Hey, Sensible sun exposure, especially between the hours of 10:00 am and 3:00 pm produces vitamin D in the skin that may last twice as long in the blood compared with ingested vitamin D. Foods thought to contain high amounts of vitamin D3 are oily fish, such as salmon, mackerel, and blue fish, as well as fortified milk and other dairy products. After correction of their vitamin D status with oral vitamin D, patients should have a repeat test of their 25(OH)D level to confirm that they are in the normal range.