Also, Cassava, a food first domesticated 10,000 years ago and a current staple for over 'half a billion people', is toxic (Cyanide) unless processed.
https://en.wikipedia.org/wiki/Cassava#Food_use_processing_an...
https://en.wikipedia.org/wiki/Cassava#Food_use_processing_an...
http://www.smithsonianmag.com/arts-culture/horrific-tales-of...
In the 1960s some potato breeders accidentally produced a poisonous breed of potato by crossing two perfectly harmless versions, and some people (mostly the potato breeders themselves!) were quite ill before anyone realised what was going on.
http://boingboing.net/2013/03/25/the-case-of-the-poison-pota...
Also, seriously don't eat potato berries.
So I would say, no, they're not bad. But don't go overboard.