Controlling adverse and beneficial effects of solar UV radiation by wearing suitable clothes – Spectral transmission of different kinds of fabrics

• Model for the vitamin D effective doses for a person worn transparent textiles.
• Textiles with the UV protection factor of ∼10 may be used for pro-health sunbathing.
• Prolonged dressed sunbathing yields adequate vitamin D level without erythema risk.

Humans should avoid prolonged exposure to the Sun during the warm subperiod of the year with naturally high solar UV level. One of the known recommendations to avoid excessive UV radiation is wearing clothes with UV protection additives. However there is an important question: how do we get an adequate solar UV radiation, which maintains a healthy status of vitamin D, without facing overexposure risks? It is found that some kind of 100% cotton knitted fabric, used in the production of normal daily clothing, has ∼15% transmittance of solar UV. Model studies show that a garment made of this fabric allows larger synthesis of vitamin D3 in human body without the erythema risks (skin redness). Thus the adequate level of vitamin D could be attained safely by a person exposing only small part of the body (face, palms) during the period (May–August) of the year.