Question: Are there really “antinutrients” in beans and whole grains? Aren’t beans and whole grains good for you?
Answer: The answer is yes, to both questions. Antinutrients are substances in food that interfere with the availability or absorbability of nutrients. Many substances are considered antinutrients. Protease inhibitors in soybeans can interfere with protein digestion; glucosinolates in cruciferous vegetables like Brussels sprouts and cauliflower can interfere with iodine absorption (Suliburska & Krejpcio 2014); even fiber can be an antinutrient because it may get in the way of mineral absorption. Phytic acid—found in whole grains, nuts and legumes—binds with calcium, iron and zinc. Oxalic acid in spinach also interferes with calcium absorption. Polyphenols, including tannins in red wine and tea, inhibit iron and zinc absorption.