Submitted to: American Association of Cereal Chemists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2002
Publication Date: 1/14/2003
Citation: Hallfrisch, J.G., Behall, K.M. Comparisons of hydrogen and methane responses of men and women to barley and oats. American Association of Cereal Chemists.
Interpretive Summary: Americans consume far less fiber than is recommended by most health agencies even though diets high in fiber are associated with beneficial health effects such as reductions in blood pressure, blood lipids, glucose and insulin and maintenance of desirable weight. There is a perception that consumption of high fiber diets results in unpleasant intestinal symptoms. Health claims for soluble fiber from oats suggest that consumption of 3 g of soluble fiber a day will lower risk for heart disease; however, this amount would require consumption of a large amount of oats. Barley has as much or more soluble fiber than oats, but is consumed in only minimal amounts by Americans. ARS scientist George Inglett has developed a process to extract soluble fiber from grains including barley and oats, making a food ingredient (Nu-trim) which can replace fat and increase soluble fiber content. This paper reports the initial controlled human feeding trial which compares responses of these extracts to the parent grains. Middle-aged men and women consumed a test meal of glucose as a control and barley, oats, barley Nu-trim, and oat Nu- trim. Subjects consumed a range of 2-7 g soluble fiber in the test meals. Breath gases increased indicating that some of the grain extracts were not digested. However, symptoms reported after consumption were not different from those reported before consuming the test meals indicating that these extracts can be added to foods to increase soluble fiber intake without adverse gastrointestinal effects in amounts adequate to improve risk factors for cardiovascular disease. This research will benefit health professionals, the food industry, and those at risk for cardiovascular disease and diabetes mellitus.
Technical Abstract: This study was designed to compare the breath hydrogen and methane responses to consumption of high soluble beta glucan compounds extracted from oats and barley and assess possible gastrointestinal symptoms resulting from consumption. Eleven men and 11 women, non-diabetics 35-57 yr were selected for the study. All the women and 9 of the men completed the study. Subjects consumed a controlled diet for three days. On the third day of five successive periods subjects consumed one g/kg body weight of carbohydrate as glucose or 2/3 g/kg body weight sugar and 1/3 g/kg body weight as oat flour, barley flour, oat extract or barley extract (Nu-trimX) in a Latin square design. Breath hydrogen responses to barley, oats, and both extracts were higher than the responses to the glucose control ( p < 0.0001). Responses to barley and barley extract were significantly higher than the responses to corresponding oat test meals ( p < 0.05). Breath methane increased after all test meals, but the increases were not different for different meals. Some subjects reported gastrointestinal responses to the test meals, but there were no consistent correlations with specific test meals, nor did their symptoms differ from those reported before the test meals. These results suggest that responses to consumption of extracts of barley and oats are similar to the parent grain food. These foods as well as their extracts can be consumed in greater amounts by Americans to increase soluble fiber intake and lower risk for cardiovascular disease without adverse gastrointestinal effects.