One example would be Red Bull. She loved it.. read the label. Then did some research on taurine. Now she will not touch it.
The fact is we see studies showing some benefits of supplements. They don't report the negative sides etc.
Further, nobody knows how the body will react when certain chemicals are mixed.
An example of something most don't know would be this. There are a lot of prescription drugs out there that become 10X more potent when taken with Grapefruit juice!!!! That could kill you.