I am not sure how many coffee drinkers in this forum but i can't leave without it.
I started to do some research and it appears that many doctors on youtube saying that it is not so bad for our health. Food1 also have post here where he talks about benefits.
So I figured out why not to test it and see it for myself. I've done 3 tests. I tested black coffee, coffee with a milk, and instant coffee.
I documented my observation for future reference. If you are interested you can find it here.
It also helped me to figure out why in some countries Coffee served with a glass of water.