Coffee lovers should be aware that drinking three cups or more a day can lead to caffeine addiction. The recommended maximum daily caffeine intake is 400 mg for adults, 300 mg for pregnant women, and 2.5 mg per 1 kg of body weight for adolescents.
A 300 ml can of coffee contains 70 to 150 mg of caffeine. Three cans a day would exceed the recommended daily maximum. A cup of Dutch coffee sold in cafes contains over 200 mg of caffeine, up to four times more than an Americano.
Caffeine is a central nervous system stimulant that can temporarily alleviate sleepiness and boost concentration.
But excessive caffeine intake increases heart rate, leading to a pounding heart and shaking hands as well as anxiety and insomnia. As a diuretic, caffeine deposits minerals such as calcium and vitamins in the urine. It causes blood vessels to contract, temporarily increasing blood pressure, so people suffering from hypertension should watch how much coffee they consume. Some recent studies even suggest that caffeine increases intraocular pressure and can cause glaucoma.
Sensitivity to caffeine varies from person to person, so it is important to pay attention to how the body reacts when drinking coffee. And caffeine is not limited to coffee; it is also found in green tea, black tea, carbonated drinks, and chocolate. This means one may take in more caffeine than one thinks.
If one can't give it up, one should be sure to drink plenty of water to prevent dehydration and try not to drink more than three cups a day. One way to cut down is by replacing one or more of one's regular cups with tea, which has lower caffeine content.