薬理と治療

Abstract

Objective　The objective of this research was to investigate the effectiveness of daily ingestion of food containing soy isoflavone and lactobionic acid on the viscoelasticity of skin and the stratum corneum hydration in healthy adult women who were aware of skin dryness. Methods　A randomized, double-blind, placebo-controlled, parallel-group study was conducted in 70 participants aged 31 to 65 years. Participants were randomly assigned to receive a test food containing soy isoflavone and lactobionic acid or a placebo once daily for 12 weeks. Hydration of stratum corneum, trans-epidermal water loss, skin viscoelasticity, subjective evaluation of skin conditions and urinary equol and isoflavones levels were evaluated. Results　The test product significantly inhibited the decrease in hydration of stratum corneum, the increase in trans-epidermal water loss, and the deterioration of skin viscoelasticity compared to placebo. And, the test product significantly increased urinary equol and isoflavones concentration. In ad-hoc analysis focusing on equol-producing ability, equol-producing ability did not affect the results. Conclusion　It was suggested that ingestion of soy isoflavone and lactobionic acid-containing foods for 12 weeks in healthy adult women who are aware of dryness increased skin hydration and maintained skin viscoelasticity due to the promotion of absorption of soy isoflavones. In addition, under the conditions of this test, it was not affected by the equol-producing ability. （UMIN ID: UMIN000042493）（Jpn Pharmacol Ther 2022；50：817‒33）