Fiber refers to indigestible plant material that is consumed with food. Soluble fiber is a type of fiber that is water-soluble. It is absorbed into the bloodstream through the small intestine, and is believed to help lower cholesterol, especially LDL cholesterol. Foods high in soluble fiber include fruits (which contain pectin) and oat bran (which contains beta-glucan).

The other major type of fiber is insoluble fiber.