That caffeine in your drink -- is it really 'natural?'

Maik A. Jochmann, Ph.D., and colleagues point to the growing consumer preference for foods and beverages that contain only natural ingredients. Coffee, tea, colas, energy drinks and other caffeine-containing drinks are the most popular beverages in the world. Food regulatory agencies require that caffeine be listed on package labels, but do not require an indication of whether the caffeine is from natural or synthetic sources. The scientists set out to develop a faster, simpler method for categorizing caffeine's origins.

In the study, they describe use of a technique called stable-isotope analysis to differentiate between natural and synthetic caffeine. The test makes use of differences in the kinds of carbon isotopes -- slight variations of the same element -- found in caffeine made by plants and caffeine made in labs with petroleum-derived molecular building blocks. Their analysis, which takes as little as 15 minutes, found four products that contained synthetic caffeine, despite a "natural" label.

The authors acknowledge funding from the German Federal Ministry of Economics and Technology and the German Research Foundation.