Caffeine, the most widely consumed psychoactive substance in the world, is the best-known ingredient of coffee. Research on coffee and it's pros and cons for humans is nowhere near finished as new discoveries keep popping up each time.
Below are some health disadvantages of taking Coffee according to Coffee Warrior:
Bad coffee is toxic
Bad quality coffee can have a lot of impurities in it, which can cause sickness, headache, or a general bad feeling. This can happen if your coffee is made from beans that have been over ripped or otherwise ruined. Even one ruined bean can make your cup toxic. If you invest and buy high quality, speciality coffee you don't have to worry about this.
Coffee can kill you
Yes, if you drink 80-100 cups (23 litres) in a short session. This dose is lethal and will amount in 10-13 grams of caffeine within your body. Before you reach this point, however, you'll be vomiting most of it out since 23 litres of any liquid is a lot. Even drinking 23 litres of water can kill you.
It is the caffeine working here. Your recommended maximum amount of caffeine is 400 milligrams, roughly the amount that you'll get from 4 cups of coffee. If you're caffeine-sensitive, be careful with coffee. You should be aware of what amount and what kind of coffee suits, or doesn't suit you.
Coffee for kids may increase bedwetting
One survey reported that caffeine consumption of 5-7-year-old kids may increase enuresis, which is also known as bedwetting.
Increases blood pressure
This is possible in those already suffering from hypertension and those who don't normally consume caffeine. According to Caffeine Informer, people with hypertension were given 250 mg of caffeine (about 2 coffees) and the data revealed that their blood pressure was elevated for about 2-3 hours after the caffeine. A second study performed by The Mayo Clinic found similar results from a 160 mg dose. All participants experienced a marked rise in blood pressure and it was the most pronounced in those that didn't normally consume caffeine.