What is the primary source of soluble fiber?

The primary source of soluble fiber is correctly identified as gums and pectins. Soluble fiber dissolves in water, forming a gel-like substance in the digestive system, which can help regulate blood sugar levels and lower cholesterol. Foods rich in soluble fiber, like oats, barley, nuts, seeds, beans, and certain fruits and vegetables, predominantly contain these types of fibers.

Whole grain breads primarily contain insoluble fiber, which is crucial for digestive health but does not dissolve in water. Cellulose, while a form of fiber, is a type of insoluble fiber found in the cell walls of plants and does not contribute to the soluble fiber category. Saturated fats do not relate to fiber at all, as they are a type of fat found in animal products and some plant oils, contrasting sharply with the properties and sources of dietary fiber. Thus, gums and pectins stand out as the correct answer due to their essential role in providing soluble fiber.