offee is a brewedbeverageprepared from the roasted seeds of several species of an evergreen shrub of the genusCoffea. The two most common sources of coffee beans are the highly regarded Coffea arabica, and the "robusta" form of the hardier Coffea canephora. The latter is resistant to the coffee leaf rust (Hemileia vastatrix), but has a more bitter taste. Coffee plants are cultivated in over 70 countries, particularly Ethiopian harar coffee is different and has excellent quality

An important export commodity, coffee was the top agricultural export for twelve countries in 2004 and it was the world's seventh-largest legal agricultural export by value in 2005 Green (unroasted) coffee is one of the most traded agricultural commodities in the world. Some controversy is associated with coffee cultivation and its impact on the environment. Consequently, organic coffee is an expanding market.

Bilogical

Several species of shrub of the genus Coffeaproduce the berries from which coffee is extracted. The two main species commercially cultivated are Coffea canephora (predominantly a form known as 'robusta') and C. Arabica. C. Arabica, the most highly regarded species, is native to the southwestern highlands of Ethiopia and the Borena Plateau in southeastern Sudan and possibly Mount Marsabit in northern Kenya.^[36] C. canephora is native to western and central Sub-Saharan Africa, from Guinea to the Uganda and southern Sudan.^[37]Less popular species are C. liberica, C. stenophylla, C. mauritiana, and C. racemosa.

General health

Extensive scientific research has been conducted to examine the relationship between coffee consumption and an array of medical conditions. The general consensus in the medical community is that moderate regular coffee drinking in healthy individuals is either essentially benign or mildly beneficial. In 2012, the National Institutes of Health–AARP Diet and Health Study analysed the relationship between coffee drinking and mortality. They found that the amount of coffee consumed correlated negatively with risk of death, and that those who drank any coffee lived longer than those who did not

However the authors noted, "Whether this was a causal or associational finding cannot be determined from our data." A similar study with similar results was published in the New England Journal of Medicinein 2012. Researchers involved in an ongoing 22-year study by theHarvard School of Public Healthstated that "the overall balance of risks and benefits [of coffee consumption] are on the side of benefits