December 2004

Is coffee your friend or foe?

Many of us rely on a cup of coffee to kick start our day, but if you’ve ever wondered whether coffee is doing you more harm then good, you’re not alone.

Medics have been at loggerheads over whether coffee is bad for you or not for years. Some studies show that it can trigger miscarriage in early pregnancy and promote heart attacks. Other studies show that coffee can improve mental performance and relieve headaches. 

But most medics agree, it’s not always coffee that is harmful in itself, but how it is produced. 

In fact, most nutritionists think the benefits of ordinary coffee outweigh the drawbacks. Dr. Wendy Doyle of the British Dietetic Association says coffee gets blamed for a lot of things. 

‘The fact is we’ve been drinking coffee for centuries and although it is a point of discussion, there is no conclusive evidence to prove that it is bad for you, unless you are pregnant,’ he says. 

Here we look at six common questions asked about coffee – and separate fact from fiction. 

Should you ban coffee from your diet?

How many times have you wondered how much coffee you should be drinking? Surprisingly, there are no government guidelines on how much coffee an average person should be consuming. 

Dieticians claim this is because coffee affects people in different ways. Catherine Collins, chief dietitian at London’s St. George’s Hospital, says larger people tend to be more tolerant to coffee than smaller people.  

‘Larger people have a greater volume of blood than smaller people and high levels of blood dilute caffeine better. This makes people able to drink more coffee without making them hyper or jittery. 

Coffee also affects people differently depending on how often they drink it. Regular coffee drinkers tend to be less sensitive to the effects of coffee than non-regular drinkers, says Catherine Collins. 

If you drink it regularly, caffeine is a stimulant which speeds up metabolism. This means your body is able to break caffeine down more quickly, thus raising caffeine tolerance. 

Most dietitians agree that four cups of coffee each day are not harmful. In, fact, Catherine Collins thinks coffee is better for you than some fizzy drinks lacking in nutritional value. 

‘Coffee with milk is an excellent way to get your calcium intake,’ she says. “People who drink around six cups of milky coffee each day can get more than half their daily calcium requirement.” 

However, she points out that the Food Standards Agency recommends that women in early pregnancy (within the first trimester) should have no more than 300mg of caffeine a day. This is the equivalent to three average mugs, four standard-sized cups of instant coffee, more than six cups of tea four cans of energy drinks or 400 grams of chocolate. 

Nutritionist Wendy Doyle of the British Dietetic Association says too much coffee can raise levels of homocysteine – fat cells in our body. Some studies have associated high homocysteine levels with miscarriage. “If you are planning a pregnancy – or are in early pregnancy – try to cut back to one cup of coffee a day. Better still try to avoid it altogether,” she says. 

Other studies show that if you have a weight problem, you should monitor your caffeine intake carefully. Too much caffeine can encourage the pancreas to release more insulin. This lowers your blood sugar, making you hungry and more inclined to binge. Dietitians suggest cutting down on your coffee intake to one or two cups each day. 

Will coffee give me the jitters? 

People with smaller body sizes tend to be more sensitive to coffee, claim nutritionists, because they have less blood to soak up the caffeine. Out of those people who are coffee sensitive Catherine Collins says around one in two hundred who visit her clinic complain pf palpitations or ‘the jitters’. 

Although palpitations can sometimes cause alarm, Collins says that they do not pose a health risk. The process that takes place is called vasoconstriction – when caffeine has the effect of closing up our blood vessels, slightly raising blood and giving rise to the ‘jitters’. 

In fact, some studies show that vasoconstrictions can improve mental performance. In one experiment, a psychologist with the American Army Research Institute in Massachusetts, had men take various doses of caffeine in the morning. 

He then tested his subjects with tests that measured reaction time, attention span, concentration and accuracy with numbers. The results showed that caffeine had boosted mental alertness. 

Is decaffeinated coffee better for you than caffeinated coffee?

According to some studies, decaffeinated coffee is more likely to trigger rheumatoid arthritis (RA), a chronic disease of the joints. In one by Dr. Kenneth Saag of America’s University of Alabama, researchers looked at the health effects of drinking decaffeinated coffee, caffeinated coffee and tea. More than 30,000 women aged between 53 and 69 were tested over 11 years. 

The results showed that four cups of caffeinated coffee each day showed no risk of developing RA. Regular tea drinking actually helped prevent RA – thanks to its high levels of antioxidants which are thought to have an anti-inflammatory effect. 

But the researchers showed that decaffeinated coffee doubled the risk of the disease. It is thought that in some countries certain solvents are used to dissolve the caffeine out of the beans which can have an inflammatory effect on joints in our body. 

However, Collins points out that decaffeinated coffee processed in Britain is washed out with water, rather than solvents posing no risk of developing Rheumatoid Arthritis. 

Will coffee give me heart disease? 

Evidence is emerging to show that it’s not necessarily coffee that is bad for you – but how it is brewed. It is now thought that the most risky type of coffee to drink is filtered coffee that has been sitting around for several hours. 

Scientists at the Wageningen University in the Netherlands have linked this coffee to an increased risk of heart disease. 

Although conclusive studies have yet to prove this, some researchers believe filtered coffee that has been stewed for a long period of time releases larger amounts of cafestol and kahweol – the oils contained in coffee beans that can raise cholesterol – than coffee that is prepared and drunk immediately. 

Will coffee give me a headache? 

This depends on how much coffee you drink and how ‘caffeine sensitive’ you are. (People who get easily hyper or experience palpitations after drinking coffee are said to be caffeine sensitive.) People who drink coffee regularly are less likely to experience headaches than those who drink coffee every now and again. 

Some studies show that a single cup of strong coffee can actually get rid of a mild headache. Other scientists blame coffee for being the number one headache trigger. 

‘A single cup of coffee can produce a headache in some people, whereas other people can drink coffee all day without one,’ Says Collins. ‘This is because caffeine is a vasoconstrictor – where pressure is created in the head by tightening up the blood vessels. If you drink coffee less frequently, your body is less tolerant to caffeine.’ 

Will coffee make me go to the toilet more often? 

People say that coffee is a strong diuretic, but this is an urban myth, says Catherine Collins. ’Coffee doesn’t tend to have a diuretic effect if you are a regular coffee drinker. This is because the more you drink coffee, the quicker your kidneys get used to breaking it down. 

However, she says, people who are not used to drinking coffee such as young children, may find coffee has slight diuretic effect because their bodies are not used to breaking it down.