A loss of the sense of taste might also be caused by a B vitamin deficiency(most likely B3- niacin, but perhaps also maybe B6 or B12?) or a sinus problem. Zinc is very non toxic so taking up to 50 mg a day continuously and perhaps up to 100 mg a day for short periods of time(flu, infection, after extensive dental work, etc.) should not be a problem. Adding more B vitamins(choose one with niacinamide rather than niacin to avoid the uncomfortable sensation that the niacin form can sometimes produce). Zinc and vitamin c would be good to help treat a sinus problem.