Katsuhito Kino, Akira Nakatsuma, Hiromi Nochi, Yoshimitsu Kiriyama, Takuro Kurita, Takanobu Kobayashi and Hiroshi Miyazawa
In this commentary, we present two views related to the study of riboflavin (vitamin B2): (i) future research into the photo toxicity of riboflavin and its photo-degradation product, lumichrome, should consider effects under visible light and ultraviolet (UV) light in skin because the photochemistry of these reactions differ; and (ii) future research should consider the possibility that excess lumichrome, which is metabolized from riboflavin by intestinal bacteria and is much less water-soluble than riboflavin, could be more readily absorbed and lead to symptoms that resemble those of fat-soluble vitamins.