The kidneys are the main organs of the urinary system. They function chiefly to filter blood in order to remove wastes and excess water. The waste and water are excreted as urine. The kidneys also reabsorb and return to the blood needed substances, including amino acids, sugar, sodium, potassium, and other nutrients.
But many popular brands actually contain considerably less than an old-fashioned cup of black coffee. An 8.4-ounce serving of Red Bull, for instance, has a relatively modest 76 to 80 mg of caffeine, compared to the 95 to 200 mg in a typical cup of coffee, the Mayo Clinic reports.
Officially, According to the page on NESCAFÃ© COM , their soluble coffee contains about 65 mg of caffeine per 175 ml (6 fl. oz.) cup. The amount of caffeine per cup of coffee depends on the amount of coffee you put in your cup and there are differences in the strength of the coffee blends in each country.