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Improvement of skin conditions by ingestion of Aspergillus kawachii (Koji) extract containing 14-dehydroergosterol in a randomized, double-blind, controlled trial

Authors Sugihara Y, Ikushima S, Miyake M, Kirisako T, Yada Y, Fujiwara D

Received 30 September 2017

Accepted for publication 15 December 2017

Published 9 March 2018 Volume 2018:11 Pages 115—124


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Jeffrey Weinberg

Yoshihiko Sugihara,1 Shigehito Ikushima,1 Mika Miyake,1 Takayoshi Kirisako,2 Yukihiro Yada,3 Daisuke Fujiwara2

1Research Laboratories for Health Science and Food Technologies, 2Central Laboratories for Key Technologies, Research and Development Division, Kirin Company, Limited, Yokohama, 3Doctorate Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan

Purpose: The present study examined the effect of ingestion of Koji extract containing 14-dehydroergosterol (14-DHE), prepared from Aspergillus kawachii NBRC4308, on improvement of skin conditions among healthy volunteers.
Subjects and methods: In a randomized, double-blind, placebo-controlled, parallel-group study, 70 healthy adult women who felt that their skin was dry ingested either a placebo dietary supplement or Koji extract (200 mg/day) supplement containing 0.1% 14-DHE for 12 weeks. Throughout the treatment period and for 4 weeks afterward, objective indicators – including moisture content of the stratum corneum, trans-epidermal water loss (TEWL), and skin wrinkles – were evaluated; in addition, the subjects answered a questionnaire on their skin conditions with ratings on a visual analog scale. Statistical analysis was conducted on the basis of differences from baseline scores.
Results: Compared with the placebo group, the Koji extract group showed significantly increased forearm moisture at 4, 8, and 16 weeks (p < 0.05 on unpaired t-test). The questionnaire survey showed a marked improvement in skin conditions, particularly crow’s feet, in the Koji extract group versus the placebo group at 8 weeks (p < 0.05 by unpaired t-test). Furthermore, the Koji extract group showed a trend (p < 0.10) toward improvement in skin moisture (at 4 weeks), dryness around the eyes/mouth (at 4 weeks), and overall skin condition (at 8 weeks) versus the placebo group.
Conclusion: Ingestion of Koji extract containing 14-DHE was demonstrated to have positive effects toward improving skin conditions – in particular, on increasing skin moisture in the stratum corneum.

Keywords: 14-dehydroergosterol, Aspergillus, Koji, skin, skin moisture, TEWL

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