vitamin d is made when uv-b rays strike the skin. one general recommendation has been to have 20 minutes of sun exposure to [the] face arms legs or back twice a week during the most intense times for sun exposure (10:00 a. m. through 3:00 p. m. ). alas the amount of vitamin d that can be obtained this way can be limited by several factors. if one has dark skin uses an eight or greater spf sunscreen wears occlusive clothing or gets sun exposure only through window glass -- the amount of vitamin d is greatly decreased. if one lives above the 42nd parallel the months of november through february do not produce sufficient vitamin d even when the sun is not hidden by clouds. cloud cover shade and air pollution will further reduce the amount of uv-b. many of us prefer to get vitamins naturally from whole foods as opposed to supplements. some of the highest sources of vitamin d are listed below: cod liver oil one tablespoon = 1 360 iu. cooked salmon 3. 5 ounces = 400 iu. sardines in oil drained 1. 75 ounces = 250 iu. tuna in oil drained 3 ounces = 200 iu. vitamin d fortified orange juice 1 cup = 142 iu. vitamin d fortified milk 1 cup = 98 iu. vitamin d fortified yogurts 6 ounces = 80 iu. egg yolk one = 20 iu. for comparison the usual amount of vitamin d in a multivitamin pill is 400 iu (international units).
what are some common sources of vitamin d?