April 2018 Issue

Safety and Efficacy of Energy Drinks
By Densie Webb, PhD, RD
Today's Dietitian
Vol. 20, No. 4, P. 30

Consumer demand for these beverages is huge, but their safety continues to be questionable.

Energy drinks, not to be confused with sports drinks, are defined as beverages that typically contain large amounts of caffeine, added sugars, and legal stimulants, such as guarana, taurine, and L-carnitine, plus any number of vitamins, minerals, and herbs, which together can increase alertness, attention, and energy, while also raising blood pressure, heart rate, and breathing. Energy drinks were introduced to the United States in 1997. Today there are more than 500 energy drinks on the market, and consumption is on the rise.1 The global energy drink market is forecast to exceed $61 billion by the year 2021.2

These drinks generally are sold in cans or bottles in grocery stores, vending machines, convenience stores, and bars, and other places where alcohol is sold. They're promoted as a way to boost energy, decrease fatigue, and enhance concentration.3 The biggest misconception about energy drinks, says Kelly Pritchett, PhD, RDN, CSSD, an assistant professor of health science at Central Washington University and national media spokesperson for the Academy of Nutrition and Dietetics, is that "they will keep you energized throughout the day or give you a boost. In reality, energy drinks are unpredictable; you will likely feel good for a brief period of time, then you'll crash."

Past and present energy drinks are associated with provocative slogans: "Drink it in seconds, feel it in minutes, lasts for hours." "Drinks like a soda, kicks like an energy drink." One deemed itself "the legal alternative" to illegal narcotics. And possibly the most easily recognized slogan, "gives you wiiings." Some lesser-known brands even claim to "burn body fat." Such tag lines are incredibly appealing, especially to young consumers.

Labeling of Energy Drinks
While the American Beverage Association (ABA) recommends energy drinks be labeled as conventional foods and beverages, not as dietary supplements, not all products follow those guidelines. The ABA also requires that the total amount of caffeine in the container (not just per serving) be displayed on the Nutrition Facts label. However, the FDA doesn't require manufacturers to provide the caffeine content or label the amounts of other ingredients, such as taurine and guarana. The ABA states that members, which represent 95% of the energy drinks sold in the United States, must comply with its recommendations and voluntarily provide caffeine content on the label.4 But it turns out that labeling may not always accurately reflect caffeine content. A small sampling of seven energy drinks found that six had less caffeine (<1% to almost 12% less) than declared on the label, and one had 11% more than was listed on the label.5 While it's true that most energy drinks are labeled as beverages and do carry a Nutrition Facts label, a regulatory twist leaves the decision of whether to label their products as beverages or supplements up to manufacturers, and some smaller companies label their products as supplements, which have less stringent labeling regulations. In fact, Monster Energy drinks, one of the most popular brands, were originally labeled as supplements and, in compliance with ABA guidelines, were reclassified as beverages and product labeling was revamped accordingly.6

What's Inside Energy Drinks?
Energy drinks can contain several ingredients from caffeine to herbal stimulants to vitamins and minerals to amino acids.

As the world's most commonly consumed central nervous system stimulant, caffeine isn't a new ingredient in beverages. Most consumers have long gotten caffeine from coffee, tea, and soda. Caffeine also is naturally present in dark chocolate and in some ingredients found in energy drinks, including guarana. Energy drinks typically contain anywhere from 17 to 242 mg caffeine per serving (not always per container). In small quantities, caffeine may boost energy, alertness, and even athletic performance. For healthy adults, the FDA has determined that up to 400 mg per day is safe—that's about four or five small cups of coffee—an amount not generally associated with dangerous, negative effects.7 The safe limit is set at only 100 mg per day for adolescents (aged 12 to 18), the amount of caffeine in one cup of coffee.8 A single serving of many energy drinks exceeds that amount.9

Canada has set a legal limit of 180 mg caffeine per serving of energy drinks, but a container may provide more than a single serving.10 While the FDA doesn't require products to list caffeine content on product labels, leading brands provide the information voluntarily. Energy drinks that are labeled as supplements, rather than beverages, aren't subject to the FDA's enforced limit of 71 mg caffeine per 12 oz for soda.11

"While the safe limit of caffeine is set at 400 mg per day for 'most' adults, I've had some patients that have negative effects, such as heart palpitations, insomnia, and nervousness from caffeine after just 100 mg," says Angela Lemond, RDN, CSP, LD, owner of Lemond Nutrition in Plano, Texas, and a national spokesperson for the Academy of Nutrition and Dietetics. "Just like any other drug, it affects each body system differently."

To put caffeine content into perspective, a 16 oz (Grande) medium roast coffee at Starbucks contains 310 mg caffeine, more than is found in 16 oz of the Java Monster Mean Bean variety (188 mg), one of the more highly caffeinated energy drinks (see table).

Sugar and Calories
While most energy drinks provide as much sugar as a soft drink or a fruit drink,12 some have historically contained as much as 27 teaspoons of sugar in a 32-oz container. Typically, one 20-oz can contains between 220 and 280 kcal and 54 to 62 g carbohydrate, nearly all of which are from added sugars (about 14 to 16 teaspoons of sugar). There's some suggestion that sweetened energy drinks may affect weight management. A small study of young women found that energy drink consumption slowed lipolysis, and the researchers suggested that this could contribute to obesity.13 Other energy drinks are sugar-free and are sweetened with the artificial sweeteners aspartame and acesulfame K, which would appear to be in opposition to the promise of quick energy.

Most energy drinks contain moderate amounts of sodium, less than sports drinks, but more than soft drinks. However, at least one variety of one brand contains 340 mg sodium per 8-oz serving, about 15% of the maximum recommended daily intake. Sodium content is provided on most labels of energy drinks.

B Vitamins
B vitamins are, of course, essential for good health, but too much can be harmful. Some energy drinks contain extremely high levels of B3 (niacin), B6, and B12, which in excess can cause skin conditions, gastrointestinal problems, liver toxicity, blurred vision, headaches, and nerve damage. Some energy drinks contain several hundred times the DV for some of the B vitamins; Bonnie Taub-Dix, MA, RDN, CDN, nutrition consultant and author of Read It Before You Eat It, says, "They are the equivalent of taking a mega, mega vitamin, something that needs to be reconsidered, especially if you're already taking supplements."

Other Ingredients
Other common ingredients found in energy drinks include taurine, Gingko biloba, ginseng, tyrosine, ginger, green tea, calcium, and beta-alanine in varying amounts not often listed on the nutrition label.

While most conventional extra ingredients are Generally Recognized as Safe by the FDA—a designation that a chemical or substance added to food is considered safe by experts—and so is exempted from the food additive requirements, it isn't known what the combined effects might be.

Safety Concerns
"Another misconception of energy drinks," Lemond says, "is that there is benefit without risk." While some studies have found an association between the ingredients in energy drinks and improved alertness, reduced fatigue, and improved physical activity performance and strength, the vast majority of the available evidence suggests there are both short-term and long-term negative health effects.11 The World Health Organization and the American Academy of Pediatrics have warned of the dangers of energy drinks.14,15 The American Academy of Pediatrics has taken it further and stated that "Rigorous review and analysis of the literature reveal that caffeine and other stimulant substances contained in energy drinks have no place in the diet of children and adolescents."9

Some countries have banned the sale of energy drinks to children under the age of either 16 or 18. The ABA's 2014 guidelines for the marketing of energy drinks state, "Energy drink manufacturers will not market their energy drink products to children under 12 years of age … [and they] will not sell or market in K–12 schools."4 While there may not be direct marketing to a young demographic, the energy drink companies are regular sponsors of events such as skateboarding, surfing, BMX riders, Formula 1 racing, gaming, and concerts, all of which attract young audiences.

Between 2007 and 2011, the overall number of energy-drink related visits to emergency departments (EDs) doubled. While the drinks have wide appeal among youth, the most significant increase (279%) of ED visits was among people aged 40 and older.

A growing trend among young adults and teens is mixing energy drinks with alcohol. About 25% of college students consume alcohol with energy drinks, and they binge drink significantly more often than students who don't mix them. In 2011, 42% of all energy drink-related ED visits involved combining these beverages with alcohol or drugs, including marijuana and central nervous system stimulants like Ritalin or Adderall.16

Energy drinks are sometimes drunk along with alcohol in the hope of being able to drink more while feeling less drunk. However, studies have shown that while the energy drink may reduce sensations of intoxication, motor coordination and visual reactions as well as breath alcohol concentrations are unchanged.17 The combination can be dangerous, Lemond says. "The feeling of being 'buzzed' is an indication to slow down to prevent alcohol intoxication. You may not get the warnings of intoxication when drinking a beverage that contains both alcohol and caffeine."

Large amounts of caffeine can cause serious problems such as heart rhythm disturbances and increases in heart rate and blood pressure. Caffeine also can harm children's still-developing cardiovascular and nervous systems and may be associated with palpitations, anxiety, sleep problems, digestive problems, elevated blood pressure, and dehydration. Excessive energy drink consumption may disrupt teens' sleep patterns and may fuel risk-taking behavior. Guarana, commonly added to energy drinks, contains caffeine. Therefore, the addition of guarana increases the drink's total caffeine content.

A study out of Finland found that consumers of energy drinks had a 4.6 times greater risk of headaches, 3.6 times greater odds of sleeping problems, and 4.1 times greater chance of having an irritable mood compared with nonconsumers.18 Individual ingredients in energy drinks have the ability to affect the heart's electrophysiological properties, but their effects when consumed together in energy drinks is unknown.1

A recent study published in the Journal of the American Heart Association found that 32 oz of an energy drink with 320 mg caffeine raised blood pressure and increased the risk of a higher cardiac QT interval, which is associated with sudden death.1 More serious problems occur when two, three, or four drinks are consumed over a short period of time. A published case study found that drinking six energy drinks per day resulted in cardiopulmonary arrest in a man aged 27.

Recommendations for Practice
Consuming one can of an energy drink likely is safe for most healthy individuals who aren't sensitive to caffeine. The World Health Organization recommended in 2014 that an upper limit for the amount of caffeine allowed in a single serving of these types of drinks be established along with regulations to enforce labeling restrictions and the sale of energy drinks to children and adolescents.14 However, this hasn't happened. Until then, educate clients on the difference between energy drinks and sports drinks and the potential dangers of consuming highly caffeinated beverages, especially in quantity and in combination with alcohol.

— Densie Webb, PhD, RD, is a freelance writer, editor, and industry consultant based in Austin, Texas.

1. Fletcher EA, Lacey CS, Aaron M, Kolasa M, Occiano A, Shah SA. Randomized controlled trial of high-volume energy drink versus caffeine consumption on ECG and hemodynamic parameters. J Am Heart Assoc. 2017;6(5).

2. Global energy drinks market 2015-2021: insights, market size, share, growth, trends analysis and forecasts for the $61 billion industry. Cision PR Newswire website. https://www.prnewswire.com/news-releases/global-energy-drinks-market-2015-2021-insights-market-size-share-growth-trends-analysis-and-forecasts-for-the-61-billion-industry-300137637.html. Published September 3, 2015. Accessed February 6, 2018.

3. Watson E. The evolution of energy drinks: what next for Monster, Red Bull and 5-Hour Energy? Beveragedaily.com website. https://www.beveragedaily.com/Article/2013/02/04/The-evolution-of-energy-drinks-What-next-for-Monster-and-Red-Bull. Updated February 4, 2013. Accessed February 6, 2018.

4. American Beverage Association. ABA guidance for the responsible labeling and marketing of energy drinks. http://www.ameribev.org/files/resources/2014-energy-drinks-guidance-approved-by-bod-43020c.pdf. Accessed February 6, 2018.

5. Attipoe S, Leggit J, Deuster PA. Caffeine content in popular energy drinks and energy shots. Mil Med. 2016;181(9):1016-1020.

6. McNamara B. Monster Energy switches from supplement to beverage. New Hope Network website. http://www.newhope.com/beverages/monster-energy-switches-supplement-beverage. Published February 13, 2013. Accessed February 6, 2018.

7. Caffeine and kids: FDA takes a closer look. US Food and Drug Administration website. https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm350570.htm. Updated January 4, 2018. Accessed February 6, 2018.

8. Seifert SM, Schaechter JL, Hershorin ER, Lipshultz SE. Health effects of energy drinks on children, adolescents, and young adults. Pediatrics. 2011;127(3):511-528.

9. Committee on Nutrition and the Council on Sports Medicine and Fitness. Sports drinks and energy drinks for children and adolescents: are they appropriate? Pediatrics. 2011;127(6):1182-1189.

10. Pound CM, Blair B; Canadian Paediatric Society, Nutrition and Gastroenterology Committee, Ottawa, Ontario. Energy and sports drinks in children and adolescents. Paediatr Child Health. 2017;22(7):406-410.

11. Al-Shaar L, Vercammen K, Lu C, Richardson S, Tamez M, Mattei J. Health effects and public health concerns of energy drink consumption in the United States: a mini-review. Front Public Health. 2017;5:225.

12. Bowers J. How much sugar is in popular drinks? TheDiabetesCouncil.com website. https://www.thediabetescouncil.com/how-much-sugar-is-in-popular-drinks. Updated January 15, 2018.

13. Rush E, Schulz S, Obolonkin V, Simmons D, Plank L. Are energy drinks contributing to the obesity epidemic? Asia Pac J Clin Nutr. 2006;15(2):242-244.

14. Energy drinks cause concern for health of young people. World Health Organization website. http://www.euro.who.int/en/health-topics/disease-prevention/nutrition/news/news/2014/10/energy-drinks-cause-concern-for-health-of-young-people. Published October 14, 2014. Accessed February 7, 2018.

15. Kids should not consume energy drinks, and rarely need sports drinks, says AAP. American Academy of Pediatrics website. https://www.aap.org/en-us/about-the-aap/aap-press-room/pages/kids-should-not-consume-energy-drinks,-and-rarely-need-sports-drinks,-says-aap.aspx. Updated May 30, 2011. Accessed February 2018.

16. Energy drinks. National Center for Complementary and Integrative Health website. https://nccih.nih.gov/health/energy-drinks. Updated October 4, 2017.

17. Ferreira SE, de Mello MT, Pompéia S, de Souza-Formigoni ML. Effects of energy drink ingestion on alcohol intoxication. Alcohol Clin Exp Res. 2006;30(4):598-605.

18. Koivusilta L, Kuoppamäki H, Rimpelä A. Energy drink consumption, health complaints and late bedtime among young adolescents. Int J Public Health. 2016;61(3):299-306.