Reduced Mineral Absorption

High dietary fiber intake can reduce the absorption of essential minerals like iron, zinc, calcium, and magnesium. This effect is more significant with excessive fiber consumption or certain fiber types, but unlikely to cause deficiencies with a balanced diet.

Excessive intake of dietary fiber, particularly insoluble fiber such as bran, can interfere with the absorption of certain minerals, including iron, zinc, calcium, and magnesium. This interference occurs as fiber binds to these minerals in the digestive tract, preventing their absorption into the bloodstream. The effect is more pronounced with very high fiber doses (significantly exceeding recommended daily intake) or specific types of fiber that have a high binding capacity. Symptoms of mineral deficiencies resulting from reduced absorption can include fatigue, weakened immune function, bone problems, and neurological issues, though these are unlikely with a balanced diet.