The second part of the unhealthy effects Immunity 911 Review of coffee is the quantity of caffeine in it. A typical cup of coffee can have as much as fifty milligrams of caffeine in it. Caffeine belongs to the uric acid group of substances. The human body treats uric acid as a foreign invader, metabolizes it into urea, and then disposes of it as waste. As a result, every time caffeine enters our blood stream our liver is handed the stressful task of metabolizing it. This puts an unnecessary burden on an already overworked liver. The liver of a heavy coffee drinker is begging for a vacation not much unlike that of an alcoholic. Now could be a good time to give it one before it goes on strike!