The most common known/reported hazard is by inhalation into the lungs (because that's the most common way to be exposed); however it's effect on any soft tissue in the body can result in similar effects. I/my husband have over two decades in the 'rock business'; we have seen MANY lapidaries and rock cutters incur major damage from inhalation and ingesting crystalline silica.
My husband has been certified by Melody as a Master of Crystology, and he has never heard of eating ground crystalline silica. If there is product/website that sells crystalline silica, please let me know it's name so that we can research it.