Vitamin D3 can contribute to the maintenance of your bones, teeth, muscle function, and immune system. It can also play a role in regulating the absorption of calcium and phosphorus — two minerals that contribute to bone health. However, Vitamin D3 (also called the “sunshine vitamin”) is hard to get naturally. Not found in significant amounts in most foods, the best way to get the necessary amount of Vitamin D3 is through sun exposure. Ultra violet B rays provide most of the Vitamin D3 you need, but for those in the Northern Hemisphere living busy lives, sunshine may not be part of your daily routine.