WASHINGTON -- Caffeine is a central part of most Americans' daily routines -- from the morning coffee to the lunchtime soda to the post-dinner square of chocolate. And while the substance occurs naturally in more than 60 plants, not all of the caffeine consumed is natural. Much of it is synthesized in pharmaceutical plants overseas.
Murray Carpenter, author of "Caffeinated: How Our Daily Habit Helps, Hurts and Hooks Us," explains there are two ways to obtain the pure powdered form of caffeine.
One way is to extract it from a product in which caffeine naturally occurs, such as coffee or tea. The other way is to synthesize, or make, caffeine from urea and other chemical precursors.
Carpenter says the U.S. imports 15 million pounds of synthetic caffeine powder each year; most of it is blended into soft drinks.
"That's enough to fill a freight train 2.5 miles long," Carpenter says.
"If you look at a can of, say, Coca-Cola, and you think, ‘Where did the caffeine in this Coke come from?,' more likely than not, it came from a pharmaceutical plant in China."
Synthetic caffeine is not new; the process for making it was developed by German chemists in the late 1800s. But it wasn't until the 1940s when synthetic caffeine became an industrial-scale product, Carpenter says. Now, most of the caffeine we consume in products that don't naturally contain the compound is synthesized.
In the three years Carpenter spent conducting research for his book, he traveled across the world to see some of the places where we get the majority of our man-made caffeine. He approached pharmaceutical plants in China, India and Germany, but no one would give him access to what went on behind their walls. But he wasn't surprised; Carpenter says the caffeine part of the pharmaceutical industry is "pretty opaque."
One of the plants on his journey was the largest synthetic caffeine plant in the world; it's in Shijiazhuang, about two and a half hours southwest of Beijing. There too, Carpenter was not allowed inside -- so he stood outside the "kind of run-down industrial park," instead.
Even without being able to see inside the plants, Carpenter says the experience was "a bit of an eye-opener [as to] where our caffeine comes from," especially since FDA regulators often don't inspect caffeine production plants.
"When they do, sometimes inspections have revealed pretty horrendous conditions," he says. "The pharmaceutical industry has mostly been off-shored in recent years. Many of our largest pharmaceutical plants are now in China and in India, and FDA regulators have a hard time inspecting these plants."
But while conditions may be less than ideal in some plants, Carpenter says it's highly unlikely the caffeine synthesized there could be dangerous.
"It would take an awful lot of impurities to really cause significant harm to human health, unlike some other pharmaceutical products," he says.
"Either natural or synthetic caffeine could have impurities associated with it, and these could be harmful to your health, but if the caffeine is pure caffeine, either synthesized or naturally extracted, its effect on your physiology should be exactly the same."
While the revelation of how caffeine is made and where a significant amount of it comes from may shock consumers, Carpenter does not predict people will stop drinking their beloved caffeinated beverages.
The average adult in the U.S. consumes 200 mg of caffeine each day, the FDA reports. That's the equivalent of two cups of coffee or four sodas. And 90 percent of the world's population consumes caffeine in some form.
In the 1950s, Carpenter says, Americans consumed twice as much coffee as we do now, but we drink five times as many soft drinks now than they did then. And an increase in the options for caffeinated beverages will most likely continue to fuel the demand for caffeine in the future.
"The consumption of caffeine emerged independently on at least three continents. In Central America, people were using it in chocolate 3,000 years ago; In Asia at the same time, people were learning about tea. People learned about coffee in Eastern Africa 1,500 years ago. I think there's a natural, human tendency to gravitate toward caffeine and I think it will always be part of our diet," Carpenter says.
"I think it's a really fascinating compound and I think we consistently underestimate the role that it plays in our lives."
© 2014 WTOP. All Rights Reserved.