Caffeine

What is caffeine?

Caffeine is a stimulant drug which makes the central nervous system speed up the messages to and from the brain. It is a substance found in the leaves, seeds or fruit of a number of plants, such as coffee and tea plants. A wide range of food and drinks contain caffeine, including chocolate, soft drinks, energy drinks, tea and coffee. It can also be taken in capsules, tablets, or powder form.

Caffeine content

The approximate amount of caffeine found in coffee, tea, chocolate, cola, energy drinks, and caffeine tablets is shown in the table below. 

Product                                  Caffeine content (mg/100ml)
Typical tablet                                100
Cup of instant coffee*                  60-80
Cup of brewed coffee*                 60-120
Cup of black tea                           10-50
Cola drink                                      13
Can of cola 375 ml                       48
Bottle of cola 600 ml                    78
Red Bull 250 ml                            80
'V' 250 ml                                      80
Guarana tablet 1000 mg               40
Cup of hot chocolate                    5-10

*amount of caffeine is depends on the type of coffee bean and size of cup

Effects of caffeine

The effects of caffeine differ from person to person, depending on your age, body size and general health. If you regularly have caffeine you might have different reactions than if you have caffeine only occasionally.

Short-term effects

Caffeine takes five to 30 minutes to circulate around the body. Physical effects of caffeine include increased heartbeat, respiration, basal metabolic rate, and increased stomach acid and urine.

Small to medium amounts of caffeine, up to 300mg, can speed up the brain and the central nervous system so that you feel more awake. It also increases your concentration and alertness. However, caffeine isn't a substitute for sleep.

Long-term effects

Research has shown that moderate caffeine consumption (up to 300mg) does not cause miscarriage, early delivery or low birth weight. As with any drug, if you are pregnant or nursing, check with your doctor. 

Some research has shown links between heavy use (ie greater that about 350mg or three cups per day) of caffeine and osteoporosis, high blood pressure and heart disease, heartburn, ulcers, severe insomnia and infertility. Some studies have shown that women who consume high amounts of caffeine have increased risk of miscarriage, difficult birth and delivery of low-weight babies.

Can you overdose on caffeine?

If you consume too much caffeine it is possible that you might have serious health consequences, or even die in extreme circumstances, but this is extremely rare. A person would have to consume five to ten grams of caffeine (or 80 cups of strong coffee, one after the other) to have an overdose.

Addiction and withdrawal

Caffeine is addictive according to several definitions of 'addiction'. It causes withdrawal symptoms when you stop after having it regularly (most commonly headaches). and you can develop tolerance and experience cravings when you stop having it. Regular users can also become emotionally and mentally dependent upon their daily caffeine (coffee, energy drinks, etc). Withdrawal usually last for only a few days and is minimal if you reduce caffeine gradually.

Things to remember

Often caffeine pills or energy drinks such as Pro Plus caffeine tablets or Red Bull are taken by young people during exam or study periods in an effort to stay awake and alert to study more. But caffeine is not a substitute for normal sleep patterns. It might be an idea to try substituting your caffeine intake with ginseng tablets if you are in need of a boost but are overdoing it on the caffeine front. Avoid caffeine products while taking these though.
Caffeine is a drug and can affect the effectiveness of other drugs, so before taking any medication make sure you tell your doctor or pharmacist how much caffeine you take.