Coffee is a drink made from coffee beans, which are the roasted fruit of the Coffea arabica bush.
People drink coffee to relieve mental and physical fatigue and to increase mental alertness. Coffee is also used to prevent Parkinson’s disease, gallstones, type 2 diabetes, gastrointestinal cancer, lung cancer, and breast cancer. Other uses include treatment of headache, low blood pressure, obesity, and attention deficit-hyperactivity disorder (ADHD).
Rectally, coffee is used as an enema to treat cancer. Coffee enemas are used as a part of the “Gerson Therapy.” In the Gerson Therapy, cancer patients are treated with caffeinated coffee in the form of enemas every four hours on a daily basis. During the treatment people are given a diet of liver, vegetables, and a variety of medicines, including potassium, pepsin, Lugol’s solution, niacin, pancreatin, and thyroid extracts. The Gerson Therapy is considered an unacceptable medical practice in the U.S., but continues to be used at The Hospital of the Baja California in Tijuana, Mexico, one mile from the U.S.
How does it work?
Coffee contains caffeine. Caffeine works by stimulating the central nervous system (CNS), heart, and muscles.
USES & EFFECTIVENESS
Likely Effective for…
- Mental alertness. Drinking coffee and other beverages that contain caffeine throughout the day seems to increase alertness and clear thinking. Caffeine can also improve alertness after sleep deprivation. Combining caffeine with glucose as an “energy drink” seems to improve mental performance better than either caffeine or glucose alone.
Possibly Effective for…
- Reducing the risk of colorectal cancer. Some research suggests that drinking more than 3 cups of coffee daily may significantly reduce the risk of rectal cancer.
- Preventing dizziness in older people caused by low blood pressure after eating a meal (postprandial hypotension). Drinking caffeinated beverages like coffee seems to increase blood pressure in elderly people who experience dizziness after meals.
- Preventing or delaying Parkinson’s disease. There is evidence that people who drink caffeinated beverages such as coffee, tea, and cola have a decreased risk of Parkinson’s disease. For men, the effect seems to depend on the amount of caffeine consumed. Men who drink the most caffeinated coffee, 28 ounces (three to four cups) per day, seem to have the greatest reduction in risk. But drinking even 1 or 2 cups of coffee cuts their Parkinson’s disease risk significantly. In women, the effect does not seem to depend so much on the amount of caffeine consumed. Moderate consumption of caffeinated coffee, 1-3 cups daily, provides the most reduction in risk in women. Interestingly, coffee does not seem to help prevent Parkinson’s disease in people who smoke cigarettes.
- Preventing gallstones. Drinking caffeinated beverages, including coffee, that provide at least 400 mg of caffeine per day seems to reduce the risk of developing gallstones. The greater the intake of caffeine, the lower the risk. Drinking 800 mg caffeine per day (four or more cups of coffee) has the greatest reduction in risk.
- Preventing type 2 diabetes. Drinking caffeinated coffee seems to significantly reduce the risk of developing type 2 diabetes. As caffeine consumption goes up, the risk of developing diabetes goes down. But the effect seems to be different in different groups of people. In North American adults, drinking 6 or more cups of coffee per day is associated with a 54% lower risk of developing diabetes in men and a 29% lower risk in women. In European adults, drinking 5-6 cups of coffee per day reduces diabetes risk by 61% in women and 30% in men. Drinking 10 or more cups of coffee per day reduces diabetes risk by 79% in women and 55% in men. Japanese adults who drink 3 or more cups of coffee per day have a 42% lower risk of developing type 2 diabetes compared to those who drink only one cup per day or less. Decaffeinated coffee doesn’t seem to lower the risk of getting diabetes.
Possibly Ineffective for…
- Reducing the risk of digestive tract cancers, including esophageal, stomach, and colon cancers.
- Reducing the risk of breast cancer.
Insufficient Evidence to Rate Effectiveness for…
- Lung cancer. Some research concludes that drinking caffeinated coffee may help to prevent lung cancer, but other research disagrees. It’s too early to draw firm conclusions. Meanwhile, some research suggests that drinking decaffeinated coffee may help to prevent lung cancer.
- Gout. There is some evidence that both caffeinated and decaffeinated coffee seem to help to prevent gout, but caffeinated coffee works better.
- Improving thinking. There is developing evidence suggesting that drinking more coffee over a lifetime might improve thinking skills among women older than 80 years of age.
- Other conditions.
Coffee is safe for most adults. Drinking more than 6 cups/day might cause “caffeinism” with symptoms such as anxiety or agitation. People who drink a lot of coffee every day may need to drink more coffee to get the same effects. They may also become “dependent” on coffee to the point that they develop withdrawal symptoms if they suddenly stop drinking it.
Coffee containing caffeine can cause insomnia, nervousness and restlessness, stomach upset, nausea and vomiting, increased heart and breathing rate, and other side effects. Consuming large amounts of coffee might also cause headache, anxiety, agitation, ringing in the ears, and irregular heartbeats.
Drinking unfiltered coffee can increase total cholesterol, low-density lipoprotein (LDL), and levels of another type of blood fat called triglycerides. This might increase the risk of developing heart disease. Using coffee filters helps to reduce these effects on cholesterol.
There is some concern that drinking more than 5 cups of coffee per day might not be safe for people with heart disease. But for people who don’t have heart disease, drinking several cups daily does not seem to increase the chance of developing a heart problem.
There is also concern that occasional coffee drinking might trigger a heart attack in some people. People who usually don’t drink more than one cup of coffee daily and also have multiple risk factors for heart disease seem to have an increased risk for heart attack within an hour after drinking coffee. But people who regularly drink greater amounts do not seem to have this risk.
Coffee might be unsafe when given rectally as an enema. Coffee enemas have been linked to cases of severe side effects including death.