Caffeine addiction

Caffeine is a mild stimulant. High doses can make someone feel jittery or on edge and may prevent sleep. Very large doses may cause flashes of light or odd noises. As with other stimulants, the greater the high, the greater the fall. It also can increase heart rate and blood pressure, is a weak diuretic (encourages urine formation) and increases the respiratory rate.

Coffee is drunk in every country of the world and is a mainstay of most offices in the Europe and the US.The standard dose needed for stimulant effects is 200mg, or the equivalent of two cups of strong coffee or three cans of soft drink.As many as 30% of coffee drinkers say they "couldn't do without it" and are probably mildly addicted. Tolerance can develop rapidly.

Death from caffeine has been known, but only after doses of around 10 grams, the same as 100 cups of coffee. High doses of caffeine may affect the size of babies at birth.The foetus is especially likely to be harmed in the last three months of pregnancy, when the mother's ability to get rid of caffeine is reduced.Low birth weight, miscarriage and withdrawal symptoms in babies (breathing difficulties) have all been described.

Mothers who are heavy drinkers of coffee or cola drinks in pregnancy have twice the risk of their babies dying suddenly, even when other factors are allowed for such as age at motherhood, smoking and bottle feeding. Heavy caffeine intake also increases the risk of sudden death of babies after birth.Tea, coffee and cola should therefore be avoided in large doses in pregnancy.

Caffeine increases the effect on the unborn of other substances, such as tobacco and alcohol, shutting down the blood supply to the placenta, starving the foetus of oxygen and increasing the risk of low birth weight or malformations.However caffeineis harmless to the human fetus when intake is moderate and spread out over the day.

A possible reason for increased cot death in babies of heavy caffeine consuming mothers is that caffeine stimulates respiration and when this is removed, the baby has less drive to breath. That may make all the difference when it comes to fighting off infection or other problems.

Coffee addicts

"I'm dying for a cup of coffee" is a very familiar refrain, repeated perhaps a million times a day in Britain alone - usually half in jest.But what is the reality? Someone used to drinking six or seven cups of strong coffee a day will begin to experience withdrawal symptoms on waking and then every two to three hours after the last coffee drink. Caffeine withdrawal results in headaches and a range of other mildly unpleasant symptoms including drowsiness and lethargy.