Which statement correctly describes soluble and insoluble dietary fiber?

• A. Soluble fiber dissolves in water and can lower cholesterol and help control glucose; insoluble fiber increases stool bulk and aids digestion.
• B. Insoluble fiber dissolves in water and lowers cholesterol; soluble fiber adds stool bulk.
• C. Both fibers dissolve in fat; they have no role in digestion.
• D. Soluble fiber increases stool bulk; insoluble fiber lowers cholesterol.

Answer: (A)

The main idea here is how soluble and insoluble dietary fiber behave in water and what they do in the digestive system. Soluble fiber dissolves in water, forming a gel-like substance. This gel can bind bile acids and cholesterol in the gut, leading to increased excretion of cholesterol and, as a result, lower LDL cholesterol. It also slows the rate at which the stomach empties and slows carbohydrate absorption, which helps with blood glucose control after meals. Insoluble fiber does not dissolve in water; it adds bulk to the stool by absorbing water, which speeds up intestinal transit and promotes regularity, aiding digestion.

So the statement is correct because it accurately pairs the solubility properties with the distinct digestive and metabolic effects: soluble fiber dissolves in water and can lower cholesterol while aiding glucose control, and insoluble fiber increases stool bulk and supports digestion. The other options misstate solubility or the fibers’ roles in digestion.