According to researchers at Bristol University, caffeinated coffee taken first thing in the morning increases work efficiency. However, drinking more than four cups a day has been linked to ill health. On the other hand, coffee in the afternoon or evening ...

Dr Lotan Shilo and colleagues at Tel Aviv University (Israel) studied the sleep and melatonin levels of six volunteers who were given caffeinated or decaffeinated coffee before and after lunch. The effect of caffeinated coffee taken before lunch appeared to have worn off by bedtime, but post-lunch caffeinated definitely impoverished sleep quality. The researchers believed that it interfered with the body’s production of the brain hormone melatonin, an adequate level of which is essential to good sleep.

Coffee type-------------------------Decaffeinated ----------Caffeinated

Ave. length of sleep ---------------7 hours -------------------5.5 hours
Time to drop off --------------------15 mins. -------------------30 mins.
Tossing and turning --------------Y amount -----------------Twice Y
Melatonin levels --------------------Z amount -------------------Half Z

Ed.- Melatonin is also increasingly recognised as a powerful anti-cancer agent.