Comparison of Hormone and Glucose Responses of Overweight Women to Barley and Oats

Abstract

Objective: To determine the effect of particle size (flour vs. flakes) on glycemic responses after oats and barley (Prowashonupana cultivar), which contain high amounts of soluble fiber, are consumed by overweight women.

Design: Ten women, average age 50 years and body mass index 30, consumed glucose (1 g/kg body weight) and four test meals (1 g carbohydrate/kg body weight; 2/3 of the carbohydrate from oat flour, oatmeal, barley flour, or barley flakes and 1/3 from pudding) in a Latin square design after consuming controlled diets for 2 days. Blood samples were collected at fasting and periodically after each meal.

Results: Peak glucose and insulin levels after barley were significantly lower than those after glucose or oats. Glucose areas under the curve (AUCs) after test meals compared with AUCs after glucose were reduced after both oats and barley (29–36% by oats and 59–65% by barley) (p < 0.002). Insulin AUCs after test meals compared with glucose AUCs were significantly reduced only by barley (44–56%) (p < 0.005). Indexes for insulin resistance (HOMA, MFFM, Cederholm) after the oat and barley meals were not different from indexes after the glucose meal. Glucagon and leptin responses did not significantly differ for the carbohydrates tested.

Conclusions: Particle size of the oats or barley had little effect on the glycemic responses. Both oat and barley meals reduced glycemic responses; the high soluble fiber content of this barley appeared to be a factor in the greater reduction observed.

• whole grains
• insulin
• glycemic response
• insulin resistance
• soluble fiber

• AUC = area under the curve
• BMI = body mass index
• HOMA = homeostasis model assessment
• TSH = thyroid stimulating hormone

We thank Evelyn Lashley, chief dietitian of the Human Study Facility; Sue Burns and the late Linda Lynch, research cooks; Willa Mae Clark, Demetria Fletcher, and Razia Hussain, technical staff; and all subjects who participated in the study.

Notes

Prowashonupana barley flakes and flour and partial financial support were provided by ConAgra, Omaha, NE. Presented in part at the Diet and the Metabolic Syndrome International Symposium. Ystad, Sweden, August 26, 1999.