trivia:
women are more likely to have autoimmune thyroid problems than men.
Toxic beryllium used to be called "glucinium" because it tasted like sugar (glucose), back when chemists tasted everything they made.
Every molecule of nutrasweet is broken down into one molecule of methanol in the body. Methanol can be toxic in large doses, but we also get a lot of it in fruits and other foods.
Splenda has a structure like sugar, but has a bunch of chlorines in place of hydroxyl groups... as a chemist that scares the crap out of me, since usually chlorinated organic compounds are carcinogenic.
"Tannins" in tea and other plants (grapes, etc) are called such because the "tannins" from oak trees used to be used to tan leather.
Arsenic is toxic, but chicken that are fed food with a complete lack of arsenic in it don't grow properly. We still don't know what the function of the very trace amounts of arsenic are that are needed for growth.
Mercury, a toxic metal, used to be used in many many medicines. Some traditional chinese medicines still have mercury as ingredients. Mercury was used in gold-mining, so mercury pollution is common in parts of california, alaska, and brazil.
Ok, one more...
Lead is toxic, but was used for plumbing in ancient times (hence the chemical symbol, Pb, for "plumbum" in latin). Romans would add Lead acetate to their wine because it was sweet. They would get it by boiling vinegar (dilute acetic acid) down in lead containers. The fall of Rome may be partially due to Lead poisoning of the ruling class, leading to sickness and insanity. Lead is in most soils next to roads because tetraethyllead was in all the gasoline as a anti-knocking agent (hence we now use "unleaded" gasoline). Lead oxide is a very white pigment and was used in most white paint prior to the 1970s (Dont lick your walls!).
SCIENCE!