COMPARISON OF HORMONE AND GLUCOSE RESPONSES OF OVERWEIGHT WOMEN TO BARLEY AND OATS.

Authors: Behall, Kay; Scholfield, Daniel; Hallfrisch, Judith

Submitted to: Journal of American College of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2004
Publication Date: 6/5/2005
Citation: Behall, K.M., Scholfield, D.J., Hallfrisch, J.G. 2005. Comparison of hormone and glucose responses of overweight women to barley and oats. Journal of American College of Nutrition. 24:182-188.

Interpretive Summary: Consumption of oats, and its soluble fiber, has been recognized as promoting beneficial reductions in the rise of glucose and insulin after a meal. Barley also has high amounts of soluble fiber but is consumed in much smaller quantities than oats. This study investigated the barley cultivar Prowashonupana, containing approximately four times the soluble fiber of common oats, for its glycemic effects in overweight women. Nine women, averaging 50 years old and a body mass index of 30, consumed glucose alone and four test meals (1 g carbohydrate/kg body weight, 2/3 of the carbohydrate was from oat flour, oatmeal, barley flour or barley flakes) in rotation. Blood samples were collected before and after each meal. Particle size of the oats and barley had little effect on responses after the meals. Peak glucose and insulin levels after barley were significantly lower than those after glucose or oats. Glucose responses (areas under curve) compared to that after glucose were reduced after both oat and barley (10-22% by oats and 57-63% by barley), however, only the reduction after the barley tolerances were significant. Insulin responses compared to that after glucose were significantly reduced only by barley (53-60%). Glucose values were normalized after oatmeal and barley in two women with impaired glucose tolerance. The higher soluble fiber in this barley was more effective than oats in reducing both glucose and insulin responses. Like oats, consumption of meals enriched with barley show potential benefit in reducing elevated glucose or insulin in people with impaired glucose tolerance or insulin resistance, common risks factors in diabetes and overweight individuals.

Technical Abstract: Objective: Consumption of oats, and its soluble fiber, has been recognized as promoting beneficial reductions in glucose and insulin responses. Less commonly consume, barley also has high amounts of soluble fiber. This study investigated the barley cultivar, Prowashonupana, for glycemic effects in overweight women. Methods: Nine women, averaging 50 years and 30 body mass index, were selected after medical evaluation. Subjects consumed glucose (1 g/kg body weight) and four test meals (1 g carbohydrate/kg body weight, 2/3 of the carbohydrate was from oat flour, oatmeal, barley flour or barley flakes) in a Latin Square. Blood samples were collected at fasting, and 1/2, 1, 2, and 3 hours after the meal. Results: Peak glucose and insulin responses occurred 1/2 and 1 hour after the tolerance regardless of the carbohydrate load. Peak glucose and insulin levels after barley were significantly lower than those after glucose or oats. Glucose responses (areas under curve) compared to that after glucose were reduced after both oat and barley (10-22% by oats and 57-63% by barley), however, only the reduction after the barley tolerances were significant. Insulin responses compared to that after glucose were significantly reduced only by barley (53-60%). Glucose values were normalized after oatmeal and barley in two women with impaired glucose tolerance. Glucagon and leptin responses did not significantly different between the carbohydrate tolerances. Conclusions: Particle size of the oats and barley had little effect on the responses. The higher soluble fiber in this barley was more effective than oats in reducing both glucose and insulin responses.