Green tea is fine and has many health benefits, but black tea contains caffeine: an addictive stimulant/drug which is enervating or wastes the life-force or nerve energy.
"Caffeine, like nicotine, albeit to a lesser extent, meets some of the criteria of the World Health Organization and the American Psychiatric Association for a drug of dependence and acts on the dopamine system in the same way as amphetamines and cocaine. Caffeine and its metabolites are known to cross the blood-brain barrier readily in adults and fetuses alike"............... http://www.healingnaturallybybee.com/articles/mn5.php