Monday Sep 29, 2008 (foodconsumer.org) -- A review published in Journal of the American Pharmacists Association found caffeine and sugar, but not other ingredients present in energy drinks may cause a variety of adverse health effects.

The review by Clauson KA and colleagues at Nova Southeastern University in Palm Beach Gardens, Florid covered studies published between 1980 and Sep 2007.

Most energy drinks studied contain natural products such as guarana, ginseng, and taurine.  The products studied including Cocaine, Pimp Juice, Red Bull and Spike Shooter contained caffeine at a dose anywhere between 80 and 300 mg and 35 grams of processed sugar per 8-ounce serving.

Ingredients such as taurine, ginseng and guarana used in the amount in energy drinks were not found to have any side effect.

However, caffeine, the major ingredient of energy drinks was associated with adverse effects including insomnia, nervousness, headache, and tachycardia.

One adverse effect is commonly known as caffeine intoxication and it could occur when more than 300 mg is ingested depending upon body weight and levels of caffeine tolerance.

Caffeine intoxication may include symptoms like restlessness, nervousness, excitement, insomnia, flushing of the face, increased urination, gastrointestinal disturbance, muscle twitching, a rambling flow of thought and speech, irritability, irregular or rapid heartbeat, and psychomotor agitation, according to wikipedia.

The worst cases reported were four caffeine-associated deaths and four separate cases of seizures associated with consumption of energy drinks, according to the review study.

The authors concluded that the amounts of guarana, taurine and ginseng used in energy drinks were below the levels that are expected to have therapeutic benefits or adverse events, but caffeine and sugar in the drinks could cause a range of adverse health effects.

Caffeine is a bitter xanthine alkaloid that acts as a psychoactive stimulant drug and a mild diuretic--speed up urine production-- in humans and animals.

Caffeine is not just used in energy drinks.   It can be present in other food and beverages such as tea, coffee and other non-alcoholic drinks.

The problem with caffeine in energy drinks if any could be the amount of caffeine, which varies greatly from brand to brand and it can be anywhere between 50 mg and 505 mg per can or bottle, according to Reissig CJ, Strain EC, and Griffiths RR at the Johns Hopkins University School of Medicine who recently published a report in Drug and Alcohol Dependence calling for warning labels for energy drinks due to the large amount of caffeine.

Ingestion of too much caffeine in forms of energy drinks or otherwise could potentially cause some adverse effects that are important, yet unknown to many people including anxiety, sleep disorders, Parkinson's disease, and effect on memory and learning, on the heart, children and pregnant women, according to wikipedia.

For more information on caffeine, read http://en.wikipedia.org/wiki/Caffeine

For more information on energy drinks, read http://en.wikipedia.org/wiki/Energy_drink