CANBERRA (Reuters) -
Just one can of the popular stimulant
energy drink Red Bull can increase the risk of heart attack or
stroke, even in young people, Australian medical researchers
said on Friday.

The caffeine-loaded beverage, popular with university
students and adrenaline sport fans to give them “wings,” caused
the blood to become sticky, a pre-cursor to cardiovascular
problems such as stroke.

“One hour after they drank Red Bull, (their blood systems)
were no longer normal. They were abnormal like we would expect
in a patient with cardiovascular disease,” Scott Willoughby,
lead researcher from the Cardiovascular Research Centre at the
Royal Adelaide Hospital, told the Australian newspaper.

Red Bull Australia spokeswoman Linda Rychter said the
report would be assessed by the company's head office in
Austria.

“The study does not show effects which would go beyond that
of drinking a cup of coffee. Therefore, the reported results
were to be expected and lie within the normal physiological
range,” Rychter told Reuters.

Willoughby and his team tested the cardiovascular systems
of 30 young adults one hour before and one hour after consuming
one 250ml can of sugar-free Red Bull.

The results showed “normal people develop symptoms normally
associated with cardiovascular disease” after consuming the
drink, created in the 1980s by Austrian entrepreneur Dietrich
Mateschitz based on a similar Thai energy drink.

Red Bull is banned in Norway, Uruguay and Denmark because
of health risks listed on its cans, but the company last year
sold 3.5 billion cans in 143 countries. One can contains 80 mg
of caffeine, around the same as a normal cup of brewed coffee.

The Austria-based company, whose marketing says “Red Bull
gives you wings,” sponsors Formula 1 race cars and extreme
sport events around the world, but warns consumers not to drink
more than two cans a day.

Rychter said Red Bull could only have such global sales
because health authorities across the world had concluded the
drink was safe to consume.

But Willoughby said Red Bull could be deadly when combined
with stress or high blood pressure, impairing proper blood
vessel function and possibly lifting the risk of blood
clotting.

“If you have any predisposition to cardiovascular disease,
I'd think twice about drinking it,” he said.

(Editing by David Fogarty)