The recommended vitamin D level in the body is 20 to 50 nanograms per milliliter, according to WebMD. The recommended dietary allowance for people between 1 to 70 years old is 600 international units. People older than 70 are recommended to take a daily dosage of 800 international units.
The 25-hydroxyvitamin D blood test determines the amount of vitamin D present in the body, states WebMD. Individuals with a vitamin D level below 12 nanograms per milliliter require treatment for vitamin D deficiency. Treatment includes obtaining vitamin D from food sources and supplements. People who often avoid the sun or use sunscreen to protect the skin often take a vitamin D supplement based on a doctor?s recommendations.