They are denatured –
According to consumer reports whey protein isolates contain trace amounts of harmful heavy metals including lead, cadmium, and arsenic or mercury. Long term use of whey isolates increases your risk of chronic low-level muscle and joint pain, fatigue, headaches and constipation.
Most soy protein isolates go through a process using hexane. Hexane is a petroleum byproduct of gasoline refining. In addition to extracting oil from soy beans, hexanes are used in cleaning agents (degreasers) and solvents for glues, inks, and varnishes.
The CDC has classified Hexane as a neurotoxin. Potential risks include skin irritation, drowsiness or dizziness. Hexanes cause damage to organs through prolonged use or repeated exposure and are suspected of damaging fertility for the unborn child. The FDA does not currently have a limit to how much hexane residue is allowed in soy foods.
How to avoid hexanes –
Buy organic as it is forbidden in organic foods and avoid processed foods.