Objective: To evaluate the long-term effects oat bran concentrate bread products in the diet of free-living subjects with non-insulin-dependent diabetes (NIDDM) via dietary, clinical, and biochemical methods.
Design: A 24-week crossover study consisting of two 12-week periods.
Subjects/setting: Eight men with NIDDM (mean age = 45 years) who lived in the community. Glucose and insulin profiles were conducted in a clinical investigation unit.
Intervention: Palatable, high-fiber, oat bran concentrate (soluble fiber [beta-glucan] content = 22.8%) bread products were developed. Four randomly chosen subjects ate oat bran concentrate breads first; the other subjects ate control white bread first.
Main outcome measures: Dietary intake (four 48-hour dietary recalls per period) was assessed. Blood glucose and insulin (8-hour profiles) and lipid parameters after fasting were measured (at 0, 12, and 24 weeks).
Statistical analyses performed: Analysis of variance and repeated-measures analysis of variance.
Results: Total energy and macronutrient intakes were similar in both periods. Mean total dietary fiber intake was 19 g/day in the white bread period and 34 g/day (9 g soluble fiber per day from oat bran concentrate) in the oat bran concentrate period. Body weight remained stable. Mean glycemic and insulin response areas (area under the curve) were lower (P < or = .05 and not significant, respectively) for the oat bran concentrate period than the white bread period. After breakfast, area under the curve for the oat bran concentrate period was lower for glucose (P < or = .01) and insulin (P < or = .05); insulin peak was reached earlier (P < or = .05) than in the white bread period. Dietary fiber intake was correlated negatively with insulin area under the curve (P < or = .05). Mean total plasma cholesterol and low-density lipoprotein cholesterol levels were lower (P < or = .01) in the oat bran concentrate period than in the white bread period. In the oat bran concentrate period, the mean ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol was reduced by 24% (P < or = .05).
Conclusions: The well-accepted oat bran concentrate bread products improved glycemic, insulinemic, and lipidemic responses.