Most Koreans are too busy working or studying to go out and get a healthy amount of sunshine. To make matters worse, when people do venture out, most of them hide from the sun's rays behind sunscreen or parasols.
Exposure to sunlight causes human skin to produce vitamin D, which helps prevent osteoporosis, depression and cardiovascular diseases.
According to a national health and nutrition survey conducted in 2010, 93 percent of Koreans had vitamin D deficiency.
"As most Koreans prefer fair skin, they try to avoid exposure to the sun. And as adults tend not to eat many dairy products, vitamin D deficiency is common", said Kim Kyung-min, a professor at Seoul National University Hospital in Bundang.