Has fiber been shown to affect absorption of calcium, zinc, or magnesium significantly?

• A. Yes, significantly in most cases
• B. No
• C. Only zinc
• D. Only calcium and magnesium

Answer: (B)

In typical dietary patterns, fiber itself does not significantly alter the absorption of calcium, zinc, or magnesium. Any potential effect is usually linked to other components, like phytates in some high-fiber plant foods, rather than fiber alone, and even then the impact on mineral absorption is generally small. Calcium absorption depends largely on vitamin D status and other factors, while magnesium absorption is relatively robust and zinc absorption is more sensitive to phytates than to fiber per se. So, under usual conditions, fiber hasn’t been shown to cause clinically meaningful changes in the absorption of these minerals.