Title: Caffeine Dependence
Key words: withdrawal symptoms, headaches, fatigue, physical dependence, children
Date: Aug 2000
Category: 4. Food Data
Author: DJE Candlish
A can of soda may do more than quench your thirst and satisfy your sweet tooth. A new study suggests that the caffeine in soft drinks can produce physical dependence and lead to headaches and fatigue - withdrawal symptoms associated with stopping caffeine use. In the study, researchers at Johns Hopkins University challenged the claims by the soft drink industry that adding caffeine to soft drinks is done purely for taste. They found that the majority of people who claim to be soft drink connoisseurs couldn't tell whether a soda contains caffeine or not. "Despite the claims to the contrary, the flavour of caffeine is relatively unimportant to the great majority of soft drink consumers," says Dr. Roland Griffiths, lead author of the study, and professor in the departments of Psychiatry and Neuroscience at Johns Hopkins University School of Medicine in Baltimore, Maryland. According to researchers, Americans consume a huge quantity of soft drinks, which include any carbonated, flavoured beverage, and 70% of them contain caffeine. On average, each American consumes nearly 600 cans per year.
"People should recognize that caffeine is a mood altering-drug," says Griffiths. "A more likely explanation for the high rates of soft drink consumption is the central nervous system effect of mood-altering drugs that produces physical dependence that leads to and perpetuates the daily use." Researchers studied 25 adults who are avid cola drinkers. They found that only two out of the 25 could detect caffeine in cola at concentration of 0.1 milligram per milliliter, the concentration in Coca-Cola Classic or Pepsi. The rest of the group couldn't taste the difference between caffeine-containing and caffeine-free cola until caffeine levels were raised to much higher levels, beyond those approved by the US Food and Drug Administration (FDA).
Given the fact that caffeine consumption may often go undetected, Griffiths says, "People should come to know how caffeine affects them when they take it, and if they are chronic users, how caffeine affects them if they stop taking it, that is withdrawal." Griffiths says that he is not opposed to caffeine consumption. "It can be a useful drug and adults can make a decision about it," says Griffiths. "But some thought should be given to the aggressive marketing to children who are vulnerable and are less likely to make an informed decision."
Dr. Gail Berstein conducted a study in 1998 on "Caffeine Withdrawal In Normal School-Age Children," which was published in the Journal of the American Academy of Child and Adolescent Psychiatry. Bernstein says that her study showed that children were at risk for withdrawal symptoms when switched from high daily amounts of caffeine to caffeine-free drinks. "We found that 24 hours after children discontinue their caffeine use, there is a change, specifically a deterioration in their performance on a computerized test of attention," says Berstein, associate professor and director in the Division of Child and Adolescent Psychiatry at the University of Minnesota Medical Center in Minneapolis. "It is consistent with the possibility of them being in caffeine withdrawal."
Jeff Nedelman, a spokesman for the National Soft Drink Association in Washington, DC, says that there is no credible scientific evidence to back caffeine's effect on children. He says that caffeine plays an important role in the flavour of soft drinks and that it is listed in these products' ingredients. "Caffeine is on the ingredient statement," says Nedelman. "All of the major companies make their ingredients available either on their web sites or consumer hotlines." But researchers say they would like to see more prominent caffeine labeling on soft drinks. "Given that sodas are aggressively marketed to kids, manufacturers should openly say why the caffeine is there," says Griffiths. "We should tell what the caffeine dose is. It's a case of knowing what you're getting and why."
References: Archives of Family Medicine, August 14, 2000
Caffeine Withdrawal In Normal School-Age Children, Journal of the American Academy of Child and Adolescent Psychiatry. 1998