It is generally frowned upon to feed the body before praying to God in the morning. Does this extend to milk (since coffee with milk is fine). Is milk by itself any different?
It seems that only foods that were considered 'luxurious' in their time were forbidden.
Writing about adding milk and sugar and coffee, Dose of Halacha writes:
R’ Shlomo Zalman Auerbach (Halichos Shlomo p8) and R’ Ovadia Yosef (Yabia Omer 4:11) however, allow milk and sugar, as these are no longer considered such luxuries (See Aruch Hashulchan 89:23)
These sources don't make an exception for coffee and tea, actually, though anything that will help one.