If your adrenal system is bad then too much coffee can be a harmful thing I guess. It's important to have it with sugar or some sugary pastry so to not dip down on your glycogen levels.
Coffee drinkers have a lower incidence of thyroid disease, including cancer, thannon-drinkers.
Caffeine protects the liver from alcohol and acetaminophen (Tylenol) and other toxins, and coffee drinkers are less likely than people who don’t use coffee to have elevated serum enzymes and other indications of liver damage.
Caffeine protects against cancer caused by radiation, chemical carcinogens, viruses, and estrogens.
Caffeine synergizes with progesterone, and increases its concentration in blood and tissues.
Cystic breast disease is not caused by caffeine, in fact caffeine’s effects are likely to be protective; a variety of studies show that coffee, tea, and caffeine are protective against breast cancer.
Coffee provides very significant quantities of magnesium, as well as other nutrients including vitamin B1.
Caffeine “improves efficiency of fuel use” and performance: JC Wagner 1989.
Coffee drinkers have a low incidence of suicide.
Caffeine supports serotonin uptake in nerves, and inhibits blood platelet aggregation.
Coffee drinkers have been found to have lower cadmium in tissues; coffee making removes heavy metals from water.
Coffee inhibits iron absorption if taken with meals, helping to prevent iron overload.
Caffeine, like niacin, inhibits apoptosis, protecting against stress-induced cell death, without interfering with normal cell turnover.
Caffeine can prevent nerve cell death.
Coffee (or caffeine) prevents Parkinson’s Disease (Ross, et al., 2000).
The prenatal growth retardation that can be caused by feeding large amounts of caffeine is prevented by supplementing the diet with sugar.
Caffeine stops production of free radicals by inhibiting xanthine oxidase, an important factor in tissue stress.
Caffeine lowers serum potassium following exercise; stabilizes platelets, reducing thromboxane production.