DEAR DOCTOR: Could energy drinks really lead to stimulant use? How can that be? No one's ever linked coffee or cola consumption to an increased risk of drug abuse. This sounds like some kind of urban legend.
DEAR READER: Considering the centuries-long history of coffee drinking, and the estimated 2.5 billion (!) cups of the stuff consumed each day worldwide, your skepticism is understandable. However, a 2009 study by researchers at the University of Maryland indeed suggested a link between the sustained use of energy drinks by young adults and the chance of future abuse of certain types of drugs.
The study began with 1,060 first-year college students with an average age of 18. Over the course of the following three years, the students completed three annual interviews regarding their use of energy drinks, any other sources of caffeine, and alcohol and tobacco use. The students also reported the use of prescription drugs, and any illegal drugs. In a series of post-college interviews, which took place when the participants were between the ages of 21 and 25, the researchers assessed their drug use.
Over the course of the first three years of the study, about half of the students either diminished or stopped using energy drinks. The other half continued to consume them in the same large quantities. When they followed up several years later, researchers found that students who continued robust energy drink use went on to have a markedly higher risk of using cocaine or illicit stimulants after the age of 25 than did the group of occasional or nonusers. The high-use group was also found to have an increased risk of alcohol abuse.
Whether the energy drinks themselves set the stage for the future drug abuse, or whether the individuals who were naturally susceptible to drug or alcohol abuse were also drawn to the effects of the energy drinks, is not known. However, the researchers concluded that the implied connection between sustained energy drink usage among young adults and the potential for future illicit stimulant use deserves further study. With an estimated one-third of teens between the ages of 12 and 17 now regularly downing several energy drinks per day, we heartily agree.
Addiction aside, ongoing studies continue to identify a range of health risks associated with energy drinks. These include increased blood pressure, heart arrhythmias, sleep disturbance, damage to the heart and blood vessels, kidney damage and weight gain. This last may seem counterintuitive for a product engineered to rev you up, but many varieties of energy drinks contain excessive amounts of sugar, up to 2 or more tablespoons per 8-ounce can. That means just one energy drink will put you over the recommended allotment of sugar for the day.
In addition to caffeine and sugar, energy drinks contain a range of herbs, enzymes, vitamins and other additives. And because the products are not regulated, you can't always know exactly what you're ingesting. Bottom line -- research repeatedly shows that energy drinks can have serious health effects, particularly in children, teenagers and young adults.
Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.