According to researchers at the University of Florida (UF) some carbonated sodas and energy drinks are so loaded with caffeine they can give an unhealthy pick-me-up to unsuspecting consumers.
Bruce Goldberger, director of UF's William R. Maples Center for Forensic Medicine, says because caffeine can pose health risks for people with certain medical conditions, beverages containing the additive should clearly list the amount they contain.
Toxicologist Goldberger says the high caffeine content in some beverages could present problems for pregnant women and children, and for adults with hypertension, heart disease or mental health ailments such as anxiety.
Goldberger, who is also director of toxicology and a professor of pathology and psychiatry at UF's College of Medicine, says the presence of caffeine in the sodas and some of the other beverages was not a surprise but the high concentration of caffeine in some of the energy drinks was, and far exceeded the government's recommendations for cold beverages.
The Food and Drug Administration recommends a maximum caffeine concentration of 65 milligrams per 12-ounce serving of cola beverages, though it does not regulate caffeine content of these drinks.
Although the agency requires the presence of caffeine be disclosed, it does not mandate that caffeine quantity be specified on labeling for energy drinks and cold coffee beverages.
Goldberger's team tested 10 energy drinks, 19 sodas and seven other beverages and found some energy drinks have up to 141 milligrams in a single serving - more than twice the content of some espresso coffee drinks.
The sodas tested, included Coca-Cola and Pepsi products, which ranged from 0 to 48 milligrams a serving, well below the maximum recommended amount.
A&W Root Beer, Sprite, 7-Up and Seagram's Ginger Ale were among the caffeine-free drinks.
However, the caffeine content of most energy drinks exceeded the maximum recommended limit.
Such drinks are often marketed as enhancing performance and stimulating metabolism and are sometimes described as being "highly vitalizing."
But Goldberger says in certain people, consumption of caffeine causes serious health effects, such as anxiety, palpitations, irritability, difficulty sleeping and stomach complaints.
Because the amount of caffeine is not labeled on the drinks people may unwittingly ingest too much, he says.
The American Dietetic Association suggests women avoid caffeine while pregnant or breastfeeding, citing findings from studies linking caffeine consumption to miscarriage and low-birth weight babies.
According to Roland Griffiths, a professor of behavioral biology in the Solomon H. Snyder department of neuroscience at Johns Hopkins University School of Medicine, caffeine is the most widely used mood-altering drug in the world.
Although caffeine is not considered highly toxic, physicians often recommend cutting back or eliminating caffeine consumption for patients who are pregnant or who have anxiety, panic attacks, insomnia or some kinds of stomach and heart conditions.
Griffiths says the daily use of even relatively low doses of caffeine (about 100 milligrams a day) results in physical dependence, with abstinence characterized by withdrawal symptoms such as headache, fatigue, depressed mood and difficulty concentrating.
Goldberger says many people are aware of their food's nutritional content but most know little about the ingredients of their beverage, but only whether it is sugar-free or regular.
The study is published in the Journal of Analytical Toxicology.