Vitamin D Intake and Serum 25-Hydroxyvitamin D Levels in Korean Adults: Analysis of the 2009 Korea National Health and Nutrition Examination Survey (KNHANES IV-3) Using a Newly Established Vitamin D Database

Vitamin D is important for maintaining bone health and may prevent various diseases (i.e., cardiovascular disease and cancer). The aim of this study was to estimate vitamin D intakes of Korean adults using the Korea National Health and Nutrition Examination Survey (KNHANES, 2009) data and a newly established vitamin D database. KNHANES (2009) participants (n = 4541; 2021 men; 2520 women) aged ≥20 years were included. Dietary vitamin D intake, serum 25-hydroxyvitamin D (25(OH)D), and the relationship between vitamin D intake and serum 25(OH)D were evaluated. In men and women, vitamin D intakes were 4.00 ± 0.17 µg/day and 2.6 ± 0.1 µg/day respectively, and serum 25(OH)D concentrations were 19.78 ± 0.33 ng/mL and 17.10 ± 0.26 ng/mL respectively. Serum 25(OH)D concentrations of men aged <50 years and women aged >20 years were under 20 ng/mL. After adjusting for confounding factors, the positive relationship between vitamin D intake and serum 25(OH)D was observed in total subjects (p < 0.05), excluding participants ≥50 years old. The main food sources for vitamin D among Korean adults were fish/shellfish (71.34%) and egg (14.89%). Korean adults should increase their serum 25(OH)D concentrations by increasing vitamin D intake.