Coffee Drinking: Health Benefits and Life Expectancy
A Healthy Beverage With Some Drawbacks
Coffee has had a reputation as a delicious but not-very-healthy beverage for a long time. Recently though—to the joy of coffee lovers everywhere that the news has reached—it's been found to have some important health benefits. According to researchers, drinking coffee significantly reduces the risk of several serious diseases that are more likely to strike us as we grow older, including type 2 diabetes, Parkinson's disease, prostate cancer, liver disease, liver cancer, one type of skin cancer, and Alzheimer's disease.
Experiencing fewer diseases, especially those that may be fatal, can do wonders for increasing our lifespan. It certainly seems that we would have a chance of living longer if we drank coffee regularly, but it would be nice to have evidence for this assumption. In May, 2012, The New England Journal of Medicine published the results of an almost fourteen year study of over 400,000 people. People who drank coffee every day were significantly less likely to die than non-coffee drinkers.
The survey has been criticized by some researchers, but others say that since it included so many people it's probably fairly accurate. In addition, more recent research has shown specific health benefits of coffee. Drinking coffee has some drawbacks, but according to the present state of our knowledge its potential benefits may far outweigh its disadvantages.
Coffee Drinking and Longevity
The survey of coffee drinkers published in The New England Journal of Medicine asked 400,000+ people to fill in a questionnaire at the start of the study. In this questionnaire, people aged 50 to 71 described their coffee drinking habits. Those who had a serious illness were excluded from the study and the data from those who smoked was eliminated. After about 13.6 years the people were surveyed again to see if they were still alive.
In general, the survey showed that the greater the number of cups of coffee drunk in one day, the lower the chance of dying. This trend held true up to and including four or five cups of coffee a day. At six cups a day the benefit was still present but had decreased slightly. The maximum decrease in death risk was 16% for women and 12% for men. The results were unaffected by whether the coffee was caffeinated or decaffeinated.
There have been criticisms of the study. First, as in any survey-type study, we can't prove that in every case coffee drinking kept someone alive. People may have lived longer because they had a healthier lifestyle than other people in the study or because they had genes that gave them longevity, for example. Another criticism is that people were asked about their coffee drinking habits only at the start of the survey. People's choice of beverage can change over a thirteen to fourteen year period. The large number of people involved in the survey helps to reduce the possible sources of error, however.
Coffee Consumption and Decrease in Death Risk
Cups of Coffee Drunk Per Day
Decrease in Death Risk in Females
Decrease in Death Risk in Males
two to three
four to five
six or more
Possible Reasons for Life Extension
There are two possible explanations for why coffee (apparently) reduces death risk. The beneficial effect could be due to coffee's ability to lower the risk of specific diseases and/or it could be due to helpful substances in the roasted coffee beans. The beans are believed to contain a thousand or more different chemicals, including antioxidants and antibacterial substances. One coffee antioxidant of special interest to researchers in relation to human health is chlorogenic acid, a member of the polyphenol family. Antioxidants fight potentially dangerous free radicals which are made in the body as chemical reactions occur.
Is Coffee Good for You?
The discoveries showing that coffee drinking reduces the risk of certain diseases are exciting. Some of the diseases are listed below. It should be noted that that the statistics are obtained from surveys rather than clinical trials. While survey results are important, they don't provide definite proof that a substance has a health benefit.
- Drinking four to five cups of caffeinated coffee every day in midlife has been shown to protect against Alzheimer's disease in old age. Starting to drink coffee at an older age has some protective benefit as well.
- In mice, researchers have shown that caffeinated coffee reduces the buildup of beta-amyloid in the brain. This substance makes up the characteristic plaque seen in the brains of human Alzheimer's patients. Drinking other caffeinated beverages doesn't have the same benefit.
- Australian scientists analyzed survey results and found that drinking one cup of coffee per day reduced the risk of type 2 diabetes by 7%. Drinking three to four cups a day produced a 25% lower risk. Drinking more than three cups of decaffeinated coffee a day produced a 33% lower risk.
- Drinking two to three cups of caffeinated coffee a day seems to reduce the risk of Parkinson's disease by about 25%, according to an analysis of different research studies.
- A small study has shown that the caffeine equivalent of three cups of coffee a day improves movement problems in people with Parkinson's disease.
Coffee and Skin Cancer
Cancer Risk and Cardiovascular Problems
Coffee may reduce the risk of some types of cancer. The beverage seems to be both beneficial and detrimental with respect to cardiovascular problems.
- According to a twelve year study of more than 47,000 men in the United States, the men who drank six or more cups of coffee a day had a 20% lower risk of developing prostate cancer and a 60% lower risk of developing the most dangerous form of prostate cancer. Drinking one to three cups of coffee a day resulted in a 30% lower risk of the most dangerous form of prostate cancer. The results of the study were unaffected by the amount of caffeine in the coffee.
- Some surveys suggest that drinking coffee significantly reduces the rate of liver disease or liver cancer. A recent study discovered that the rate of hepatocellular cancer decreased as the number of extra cups of caffeinated coffee per day increased (up to five extra cups of the beverage a day). Decaffeinated coffee was also effective, but to a lesser extent.
- A survey of 113,000 nurses and health professionals found that women who drank more than three cups of caffeinated coffee a day had a 21% lower chance of developing basal cell carcinoma, one form of skin cancer. Men had a 10% risk reduction. Consumption of an equivalent amount of caffeine from other foods or drinks had a similar benefit.
- Some research suggests that coffee reduces the risk of heart attacks and strokes in the long term, but a few studies show that immediately after drinking the beverage the risk of a heart attack or stroke temporarily increases.
Types of Coffee
Different types of coffee may have different effects on health. This is a topic that needs to be investigated in more detail.
A Coffee Poll
How often do you drink coffee?
Some Disadvantages of Drinking Coffee
There are disadvantages to drinking coffee. Some—but not all of them—can be avoided.
- Coffee stains teeth. These stains can be reduced by rinsing the mouth out with water immediately after drinking the beverage, however. A dental hygienist can also remove the stains.
- Unfiltered coffee contains two chemicals—cafestol and kahweol—which raise the level of LDL cholesterol in our blood. This is the type of cholesterol which can cause the buildup of fatty deposits in the lining of the arteries and increase the risk of a heart attack or stroke. Most coffee is filtered, however, which removes the chemicals. Espresso does contain cafestol and kahweol, but it's drunk in smaller quantities than other types of coffee.
- In some people caffeine has a diuretic effect, increasing the person's need to urinate.
- Coffee can relax muscles in the digestive tract and cause defecation and even diarrhea. In addition, it may cause acid reflux.
- Caffeinated coffee may have a very energizing effect and produce "jitters" in sensitive people. It may also trigger heart palpitations.
- Coffee has a dual effect on headaches. It has been found to make some pain relievers more effective, which can help a headache. On the other hand, drinking coffee can give some people a headache.
It's important to remember that discussions about coffee's potential health benefits are concerned with the beverage on its own and not with ingredients that may be added to it. These can make a big difference to any beneficial effects of the drink. Drinking several cups of coffee a day that contain added fat and sugar isn't healthy.
The Possible Role of Genetic Differences
If you already drink coffee, it's good to know that it most likely has important health benefits. Should you start drinking coffee if you don't already do so, or should you increase your consumption of the beverage? Scientists are reluctant to recommend this action, especially since there may be major drawbacks for some people.
In recent years, some scientists have suggested that our genetic makeup may affect our body's response to coffee and caffeine. Since we don't know what genes we possess, the best that we can do when deciding whether we should drink coffee is to observe our symptoms. For some people, the drawbacks of drinking the beverage may be too unpleasant. Continuing reports of coffee's health benefits make coffee consumption very tempting if there are no or only minor drawbacks, however.
References: Coffee Health Benefits
- Coffee and Disease Prevention from Harvard Health Publications
- Alzheimer's Disease from ScienceDaily
- Type 2 Diabetes from the CBC (Canadian Broadcasting Corporation)
- Parkinson's disease and other health problems from the Harvard Gazette
- Prostate Cancer from Science Daily
- Liver Cancer from the NIH (National Institutes of Health)
- Hepatocellular Cancer from the University of Southampton
- Basal Cell Carcinoma from Scientific American
© 2012 Linda Crampton