Exposure to ultraviolet B radiation in sunlight provides the mechanism for more than 90% of the vitamin D production in most individuals. Concern has been expressed in recent years that the widespread use of sunscreens, particularly those with high sun protection factors, may lead to a significant decrease in solar-induced previtamin D(3) in the skin, resulting in a vitamin D level which is con...

In his recent commentary, Robins (2009) disputed the role played by ultraviolet radiation (UVR), namely, the vitamin-D-producing wavelengths of ultraviolet B (UVB), in the evolution of human skin. He questioned the theory that reduced levels of pigmentation in human skin were selected to facilitate absorption of UVB. He provided evidence to support his idea that people can produce enough vitami...

Vitamin D, a fat-soluble vitamin naturally present in very few foods, is synthesized when ultraviolet rays from sunlight contact the skin. Research suggests that vitamin D insufficiency may result from lack of exposure to sunlight and ultraviolet-B radiation. Individuals from geographic areas of high latitude and low sunlight exposure may be at increased risk for vitamin D deficiency. Emerging ...

introduction: ultraviolet (uv) radiation affects human organs such as skin, eyes and immune system, as well as animals and plants. the main natural source of uv radiation is the sun. to study the effects of solar uv radiation there is a need to quantify variations of solar energy received on the earth surface at different intervals. materials and methods: to measure uv radiation a broadband fib...

The annual death numbers of influenza and pneumonia in Norway were studied for the time period 1980-2000. No direct relationships were found with the variations of the annual UVB fluences, probably due to the fact that these variations did not exceed 30%. However, there was a very pronounced seasonal variation of both influenza deaths and pneumonia deaths, the vast majority occurring during the...

Observational studies suggest that people with a high serum 25-hydroxyvitamin D (25(OH)D) concentration may have reduced risk of chronic diseases such as osteoporosis, multiple sclerosis, type 1 diabetes, cardiovascular disease, and some cancers. The AusD Study (A Quantitative Assessment of Solar UV Exposure for Vitamin D Synthesis in Australian Adults) was conducted to clarify the relationship...

Solar ultraviolet (UV) radiation is the main source of vitamin D production and is also the most important environmental risk factor for cutaneous malignant melanoma (CMM) development. In the present study the relationships between daily or seasonal UV radiation doses and vitamin D status, dietary vitamin D intake and CMM incidence rates at different geographical latitudes were investigated. No...

Observational studies suggest that people with a high serum 25-hydroxyvitamin D (25(OH)D) concentration may have reduced risk of chronic diseases such as osteoporosis, multiple sclerosis, type 1 diabetes, cardiovascular disease, and some cancers. The AusD Study (A Quantitative Assessment of Solar UV Exposure for Vitamin D Synthesis in Australian Adults) was conducted to clarify the relationship...

1. Vitamin D deficiency was induced in anicteric Wistar rats, Wistar rats before common bile-duct ligation was performed and Gunn rats with unconjugated hyperbilirubinaemia. 2. The effect of ultraviolet radiation on plasma concentrations of 25-hydroxy-vitamin D was studied in a group of control anicteric Wistar rats (n = 11), Wistar rats 8 days after common bile-duct ligation (n = 7) with conju...

Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies s...