The caffeine contained in energy drinks can
make people feel wide awake and encourage
them to drink more than normal.
Medics say this could also cause problems
sleeping and a raised heart rate, although
more research is needed.
Charity Drinkaware does not recommend mixing
alcohol and energy drinks.
Mixing spirits and liqueurs with energy drinks,
such as Red Bull and Monster, has become increasingly
popular - in pubs and clubs, and at home.
But recent research suggests that drinking
alcohol mixed with high-caffeine energy drinks
could be more risky than drinking alcohol
on its own, or with a more traditional mixer.
This is because it can make people "wide awake
drunk" - a result of the stimulating effects
of caffeine and the brain-slowing effects
of alcohol.
What are the risks?
In a review of 13 studies published between
1981 and 2016, researchers at the University
of Victoria, Canada, found a link in 10 studies
between intake of alcohol mixed with energy
drinks and an increased risk of falls, fight
and accidents.
But they said they were unable to pin down
the size of the injury risk because of the
varied nature of the studies and the difficulty
of comparing results.
When it comes to the question of whether mixing
alcohol and energy drinks is harmful to health,
larger studies are still needed to work this
out.
At present, the Food Standards Agency and
the Committee of Toxicity says the evidence
is not clear.
What is in energy drinks?
Energy drinks contain high levels of caffeine,
usually about 80mg in a 250ml can - equivalent
to a mug of instant coffee.
In comparison, a 330ml can of classic Coca-Cola
contains 32mg and a can of Diet Coke 42mg.
Energy drinks also contain lots of sugar as
well as other ingredients, such as glucuronolactone
and taurine, and sometimes vitamins and minerals
or herbal substances.
Some smaller "energy shot" products can contain
as much as 160mg of caffeine in a 60ml bottle.
How much caffeine is too much?
High levels of caffeine can lead to anxiety,
panic attacks and increased blood pressure.
Pregnant and breast-feeding women are advised
not to have more than 200mg of caffeine over
the course of a day.
There is more information on NHS choices.
European advice says that most other adults
are safe to drink up to 400mg a day.
Children should have caffeine in moderation
- a daily intake of less than 3mg of caffeine
per kilogram of body weight in children and
adolescents is safe, the European Food Safety
Authority says.
Under current UK rules, drinks that contain
more than 150mg per litre of caffeine (apart
from teas and coffees) must carry a warning
saying: "High caffeine content.
Not recommended for children or pregnant or
breast-feeding women".
But there are currently no legal restrictions
on the amount of caffeine that may be present
in a food or drink product in the UK.
What are the recommended limits on alcohol?
Men and women should not drink more than 14
units of alcohol a week.
That's equivalent to six pints of average
strength beer or seven glasses of wine.
The advice, from the Department of Health,
also says that it's best not to save up units
and drink them all in one go and to make sure
you have alcohol-free days every week.
