I will refrain from saying I told you so, but the evidence keeps piling up! Another study finds that coffee is actually good for you! The Harvard School of Public Health just published a study in the Archives of Internal Medicine which finds that coffee consumption seems to reduce incidence of depression in women. They found that women who drank 2-3 cups of coffee a day were 15% less likely to develop depression compared to those who drank 1 or fewer cups.
The association between coffee drinking and reduction of depression makes sense from a Chinese medicine standpoint. Coffee affects the Liver in Chinese medicine and the Liver plays a major role in patterns which result in depression. Even from a biomedical perspective the liver is responsible for breaking down compounds which are then reassembled to form other ones like hormones and neurotransmitters. If this process is sluggish, well there's got to be some effect.
To treat depression we often "move" and "nourish" the liver. Coffee stimulates the Liver/Gallbladder system. People often find that a cup of coffee in the morning keeps their bowls "regular". This is because coffee stimulates the gallbladder to secrete bile. So we can we can see that one has to be careful in the dosage of this stimulating substance. We might want to move the Liver, but probably not to Kansas. People who are sensitive to caffeine should be more cautious. Unfortunately, the study didn't find decaf to have any effect on depression.
Those concerned with calcium loss with coffee should note that studies only fine a loss of 2-4 mg per cup. Coffee is a diuretic so be careful to drink enough non-caffeinated liquids to make up for this. Dark roast coffee has less caffein and acids than lighter roasts - so surprise, that expresso after dinner will affect your sleep less than regular! See grandma was right!