Giving up your skinny latte or double espresso every morning is currently top of the list of finance editors' tips for pain-free belt-tightening in the face of the looming recession. Starbucks and other coffee-shop giants are now seriously feeling the pinch. And a good thing too, you may think. Coffee may be your favourite stimulant, but isn't it also a dangerous diuretic that has also been linked to a range of serious illnesses, including heart disease and cancer?
Well, before you let your local supplier go to the wall, it's worth getting the bigger picture on the health benefits of coffee, which has emerged from studies that have monitored large populations over several years. The results from these long-term studies tell a very different story – showing just how badly earlier research misjudged the health benefits of the roasted bean. So here are some reasons why drinking coffee early and often is good for you:
1. Coffee is as hydrating as plain water.
It's a complete myth that a normal cup of coffee is a diuretic. A large Starbucks has only 330mg of caffeine – and you have to absorb at least 550mg of caffeine in a single drink to produce dehydrating levels of urine, according to a new review of coffee studies carried out by the US Center for Science in the Public Interest. So you can count your morning cup of coffee as part of your daily water requirement. It's only when your drink contains more than 550mg of caffeine that you'll start to produce dehydrating levels of urine, according to the review
2. It probably cuts your risk of heart disease, and certainly doesn't raise the chances of a heart attack.
People with high blood pressure commonly avoid coffee as a stimulant that might make their condition worse. Yet a series of large clinical trials show that the opposite is true. University of California cardiologists studied the 10 biggest trials of heart disease and recently concluded there was no evidence that coffee increases the risk of heart attack, sudden death or abnormal heart rhythms.
Most dramatically, a study of 27,000 women, followed for 15 years, found that those who drank one to three cups of coffee a day reduced their risk of heart disease by 24 per cent. Exactly why isn't fully understood. It's known that caffeine does bring about a small, temporary rise in blood pressure. But while regular consumers of caffeine-rich cola are more likely to develop permanent high blood pressure, the same is not true of regular coffee drinkers, according to a 2005 study following 155,000 nurses for 12 years. The explanation may be in non-caffeine components of coffee. So far, 800 different aromatic compounds have been identified, including many powerful antioxidants.
3. It cuts the risk of some cancers and has no adverse effect on others.
There was widespread alarm when research published in the early 1980s suggested that coffee raises the risk of pancreatic cancer. An international review of 66 clinical trials, published in 2007, provided final confirmation that coffee consumption is not carcinogenic – the cigarette-smoking that accompanied the coffee was the likeliest cause. Another study of 59,000 Swedish women showed no connection between caffeine consumption and breast cancer.
There's even a suggestion that coffee-drinking can prevent cancer. Japanese researchers monitored the health of 90,000 men and women for over a decade, and reported in 2005, in the Journal of the National Cancer Institute, that regular consumers of two cups of coffee a day had half the risk of developing liver cancer compared with those who never drank it.
4. The cream in your coffee more than offsets the slight reduction in calcium-absorption that caffeine appears to cause.
Caffeine does bring about a slight reduction in the absorption of calcium in the bones, and some scientists have claimed that people who drink coffee regularly have a higher risk of bone loss and fractures. This is probably because coffee drinkers are less likely to have milky drinks, according to bone biologist Dr Robert Heaney of Creighton University, Omaha. He says that the small caffeine-related increased risk of osteoporosis is easily offset by adding a couple of tablespoons of milk per cup.
5. It makes you feel good.
It's not imaginary: a decent cup of coffee improves your sense of well-being, happiness, energy, alertness and sociability, according to research at John Hopkins School of Medicine in Baltimore. You have to drink the stuff regularly, however. Having the odd cup is likely to cause anxiety and a feeling of being unwell.
Those with a coffee habit, however, may even be better protected from potentially lethal depression. When Harvard University researchers monitored the mental health of 86,000 nurses over a period of 10 years, they found those who were regularly drinking between two and four cups of coffee a day were significantly less likely to have committed suicide.
The finding is still controversial. Researchers acknowledge that people suffering from depression may have been advised not to drink coffee – so that the group most likely to commit suicide would not be drinking the beverage. "An intriguing possibility, however, is that caffeine can help prevent or ameliorate depression," commented the Lead Researcher, Professor Ichiro Kawachi.
6. It helps sports men and women recover from extreme exercise.
New research has shown adding a few cups of coffee to the carbohydrates eaten by athletes following exercise boosts muscle recovery by up to 60 per cent – apparently solving a problem that has foxed sports physiologists until now. The study, published in the Journal of Applied Physiology in July, has found a solution to a problem that has resulted in increasingly complex dietary schemes designed to help athletes recover faster.
"If you give an athlete more petrol in the tank, they will go further. What we've done is to give them 50-60 per cent more petrol," said Professor John Hawley, head of the exercise metabolism group at the Royal Melbourne Institute of Technology in Victoria, Australia. "It has been incredibly hard for exercise physiologists to help athletes in this way, and it's a dilemma that has occupied researchers for decades. We asked athletes to ingest caffeine, which has no nutritional benefit, and the results were astounding."
In the study, athletes cycled to exhaustion before eating a carbohydrate sports drink, bar or gel with a high caffeine dose – the equivalent of five or six cups of strong coffee – immediately after the exercise, and then two hours later. "We found that the amount of carbohydrate that could be stored by the muscles when ingested along with caffeine was about 60 per cent higher than with carbohydrates alone. If you've got 60 per cent more fuel there for your next day's run, cycle ride or football game, there is no question that you would be able to go further or faster.
"The practical outcome of that is an athlete training or competing the next day will have a better training session or race," Dr Hawley predicted. "Caffeine has a wonderful effect on both short-term sprint performance and on endurance. It is a remarkable drug that affects both ends of the spectrum."
7. It appears to offer protection from diseases.
There are suggestions that a couple of cups of coffee daily reduces the risk of Alzheimer's as well as Parkinson's disease, and possibly diabetes. Caffeine appears to protect the brain from the harmful effects of cholesterol, which is involved in the destruction of the brain cells that leads to Alzheimer's. Other research has shown people who drink four or more cups of coffee a day are less likely to develop Parkinson's disease, and that coffee intake appears to be linked to a lower risk of Type 2 diabetes.
-- Coffee is no 'cure' for a hangover
The water in coffee will help to rehydrate you, and the caffeine will give your brain a jolt, but the overall effect is likely to make you feel worse. A strong coffee will irritate further your already delicate stomach, and the increased blood flow to the brain can increase the pounding in your head. The favourite hangover remedy of a cocktail of black coffee and paracetamol is potentially toxic, scientists reported in the journal Chemical Research in Toxicology last year. Caffeine triples the amount of a toxic by-product of paracetamol being broken down, increasing the risk of potentially fatal liver damage.
-- Coffee is addictive
Caffeine really is an addictive drug, according to neuroscientists at John Hopkins University, Baltimore. They reviewed 66 studies on caffeine withdrawal in 2004, and concluded that altering coffee-drinking routines is likely to be a painful experience. Stopping drinking even a single small cup of coffee every day produces withdrawal symptoms. One in two people experiences a throbbing headache that begins 12 to 24 hours after the last cup is drunk – and lasting up to nine days. Less common symptoms include clinically significant distress and an inability to function normally.
-- You can drink too much coffee
Caffeinism is a controversial diagnosis, but there is evidence that you can overdose on caffeine, causing symptoms similar to panic attacks and chronic anxiety, including palpitations, muscle-twitching, flushing and diarrhoea.
How much caffeine?
-- Cup of tea: 47mg
-- Cup of filter coffee: 95mg
-- Starbucks coffee grande: 330mg
-- Can of cola: 35mg
-- Diet Coke: 47mg
-- Can of Red Bull: 76mg