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.
The study report, as quoted by Carpenter, is charming: After the equivalent of a cup of coffee, one subject reported a "gradual rise of spirits till 4:00. Then a period of exuberance, of good feeling. Fanciful ideas rampant." Another participant, dosed only on placebos, complained that he "Felt like a ‘bone head’ all day."
The case was dismissed at the request of Coca-Cola, and so "the jury issued no verdict on the larger questions argued in the courtroom":
How much caffeine is too much? Is it different when added to soft drinks than as a natural constituent of coffee? Is it habit-forming? Should it be marketed to youths? And how should the federal government regulate it?\n
What's even more extraordinary is that, to a large extent, those questions still remain unanswered today.
Last fall, the FDA banned Four Loko and its kin, ruling that caffeine is "an unsafe food additive" to alcoholic drinks. But although the agency limits caffeine content in sodas and "cola-type beverages" to 0.02 percent or 68 milligrams per regular 12 oz can, the caffeine content of energy drinks and shots is still completely unregulated.
Carpenter quotes a recent article in the Journal of the American Medical Association calling for more research to determine "a scientifically validated upper limit on the amount of caffeine a manufacturer can include in a single serving of any beverage." Its authors note research showing the adverse effects of caffeine consumption in sensitive individuals (adolescents, pregnant women, and drunks), but their comments only serve to highlight the huge data gap in our scientific understanding of the effect of caffeine on human physiology.
Which brings me to the spiders in the title of this post. In 1995, NASA tested the impact of various drugs on the web-weaving behavior of the common house spider, as part of a series of experiments to find a better animal species on which to test chemical toxicity. The results were astonishing.
On the left, above, is a normal spider web. To its right is the web spun by a spider dosed with caffeine. The webs below were spun under the influence of marijuana (on the left) and benzedrine (on the right). As you can see, pot and speed both sent the spiders a little haywire, resulting in webs with big holes and a looser structure. But on caffeine, the researchers reported, a spider "seems unable to do more than string a few threads together at random."
I'm a true addict, so I don't know whether this broken web evidence is scary enough to keep me away from coffee—but if spiders are any guide, then it's more than time for the FDA to fill the gaps in our knowledge about caffeine.