Negative attitudes and feelings of helplessness and hopelessness can create chronic stress, which upsets the body's hormone balance, depletes the brain chemicals required for happiness, and damages the immune system. Chronic stress can actually decrease our lifespan.
It’s better not to. Coffee in general will effect your bloodwork, and it is no different with black coffee. This is due to the caffeine in it which might skew the results. It’s also a natural diuretic, so your bladder will not last as long.
Hope this was helpful!
Vitamins ? Let me know if I'm right :) hope this helps some !