was significantly higher than hydrogen expiration after glucose. Boiling or baking the pudding containing oat extracts did not significantly change hydrogen or methane expiration compared with expiration after the uncooked oat extracts. Study 2: After 1 wk of a maintenance diet, 23 subjects consumed oat extractsþ1% or 10% beta-glucan by weightþincorporated in the diet for 5 wk each in a crossover pattern. Breath hydrogen was significantly higher (P < 0.005) after both oat extracts than after glucose alone. Hydrogen excretion after the 10% beta-glucan oat extract was higher at 4, 5, and 6 h than after the 1% beta-glucan oat extract; breath methane was not significantly different. These data indicate that bacterial digestion of oat extracts was minimal and occurs after both cooked and uncooked products without adversely affecting the previously reported health benefits.