What is the role of dietary fiber in nutrition therapy?

• A. Supports muscle growth.
• B. Supports GI health, aids bowel regularity, and can improve lipid profiles and glycemic control.
• C. Directly provides most of the energy.
• D. Increases phosphorus absorption.

Answer: (B)

Dietary fiber in nutrition therapy focuses on how it affects the GI tract and metabolic risk factors. It supports GI health by promoting regular bowel movements and a healthy gut microbiota; insoluble fiber adds bulk and speeds transit, while soluble fiber forms a gel that slows digestion and helps with stool softness. This slower digestion also helps with satiety and improves postprandial glycemic responses, aiding glycemic control. Fiber’s interaction with cholesterol metabolism—soluble fibers binding bile acids and prompting the liver to use more cholesterol to make new bile acids—can lower LDL cholesterol and improve the lipid profile. Because of these combined effects, increasing fiber intake is a common strategy in nutrition therapy for constipation, lipid management, and blood sugar control. Note that fiber does not directly provide energy or promote muscle growth, and it does not increase phosphorus absorption; in fact, high fiber can influence mineral absorption if intake is very high, so hydration and a balanced plan are important.