Expert Testimony: Dr. Kathleen Miller

Kathleen MillerKathleen Miller is a Senior Research Scientist at the State University of New York at Buffalo. Dr. Miller’s current research focuses on alcohol mixed with energy drink use, and problem behaviors like sexual risk-taking and interpersonal aggression. She has published over 30 peer-reviewed articles, including “Wired: Energy drinks, jock identity, masculine norms, and risk-taking,” “Energy drinks, race, and problem behaviors among college students,” and “Alcohol mixed with energy drink use and sexual risk-taking: Casual, intoxicated, and unprotected sex.”

We interviewed Dr. Miller via email. Her answers have been edited for clarity and length.

How did you first become aware of the hazards of energy drinks?

Energy drinks crossed my radar in 2006 when I was designing a survey on athletic involvement and substance use for administration to a college population. At that time, Red Bull had been on the U.S. market for almost a decade and was growing rapidly in popularity among youth consumers, but it had received virtually no attention from the public health community. I added a couple of questions on energy drink use to my survey, just out of general curiosity, and was startled to find that it was a very strong predictor of a wide range of problem behaviors.

What kinds of problem behaviors?

An adolescent or young adult who regularly consumes energy drinks is also at significantly higher risk than his/her peers for problem drinking, recreational use of other stimulant drugs (like Adderall), unsafe sex, physical fighting, driving without a seatbelt, and so on. That doesn’t mean that drinking Red Bull or Monster causes people to take health-compromising risks. It’s more likely that these drinks appeal to people whose personalities or life circumstances predispose them to risky behavior in general, both because they provide a mild stimulant buzz and because they are marketed with a seductive, extreme-lifestyle, risk-oriented appeal. However, energy drink use—especially frequent use—is a very effective red flag for these behaviors.

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Why are these drinks so much more dangerous for children and adolescents versus adults?

Children are more sensitive to caffeine than adults. They metabolize it more slowly, and their low body mass means that the same dose of caffeine packs a stronger punch for a child than for an adult. Children also lack the body of lived experience to know how caffeine will affect their individual metabolism, so they’re less able to judge what is a safe level for them personally. According to the National Poison Data System, of the 6,309 poison reports involving energy drinks, three out of four happened to people under the age of 20.

The American Academy of Pediatrics’ official position is that energy drinks have no place in children’s diets.

How much research has been done on these drinks, their ingredients, and their long-term effects?

Compared to most other substances, research on energy drinks is still in its early stages. Most of the research has focused on the behavioral consequences of mixing alcohol with energy drinks. The other research with which I’m familiar focuses on the caffeine in energy drinks, rather than ingredients such as taurine, B vitamins, and plant/herbal extracts. While the latter are potentially of interest, the active ingredient in these drinks—the one primarily driving the risks and behavioral consequence—is caffeine. There is definitely some concern about the potential interaction of caffeine with various plant/herbal extracts, particularly since those don’t fall under the jurisdiction of the FDA and therefore are quite poorly understood.

There’s really no research yet on the long-term effects.

What can parents do to keep these drinks out of their children’s hands?

The first, most important thing for parents to do is educate themselves. The more they know about the contents and potential risks of these drinks, the more informed choices they can make about monitoring or restricting their children’s intake. There are several common misconceptions about energy drinks, namely that they are equivalent to sports drinks (definitely not: using energy drinks while exercising is a potential risk), that they are basically tarted-up soft drinks (in fact, they’re about three times stronger).

Parents should also be aware that if they want to keep energy drinks out of their children’s hands, they’re probably going to need their children’s cooperation to do it. These drinks are as available as soft drinks—not just at grocery stores, convenience stores, and gas stations, but vending machines everywhere, including child-oriented venues like schools and amusement centers.

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What would you like the FDA to do in terms of regulation?

The most viable option would be instituting mandatory nutrition labels with full caffeine disclosure, including both natural and added sources, and clear explanations of both the dosage and the risks. Canada is a really good model for this. Their labeling includes the individual dosages of all “medicinal ingredients”: not just caffeine but taurine, ginseng, vitamins, etc., including the note that guarana—a very common herbal ingredient—is itself 22% caffeine. Dosages are shown for the full can, not “per serving” as is currently done in the U.S.


This is important, because energy drinks are carbonated and come in pop-top cans, so it’s not possible to drink just half of the can and leave the other half for later because it goes flat. The real serving size is the whole can. Canada’s mandatory labels are also considerably more detailed with respect to the risk categories.

A second approach would be to impose limits on caffeine dosages in energy drinks, comparable to the FDA limits that already exist for regular soft drinks, which are permitted no more than 71mg caffeine per 12-ounce can. For comparison, an 8-ounce can of Red Bull is 80mg; a 16-ounce can of Monster is 160mg.

What is the first thing that comes to mind when you think of energy drinks?

The first thing that comes to mind is caffeine. We tend to think of caffeine as just another food ingredient, but in fact it’s a stimulant drug—a relatively mild one, but a drug nonetheless. At low to moderate doses, it’s harmless, even beneficial in its effects on alertness and concentration. In higher doses, it’s harmful, causing jitters, anxiety, racing pulse, elevated blood pressure, sleep disturbances, headaches, nausea, and other symptoms. At very high doses, it’s actually been associated with seizures, stroke, manic episodes, or even death. Because it’s used without any noticeable negative consequences by an overwhelming majority of people in the United States, we don’t take it seriously as a drug. We should.