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Caffeine and your health
The next time you pick up that cup of coffee think!!
Date: 3/8/2009 6:40:20 PM ( 15 y ) ... viewed 2819 times Caffeine and Your Health
Source : Australian DietClub
Cup of coffee Do you rely on a cup of tea or coffee to kick-start your day? Or do you put the kettle on every time you need an afternoon pick-me-up? If you're drinking more than four cups of coffee or tea a day – depending on the blend and strength – you may be dependant on caffeine.
Caffeine occurs naturally in over 60 different types of plants. The most common sources of caffeine in the Western diet include coffee, tea, cola, energy drinks and, to a lesser extent, chocolate. The popularity of guarana is also on the increase and, contrary to popular belief, guarana does contain caffeine, as does green tea.
The effects of caffeine
The short-term effects of drinking caffeine are well known: caffeine is a mild stimulant that makes you feel more alert, makes your heart beat faster, is a diuretic, so it makes you go to the toilet more, raises your body temperature and makes your digestive system produce more acid.
If you drink large does of caffeine, you may experience high blood pressure, restlessness, headaches, nervousness or insomnia.
Sleep disturbance is one of the more negative effects of caffeine consumption. Caffeine can make it harder to get to sleep and can reduce the overall quality of sleep. Some people find that as little as one cup of coffee can interfere with their sleeping patterns. If you suffer from insomnia, try cutting out caffeine and you may find that you get a good night's sleep.
Caffeine affects different people in different ways, so your individual sensitivity will determine the positive or negative experiences you have with this substance. The effects generally depend on the amount of caffeine you consume, your age, any medications you are taking, alcohol you consume, the time of day you consume caffeine, your mood and your level of tiredness.
Some people find that caffeine makes them more alert and better able to concentrate for longer periods of time. Studies have shown that people who consume caffeine may increase their memory and powers of reasoning. People who consume caffeine have scored higher on tests that measure motor skills and their reaction times are faster.
However, Professor Jack James, of the University of Ireland, disagrees with these types of conclusions. "After ingesting caffeine," he says, "habitual consumers show no absolute benefits, they merely perform better than when they were caffeine-deprived. It is the harmful effects of caffeine deprivation that has created the illusion that caffeine is beneficial."
The effects of caffeine are temporary. Caffeine does not accumulate in the body and is excreted after a few hours.
Is caffeine addictive?
Caffeine is a drug. Most people who drink caffeine on a regular basis develop a tolerance to its effects. This means that, over time, you need to drink more and more cups of coffee, tea, cola or energy drinks to get the same 'buzz' caffeine brings. However, caffeine is safe to use at levels of approximately 250 mg per day. Overdose from caffeine is possible but rare – there have only ever been 20 deaths in Australia from caffeine overdose. You risk overdose if you eat or drink more than 10 grams of caffeine in one session – that's over 160 cups of normal instant coffee, which is highly unlikely, even for the most hard-core coffee addict!
Caffeine is classified as a restricted substance by the International Olympic Committee due to its stimulant effects.
If you decide to give up caffeine, you may experience withdrawal symptoms, that can include:
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Headaches
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Fatigue
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Drowsiness
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Irritability.
These negative effects are temporary and will cease after a few days. If you want to avoid these withdrawal symptoms, try to cut your caffeine down gradually rather than all at once. You could try substituting one or two of your normal drinks with decaffeinated coffee or tea products, or caffeine-free alternatives, such as Caro or Ecco for coffee, or different types of herbal tea.
Health concerns
Over the years, caffeine has been linked to a wide range of health concerns. Overall, caffeine use is considered safe by organisations such as Food Standards Australia and New Zealand and the International Food Information Council (IFIC). The following is a run-down of some of the recent research in the different areas of health concern.
Caffeine and cardiovascular disease
Many studies have found increases in blood pressure related to caffeine consumption however, some of these studies were not adjusted for other factors such as smoking and alcohol use. The IFIC states that "A number of studies have shown that any temporary rise in blood pressure due to caffeine consumption is less than the elevation produced by normal, daily activities."
One study shows that single, high doses of caffeine produce acute increases in blood pressure, while another study found that patients over 58 years of age with existing hypertension experienced higher blood pressure levels after consuming 250 mg caffeine.
This means that if you've got an existing problem with high blood pressure, you may need to keep an eye on your caffeine intake.
A 1997 study found that there is little association between caffeine consumption and heart attacks, while another study in 1998 found that there is only a 2.1 per cent increased risk of stroke for those consuming three cups of caffeinated drinks per day.
Caffeine and cancer
The IFIC says that over the years, both caffeine and coffee have been linked to certain cancers but these associations are no longer supported by medical research.
Recently, however, scientists in Germany discovered that coffee beans contain acrylamide – a substance that has been found to cause cancer in animals. In June 2002, the World Health Organisation said that acrylamide was a cause of concern but that more research was needed about its effects on humans.
Winifried Tigges, head of the German Coffee Federation, said "Acrylamide is not present in raw coffee beans but is formed when they are roasted." Researchers are currently experimenting with new ways of producing coffee beans that do not create a build-up of acrylamide.
In another area, caffeine is said to have a positive effect on skin cancer when tested on mice. It works by blocking the genetic changes to cells that are caused by solar rays.
Women's health
Caffeine is thought to have some negative associations with certain areas of female health, particularly pregnancy and foetal development.
There is little evidence to suggest that caffeine has an adverse effect for women who are trying to conceive. Caffeine may, however, effect sperm motility in men, which may make a contribution to fertility issues.
Pregnant women are advised to limit their level of caffeine consumption to no more than 200 mg per day. Any caffeine consumed by a pregnant woman does reach the foetus. The caffeine may disrupt the developing baby's rest periods and it is common for newborns to experience caffeine withdrawals.
There has been anecdotal evidence that abstaining from caffeine may reduce breast tenderness for women who suffer from benign breast disease, or fibrocystic breast disease. Women who have this condition have benign, fibrous lumps in their breasts. Caffeine is not linked to the development of the disease.
Osteoporosis
Excess caffeine can increase the risk of osteoporosis and fractures. However, there appears to be no detrimental effect on bone density in healthy, post-menopausal women with calcium intakes above 800 mg per day. This is equivalent to three serves of dairy foods – one serve is equal to one glass of milk, a 200 g tub of yoghurt or 30 g of cheese.
Diabetes
In a recent study in the Netherlands, those drinking seven or more cups of coffee per day were half as likely to develop type 2 diabetes than those who drank two cups or less per day. However, it is not recommend that you increase your caffeine intake in line with these findings. Research shows that healthy diet and exercise and maintaining a healthy weight can prevent the onset of type 2 diabetes.
Stress
Caffeine can increase your stress levels. Researchers in a recent study found that coffee drinkers felt more stressed, their adrenaline levels were higher and they had an increased heart rate. Some people rely on caffeine to get them through a stressful period, such as exams or a deadline, but if you are feeling very stressed, cutting down or cutting out caffeine may reduce your stress levels. While moderate caffeine intake is safe, a stressful lifestyle is not healthy over the long term, so any steps to alleviate stress are beneficial.
Children and caffeine
There has also been a great deal of concern surrounding caffeine consumption in children. As little as 100 mg of caffeine, the equivalent of two cans of cola drinks, can cause anxiety and reduce the ability to sleep.
Some experts blame caffeine for a number of behavioural problems, such as a fidgety, distracted and inattentive child. These symptoms may mirror those of Attention Deficit Hyperactivity Disorder (ADHD) so caffeine consumption may be worth investigating if your child is a candidate for ADHD.
Children who regularly choose cola or energy drinks over water, milk or fruit juice may be missing out on essential nutrients and may be at risk of dehydration.
Guarana and energy drinks
Like caffeine, Guarana is a natural substance. It is found in the seed of the Paullinia Cupana vine – a plant found in the Amazon rainforest. A four gram dose of guarana contains about 160 mg of caffeine, or twice the amount of caffeine in a normal cup of instant coffee.
Energy drinks have become a popular source of a pick-me-up. These drinks contain a combination of carbohydrates, amino acids, vitamins, minerals and herbs. Most of them also contain either caffeine or guarana at varying levels, so check the label before you knock one back.
Food Standards Australia and New Zealand has proposed that these drinks be labelled as unsuitable for children or people who are sensitive to caffeine. Some young boys have admitted to drinking up to five cans of caffeinated drinks before a sporting event, believing that the drinks enhance their sporting performance. If using these drinks before exercise it is important to note that the caffeine contained may produce a diuretic effect, making dehydration a possibility.
Caffeinated vs. decaffeinated
Decaffeinated beverages may not be the healthy alternative that you're looking for. One study found that women who drank decaffeinated coffee were more likely to develop rheumatoid arthritis than those who drank normal coffee or other caffeinated drinks.
Researchers in Switzerland have found that decaffeinated coffee also raises blood pressure levels, despite the absence of caffeine, indicating that there may be another ingredient in coffee that produces the stimulant effect. It may pay to keep this in mind if you are watching your blood pressure and are looking for coffee alternatives.
To drink, or not to drink?
When it comes to caffeinated drinks, moderation is, yet again, the key. A moderate intake of caffeine – up to 250 mg per day, or four cups of tea or coffee – is unlikely to do any harm. Excessive caffeine intake can, however, have negative impacts on your health. If you are pregnant, diabetic or have a pre-existing heart condition, you should probably abstain from caffeine.
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