Coffee drinkers looking to escape caffeine's clutches by switching to decaf may not be making the clean break they think they are, according to the findings of a new study.
In fact, University of Florida researchers found that almost all decaffeinated coffee tested contained at least some caffeine.
“If someone drinks five to 10 cups of decaffeinated coffee, the dose of caffeine could easily reach the level present in a cup or two of caffeinated coffee,” said co-author Bruce Goldberger, a professor and director of the university's William R. Maples Center for Forensic Medicine.
“This could be a concern for people who are advised to cut their caffeine intake, such as those with kidney disease or anxiety disorders.”
In the first phase of the study, researchers bought 10 16-ounce decaffeinated drip-brewed coffee beverages from nine U.S. national chains or local coffee houses and tested them for caffeine content.
Each serving with one exception — Folgers Coffee Crystals — contained caffeine, ranging from 8.6 milligrams to 13.9 milligrams.
By comparison, an eight-ounce cup of drip-brewed coffee normally contains about 85 milligrams of caffeine.
In the second phase of the study, researchers analyzed 12 samples of Starbucks decaffeinated espresso and brewed decaffeinated coffee taken from a single store. The espresso drinks contained between three milligrams and 15.8 milligrams of caffeine per shot, while the brewed coffees had caffeine concentrations ranging from 12 milligrams to 13.4 milligrams per 16-ounce serving, the study found.
Dr. Mark Gold, co-author of the study and professor of psychiatry, neuroscience and community health and family medicine at the university's College of Medicine, said, while the caffeine levels are considered low, they could still have an impact on some people.
“One has to wonder if decaf coffee has enough, just enough, caffeine to stimulate its own taking,” he said in the report.
“Certainly, large cups and frequent cups of decaf would be expected to promote dependence and should be contraindicated in those whose doctors suggested caffeine-free diets.”
