If one knows or believes something is bad for them , it may well be defiling to their conscience to continue to partake . But is coffee really bad for us ? In some instances it is , like in excess , or if taken in combination with poor dietary practices . Coffee depletes certain B vitamins , so if one's diet allows for good sources of those B vitamins ( Nutritional yeast is one really good one ) , then a moderate amount of coffee is likely to not be harmful... but if one is lacking a good source of B vitamins , then perhaps even a little coffee would be a negative , much more than a positive . Coffee does have some beneficial antioxidants and medicinal effects . Certain denominations consider drinking coffee a " sin " , or at least a foolish practice ; but most folks accept , that in moderation ( along with a decent diet otherwise ) , it's not a problem , for most of us .
wm