Coffee, one of the most popular drinks in the world, is made from the roasted beans of plants of the Coffea genus, native to southern Africa and tropical Asia. The exact origins of coffee as a drink are shrouded in mystery, but we do know that it was being brewed in Yemen by the 15th century.
Caffeine is the best known substance found in coffee, but a standard cup of coffee also contains magnesium, niacin and riboflavin.
Caffeine has been widely studied. It is the world's most consumed psychoactive drug, and it works as a stimulant, providing a mood boost and increasing alertness and reaction time. Caffeine inhibits adenosine, a neurotransmitter responsible for the feeling of drowsiness. At the same time, it increases the reactions of "feel good" neurotransmitters such as dopamine.
Some major studies have shown that regular coffee consumption can help to cut the risk of diabetes, and preliminary studies have also shown that it may be helpful in reducing the risk of both Parkinson's and Alzheimer's.
Coffee also appears to have a protective effect on the liver, and is rich in antioxidants, which work throughout the body to limit the damage caused by free radicals.