Caffeine is the most widely consumed drug in the world. And because coffee is a major source in the supply line, people advised to avoid caffeine because of certain medical conditions like hypertension should be aware that even decaffeinated brew can come with a kick, UF researchers report in this month's Journal of Analytical Toxicology.
"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, Ph.D., a professor and director of UF'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."
Despite caffeine's widespread use, most medical texts have no guidelines for intake, Goldberger said, but even low doses might adversely affect some people. So UF researchers set out to conduct a two-phase study designed to gauge just how much caffeine is likely to turn up in decaffeinated coffees.
First they purchased 10 16-ounce decaffeinated drip-brewed coffee beverages from nine national chains or local coffee houses and tested them for caffeine content. Caffeine was isolated from the coffee samples and measured by gas chromatography. Every serving but one - instant decaffeinated Folgers Coffee Crystals - contained caffeine, ranging from 8.6 milligrams to 13.9 milligrams.
In comparison, an 8-ounce cup of drip-brewed coffee typically contains 85 milligrams of caffeine.
In the study's second phase, scientists analyzed 12 samples of Starbucks decaffeinated espresso and brewed decaffeinated coffee taken from a single store. The espresso drinks contained 3 milligrams to 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.
Even though the amount of caffeine in these coffees is considered low, some people could conceivably develop a physical dependence on the beverages, said co-author Mark S. Gold, M.D., a distinguished professor of psychiatry, neuroscience and community health and family medicine at UF's College of Medicine.
"One has to wonder if decaf coffee has enough, just enough, caffeine to stimulate its own taking," Gold said. "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."
And even moderate caffeine levels can increase agitation, anxiety, heart rate and blood pressure in some susceptible individuals, Goldberger said.
"Carefully controlled studies show that caffeine doses as low as about 10 milligrams can produce reliable subjective and behavioral effects in sensitive individuals," said Roland Griffiths, Ph.D., a professor of behavioral biology and neuroscience at the Johns Hopkins School of Medicine. "More than 30 percent can discriminate the subjective effects of 18 milligrams or less. The present study shows that many decaffeinated coffee drinks deliver caffeine at doses above these levels.
"The important point is that decaffeinated is not the same as caffeine-free," Griffiths added. "People who are trying to eliminate caffeine from their diet should be aware that popular espresso drinks such as lattes (which contain two shots of espresso) can deliver as much caffeine as a can of Coca-Cola - about 31 milligrams."
Denise Trunk | EurekAlert!
Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences