I am beginning to wonder if the FDA's primary policy is to allow anything that reduces brain function, as this additive is know to do. Struvite, or magnesium ammonium phosphate hexahydrate, forms these very long sharp clear crystals that you almost wouldn't notice. I wouldn't be surprised when it is discovered that they cause intestinal irritation as well. If you are interested I did find the most common source of this very inexpensive chemical. It is precipitated from drainage water (not sewage) and is a byproduct of fertilizer.