High‐Fat Diet Intake Enhances Ultraviolet‐Induced Melanin Production in the Skin
Nobutomo Ikarashi, Keito Tabata, Yui Shinozaki, Masaya Takei, Yoshihiro Kato, Kosuke Kaneko, Hiyori Aizu, Takahiro Toda, Risako Kon, Hiroyasu Sakai, Tomoo HosoeABSTRACT
The intake of a high‐fat diet (HFD) increases the risk of metabolic diseases such as obesity and type 2 diabetes and has also been associated with age‐related changes in various organs. However, its effects on the skin remain poorly understood. Ultraviolet (UV) exposure is a major environmental factor that induces skin pigmentation through enhanced melanogenesis. However, little is known about the effects of HFD intake on UV‐induced skin pigmentation. This study investigated whether HFD intake modulates UV‐induced melanogenesis. HRM‐2 mice were fed either a standard diet or an HFD for 5 weeks. The melanin content in the dorsal skin of UV‐exposed HFD‐fed mice (UV + HFD group) was significantly greater than that in the dorsal skin of UV‐exposed mice fed a standard diet (UV group). The mRNA levels of tyrosinase ( Tyr ), dopachrome tautomerase ( Dct ), and tyrosinase‐related protein‐1 ( Tyrp1 ) were higher in the UV + HFD group than in the UV group. The protein expression of TYR and microphthalmia‐associated transcription factor (MITF) was significantly greater in the UV + HFD group than in the UV group. HFD intake enhances the UV‐induced upregulation of the expression of MITF and melanogenic enzymes, resulting in exacerbated skin pigmentation. These findings suggest that nutritional status may influence susceptibility to UV‐induced pigmentation and that dietary modulation represents a potential strategy to control UV‐induced hyperpigmentation.