Here, we have scooped up some of the latest coffee research to try to sort the beans from the granules when it comes to health claims. It's not an easy task. According to Harvard School of Public Health, coffee contains hundreds of different compounds: some are good for human health; others aren't.
This complexity accounts for the fact that scientific opinion about coffee has 'flip-flopped' in the past. The good news is that your coffee addiction probably is not bad for you (apart from the impact on your wallet) - but it falls a long way short of being a health drink.
1. Heart disease
A Korean study published in the journal Heart last month showed that drinking 3 to 5 cups of coffee a day (what they called "moderate consumption") was associated with less calcium build-up in the arteries. But headlines declaring that coffee "prevents heart attacks" were wrong, because the study did not find that coffee drinking confers actual benefits. (The British Heart Foundation also urged caution about interpreting results from a survey carried out in South Korea, where people enjoy a different diet and lifestyle to those in the UK) The new Harvard study suggests moderate coffee consumption reduces the risk of dying prematurely from heart disease. But some other studies actually link coffee to risk factors like raised blood pressure and cholesterol, so more research is needed in this area.
2. Mortality
A Harvard School of Public Health review of coffee research recently found that drinking up to six cups of coffee per day was safe and did not increase the chances of dying from any particular cause, including cancer or heart disease. But closer reading of the study reveals it does not give the green light to rampant coffee consumption. The research involved men and women in their 40s and 50s who were healthy to start with, and was based on standard 240ml cups of coffee containing 100mg of caffeine with a little milk or sugar. Many consumers buy larger cups of coffee containing as much as 330mg of caffeine per serve, which are often loaded with sugary flavourings and/or whipped cream.
3. Type 2 Diabetes
An American Diabetes Association review of coffee research last year found "strong" evidence that drinking 6 cups of coffee per day could reduce the risk of type 2 diabetes by 33 per cent for both men and women, and the new Harvard study backs this up. However, the link is still unclear. Studies show the results are roughly the same for both caffeinated and decaffeinated coffee, suggesting an ingredient other than caffeine is responsible. Some studies also suggest that people who have diabetes and struggle to control their glucose levels might be better opting for decaffeinated coffee.
4. Parkinson's, Alzheimer's and Multiple Sclerosis
Various studies have linked higher caffeine intake to a "significantly" reduced risk of developing diseases that involve degeneration of brains cells including Parkinson's, Alzheimer's and Multiple Sclerosis. But researchers say the findings do not prove that coffee fights these conditions and that other factors might be involved. Again, more research is needed before doctors actually recommend drinking coffee to reduce the risk of developing these conditions.
5. Types of coffee
While research pointing to the potential health benefits of coffee is growing, it's worth considering that not all cups of java are the same. According to Harvard School of Public Health, coffee contains cafestol, a "potent" stimulator of cholesterol levels, which is strained out in coffee made using filter papers but present in coffee made other ways, such as in a caffetière or espresso machine. People concerned about their cholesterol should opt for filtered coffee, say the experts.
6. Sleep
It's not a myth: coffee really does disrupt your sleep. Studies show that to enjoy a peaceful night's sleep, avoid drinking coffee for at least six hours before going to bed.
7. Other health risks
Experts point out that coffee drinking often goes hand in hand with cigarette smoking, while some studies also show that people who drink lots of coffee tend to exercise less. Pregnant women in particular are advised to restrict their coffee intake to one cup per day. The precise effect is unclear, but studies appear to confirm that caffeine passes through the placenta to be absorbed by the foetus.
