[Deborah Blum's latest book is"The Poisoner's Handbook: Murder and the Birth of Forensic Medicine in Jazz Age New York"] In the mid-19th century in Europe, a rather strange theory arose — the idea that eating arsenic could improve one's health. It originated with the discovery that peasants in the Austrian mining region of Styria liked to mix a little of the poison into their morning coffee. As reported in 1855, the miners had discovered that exposure to arsenic — an element naturally occurring in metallic rocks — brought "beauty and freshness to the complexion."...

And today, while people don't deliberately add the poison to their diet, we still encounter arsenic in our daily lives. It is still used as a pesticide. And we still eat it with our food, especially during holidays like Thanksgiving that make poultry a centerpiece of the celebration.

Most commercial-grade poultry feed today contains an arsenic-based pesticide. Like the Victorians, farmers use the poison because of its ability to improve appearances — in this case because arsenic's potent effect on blood vessels makes the chicken and turkey we buy look pinker and therefore fresher....