One hundred years ago, the predecessor of the FDA had no data on how caffeine affects humans. Unbelievably, the same is pretty much true today.
A fascinating article in Monday's New York Times looks at the long debate over safe limits for caffeine consumption in the United States. "Long" in this instance means 100 years—journalist Murray Carpenter tells the story of the USDA vs. Coca-Cola, which went to trial a century ago this month.
At the time, Coke contained 80 milligrams of caffeine per serving, as much as a Red Bull today. To defend themselves against the government's charge that caffeine was a harmful ingredient, they hired a scientist to look at the effects of the stimulant on the mental and motor skills of both abstainers, occasional, and heavy users. No one had gathered this kind of data before.