A workshop on The Use and Biology of Energy Drinks: Current Knowledge and Critical Gaps was held at the NIH on August 15 and 16, 2013. The workshop was sparked by the rapidly increasing consumption of "energy drinks" and interest in their claimed effects on alertness, fatigue, cognitive function, physical energy and weight loss or maintenance. If supported by rigorous research, these properties have potential public health benefits (as well as risks), and potential to shed light on a number of biological and behavioral research questions.
Given the variety of energy products on the market, the workshop organizers (please see below) chose to focus on the largest portion of the market; beverages that claim to increase mental or physical energy and that contain caffeine along with other ingredients such as amino acids, vitamins, herbal supplements, and sugar or other sweeteners. These drinks are the fastest growing component of the U.S. beverage market, with sales reaching $12 billion in 2012. At least half of energy drink consumers are reportedly under 25 years old. Despite their growing use, there are limited published data on the biological effects of many of the ingredients (other than caffeine) in these products, and on their combined effects.
In addition to interest in the claimed effects of energy drinks on fatigue, alertness, and physical energy and performance, recent interest in energy drinks has been elicited also by publications such as the January 2013 Drug Abuse Warning Network report that the number of emergency department visits involving energy drinks doubled between 2007 and 2011, when it reached 20,783 visits. This interest was reflected in an Institute of Medicine (IOM), Workshop on Potential Health Hazards Associated with Consumption of Caffeine in Food and Dietary Supplements, held at the IOM on August 5 and 6, 2013. The IOM workshop had a strong focus on populations vulnerable to or at higher risk from exposure to caffeine, with emphasis on cardiovascular effects.
The NIH workshop, led by the Office of Dietary Supplements and the National Center for Sleep Disorders Research at the NIH, was organized with substantial advice and/or support from a range of NIH components, including the National Cancer Institute, the National Institute on Alcohol Abuse and Alcoholism, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute on Drug Abuse (NIDA), and the National Institute of Diabetes and Digestive and Kidney Diseases, as well as from colleagues at the Uniformed Services University of the Health Sciences.
The goal of the workshop was to bring together subject matter experts to summarize the relevant research and highlight the most critical research gaps. Research areas addressed in the NIH workshop included:
- Prevalence and patterns of energy drink and caffeine consumption,
- Reasons for use of energy drinks by children and young adults, as well as in the military,
- Potential for energy drink use to contribute to health disparities, and
- Effects of energy drinks on nutrient and muscle metabolism, and on physical performance.
To provide context for discussions of biological effects of energy drinks, early in the workshop several speakers analyzed the available data on prevalence and patterns of use of energy drinks. Data from several national surveys show relatively low levels of use, while surveys of college students, bar patrons, and the military suggest much higher levels of use in these populations. Dr. Grandner (University of Pennsylvania) presented data on energy drink use by minorities that suggest significant variation between populations and geographic areas both globally and within the US.
Drs. Carskadon (Brown University), Dinges (University of Pennsylvania), and Owens (Children’s National Medical Center) summarized some of the developmental and social factors that may lead adults (especially young adults), children, and adolescents to consume energy drinks, including perceived need to increase alertness or energy at school, at work, while studying, or playing sports, and Dr. Dinges and NIDA’s Dr. Khalsa reviewed data on the mechanisms of action of caffeine in the central nervous system. Drs. Wesensten (Walter Reed Army Institute of Research) and Stephens (Uniformed Services University of the Health Sciences) summarized data on the use of energy drinks in the military, as well as some of the attempts to minimize adverse effects of caffeine on the ability of personnel to sleep when off duty. Drs. Arria (University of Maryland) and Marczinski (Northern Kentucky University) discussed the prevalence of use of energy drinks in combination with alcohol, as well as the limited data on interactions between caffeine and alcohol in modulating alertness and risk behaviors, and Dr. Childs (University of Chicago) summarized the literature on the effects of caffeine, energy drinks, and other energy drink ingredients on mood and behavior. Dr. Hong (Northwestern University) summarized data on the molecular mechanisms linking the circadian cycle with metabolism of carbohydrates and fats, and the potential for caffeine to modulate these. Finally, Drs. Mora-Rodriguez (University of Castilla-La Mancha), Graham (University of Guelph) and Shearer (University of Calgary) summarized data on the effects of caffeine and energy drinks on athletic performance and on metabolism, especially in skeletal muscle.
Speakers noted that data on the effects of energy drinks in most of these contexts are limited, and data on the contributions of energy drink ingredients beyond caffeine to these effects are even more limited. Additional areas where speakers cited pressing needs for more or finer-grained data included effects of caffeine and energy drinks on circadian rhythms, including alertness, learning, performance, and sleep.
The workshop organizers have posted speaker PowerPoint presentations, and are working on a journal issue dedicated to papers based on the workshop presentations. A symposium titled, "Energy Drinks: Current Knowledge and Critical Research Gaps" accepted for the April 2014 FASEB meeting will provide an opportunity for additional experts, and several speakers from the 2013 workshop to present relevant data obtained since the August meeting.