You might want to be more vigilant of your coffee consumption. A Kyushu-based Japanese man in his 20s died last year from caffeine intoxication after drinking too much caffeinated beverages to ward off fatigue, reported Fukuoka University researchers.

The forensic probe showed that the death – considered accidental with no sign of intentional overdose – was most likely a result of consuming excess amounts of caffeinated drinks, although a caffeine pill could possibly have been extracted from the man’s stomach.

Japan’s Health, Labor and Welfare Ministry considered the first reported case in the country of a deadly caffeine overdose through beverage consumption.

“We had never heard of fatal caffeine,” said the ministry, as quoted by a local paper.

The victim was believed to consume caffeinated soda in huge quantities in order to stay awake and fight fatigue during his work shift at a 24-hour gasoline station. Prior to his death, he had been vomiting multiple times, a sign of caffeine overdose.

The forensic medicine team at Fukuoka University found no other abnormalities or disease, but recognized a small amount of alcohol in his blood. Caffeine was present in high levels in his blood, gastric residuals, and urine.

Energy drink manufacturers often warn consumers against mixing their products with alcohol, a combination that can bring about a number of adverse effects.

A legal autopsy could not be done on the body because there were no signs of foul play. As a result the university team failed to analyze the caffeine tablet found in his gut and how it potentially contributed to his untimely death.

According to experts, caffeine overdose is a very real threat. The Mayo Clinic noted that 400 milligrams is the safe daily caffeine limit for healthy adults, amounting to around four to five coffee cups or 10 cans of soft drinks. This amount also translates to two “energy shot” beverages.

Unwanted side effects are believed to manifest after ingesting 400 to 600 milligrams of caffeine.

The Mayo Clinic said adolescents should not consume over 100 milligrams of caffeine per day, while the American Academy of Pediatrics – mourning the heavy marketing of these products to the demographic – discouraged any amount of intake among kids and teens.

In 2013, the U.S. Food and Drug Administration began probing the safety of caffeine following a worrisome trend: caffeine’s addition to a growing array of food and beverages. It was about the same time that American company Wrigley’s promoted a new chewing gum product that contains the same caffeine amount in a half cup of coffee in every piece.

That year the agency also started investigating the link of a beverage known as 5-Hour Energy to 13 reported deaths in the country.

Marcie Beth Schneider, co-author of a 2011 AAP report, cited “a lot of confusion” surrounding sports drinks and energy drinks.

“Some kids are drinking energy drinks, containing large amounts of caffeine, when their goal is simply to rehydrate after exercise,” she said, warning that this could lead to huge amounts of caffeine as well as other stimulants that can spell danger to one’s health.

The U.S. has some of the highest coffee consumption rates in the world, with Americans spending $21.32 on average for their weekly coffee.

Photo: Dean Hochman | Flickr