Taste disorder in the elderly is not only a disorder of one of the five senses but also important from the viewpoint of frailty prevention for healthy longevity.

However, treatment of this disorder has changed little over time with zinc replacement therapy as the sole established method. A detailed review of the literature of polaprezinc for idiopathic and zinc-deficient taste disorders provides insufficient evidence for its efficacy. In recent years, treatment with zinc acetate hydrate containing more zinc than does polaprezinc has emerged, and is expected to be more effective than polaprezinc. Ethyl loflazepate was also reported as an alternative to zinc supplementation.

Serum zinc levels are an essential test item in clinical trials of taste disorders, but there are many points to be noted in its measurement and evaluation. Appropriate evaluation of serum zinc levels is necessary based on a thorough understanding of these factors.

In this review, I will outline the problems of serum zinc levels, changes in zinc replacement therapy for taste disorders, and discuss future treatments.