Greg Reese does a mother great story on nanoparticles in food. These are nano versions of materials that are considered safe in general so are allowed to be used in nano form due to this safety at a macro level. The problem is nano particles in the body are not stopped by barriers of the body. Most notable of these being the blood / brain barrier. This barrier is supposed to keep these types of things from entering the brain. We have no way to really know the impact of these metal on the brains physiology. This is uncharted territory. This story also touches on something I wrote about in another video, the use if human bodies as fertilizer. I drew the analogy to the movie Soylent Green as does this video. Good watch and an eye opener.
