New risks associated with coffee, tea, cola, & chocolate
Judging from the vast number of crowded cafes specialising in fancy coffee drinks, a lot of Sydneysiders are consuming a lot of coffee these days. Not only are all these venues thriving but new ones are popping up every time you walk down the street. In the past few years, the drinking habits of Australians have changed a great deal, judging from the proliferation of Starbucks, McCafes, and Gloria Jeans.
Of course there is still a widespread consumption of regular tea, and green tea. Carbonated drinks like Coca-Cola and Pepsi are still popular. Others have taken to drinking energy drinks with guarana, such as Red Bull. And almost everyone loves a frothy cup of hot cocoa.
Altogether it results in Australians consuming a high intake of the central nervous system stimulant common to each of these beverages, caffeine. This situation bears looking at, in order to consider what kind of effect this may be having. Caffeine, although legal, is, after all, classified as a stimulant drug.
Medical researchers have been studying caffeine’s effects and recently discovered a whole range of information worth considering.
The answer to whether caffeine is bad for us is, naturally, not simple. Recent research in California has shown that drinking coffee can actually be protective for people over age 50 against developing “Type 2” diabetes. In fact, they have an impressive 62-64% less chance of becoming diabetic compared to over-50’s who do not drink coffee. This effect was independent of other aspects measured such as level of physical activity, how fat you are, high blood pressure or fasting glucose levels. “Decaf” did not have the same protective effect, however, so it is reasonable to conclude that the caffeine is responsible.
In other research both tea and coffee drinking were found to be mildly protective for everyone against colon cancer, and this included decaffeinated coffee and tea. Several large studies have shown that caffeine intake is associated with a reduced risk of developing Parkinson’s Disease in men, but studies in women have been inconclusive. The same protection has not been found in soft drinks such as Pepsi and Coke. They contain so much sugar that they are being eyed as one culprit in the epidemic of obesity that is overtaking us. Neither the sugar content nor the caffeine is good for children.
Chocolate contains caffeine, although at low levels, and dark chocolate is now touted for its health benefits such as promoting cardiovascular health by making the blood vessels more elastic, which helps prevent blood clots and strokes.
On the down side, research carried out at the Lawrence Berkeley Laboratory in California indicates a high caffeine intake may trigger DNA damage in sperm. Men consuming over 308 mg per day of caffeine had significantly increased sperm double-strand DNA breaks. This damage increases the risk of developmental defects and genetic diseases among their offspring.
The American Journal of Obstetrics and Gynaecology has just this week called for expectant mothers to limit or even stop drinking coffee, as just 200 mg of caffeine daily doubles the risk of miscarriage. They cite research from Kaiser Permanente Research Division in California which suggests expectant mothers be cautious with all caffeine drinks, as they may damage growing cells and decrease placental blood flow, endangering the unborn baby.
Some people, due to their susceptibility, are more sensitive to caffeine than other people, and can run into strife by over-indulgence. What would not pose a problem for most people could cause a serious one for them. Beside the fact that they can develop a physical dependency, they may have symptoms they do not connect with their beverage consumption, such as sleeplessness, anxiety, restlessness, inability to concentrate, fatigue, or depression. The most extreme caffeine-dependent person may develop flu-like symptoms such as nausea, muscle pain and stiffness when they do not get caffeine. Withdrawal symptoms peak after two days but can last up to 9 days, if one continues without caffeine.
Caffeine intoxication occurs with doses in excess of 400 mg and can result in over-stimulation, with symptoms of nervousness, excitement, insomnia, flushing of the face, muscle twitching, rambling thought and speech, irritability, rapid heart beat and agitation. In cases of caffeine overdose there can be mania, disorientation, delusions, psychosis and even death. Overdose happens most frequently with users of caffeine tablets, with as little as 2 grams of caffeine requiring hospitalisation.
One professor of behavioural biology and neuroscience at the Johns Hopkins School, Roland Griffiths, believes that “caffeine withdrawal” could technically be classified as a psychological disorder, and should appear in the Diagnostic and Statistical Manual of Mental Disorders. Griffiths says that people who regularly took in as little as 100 mg of caffeine per day could develop a dependency that would trigger withdrawal symptoms if they stopped drinking it abruptly.
Amounts of caffeine in beverages vary widely, depending on method of brewing or steeping, the source and age of the bean or leaves etc. Typical amounts are:
Brewed coffee (250 ml) 60-120 mg
Instant coffee (250 ml) 70 mg
Espresso (2 oz) 45-100 mg
Decaf coffee (250 ml)1-5 mg
Black tea (250 ml) 45 mg
Decaf tea 5 mg
Green tea (250 ml) 20 mg
Decaf green tea <5 mg
Pepsi (375 ml) 38 mg
Coke (375 ml) 34 mg
Red Bull (250 ml) 80 mg
Milk chocolate (1 oz) 6 mg
Hot Cocoa (250 ml) 10 mg
Chocolate milk (8 oz) 4 mg
Dark chocolate (1 oz) 20 mg
It should be noted that some people are hypersensitive and should avoid all forms of caffeine, even the decaffeinated products, as some residual caffeine still remains.
Leslie McCawley BS, MPH
EA/Research Advisor
Office of Rev the Hon Dr Gordon Moyes AC MLC
References:
National Geographic “Caffeine” January 2005 T.R. Reid
Psychopharmacology October 2004 Roland Griffiths
http://En.Wikipedia.org/Caffeine
http://coffeetea.about.com/library/blcaffeine.htm
Complementary Medicine January/February 2007
www.dailytelegraph.com.au 22 Jan. 08 p.11