The answer to this question is unlikely to be unambiguous, as it is important to consider the existing diseases in the person and the volumes of coffee/tea consumption in the first place. People without any health problems can safely drink 3-4 cups of coffee or tea per day. If a person has obvious health problems, especially the heart or vascular system related, coffee is definitely not recommended. It is best to abstain from this drink and give preference to tea. Moderate consumption of coffee and tea for a healthy person can not pose any danger at all and does not promote disease. Adequate measures are the only guarantee for the safe consumption of coffee and tea. Without them, drinking strong tea in unlimited amounts can cause tachycardia and other adverse caffeine effects. Green tea is considered to be more beneficial than black tea or coffee, so if you are concerned about your health, you may prefer such tea or choose decaf.