Soluble fiber impact on blood glucose?

• A. Increases plasma glucose and HbA1c
• B. No effect on glucose
• C. Slight decrease on plasma glucose and HbA1c
• D. Dramatic decrease in glucose

Answer: (C)

Soluble fiber slows carbohydrate absorption by increasing the viscosity of intestinal contents, which blunts the rise in blood glucose after meals. This leads to a modest reduction in both postprandial and fasting glucose levels, and over time a small improvement in HbA1c. The effect is typically modest, not dramatic, and not absent—though the amount of benefit depends on the amount of soluble fiber in the diet and overall dietary patterns. In short, soluble fiber can slightly lower plasma glucose and HbA1c rather than having no effect or causing large changes.