Dietary fiber decreases fasting blood glucose levels and plasma LDL concentration in noninsulin-dependent diabetes mellitus patients

Realistic high-fiber and regular low-fiber diets were given for 8 wk each to noninsulin-dependent diabetes mellitus (NIDDM) patients whose diabetes was being controlled satisfactorily by diet alone. The purpose of the study was to evaluate the metabolic effects of dietary fiber without changing energy intake or proportions of protein, fat, and carbohydrates. The high-fiber diet induced lower fasting blood glucose levels (p less than 0.01) and decreased the ratio of low-density lipoproteins to high-density lipoproteins (p less than 0.025); no difference was found in HbA1c between the two diet periods. Continuous glucose monitoring also showed a difference in fasting glucose levels that remained after identical low-fiber test meals. The incremental glucose responses did not differ. The fasting and incremental postprandial levels of insulin, C-peptide, glucagon, and somatostatin did not change, whereas the mean triglyceride concentrations were lower after the high-fiber diet. The results suggest a beneficial effect of dietary fiber in the metabolic control of NIDDM.