Contemporary painting has many surprising components as well: I know painters who use rabbit-skin glue[1] to prime or gesso their canvases. Heavy metals and raw hydrocarbons are also pretty common.
(This isn't to imply that grinding up a human being into paint is okay.)
(This isn't to imply that grinding up a human being into paint is okay.)
[1]: https://en.wikipedia.org/wiki/Rabbit-skin_glue