Determining an effective UV radiation exposure time for vitamin D synthesis in the skin without risk to health: Simplified Estimations from UV observations

著者

Miyauchi M., Nakajima H.

雑誌名

Photochemistry and Photobiology, 92(6) 863-869

DOI

10.1111/php.12651

概要

UV radiation contains erythemally weighted UV, as well as UV that synthesizes vitamin D₃. Here, we attempted to determine the relationship between these factors by numerical simulation of atmospheric parameters, such as total ozone, using a simplified “SMART2” model for radiative transfer. Both forms of UV were almost linearly correlated with each other for a comparably large UV radiation exposure, larger than UV Index ~1.6. If erythemally weighted UV, which carries a risk of sunburn, is known, the amount of UV exposure needed for vitamin D synthesis in the epidermis can be estimated using this relationship. The production of 10 lg (400 IU) of vitamin D per day takes approximately 1/3 of the time needed to reach the minimal erythemal dose (MED) for an effective skin area of 600 cm² for skin phototype III. For an area of 1200 cm², 1/6 of that exposure time suffices. From a UV Index that is commonly used, the risks and benefits can be evaluated using this linear relationship, which will enable people to effectively manage their UV exposure and consider the risks and benefits to optimize health outcomes.

宮内正厚・中島英彰「体内でビタミンDを生成するための紫外線の有害性を考慮した有効な紫外線照射時間の推定」地球環境研究センターニュース2017年2月号