Secondarily, both contains oxalate in proportions of 1% of black pepper and 2% of turmeric by mass, which leads to the formation of kidney stones.

It's worse in the US because the FDA effectively "washes its hands" of anything deemed a "supplement". In general, the precautionary principle is difficult to find in America outside of FDA-approved procedures, medical devices, and medications. Food and supplements are desperately under-regulated.