Consumers have been indulging in increased consumption of popular energy drinks. It is felt that these energy drinks are benign and are packed with good ingredients such as B vitamins and amino acids that do not have adverse effects.
Energy drinks contain a blend of B vitamins, the energy blend, and enzymes. The vitamins they contain include vitamin B6, vitamin B3, vitamin B12, and vitamin B9; the energy blend consists of citicoline, taurine, tyrosine, phenylalanine, malic acid, caffeine, and glucuronolactone; and the enzymes they contain include amylase, protease, cellulase, protease, and lactase (Table ).
Ingredients of the energy drink (as listed on the manufacturer's product label)a
is important in heme, nucleic acid, lipid, carbohydrate, and amino acid metabolism. Toxicity occurs when megadoses of vitamin B6
(> 500 mg/day) are ingested [1
]. Symptoms of toxicity include peripheral neuropathy with deficits in a stocking-glove distribution, progressive sensory ataxia, and severe impairment of position and vibration senses. Vitamin B6
toxicity is not linked to hepatotoxicity. The treatment of vitamin B6
toxicity is to discontinue vitamin B6
consumption, and recovery is slow and, for some patients, incomplete.
Niacin and its derivatives are vital to cell metabolism. They have been used for decades in the treatment of patients with disturbed lipid and lipoprotein metabolism. They have been associated with skin flushing and, rarely, hepatotoxicity when used in pharmacological doses (1 g/day to 5 g/day). Hepatotoxicity manifests as a spectrum that includes mild elevation of liver enzymes, hepatic steatosis, hepatic necrosis, and, rarely, hepatic failure. Treatment includes discontinuation of niacin, and usually the liver enzymes return to normal. The smallest dose of niacin that leads to hepatotoxicity described in the literature is 1 g/day [2
]. Our patient ingested around 300 mg of niacin daily (30 mg/can × 10 cans/day), making this the smallest reported dose that induced niacin toxicity.
Vitamin B12 is involved in nucleic acid metabolism, the formation of red blood cells (RBCs), and myelin synthesis and repair. It has a very low potential for toxicity even when taken in large doses. This does not imply that it has no adverse effects. Because data on the toxic profile of vitamin B12 are limited, consumers, especially pregnant women, should be cautious when ingesting large amounts of vitamin B12.
Folic acid is required for DNA synthesis, RBC synthesis, and cell growth. Since it is water-soluble and regularly excreted by the body, toxicity as a result of excessive ingestion does not commonly occur. According to the National Academy of Sciences, the daily intake of folic acid in adults should not exceed 1000 μg. Very high doses (> 15,000 μ g/day) can cause stomach problems, sleep problems, skin reactions, and seizures.
Citicoline functions as a neuro-protective agent. It exhibits a very low toxicity profile in humans. In a short-term, placebo-controlled study that compared citicoline to placebo, transient headaches occurred in patients in the citicoline group compared to the placebo group. No changes or abnormalities were observed in hematologic, biochemistry, liver function, or neurological tests in patients in that study [3
Taurine is a normal metabolite in humans that is involved in the modulation of neuronal excitability, membrane stabilization, production of bile salts, and the detoxification of certain xenobiotics. There have been no adequate studies done to observe toxicity and/or carcinogenicity linked to taurine ingestion.
Caffeine functions as a psychoactive stimulant and a mild diuretic in humans. In large amounts, and especially over extended periods of time, caffeine can lead to a condition known as caffeinism [4
]. Caffeinism refers to a wide range of symptoms that include anxiety, insomnia, headaches, respiratory alkalosis, and palpitations. Increased use over time can lead to peptic ulcers and gastroesophageal reflux disease. Acute caffeine intoxication (> 300 mg/day) leads to serious symptoms that include restlessness, arrhythmias, and psychomotor agitation. Extremely large doses of caffeine can cause acute psychosis, rhabdomyolysis, and even death. The treatment of severe caffeine intoxication is generally supportive, and dialysis may be required if the levels of caffeine are extremely high.
Tyrosine is involved in the synthesis of neurotransmitters in the brain. It has the potential for very low toxicity, and there have been very few reports of toxicity reported, none of which involved hepatotoxicity.
Phenylalanine is converted to tyrosine in the body and serves the same function as tyrosine. Toxicity symptoms include increased blood pressure, emotional agitation, insomnia, and headaches.
Malic acid is important in boosting immunity, maintaining oral health, and reducing the risk of poisoning from a build-up of toxic metals. There are no known reported contraindications or toxicities linked to malic acid.
D-Glucurono-γ-lactone is a natural metabolite of glucose and regulates the formation of glycogen. There is very little known about the toxicity of this substance.