“I have measured out my life with coffee spoons." T.S. Eliot
Since coffee has long had a reputation for being unhealthy, many people, particularly with heart disease, have been advised to avoid it. Looking at the research, however, the potential benefits of drinking coffee are surprisingly large.
One of the biggest meta-analyses of 36 studies published last year, has shown that people who consumed about three to five cups of coffee a day were at the lowest risk of cardiovascular disease and those who had more than five cups a day had no higher risk than people who didn’t drink coffee at all. The combined data involved more than 1,270,000 participants from all over the world. It is important to mention that research on coffee refers exclusively to black coffee. All kind of variations such as caramel collate or white chocolate mocha are high in calories and excluded from research protocols.
Another meta-analysis of eleven studies was looking at how coffee might be associated with heart failure. The results were consistent, showing that moderated consumption is linked with a lower risk of heart failure, with the lowest risk among people who consumed four cups a day.
The studies haven’t suggested that drinking coffee improves our health. They have proven, however, that moderated amounts of coffee lower the risk of heart disease, diabetes, stroke, Alzheimer's disease, depression and inflammation.
In the last few years, some individual studies have found that drinking coffee may be associated with an increased risk of cancer. Researchers decided to investigate further and published results of a large meta-analysis in 2007. It turned out that increased coffee consumption by two cups a day lowered the risk of liver cancer by more than 40 percent. This founding was confirmed in two more recent studies.
Fig. 1. Risk of death over 12-13 year follow-up in relation to the amount of coffee consumption. Source: New England Journal of Medicine 2012.
More high-quality studies were published last year looking at prostate cancer and breast cancer. The data from meta-analyses looking at prostate cancer found that drinking coffee wasn't associated with a higher risk of prostate cancer, and there was no significant association for breast cancer. The results on lung cancer did show an increased risk of cancer for coffee consumers, but that’s only among smokers.
Two years ago a few prospective studies were looking at how coffee might be associated with stroke. Almost 480,000 participants were observed over the period of 24 months. The data showed that drinking two to six cups of coffee a day was linked to a lower risk of stroke compared with people who didn’t drink at all.
Drinking coffee is also related to a decreased risk of type 2 diabetes. A few large earlier studies suggested that people with the highest level of coffee consumption have approximately 30% the risk of diabetes compared with those with the lowest levels of consumption. The updated study, published in 2014, included more than 1.1 million people. Once again, the data confirmed that the more coffee we drink, the lower the risk (the upper limit was 8 cups a day including both caffeinated and decaffeinated coffee). Considering that by 2025, the number of people affected by type 2 diabetes may increase by 65% to reach an estimated 380 million individuals worldwide, drinking coffee may indeed contribute to our positive health.
Fig. 2. Coffee consumption in relation to type 2 diabetes. Source: Arch Intern Med. 2009
The most recent meta-analyses from Harvard University on mental disorders showed that coffee intake reduces the risk of depression by 20% and the risk of suicide by 53%. Drinking coffee was also associated with lower risk of Parkinson’s disease and a potential protective effect against Alzheimer’s disease.
Does coffee lower the risk of all-cause mortality? Yes, the data shows, it does. Several studies have found that drinking coffee is associated with a significantly reduced chance of death. The largest study in this field published in the New England Journal of Medicine in 2012 enrolled 402,260 people over the age of 50 following them for 12 years. The study has shown that drinking coffee was associated with a lower mortality both in people with very good or excellent health and those with poor or fair health.
So, what makes coffee so health friendly?
The number one reason coffee is good for our health is that it acts as a powerful antioxidant. Coffee consists of more than a thousand different bioactive chemicals, most of which are formed during the roasting process. Although many of the compounds remain undiscovered, some of them, including caffeine, are well known, for example, the diterpenes cafestol and kahweol found in the oil.
Moderation is key in every area of life. The studies haven’t suggested that we drink excessively to avoid illness. The ideal amount of coffee seems to be about four to five cups a day. Drinking six or more cups a day provided no additional benefit. Finally, all the studies refer to pure black coffee, with no milk, added sugar, artificial sweeteners or extras.
Coffee keeps us happier and healthier. It's a reasonable addition to our healthy diet, with more benefits proven in research than almost any other beverage in the world.