Legend says coffee was first discovered in Ethiopia around a.d. 600-850 when a goatherd named Kaldi found that his animals became frisky after eating the red berries from the coffee tree. Kaldi ate the berries and rapidly spread the word about their stimulating properties. Local monks began cultivating the coffee tree to dry the fruit and crush it into a powder; the monks would then drink the reconstituted liquid to help stay awake during long periods of prayer. By the early 14th century, Arabs discovered the process of roasting and grinding the beans, and the rest, they say, is coffee history.
Today, coffee is the world’s most popular drink after water, with more than 1.5 billion cups consumed daily. Around 167 million Americans drink coffee each day, with more coffee drunk at breakfast than at any other time. Early studies gave coffee a bad name after it became associated with raising blood pressure and cholesterol levels, as well as increasing the risk for some cancers. Yet the latest research is revealing coffee’s health benefits. A recent American Chemical Society study identified coffee as the No. 1 source of antioxidants in the U.S. diet, and a 2006 clinical review of almost 300 studies suggests that moderate coffee drinking could help thwart a range of diseases, including type 2 diabetes, which affects an estimated 16 million Americans—more than half of them women.
Coffee and High Blood Pressure
One in three Americans is affected by high blood pressure, a recognized risk factor for heart disease and stroke. It’s well-known that the caffeine in coffee can cause a rise in blood pressure in both normal and hypertensive individuals. One study, published in the European Journal of Clinical Pharmacology in 1999, found that five cups of coffee a day over a period of about two months produced a modest increase in both systolic and diastolic blood pressure.
Research has also shown that regular coffee drinkers may develop a tolerance to caffeine but that the elderly and people with hypertension might be more susceptible to caffeine’s effects.
Coffee and Cholesterol
More than 50 percent of adult Americans, especially women, have a total cholesterol level of 200 mg/dL or higher, which is above the recommended limit. Although several early studies indicated that coffee raises serum cholesterol concentrations, it was later found that the method of brewing has a direct effect on coffee’s cholesterol- and triglyceride-raising properties. Two substances (diterpenes) in coffee, cafestol and kahweol, are thought to be responsible.
These chemicals are released by hot water but are caught by paper filters. Those of us watching our cholesterol should avoid unfiltered coffees, such as Turkish, Scandinavian “boiled” and French press (cafetière) coffees, but we still can enjoy filtered, instant or percolated coffees.
Coffee and Parkinson’s Disease
Approximately 500,000 people in the United States suffer from Parkinson’s disease, with 50 percent more men affected than women. Symptoms usually appear after age 60, and the risk increases with age. Parkinson’s develops when the dopamine-producing cells in the brain start to die and the levels of dopamine fall. Dopamine is a key chemical messenger involved in controlling balance, walking and other purposeful movements.
In general, research points to a strong link between coffee drinking and a reduced risk of developing Parkinson’s disease, especially in men. It’s not clear how caffeine achieves this but it might protect the dopamine cells from toxins. A study found that men who drink at least one cup of coffee a day reduce their risk by half compared with those who drink no coffee. But the evidence isn’t as clear for women. Some research indicates that modest amounts of caffeine reduce the risk of Parkinson’s disease, but only in postmenopausal women who have never taken postmenopausal estrogens. Conversely, the risk increases considerably in those taking estrogens and who drink six or more cups of coffee a day.
Coffee and Cancer
There’s little evidence to indicate that coffee drinking increases the risk of cancer, yet some evidence suggests it might protect against developing colorectal cancer. A large analysis published in the American Journal of Epidemiology in 1998 showed that people who drank four or more cups of coffee a day had a 24 percent lower risk of developing colorectal cancer, although not all studies have found this association. Additionally, a 2002 study of American men and women who regularly drink two or more cups of decaffeinated coffee daily showed they had a 48 percent lower risk of developing rectal cancer than those who never drank coffee.
More recently, a Swedish study published in the International Journal of Cancer in 2006 found that coffee drinking might increase the risk of stomach cancer by as much as 22 percent for each cup consumed, but this same study also reported that processed meat could be linked to an increased risk.
Coffee and Diabetes
More than 18 million Americans have diabetes, with more than 90 percent of those suffering from type 2—about 16 million people. Type 2 diabetes develops because the pancreas doesn’t produce enough insulin, which controls blood sugar, or because the body can’t use its own insulin properly.
But research suggests that moderate coffee drinking, coupled with weight control and exercise, can protect against this condition. Two large U.S. studies published in the Annals of Internal Medicine in 2004 found that for those who drank at least six cups of coffee a day, women had a 29 percent lower risk of developing type 2 diabetes and men had a 54 percent lower risk. This effect also was seen for decaffeinated coffee, though less noticeable, suggesting that other compounds aside from caffeine play a role in prevention. A more recent review of nine studies (published in the Journal of the American Medical Association in 2005) involving more than 193,000 men and women found that the risk was 28 percent lower in those who drank more modest amounts of between four and six cups a day. Scientists don’t fully understand how coffee protects against type 2 diabetes, but magnesium and a natural antioxidant called chlorogenic acid, which are both found in coffee, could play a role.
While some experts believe it’s too early to advise drinking coffee as an elixir of health, others feel there’s enough evidence to support the inclusion of coffee drinking as part of a preventive dietary plan.
Growing Coffee at Home
Growing coffee at home is relatively easy—the arabica variety is self-fertilizing, so there’s no need to worry about pollinating. Buy fresh green seeds, which germinate in less than three months (old seeds can take up to six months). Full details of how to grow your own plant can be found at www.CoffeeResearch.org.
Diane E. Halliwell is an experienced medical writer with an interest in alternative medicine, health and well-being. She lives in the county of Lancashire, England, with her family.
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