While rare, there are even deaths: Shortly after she drank two caffeinated energy drinks in 24 hours, a 14-year-old with a heart condition died after going into cardiac arrest. Another fatality was a 19-year-old Connecticut resident who took a dozen caffeine pills. And a healthy Ohio teen who was a high school wrestler died after consuming powdered caffeine.
The Food and Drug Administration has mounted an aggressive effort to warn consumers about the risks of caffeine products and to take manufacturers to task for the way they are marketed.
In 2012, the agency began investigating the deaths of 13 people preliminarily linked to the dietary supplement 5-hour Energy, whose ingredients include caffeine. In 2013, FDA talks with Wrigley prompted the company to stop making its caffeinated gum. Last week, the agency warned five distributors of pure powdered caffeine that they are selling products that are "dangerous" and "present a significant or unreasonable risk of illness or injury to consumers."
"The difference between a safe amount and a toxic dose of caffeine in these pure powdered products is very small," the FDA said. "Furthermore, safe quantities of these products can be nearly impossible to measure accurately with common kitchen measuring tools."
A bitter white alkaloid, caffeine is found naturally in the beans, leaves and fruit of more than 60 plants, and it is by far the most widely consumed psychoactive agent consumed worldwide. In the United States, 85 percent of people are estimated to consume caffeine at least once a day. This number includes children, who mostly get their caffeine in soda. Even preschoolers are ingesting it, studies show, and the likely culprit is chocolate milk. (On average, an eight-ounce cup of regular brewed coffee has about 95 milligrams of caffeine; black tea has 47, a cola, 25 and chocolate milk up to 16 milligrams.)
When it's taken in moderation - usually defined conservatively as the amount in one to two cups of coffee a day - most researchers have concluded that caffeine presents little to no risk to people's health. In fact, some studies have found that the stimulant may have some protective effects from diseases like Parkinson's and cancer.
But in recent years, hospitals have reported an uptick in cases of caffeine overdose, and from Jan. 1 to July 31 this year, poison centers across the country logged 1,675 reports involving energy drinks. Nearly two-thirds were in people 18 and younger.
The issue is so much on everyone's mind that in 2013, when the new bible of American psychiatry - the Diagnostic and Statistical Manual of Mental Disorders, or DSM-5 for short - was released, "caffeine withdrawal" was added as a bona fide mental health disorder.
Roland Griffiths, a professor of psychiatry and neuroscience at Johns Hopkins University School of Medicine, runs a caffeine withdrawal treatment clinic in Baltimore, using techniques similar to those for drugs, to wean caffeine dependents off the stimulant.
