Energy drinks are beverages whose producers advertise that they "boost energy". These advertisements usually do not emphasize energy derived from the sugar and caffeine they contain but rather increased energy release due to a variety of stimulants and vitamins.
Ingredients
The most common ingredient in Energy Beverages is caffeine, which is often combined with taurine, glucuronolactone, guarana, and B vitamins to form what manufacturers have called an “energy blend.” When higher doses of caffeine are combined with these other substances currently blended in EBs, the subsequent effect cannot always be predicted; adverse effects have been reported, including cardiac arrest.
- Taurine, a sulfur-containing amino acid, is the most abundant intracellular amino acid in humans and a normal constituent of the human diet.Taurine modulates skeletal muscle contractile function and may attenuate exercise-induced DNA damage, with some evidence showing the ability to improve exercise capacity and performance. Taurine has numerous other biological and physiologic functions: bile acid conjugation and cholestasis prevention; antiarrhythmic, inotropic, and chronotropic effects; central nervous system neuromodulation; retinal development and function; endocrine or metabolic effects; and antioxidant and anti-inflammatory properties. Taurine also assists in cell membrane stabilization, osmoregulation, and detoxification. However, the amounts of taurine found in popular EBs are far below the amounts expected to deliver either therapeutic benefits or adverse events.
- Glucuronolactone, a naturally occurring substance produced in small amounts within the body. Supplementation with D-glucarates, including glucuronolactone, may favor the body's natural defense mechanism for eliminating carcinogens and tumor promoters and their effects.Toxicokinetic data on glucuronolactone in rats, which show bioavailability and lack of accumulation, with peak plasma levels 1 to 2 hours after oral administration, are in accordance with the limited human data.
- B Vitamins water-soluble vitamins required as coenzymes for proper cell function, especially mitochondrial function and energy production. B vitamins include thiamine, riboflavin, niacin, pantothenic acid, pyridoxine hydrochloride, biotin, inositol, and cyanocobalamin. Because EBs contain large amounts of sugar, these vitamins are touted as ingredients necessary to convert the added sugar to energy. Hence, the B vitamins are the “key” needed to unlock all the energy provided by the simple sugars in EBs, and this is the extra energy that EB companies claim their product can provide.
- Guarana, also known as guaranine, Paullinia cupana, and Sapindaceae, guarana is a rainforest vine that was domesticated in the Amazon for its caffeine-rich fruits and has long been used by the Amazonians to increase awareness and energy. Guarana seeds contain more caffeine than any other plant in the world, with levels ranging from 2% to 8%; guarana also contains the stimulants theobromine and theophylline. The amounts of guarana found in popular EBs are below the amounts expected to deliver therapeutic benefits or cause adverse events.
- Ginseng is one of the most popular herbal supplements in the world and is used for treatment and prevention of many ailments. This adaptogen (a natural herb product said to increase the body's resistance to stress, trauma, anxiety, and fatigue) is purported to increase energy, relieve stress, and increase memory by stimulating the hypothalamic and pituitary glands to secrete corticotropin. Athletes use ginseng for its alleged performance-enhancing attributes; however, a recent review concluded that enhanced physical performance after ginseng administration remains to be demonstrated. Adverse effects associated with ginseng include hypotension, edema, palpitations, tachycardia, cerebral arteritis, vertigo, headache, insomnia, mania, vaginal bleeding, amenorrhea, fever, appetite suppression, pruritus, cholestatic hepatitis, mastalgia, euphoria, and neonatal death. However, the amounts of ginseng found in EBs are far below the amounts expected to deliver therapeutic benefits or cause adverse events.
- Ginkgo biloba extract is derived from the leaves of the Ginkgo biloba tree and has been used in traditional Chinese medicine for centuries. Ginkgo biloba extract has been reported to have antioxidant properties, modify vasomotor function, reduce adhesion of blood cells to endothelium, inhibit activation of platelets and smooth muscle cells, affect ion channels, and alter signal transduction. However, to date, no large, well-conducted randomized controlled trials have shown that it has important clinical effects in healthy or ill persons.
- L-Carnitine this amino acid is made predominantly by the liver and kidneys to increase metabolism. Dietary supplementation with l-carnitine has been shown to increase maximal oxygen consumption and lower the respiratory quotient, indicating stimulation of lipid metabolism.46 Recent evidence indicates that l-carnitine plays a decisive role in preventing cellular damage and favorably affects recovery from exercise stress. Uptake of l-carnitine by blood cells may promote stimulation of hematopoiesis, inhibition of collagen-induced platelet aggregation, and prevention of programmed cell death in immune cells. There is evidence of a beneficial effect of l-carnitine supplementation in training, competition, and recovery from strenuous exercise and in regenerative athletics. No advantage appears to exist in giving an oral dose greater than 2 g at one time, because absorption studies indicate saturation at this dose.
- Antioxidants during exercise, inflammation and oxidative stress are linked by means of muscle metabolism and muscle damage. Antioxidants are purported to aid the body in the recovery phase and reduce damage to muscle cells. However, there is no convincing evidence that short-term or long-term exercise modifies antioxidant requirements, nor have significant effects been shown for supplementation in well-trained athletes.
Short-term Effects
Physiologic effects occur immediately after drinking the first dose.
In one study, 15 healthy persons aged 18 to 40 years consumed 2 cans (500 mL) of a commercially available EB containing 1000 mg of taurine and 100 mg of caffeine, as well as vitamins B5, B6, and B12, glucuronolactone, and niacinamide, daily for 1 week; effects of the EB on their blood pressure, pulse, and electrocardiogram (ECG) were measured.
Within 4 hours of EB consumption, the maximum systolic blood pressure increased by 8% on day 1 and 10% on day 7.
Within 2 hours of EB consumption, the maximum diastolic blood pressure increased by 7% on day 1 and 8% on day 7.
Heart rate increased by 8% on day 1 and 11% on day 7.
Throughout the study, heart rates increased between 5 and 7 beats/min, and systolic blood pressure increased by 10 mm Hg after EB consumption.
Although no clinically important ECG changes occurred, there were significant increases in heart rate and blood pressure, and thus patients with hypertension should not consume this type of drink.
In a double-blind crossover study, 13 endurance-trained participants performed an exhaustive bout of endurance exercise at 3 different times. Before the exercise, they ingested the original Red Bull drink, a similar drink without taurine but containing caffeine, and a placebo drink without caffeine or taurine. Echocardiography was performed before ingestion of the drinks, before exercise, 40 minutes after ingestion, and in the recovery period after exercise. Stroke volume was significantly influenced only in the Red Bull group (80±21 mL before ingestion vs 98±26 mL in the recovery period), mainly because of reduced end-systolic volume. Thus, this study shows that the original Red Bull increases cardiac contractility.
Regarding fluid replacement in persons who do not typically ingest large amounts of caffeine, EBs deliver a considerable amount of caffeine, which can stimulate the kidneys to produce more urine. Thus, EBs can have a net dehydrating effect.
Long-term Effects
There are no long-term studies of the effects of caffeine, taurine, and glucuronolactone on the body. Energy beverages may exacerbate risk factors for heart disease because studies suggest that EBs may serve as a gateway to other forms of drug dependence. Norway, Denmark, and France have banned the sale of Red Bull, partly in response to a study on rats that were fed taurine and exhibited bizarre behavior, including anxiety and self-mutilation.
Whether caffeine can cause hypertension and coronary artery disease is still controversial, but questions have been raised about its safety in patients with heart failure and arrhythmia.
Disadvantages of Energy Drink
Since the introduction of Red Bull in Austria in 1987 and in the United States in 1997, the energy drink market has grown exponentially. Hundreds of different brands are now marketed, with caffeine content ranging from a modest 50 mg to an alarming 505 mg per can or bottle. The combined use of caffeine and alcohol is increasing sharply, and studies suggest that such combined use may increase the rate of alcohol-related injury. Several studies suggest that energy drinks may serve as a gateway to other forms of drug dependence. Caffeine has been clearly associated with adverse health effects in susceptible individuals. Among adolescents, caffeine consumption has been linked to elevated blood pressure and sleep disturbances. Among pregnant women, high caffeine intake is associated with risk for late miscarriages, stillbirths, and small-for-gestational-age infants. Anxiety or panic attacks, caused by ingesting excessive amounts of caffeine is seen more often in consumers with panic disorders. However, panic attacks are most often misdiagnosed with caffeinism, which is virtually indistinguishable from severe chronic anxiety. Caffeinism is a condition caused by ingesting a great amount of caffeine that shows a constellation of symptoms including insomnia, restlessness, excitement, diuresis, and tremors.
Energy Beverages: Content and Safety
Risks of energy drinks in youths
