Which type of fiber dissolves in water and provides nutrients for beneficial bacteria?

Soluble fiber is the correct choice because it dissolves in water, forming a gel-like substance. This type of fiber is known to provide various health benefits, including lowering blood cholesterol and glucose levels. Furthermore, soluble fiber serves as a food source for beneficial bacteria in the gut, contributing to a healthy microbiome. When soluble fiber is fermented by these gut bacteria, it produces short-chain fatty acids, which are essential for gut health and may contribute to other health benefits, such as improved immune function and reduced inflammation.

In contrast, insoluble fiber does not dissolve in water and primarily aids in promoting regular bowel movements by adding bulk to the stool. Functional fiber refers to isolated, non-digestible carbohydrates that have beneficial effects in humans and may not necessarily be fermentable. Fermentable fiber is a subset of soluble fiber that is specifically fermented by bacteria in the gastrointestinal tract, but the broader classification of soluble fiber encompasses all of its beneficial properties, including nutrient provision for gut bacteria.