People who need to stay up late, work through the night or keep alert while on the job – like doctors and other medical professionals - normally turn to coffee to stay awake. Here’s the not so good news for those who need their regular caffeine fix: five cups a day should be the limit. Two or three is best.

Caffeine per se is not bad. It’s too much of it that could be lethal. A young Japanese man was reported to have died after consuming too many highly caffeinated drinks so he would not fall asleep on the job at a petrol stand. 

Higher concentrations

An overdose is rare but it can happen not necessarily by drinking too much coffee but consuming other caffeinated drinks, which have higher concentrations of caffeine. Gastroenterologist Dr. Lui Hock Foong of Gleneagles Hospital said powdered caffeine, available in pill form, can be quite lethal.

A teaspoon of powdered caffeine is equivalent to 28 cups of coffee. The US Food and Drug Administration (FDA) already warned of taking caffeine pills. Some of these pills are used for dieting.

400 mg of caffeine

To keep caffeine levels in the blood safe, it’s better to limit consumption at 400 mg per day. That’s about 5 cups of regular coffee. Each cup contains between 80 to 100 mg of caffeine.

Caffeine isn’t just present in coffee, though. Other drinks in fact have higher concentrations of the compound. So if you prefer Coca Cola, keep it at 12 cans or less. Each canister contains 34 mg of caffeine. Other high caffeine drinks contain 70 mg per can so six ought to be the maximum. Energy drinks that come in canisters, too, contain 70 mg of caffeine and five should be the limit.

Another gastroenterologist, Dr. Desmond Wai, who is also a pathologist at Mount Novena Specialist Centre, confirmed that caffeine poisoning is being recognized although only a handful of cases said to have been caused by overdose have been reported.

The body will naturally break down caffeine, and it is a big help to drink lots of water after consuming coffee or anything with caffeine.

The bad of too much caffeine

Remember, caffeine intake beyond 1 g can cause hand tremors, headaches, restlessness, heart palpitations and frequent urinating. Women and young people have lower tolerance for caffeine’s effects owing to their size and body build, among other factors.

Studies have shown that people respond differently to caffeine, based on age, gender, body mass and other factors.

Caffeine levels also vary depending on the kind of coffee consumed. Brewed generally will result in higher levels of caffeine in the blood compared to instant coffee.

In low doses, caffeine increases dopamine, a neurotransmitter that triggers the brain’s reward and pleasure centre.  However, consuming lots of coffee within a short period of time can cause arrhythmia or an abnormal heart rate and may result to death. MIMS