Dr. L. Lee Coyne
Nutrition Consulting
Dr. Lee, the Healthy Professor

Energy Drinks

Energy in a Can or a Bottle? A critical review

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To use a weak pun, a new “pop” culture drink has surged into prominence in the snack food – non alcoholic beverage market. The advertised benefits include; “restoring mental alertness and wakefulness, improved endurance, relief from fatigue, boost performance, support daily wellness and vitality, rev up your metabolism and improve your reaction time.” The drinks referred to are the new slick and slender 250 ml (8 oz) aluminum cans (some now come in bottles and some are bigger) energy drinks.

With names like Red Bull, Monster, Lizard Fuel, Full Throttle, Kosmic Kola, Red Rain, Hammer, Power, Adrenaline Rush, Whoopass, Pimp Juice, No Fear and the latest all Canadian entry called Beaver Buzz, it is obvious that the target market is the young, restless and “help me stay awake all night” demographic. Then there is the softer appeal group of similar drinks targeting the alleged healthy market  with names like “Vitality 4U, FRS Antioxidant drink, 5 Hour Energy with no sugar and Hansen’s Slimdown. A visit to an on-line marketing site revealed 36 different brand names for sale.

These new drinks should not be confused with sport drinks. Sport drinks are scientifically formulated combinations of carbohydrates (sugars of various types) to maintain blood sugar levels and muscle glycogen levels during endurance exercise. They also contain some combination of electrolytes known to aid in maintaining normal metabolic functions and to help prevent dehydration or hyponatremia. The sugar content is usually in the 25 gm per drink range (100 Calories per cup) and the electrolytes range from sodium only to the more complete versions that include sodium, potassium, chloride, phosphate, calcium and magnesium. Used properly published science has demonstrated that sport drinks improve endurance performance and enhance the rate of recovery.

“Energy drinks” on the other hand appear to be designed to keep you awake and alert and to provide a tasty way to feel “reved-up”. Only a few make sport or health claims. This critical review evaluates the ingredients in general and summarizes the elative risks associated with some of the ingredients along with the validity of some of the claims.

Energy Drink Labels

Although the labels are difficult to read because of small print, text that runs together and no “Nutrition Facts Table” it becomes apparent that a number of ingredients are prevalent throughout the industry. It behooves the consumer to read the labels carefully.

Core Ingredients

The core ingredients are water, sugar of some kind and in most cases caffeine. There are some that contain no sugar and are sweetened with Sucralose, Aspartame or Acesulfame K. Type any or all of these into your search engines and receive an eye full of warnings. A study published by Sharon Fowler at the University of Texas has shown that “diet sodas” contribute to excess weight gain. If an energy drink is carbohydrate free it means the drink does not contribute to energy metabolism but rather alters neurological function to create the desired effects.

The sugar content ranges from 30 to 50 gm ( 5- 9 tsp), about the same as sodas and equals 120 to 200 Calories (up to twice the carbohydrate content of sport drinks). So don’t think of an energy drink when hydration is an issue because that much sugar will be slow to digest and leave the stomach and will draw water from the tissues in order to dilute the sugar for absorption.

The Buzz

Caffeine is the primary stimulant (Buzz creator) in these drinks. You might remember the original “counter- health” drink/energy drink Jolt that advertised “all the sugar and twice the caffeine” (compared to Coke of course). Energy drinks contain 50 to 160 mg of caffeine and that is two to three times the level in sodas and up to four times the level in an average cup of coffee. Remember that caffeine is an addictive stimulant. The caffeine content of some popular 350 ml (12 oz.) soda drinks are: Classic Coke –34 mg, Diet Coke – 46 mg, Pepsi – 37 mg, Mountain Dew – 55 mg. Dr. Pepper – 42 mg.

Although the role caffeine is well recognized for improving alertness and reaction time, it also boosts heart rate and blood pressure. There have been reports of high school football players admitted to hospital suffering from uncontrollable heart palpitations following the consumption of 3 to 4 “energy drinks” before and during a game. (This is obviously an abuse of the product and exceeds most company recommendations. In fact most companies market these products as and alternative to a cup of coffee).

Caffeine is also a diuretic that increases urine output that can lead to dehydration. There are reports in the sport science literature that caffeine can improve endurance performance but Dr. Luke Bucci from the University of Texas published evidence that it only applies to those who are not habitual caffeine users.

Guarana, 5-HTP, Bioperdine, Indian Bromine, Cola-nut and other obscure names are herbal sources of caffeine and often included in energy drinks.

Green Tea is another popular addition and touted because of the anti-oxidant properties but Green Teas does contain the same caffeine as black tea.

Taurine is a non-essential amino acid that the body produces from Methionine (an essential amino acid) and the B vitamins. The advertising copy for Taurine emphasizes that this is an amino acid necessary for “many health functions” ranging from brain and nerve function, improved cardiac function and even improved eyesight. However, if your diet is protein adequate and B complex adequate, you make all the Taurine the body can manage.  Secondly, the addition of 1000mg (1 gm) as most drinks offer falls very short of the 6 –16 gm reported in the published research implicating the effectiveness of these amino acids.

Vitamins and Minerals

Many drinks have included a few B vitamins because they play an important role in energy production.  Excess B vitamins are not stored but excreted and there is a danger or developing selected B vitamin deficiencies when overloading on a few isolated Bs. For optimum health and performance the complex of all 8 recognized B vitamins need to be maintained in balance. Vitamins B6 and B 12 in isolation can produce a diuretic effect contributing to further dehydration.

Antioxidants are added to many drinks and labelled as “antioxidant mix” with claims of immune system protection by neutralizing free radical damage. Unfortunately, the amounts included are much below the protective levels and most of the drinks do not quantify the contents.  They use phrases like “antioxidant complex or proprietary blend”. There is also evidence of poor stability among antioxidant mixtures so the ingredients originally put in the mixture may not survive through time.

Minerals like chromium and zinc are added in small amounts.  Adequate zinc, significant for immune function, is found in most good multivitamins. Chromium has a key role in insulin function but is often added to drinks to promote leanness. Numerous studies have shown that supplemental chromium is not effective in weight loss nor in muscle building.

Herbal Support

Appealing to the alternative health movement, many drinks include small quantities of many popular herbs but often fail to quantify the contents by, again, using label phrases like “energy blend” or Herbal blend”. The most popular herbs used included ginseng, ginko biloba, kava kava and St. John’s wort. Although all of these items have merit in their own right when properly prescribed, there is no evidence that the small quantities included in these drinks could have any therapeutic effect.


  1. One per day would be similar to substituting a couple of sodas or coffees.
  2. Do not use energy drinks when hydration is a factor.
  3. Energy drinks are not substitutes for Sport drinks.
  4. The vitamin, mineral and herbal contents of energy drinks are harmless but should not be used as part of a healthy supplement program. Many of the claims in advertising are over-stated.
  5. Be aware of the sugar and caffeine levels if you choose to use these drinks.

Further Reading

Sports Drinks Review - Top 10 Things to look for in a Sports Drink, 16 Sports Drinks Reviewed.
Is Coconut Water a Sports Drink? - Although coconut water is high in potassium, a valuable electrolyte, it is sorrowfully deficient in sodium
Sports Drink Science - The science and chemistry behind Sports Drinks.
Daily Water Requirements - How much water should you drink per day?
- Over Hydration - Water Intoxication.
Energy Drinks Update - One if my long standing concerns has been the inclusion of energy drinks under the regulatory umbrella of “Dietary Supplements”.

The Calgary Eyeopener, CBC News - Energy drinks could make some teens more susceptible to diabetes, says Calgary study. Researcher finds caffeinated energy shots cause short-term insulin resistance.