How much caffeine is too much caffeine The Starbucks coffee with three quarters of the safe daily dose in one cup400mg of caffeine is the recommended daily allowance for average person16oz Starbucks 'Grande' contains 330mg and 8oz Red Bull can has 83mgBut scientists stress that tolerance levels of the stimulant can vary widely

By
Alex Gore

PUBLISHED:

22:06 GMT, 6 February 2013

|

UPDATED:

08:08 GMT, 7 February 2013

A large cup of Starbucks coffee contains more than three quarters of a person's 'safe' daily dose of caffeine, scientists have warned.

The 16oz 'Grande' coffee also contains nearly double the recommended limit for a pregnant woman, while an 8oz cup of coffee is well above a 10-year-old's daily allowance.

But scientists stress that such statistical averages can vary widely from person to person, with factors such as gender and genetics having an impact on tolerance levels.

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Caffeine: Table shows a range of drinks in order of caffeine contents ad their relation to daily allowances

Caffeine: Table shows a range of drinks in order of caffeine contents ad their relation to daily allowances

A person's tolerance can also be affected by other drug use, with women who take the contraceptive pill breaking down caffeine slower, and smokers process the stimulant faster than non-smokers.

A study by the government regulatory agency Health Canada concluded that the average person can have up to 400mg of caffeine a day without experiencing negative affect, such as anxiety or heart problems.

The average allowance for a pregnant woman is 200mg, according to the Food Standards Agency, and 75mg for a 10-year-old.

A 16oz Starbucks coffee has 330mg of caffeine, according to a table compiled by Chemical and Engineering News.

This is compared to an 8oz cup of brewed coffee, which contains 133mg, and an 8oz cup of instant coffee, which has 93mg.

An 8oz can of Monster Energy has 92mg, while an 8oz Red Bull can has 83mg. A bottle of Coca-Cola contains 58mg of caffeine, while a an 8oz cup of decaf coffee has 5mg and hot chocolate has 9mg.

University of Florida's director of
forensic toxicology, Bruce A. Goldberger, told Chemical and Engineering
News: 'People often don’t understand the potential risk of these
beverages.

Too much caffeine A 16oz Starbucks 'Grande' coffee contains 330mg of the stimulant

Too much caffeine A 16oz Starbucks 'Grande' coffee contains 330mg of the stimulant

'Caffeine is a stimulant and, when consumed at high enough levels, can have negative effects.'

A fatal dose of caffeine is thought to
be around 10g – equivalent to around 75 8oz cups of coffee or 120 cans
of red bull consumed within a few hours.

A report released in the U.S. last month
by the Substance Abuse & Mental Health Services Administration
showed the annual number of emergency room visits associated with energy
drinks jumped 36 per cent to 20,000 in 2011 compared to the previous
year.

The U.S. Food and
Drug administration also announced last year that it is investigating
reports of five deaths being linked to Monster Energy drinks. The
company has denied any link.

The
family of U.S. teenager Anais Fournier, who died in 2011 from a heart
attack brought on by 'caffeine toxicity' after drinking two 24-ounce
Monster cans within 24 hours are suing the company.

The caffeinated drinks market was estimated to be worth around 6.3 billion last year globally.

Red Bull energy drink

Monster Energy Drink

Big business: Red Bull, left, and Monster, right, are part of a global market worth an estimated 6.3bn last year