Coffee increases alertness and athletic performance, and may even help to fight cancer and Alzheimer’s. But don’t overdose on it, says Sanjida O’Connell

The Times - Tuesday September 10 2002

“Coffee should be black as hell, strong as death and sweet as love,” runs a Turkish proverb. But few modern day imbibers realise that coffee is also the world’s most popular drug. "Caffeine is the most frequently self-administered drug in recreational use worldwide today,” says James Bibb, an assistant professor of psychiatry at UT Southwestern Medical Center, Dallas, Texas. Bibb is one of the authors of a study, just published in the science journal Nature, which shows that coffee effects the brain in a similar way to cocaine. According to Bibb and his colleagues it seems that the caffeine in coffee blocks a protein found in the brain called DARPP-32, which has been known to play a role in drug addiction. Altering this biochemical pathway prolongs and intensifies the effects of low doses of caffeine. In spite of this study, Bibb adds, “And yet we know little about how caffeine works in the brain, whether with the kick from a double espresso or small jolts from tea or cola.”

The human race has been drinking coffee for at least 3,000 years beginning with a dark and bitter brew from the raw berries – now our choice extends to skinny lattes, caramel macchiatos, venti cappuccinos, red eyes and frappuccinos as well as the standard flat black or long white. The average American drinks four kilos of coffee a year, a mere nothing compared to the Scandinavians whose consumption exceeds twelve kilos per person annually. But as our coffee consumption has increased, the messages we’re receiving about coffee have become more perplexing. One of the main areas of confusion surrounding coffee is caffeine. Unless it is decaffeinated, a cup of coffee can contain anything from 30 to 120 mg of caffeine. Caffeine is also found in tea and some fizzy drinks, such as Coca Cola, and it is caffeine that is responsible for both possible scares – elevated blood pressure - and potential benefits – heightened mental performance. However, coffee also contains over 800 different compounds. To date we know little about these chemicals, but new research is beginning to show that they could have a beneficial effect, possibly by protecting us from cancer.

Can coffee increase the risk of a heart attack?

What is the downside of kick-starting our working routine with a cup of coffee? Scientists from Duke University Medical Center, Durham, North Carolina, say that four to five cups of coffee in the morning contribute to elevated blood pressure and higher levels of stress hormones well into the evening. On average the stress hormone adrenaline increases by 32 per cent. Dr James Lane, who prepared the results of the study says, “Moderate caffeine consumption makes a person react like he or she is having a very stressful day. If you combine the effects of real stress with the artificial boost in stress hormones from caffeine, then you have compounded the effects considerably.” This slight increase in blood pressure can also be clinically significant, as it is associated with an increased risk of a stroke or coronary heart disease. The risk of heart disease can also be elevated by substances other than caffeine, such as terpenoids, which are only partially removed from coffee when it is filtered and, which contribute to an increased level of cholesterol.
However, Dr Collette Kelly, a nutrition scientist from the British Nutrition Institute, London, says, “These kind of studies are limited. There is not enough research to say, hand on heart, that coffee increases the risk of a heart attack.”

Is it safe to drink coffee during pregnancy?

Researchers at the National Institute of Child Health and Human Development (NICDH), Bethesda, Maryland warn that four cups of coffee a day doubles the risk of having a miscarriage. Caffeine is also able to cross the foetal blood-brain barrier and can cause brain seizures in new born infants. This highly damaging effect of caffeine has been witnessed in animals, but as a result the American Food and Drug Administration took the precaution of recommending that pregnant women limit their coffee intake. However, consuming one to two cups of coffee a day seems acceptable for pregnant women says the NICDH team.

Is coffee really a stimulant?

The caffeine in coffee can increase mental alertness according to Dr Ian Hindmarch from the Medical Research Centre at the University of Sussex. In one study he and his colleagues gave 30 volunteers one to two cups of tea and coffee (containing standardised doses of caffeine) four times a day. Hindmarch found that repeated doses of caffeine increased cognitive performance throughout the day, and although coffee had more of an effect than tea, it disrupted sleep more than tea did. However, by increasing the amount of caffeine in the tea beyond the usual amount, tea enhanced the volunteer’s cognitive abilities more than coffee. Psychologists from the University of Bristol have also shown that coffee reduces the malaise we feel when we have a cold because it enhances mental alertness.

Can coffee enhance athletic performance?

There is substantial evidence, which indicates that the caffeine in coffee increases athletic performance. For example, in 1992 a team of researchers from the Sports Science Department at Christ Church College, Canterbury, showed that coffee given to middle distance athletes decreased the time it took them to run 1500m and increased the speed at which they were able to run a final one minute sprint. This year physiologists from Canada’s research and defense establishment proved that caffeine improves time to exhaustion, increases heart rate and boosts oxygen consumption during exercise. However, people unaccustomed to drinking coffee receive the greatest benefit.

Does coffee cause cancer?

In 1997 the American Institute of Cancer Research, based in Washington, DC, and London’s World Cancer Research Fund, published a comprehensive review, which concluded that coffee was not cancerous. Indeed, coffee may help prevent cancer of the colon. An analysis of 17 studies on colorectal cancer and coffee dating from 1960 to 1990 indicated that the risk was lowered by 24 per cent amongst those who drank four cups of coffee a day. In other words, coffee does not appear to be responsible for cancer, and may confer some protective benefit.

Can coffee cure Alzheimer’s disease?

Recently research from the Faculty of Medicine in Lisbon, Portugal, has shown that coffee can reduce the risk of contracting Alzheimer’s disease. The study compared 54 people with Alzheimer’s with 54 who had not contracted the disease, matched for age and sex. They found that people who did not have Alzheimer’s had been drinking nearly 200 mg of caffeine a day for twenty years – that’s just over two cups of brewed coffee a day. There is also evidence to suggest that it can reduce the risk of contracting Parkinson’s disease.

Is coffee good for you?

“In general there are not very many good studies which show the negative effects of coffee,” says Dr Peter Martin, professor of psychiatry and pharmacology and director of the department for Addiction Medicine at Vanderbilt University Medical Center, in Nashville, Tennessee, “What people are studying is the effect of caffeine, not coffee. Coffee is much more than a tablet of caffeine.” The number of aromatic compounds in coffee has reached 800 and is still increasing, as our analytical methods are becoming more accurate. The furans are the most predominant group of compounds and these have caramel-like odours; the second largest group, the pyrazines, contribute to the toasted flavours. But what Martin and his colleague, Dr James May, are interested in are chlorogenic acids. Vanderbilt University has recently been awarded a grant to create the Institute for Coffee Research and one of the first studies that have been carried out is on antioxidants in coffee. Roasting coffee oxidises chlorogenic acid, which is broken down in the body to form dihydrocaffeic acid. This compound is an antioxidant and May has proved that it is preferentially taken up the body’s cells. Antioxidants, because they combat wear and tear on the body, can help us live longer in a healthier state and may be found in concentrations four times higher in coffee than in tea, so drinking coffee (in moderation) really does appear to be good for you.

How many cups of coffee should we drink a day?

“You have to know your own body and know how much you’re comfortable with,” says Martin, “Ultimately moderate amounts – two to four cups a day – won’t harm you and may be beneficial.” Kelly says that we should not worry about our coffee consumption. “It depends on the strength of the caffeine in the coffee,” she says, “but up to four cups of coffee a day should be okay.” Martin adds a warning caveat: “Most people drink their coffee loaded with milk and sugar and you have to ask yourself, can you afford those calories?”

Is filter coffee better for you than instant coffee?

Blending, roasting and brewing all contribute to coffee’s complex chemical composition. For example, brewing creates hundreds of different compounds. Each one weighs less than 0.3 per cent of the dry weight of the coffee but may still contribute significantly to coffee’s effects, and may act in tandem to enhance the bean’s health benefits. Most instant coffee is prepared by freeze drying and as a result many of these compounds will be retained. “My sense is that there is no appreciable difference between instant and brewed coffee if they are in similar concentration,” says Martin. However, decaffeinated instant coffee has between 30-50 per cent fewer compounds than filtered or caffeinated instant coffee.

Most studies which focus on the effects of caffeine in coffee give volunteers instant decaffeinated coffee and then add caffeine to create a standard dose. This could, of course, alter the results of psychological tests, as Hindmarch point outs: ”Instant coffee doesn’t have the same taste as brewed coffee and the taste can add a lot to the psychological effect. Drinking instant coffee is not like sitting down and having a latte. “ He adds that some of coffee’s properties can be attributed to psychology. “We wouldn’t say, ‘Let’s go to the bar and have a caffeine pill,’” he says, concluding that coffee’s taste, and it’s preparation all contribute to how we react to our daily brew.

How much caffeine is in coffee?

The amount of caffeine in any single serving of coffee depends on a number of factors, including the variety of coffee bean, where the bean was grown, how it was ground, manufactured and brewed and the size of the coffee mug. Full-bodied, dark roast coffee may contain less caffeine than coffee made from milder, more lightly roasted beans. In general, arabica beans tend to have less caffeine and taste milder than robusta beans.

Figures from the National Coffee Association