Many of us roll out of bed in anticipation of an enticing cup of coffee to stimulate our senses, while others steer clear from coffee completely, believing that it’s unhealthy.
Whether coffee is harmful or beneficial remains debatable, but recent evidence seems to point more in coffee’s favor than against it.
A large population study published in 2006, concluded that drinking coffee isn t harmful to cardiovascular health and may even be somewhat beneficial. Another recent study found that the incidence of heart disease was did not increase among male and female long-time coffee drinkers even among those who drank 6 cups a day. Several other recent studies have reached similar conclusions with a moderate intake of coffee.
However, too much coffee (over six cups a day) may actually increase the risk of heart disease for some people. Research carried out in Athens and published in 2005 found that some coffee drinkers had more stiffness of the major blood vessel in the body than non-coffee drinkers. Furthermore, other short-term studies have linked high coffee intake to heart disease and heart attacks although these have been mostly inconclusive due to other influencing factors (such as drinking alcohol and smoking).
One fact is for certain – that filtered coffee is preferable to non-filtered French press or espresso as the paper filter gets rid of two compounds that are known to raise “bad cholesterol levels, which is a risk factor for heart disease.
Overwhelming evidence suggests diabetes type 2 is markedly reduced in regular coffee drinkers. Again, shorter term studies showed conflicting results but experts believe that over the long term, caffeine may increase insulin sensitivity, helping the body to mobilize glucose, and decrease body fat, accounting for its positive effect on diabetes.
Incidents of gallstones, colon cancer, rectal cancer and liver cancer are also thought to be reduced in regular coffee drinkers, compared to those who don’t drink coffee. Coffee is seen to also protect the liver from the effects of alcohol, explaining our need for a cup of coffee after a night of drinking. One study found that heavy alcohol drinkers cut their chance of cirrhosis (inflammation of the liver) by 20 percent per cup of coffee a day; four cups correlated with an 80 percent risk reduction.
Caffeine, the main component out of the hundreds in coffee, is a psycho stimulant, stimulating specific brain regions involved in memory and concentration, according to a study published in 2005. This explains the ‘pick me up’ effect it has on our minds.
Coffee also increases the production of dopamine, a brain chemical involved in pleasure and motivation, which may explain the reduced suicide rate in regular coffee drinkers in several studies.
Parkinson’s disease is also found to be markedly reduced in male coffee drinkers (but not females) in different population studies. Other studies also suggest the incidence of Alzheimer’s is reduced in regular coffee drinkers, and that coffee drinkers maintain cognitive function for longer.
If you’re an athlete, you will know that drinking coffee prior to a workout enhances your performance (in one study, cyclists were able to cycle 21 minutes further after having a cup of coffee). In fact, caffeine s efficacy as a performance-enhancing drug has led the International Olympic Committee to consider urinary levels of caffeine exceeding 12 micrograms/ml (around 8 cups of coffee) as worthy of a ban.
During exercise, caffeine speeds up our metabolism, increasing the breakdown of fat, making the conversion from fat to energy 30 percent more efficient, keeping blood sugar levels higher for longer.
What makes coffee so beneficial? As both caffeinated and decaffeinated coffees are just as effective in most of the population studies, it seems to be the many antioxidants in coffee (four times more so than those in green tea) that exert the beneficial effects.
However coffee is not completely benign.
Researchers are concerned that it may increase the risk of leukemia and stomach cancers and may affect the growing fetus. Furthermore, coffee has fiendish withdrawal effects; headaches, drowsiness, depression and grumpiness; and too much coffee causes anxiety, insomnia, tremor and irregular heartbeat, and possible irritation of the digestive system, bladder and prostate.
Contrary to popular routine, coffee after a meal is not a good idea; iron absorption is reduced by up to 80 percent if drunk within an hour of a meal and uptake of zinc, magnesium, calcium and other minerals from the body are also reduced.
How much is too much? A cup of 8 ounces coffee has anything from 90-135 mg of caffeine (compared to tea at 15-50 mg and cola 40-60 mg for a 12 oz can) while decaffeinated coffee usually has 7-16 mg caffeine.
We all react differently to coffee and our bodies more than the scientists (studies above suggest 2-4 cups is moderate), will perhaps be better at telling us how much we should drink, as any excess will surely cause us much distress.
May El Meleigyholds a PhD in Immunology (London School of Hygiene and Tropical Medicine), an MSc in Toxicology/Pathology (Royal Postgraduate Medical School, London) and a BSc in Pharmacology (University College London). May is a medical and health journalist, and is the regional correspondent for the British Medical Journal, Lancet, and WHO bulletin. May is also producing health programs for Egyptian Television.