PATHOLOGY

Detailed explanation-1: -Sunlight, in particular UVB between the wavelengths of 290 and 315 nm, is the main source for producing vitamin D in the skin and is the primary source of vitamin D for the body. It is estimated that 90% of the daily body requirements are met by sunlight exposure (16, 17).

Detailed explanation-2: -The time and amount of skin exposed depends on both your skin type and environmental conditions such as the UV index. In good UVB light conditions–a UV index of 3 or higher, between 10:30 a.m. and mid-afternoon–adequate exposure requires about 50 to 75 percent of your skin being exposed.

Detailed explanation-3: -Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years. During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3.