The pellagra epidemic of the early 20th century may have been the deadliest epidemic of a specific nutrient deficiency in U.S. history. Part one covers what it is, its appearance in 19th-century Italy, and the first reports of it in the U.S.
Research:

Behind the Scenes Minis: Piece of Work
17:48

E. Virgil Neal: Hypnotist, Fraudster, Tycoon, Part 2
41:22

E. Virgil Neal: Hypnotist, Fraudster, Tycoon - Part 1
35:28