text: what are the bad effects (on a growing person) of coffee?   coffee is very acidic in reaction in the body, and that is why we intuitively add milk to balance it out.......coffee will pull alkaline minerals like calcium and magnesium out of the body, and therefore may inhibit the formation of bone.  coffee consumption also increases the amount of estrogen in the body, which may or may not be good, depending on whether you are male or female.