Effects of Barley and Oat Breads on Appetite

This study aimed to compare the postprandial effects of ß-glucan on glycemia and appetite of breads derived from oats and barley, which are the best natural grain sources. In addition, the positive health effects of ß-glucan were sought to be determined independent of total dietary fiber intake, using not only WB as the control food but also WWB, which has a dietary fiber content equal to that of breads containing ß-glucan. This study was planned as a multicenter, randomized, double-blind, and crossover. Twenty healthy adults (10 men, 10 women) between the ages of 19-35 years, with normal body weight (BMI 18.5-25 kg /m2) were included in the study. Participants were selected from among Erciyes University students and staff in accordance with the inclusion criteria. The eating behaviors of all participants were also evaluated using the Dutch Eating Behavior Questionnaire before starting the study. Since the total score obtained from this questionnaire >3.5 is considered as restrictive eating behavior, these individuals were not included in the study.

Participants were served barley bread (BB), oat bread (OB), and white bread (WB), and whole wheat bread (WWB) with a standard breakfast on four different days at least two days apart. Breads were prepared with similar amounts of energy, protein, fat, carbohydrate, and fiber (except WB). The test meal was served to the participants at 09:00 and they were asked to consume it within 15 minutes. A visual analog scale (VAS) was used to assess appetite before breakfast and at 15, 30, 60, 90, 120, 150, and 180 minutes after breakfast. Furthermore, the separate VAS components such as hunger, fullness, desire to eat, and prospective food consumption were combined to produce an additional measure termed 'composite appetite score'. For the postprandial glucose assessment, blood glucose measurements were made with the finger-tip glucometer at 0, 15, 30, 45, 60, 90, and 120 minutes. Postprandial appetite and glucose responses were quantified as the incremental area under the curve (iAUC) calculated according to the trapezoidal rule.

At the end of three hours, the ad libitum lunch was served to the participants as a buffet-style, and the energy and macronutrient intakes in this meal were determined. All foods (meatballs, tuna, sauce pasta, yogurt, salad, white bread, apple, banana, yogurt drink, fruit juice, and water) were weighed using a calibrated kitchen scale with an accuracy of ±1g before being served. At lunch, the participants were asked to consume the foods they wanted and continue eating until they felt completely full. After the participants completed their consumption, the remaining amounts were reweighed and the difference with the initial amounts was accepted as the amount consumed.

Inclusion criteria

• Healthy
• Normal-weight (BMI 18.5-25 kg/m2)
• 19-35 years
• Having a <3.5 score on the Dutch Eating Behavior Questionnaire (considered as unrestrictive eating behavior)

Exclusion criteria

• Applying an energy-restricted diet in the last three months
• Having a change in body weight >5 kg in the last three months
• Vegans
• Having any chronic diseases such as diabetes, hypertension, etc.
• Physician-diagnosed medications or conditions that influence metabolism
• Having fasting glucose >100 mg/dl
• Smoking
• Exercising heavily
• Having chewing/swallowing difficulties or sensitivity/allergies to any food to be used in the study
• Lack of appetite
• Pregnant and lactating women
• Skipping breakfast meals