A new study shows the majority of South Korean working women in their 20s have a vitamin D deficiency.

A study conducted by a university hospital shows that 80 percent of women and 65 percent of men in their 20s are deficient in activated vitamin D.

Vitamin D, although able to be obtained via food sources, cannot be activated by the body without exposure to the sun.

A lack of vitamin D may weaken bones and could eventually lead to osteoporosis. The vitamin promotes the intestinal absorption of calcium and enhances bone density.

The study recommends that people increase their exposure to sunlight as much as possible, especially in the winter, and try to increase their intake of foods rich in vitamin D, such as mushrooms and fish.