Brown rice is high in heavy metals, and white rice contains some, necessitating soaking or parboiling to mitigate potential reactions.

“brown rice is quite high in heavy metals and not something that humans want to be eating the removal of the hull of the brown rice leading to white rice removes a lot of the heavy metals but still leaves some which is why I soak the white rice in uh the vinegar some people have even suggested par boiling I've tried par boiling the rice as well and all of those things continue to give me some sort of reaction”