Caffeine is a stimulant that is found in coffee, tea, cola, ‘energy drinks’ and chocolate. Many people rely on it to pick them up in the morning and keep them going during the day. But is all that caffeine harmful? What are the health effects of caffeine?
How much caffeine is there in coffee, tea, cola and chocolate?
The amount of caffeine varies between drinks quite considerably, and these figures for different types of beverage and chocolate can only be a guide. Tea that has been brewed longer will contain more caffeine than a cup of weak tea.
- 1 mug of instant coffee contains approximately 100mg
- 1 cup of brewed coffee 100mg
- 1 cup of espresso approximately 40 mg
- I cup of decaffeinated coffee approximately 3 mg
- 1 cup of tea is approximately 40 – 50mg
- 1 can of cola is 18-38 mg
- 1 can of ‘energy’ drink up to 80mg
- 50g bar of plain chocolate up to 50mg
- 50g bar of milk chocolate about 25 mg
(Source: Food Standard Agency and Nutrition For Life by Hark and Deen)
Caffeine acts as a diuretic. It is often said that because of this, drinking tea and coffee leads to fluid depletion, rather than a fluid increase. Scientific research suggests that this is not true, and that consuming caffeine beverages does increase the amount of fluid in the body.
The UK Food Standards Agency urges pregnant women to consume less than 300 mg of caffeine per day.
What are the effects of caffeine on the body?
Because caffeine is a stimulant many people use it to help keep them awake and focussed.
University of Arkansas researchers found that caffeine increases the ability to focus and problem solve, but not to think creatively.
This does no harm occasionally, but it is important not to use caffeine in this way regularly, as it masks the need to sleep, relax and take care of yourself.
Caffeine also binds with some minerals (particularly iron) and so stops their absorption. If you are short of iron, avoid drinking caffeinated drinks with meals and do not wash a supplement containing iron down with a cup of tea or coffee.
Researchers from the University of South Australia used data from over 300,000 participants in the UK Biobank. They examined connections between genetically instrumented habitual coffee consumption and a full range of diseases, finding that too much coffee can increase the risk of osteoarthritis, arthropathy (joint disease) and obesity. In earlier research conducted by the same team six cups of coffee a day were considered the upper limit of safe consumption.
Professor Hyppönen, the lead researcher, said:
“While these results are in many ways reassuring in terms of general coffee consumption, the message we should always remember is consume coffee in moderation — that’s the best bet to enjoy your coffee and good health too.”
“An estimated three billion cups of coffee are enjoyed every day around the world. Knowing the limits of what’s good for you and what’s not is imperative. As with many things, it’s all about moderation – overindulge and your health will pay for it.”
In another study they found that high coffee consumption is associated with smaller total brain volumes and an increased risk of dementia. Kitty Pham, oneof the researchers says:
“This is the most extensive investigation into the connections between coffee, brain volume measurements, the risks of dementia, and the risks of stroke – it’s also the largest study to consider volumetric brain imaging data and a wide range of confounding factors.
“Accounting for all possible permutations, we consistently found that higher coffee consumption was significantly associated with reduced brain volume – essentially, drinking more than six cups of coffee a day may be putting you at risk of brain diseases such as dementia and stroke.”
Short and long term effects of coffee consumption
The British Nutrition Foundation reports:
“Short-term adverse effects of high intakes on adults and children can include issues related to the central nervous system such as interrupted sleep, anxiety and behavioural changes. In the longer term, excessive caffeine consumption has been linked to cardiovascular problems.”
Can coffee be good for us?
Yet other research has shown that filtered coffee may help prevent type 2 diabetes.
Scientists from Nottingham University have discovered that drinking a cup of coffee can stimulate ‘brown fat’, the body’s own fat-fighting defenses, which could be the key to tackling obesity and diabetes. (This conflicts with the research I mentioned earlier from scientists at the University of South Australia!)
“Women who drink two or three cups of coffee a day have been found to have lower total body and abdominal fat than those who drink less.”
Drinking more coffee may help reduce the risk of developing gallstones, according to a study published in the Journal of Internal Medicine.
A study published by the European Society of Cardiology found
” Up to three cups of coffee per day is associated with a lower risk of stroke and fatal heart disease”
So the jury is out whether caffeine and coffee are good or bad for us. But all authorities do seem to agree that excess coffee is definitely bad.
In an earlier study the Australian researchers said:
“In order to maintain a healthy heart and a healthy blood pressure, people must limit their coffees to fewer than six cups a day — based on our data six was the tipping point where caffeine started to negatively affect cardiovascular risk.”
Am I addicted to caffeine?
Caffeine, like many other things, is OK in moderation for most people. The problem comes if you consume a lot. Some people experience palpitations, panic attacks, irregular heartbeat and headaches because of the amount of caffeine they consume. Because caffeine is addictive, it is easy for your consumption to climb as your body keeps adjusting to the current intake. If this happens to you, stopping coffee, tea, cola and chocolate suddenly can result in headaches and other unpleasant symptoms. It is probably better to reduce consumption over a few weeks, or use a mix of caffeinated and decaffeinated coffee when you make a drink.