Jung-Hyun Kim

The Association Between Serum 25-Hydroxyvitamin D Concentration and Consumption Frequencies of Vitamin D Food Sources in Korean Adolescents

The objectives of this study were to investigate the status of vitamin D in Korean adolescents and to determine the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and consumption frequencies of vitamin D food sources by season (June to November and December to May). The subjects were 1,579 adolescents aged 12-18 years participating in the 2008-2009 Korean National Health and Nutrition Examination Survey (KNHANES). Consumption frequencies of vitamin D food sources were estimated by using a qualitative food frequency questionnaire (FFQ). Thirteen food items were selected as vitamin D food sources including beef, egg, mackerel, tuna, yellow corvine, pollack, anchovy, mushroom, milk, yoghurt, ice cream, all fish and dairy products from the FFQ based on previous research. The data was analyzed using proc survey procedures. The deficiency (5.25-12 ng/mL), inadequacy (12-20 ng/mL) and sufficiency (> 20 ng/mL) proportions of serum 25(OH)D from June to November and December to May were 9.9%, 51.4%, 38.7%, and 39.4%, 51.4%, 9.2%, respectively. Mean serum 25(OH)D concentration was positively related to the consumption frequencies of mackerel, anchovy, all fish and milk. These results suggest high proportion (> 61%) of Korean adolescents were vitamin D deficiency or inadequacy, and serum 25(OH)D was associated with the consumption of vitamin D food sources including fish and milk.

Calcium Intakes in Korean and American Populations

Calcium intake has been insufficient in all age groups in previous Korean national surveys. This study was conducted to investigate calcium intake in Korean and American populations at different ages. We analyzed two national survey data: the 2007~2009 Korean National Health and Nutrition Examination Survey (KNHANES) and the 2007~2008 National Health and Nutrition Examination Survey (NHANES). Statistically, survey procedures were applied using the weight, cluster, and strata variables. The mean calcium intake of Koreans at ages of 1~2 y, 3~5 y, 6~11 y, 12~18 y, 19~64 y, and 65+y was lower than American populations at those ages. The sufficient proportions based on Korean Estimated Average Requirement (EAR) of 1~2 y, 3~5 y, 6~11 y, 12~18 y, 19~64 y, and 65+y in Koreans were 45.5%, 33.1%, 24.3%, 16.6%, 32.7%, and 19.0%. While the sufficient rates based on American EAR of 1~3 y, 4~8 y, 9~13 y, 14~18 y, 19~30 y, 31~50 y, 51~70 y, and 71+y in US population were 88.5%, 54.4%, 35.2%, 35.8%, 55.3%, 55.2%, 40.6%, and 24.5%. Overall, the major foods contributing to calcium intakes in Koreans were milk, baechukimchi, and anchovies, whereas, milk products, pasta, or bread were major contributions to calcium in American populations. The calcium supplement intakes in the American population were 5.5 mg (1~2 y), 15.5 mg (3~5 y), 13.9 mg (6~11 y), 35.7 mg (12~18 y), 150.3 mg (19~64 y) and 334.4 mg ( y). These results suggest that Korean adolescents and older adults are the most insufficient in dietary calcium intakes among Koreans. In order to accurately estimate calcium intakes in Korean populations, calcium supplements and calcium-fortified foods should be considered.