Sale and distribution
Main article: Economics of coffee
Coffee ingestion on average is about a third of that of tap water in North America and Europe. Worldwide, 6.7 million metric tons of coffee were produced annually in 1998–2000, and the forecast is a rise to seven million metric tons annually by 2010.[118]
Brazil remains the largest coffee exporting nation, however Vietnam tripled its exports between 1995 and 1999 and became a major producer of robusta seeds.[119] Indonesia is the third-largest coffee exporter overall and the largest producer of washed arabica coffee. Organic Honduran coffee is a rapidly growing emerging commodity owing to the Honduran climate and rich soil.
In 2013, The Seattle Times reported that global coffee prices dropped more than 50 percent year-over-year.[120] In Thailand, black ivory coffee beans are fed to elephants whose digestive enzymes reduce the bitter taste of beans collected from dung.[121] These beans sell for up to $1,100 a kilogram ($500 per lb), achieving the world's most expensive coffee[121] some three times costlier than beans harvested from the dung of Asian palm civets.[81][82]
Commodity market
Coffee is bought and sold as green coffee beans by roasters, investors, and price speculators as a tradable commodity in commodity markets and exchange-traded funds. Coffee futures contracts for Grade 3 washed arabicas are traded on the New York Mercantile Exchange under ticker symbol KC, with contract deliveries occurring every year in March, May, July, September, and December.[122]Coffee is an example of a product that has been susceptible to significant commodity futures price variations.[123][124] Higher and lower grade arabica coffees are sold through other channels. Futures contracts for robusta coffee are traded on the London International Financial Futures and Options Exchange and, since 2007, on the New York Intercontinental Exchange.
Dating to the 1970s, coffee has been incorrectly described by many, including historian Mark Pendergrast, as the world's "second most legally traded commodity".[125][126] Instead, "coffee was the second most valuable commodity exported by developing countries," from 1970 to circa 2000.[127] This fact was derived from the United Nations Conference on Trade and Development Commodity Yearbooks which show "Third World" commodity exports by value in the period 1970–1998 as being in order of crude oil in first place, coffee in second, followed by sugar, cotton, and others. Coffee continues to be an important commodity export for developing countries, but more recent figures are not readily available due to the shifting and politicized nature of the category "developing country".[125]
International Coffee Day, which is claimed to have originated in Japan in 1983 with an event organised by the All Japan Coffee Association, takes place on September 29 in several countries.[128][129][130]
Health and pharmacology
Method of action
The primary psychoactive chemical in coffee is caffeine, an adenosine antagonist that is known for its stimulant effects. Coffee also contains the monoamine oxidase inhibitors β-carboline and harmane, which may contribute to its psychoactivity.[131]
In a healthy liver, caffeine is mostly broken down by the hepatic microsomal enzymatic system. The excreted metabolites are mostlyparaxanthines—theobromine and theophylline—and a small amount of unchanged caffeine. Therefore, the metabolism of caffeine depends on the state of this enzymatic system of the liver.[132]
Health effects
Findings have been contradictory as to whether coffee has any specific health benefits, and results are similarly conflicting regarding the potentially harmful effects of coffee consumption.[133] Furthermore, results and generalizations are complicated by differences in age, gender, health status, and serving size.
Extensive scientific research has been conducted to examine the relationship between coffee consumption and an array of medical conditions. The 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.[134] 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 Medicine in 2012.[134] Researchers involved in an ongoing 22-year study by the Harvard School of Public Health stated that "Coffee may have potential health benefits, but more research needs to be done."[135]
Polyphenols in coffee have been shown to affect free radicals in vitro,[136] but there is no evidence that this effect occurs in humans. Polyphenol levels vary depending on how beans are roasted as well as for how long. As interpreted by the Linus Pauling Institute and the European Food Safety Authority, dietary polyphenols, such as those ingested by consuming coffee, have little or no direct antioxidant value following ingestion.[137][138][139]
Cancer
Meta-analyses have suggested that increased coffee consumption is associated with a reduced risk of prostate cancer including deadlier forms of high-grade prostate cancer[140][141] and melanoma.[5] Coffee consumption does not appear to be strongly linked to the risk of developing endometrial cancer.[142]
Cardiovascular disease
Coffee is no longer thought to be a risk factor for coronary heart disease.[143] A 2012 meta-analysis concluded that people who drank moderate amounts of coffee had a lower rate of heart failure, with the biggest effect found for those who drank more than four cups a day.[144] Moreover, in one preliminary study, habitual coffee consumption was associated with improved vascular function.[145][146]
Mental health
One review published in 2004 indicated a negative correlation between suicide rates and coffee consumption,[147] but this effect has not been confirmed in larger studies.
Long-term studies of both risk and potential benefit of coffee consumption by elderly people, including assessment on symptoms of Alzheimer's disease and cognitive impairment, are not conclusive.[4][148]
Type II Diabetes
In a systematic review and meta-analysis of 28 prospective observational studies, representing 1,109,272 participants, every additional cup of caffeinated and decaffeinated coffee consumed in a day was associated with a 9% (95% CI 6%, 11%) and 6% (95% CI 2%, 9%) lower risk of type 2 diabetes, respectively.[149]
Mortality
A 2014 meta-analysis found that coffee consumption (4 cups/day) was inversely associated with all-cause mortality (a 16% lower risk), as well as cardiovascular disease mortality specifically (a 21% lower risk from drinking 3 cups/day), but not with cancer mortality.[150]
Risks
Coffee's adverse effects are more common when taken in excess, with potential health risks due mainly to its caffeine content and can therefore be avoided by drinking less coffee or using decaffeinated coffee.
Instant coffee has a greater amount of acrylamide than brewed coffee.[151] Coffee caffeine may aggravate pre-existing conditions such as migraines, arrhythmias, and causesleep disturbances. It was once thought that coffee aggravates gastroesophageal reflux disease but recent research suggests no link.[152]
Some research suggests that a minority of moderate regular caffeine consumers experience some amount of clinical depression, anxiety, low vigor, or fatigue when discontinuing their caffeine use.[153] However, the methodology of these studies has been criticized.[154] Withdrawal effects are more common and better documented in heavy caffeine users.[155]
Caffeine withdrawal from chronic use causes consistent effects typical of physical dependence,[156] including headaches,[157] mood changes and the possibility of reducedcerebral blood flow.[156][158]
credit=Wikipedia
