THE US Food and Drug Administration is investigating five deaths and a heart attack for possible links to consumption of Monster Energy drinks, an agency spokeswoman said.

“I can verify that FDA has received five adverse event reports of death and one of heart attack possibly associated with Monster Energy drink,” said Shelly Burgess in an email.

Ms Burgess cautioned that such reports “serve as a signal to FDA and do not prove causation between a product or ingredient and an adverse event.”

But she said such reports are taken seriously and diligently investigated by the agency, which regulates the food and drug industries.

Burgess urged consumers who have experienced an adverse reaction to an energy drink to notify the manufacturers, which are required to report them to the FDA within 15 days.

The family of an adolescent, Anais Fournier, who died of an arrhythmia in December 2011, allegedly after drinking two cans of Monster Energy over a 24 hour period, brought suit on Friday in California against Monster Beverage.

Her parents accused the company of not warning consumers of the potential dangers of its product.

“I was shocked to learn the FDA can regulate caffeine in a can of soda, but not these huge energy drinks,” said Wendy Crossland, the girl’s mother, who called the beverages “death traps” for adolescents.

According to the complaint, the two cans of energy drink that Fournier consumed contained about 480 milligrams of caffeine, the equivalent of 14 Cokes.

The French national health safety agency, Anses, also recently called on individuals to report adverse reactions while imbibing energy drinks to health professionals so that their cases could be reported.

“Recently, several cases have been reported to Anses, notably during the consumption of these drinks with alcohol,” the agency said in June.

Energy drinks contain stimulants like caffeine, guarana and ginseng as well as the relaxant taurine and other vitamins.