RESUMO
In recent years, it has become clear that zinc deficiency is closely related in several skin disorders. In elderly people, chronic itch and dry skin are common. In addition, the zinc concentrations are known to decrease with age. Therefore, we examined the beneficial effects of oral zinc supplementation on dry skin and itch in elderly people. Patients 65 years of age or older who visited the Jose Clinic (Odai-town, Mie Pref.) with serum zinc concentrations below 80 µg/dL were enrolled in the study (low zinc group). The participants were administered zinc acetate hydrate for 12 weeks from the start of the study, and transepidermal water loss (TEWL) and stratum corneum moisture content measurements, blood collection, and itch evaluation were performed every 4 weeks. Patients in the control group had serum zinc concentrations of ≥80 µg/dL (the normal zinc group). Results showed that TEWL was significantly higher in the low zinc group than in the normal zinc group, indicating that skin barrier function is impaired in the low zinc group. Serum zinc concentrations increased and TEWL decreased significantly over the 12 weeks of treatment. In addition, a negative correlation was observed between serum zinc concentrations and TEWL. Our results indicate that zinc supplementation is effective to improve the skin barrier function in elderly people.