• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1484-1487
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• 1999

Extraction is the most important and tedious step to determine water-soluble vitamin C in water-insoluble chewing gum. For the rapid determination of vitamin C in chewing gum, a new method of dispersion in tetrahydrofuran(THF) was performed. Vitamin C was easily extracted from gum base using THF The content of vitamin C in chewing gum was rapidly quantified with high reliability by an enzymatic method using a chewing gum sample dispersed in tetrahydrofuran.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.571-577
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• 2012

This study was carried out to develop an analytical method for the determination of vitamin D in infant formula. Vitamin D was determined by column-switching high-performance liquid chromatography (HPLC) equipped with a reversed phase column and UV detector after saponification and extraction of the formula with an organic solvent. A preseparation column ($C_8$), focusing column ($C_{18}$), analytical column ($C_{18}$) and UV-Vis detector (254 nm) were used. The limits of detection (LOD) and the limits of quantification (LOQ) for vitamin D were estimated to be $1.51{\mu}g/kg$ and $4.95{\mu}g/kg$, respectively. The linearity, recovery, precision and accuracy of the analytical method for vitamin D were evaluated through the application of a SRM (Standard Reference Material) 1846 (National Institute of Standard & Technology, USA). The linearity of this method was calculated with a value of the coefficient of determination ($r^2$) ${\geq}0.9999$. The recovery of vitamin D was $85.20{\pm}3.00%$. The intra-assay precision for vitamin D was between $1.68{\pm}0.03%$ and $5.75{\pm}0.33%$, and the inter-assay precision for vitamin D ranged from $1.73{\pm}0.03%$ to $2.96{\pm}0.09%$. The intra-assay accuracy for vitamin D was between $100.03{\pm}2.77%$ and $102.01{\pm}0.59%$, and the inter-assay accuracy for vitamin D ranged from $99.00{\pm}1.53%$ to $102.01{\pm}3.04%$. The proposed method is optimal for the separation and quantification of vitamin D from infant formula.

• Clinical and Experimental Pediatrics
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• v.58 no.9
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• pp.325-329
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• 2015

Purpose: In addition to regulating calcium and phosphorus homeostasis and bone metabolism, vitamin D is known as an immune modulator. Recently, there has been increased worldwide interest in the association between low levels of vitamin D and allergic diseases. The purpose of this study was to assess the relationship between serum vitamin D levels and allergic/vasomotor rhinitis (AR/VR) in children. Methods: This study included 164 patients. The sample included 59 patients with AR, 42 patients with VR, and 63 controls. Their ages ranged from 0 to 16 years. We examined the levels of 25-hydroxyvitamin D, Immunoglobulin E, specific IgE, and eosinophil cationic protein; peripheral blood eosinophil count; and the results of a skin prick test. Results: Serum 25-hydroxyvitamin D levels were $19.0{\pm}8.5ng/mL$ in the AR group, $25.5{\pm}10.9ng/mL$ in the VR group, and $26.9{\pm}10.7ng/mL$ in the control group. After adjustment for body mass index and season at the time of blood sampling, vitamin D levels in the AR group were lower than those of the VR group (P=0.003) and control group (P<0.001). Vitamin D levels were inversely correlated with Immunoglobulin E levels (r=-0.317, P<0.001). AR patients with food allergy or atopic dermatitis did not have lower levels of 25-hydroxyvitamin D than AR patients without these diseases. Conclusion: This study demonstrates a possible relationship between vitamin D levels and allergic rhinitis in Korean children.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.303-311
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• 2018

The aim of this study was to investigate vitamin D status and factors associated with vitamin D deficiency among Koreans in their using Korean National Health and Nutrition Examination Survey (KNHANES) V. The subjects were 1,837 people who were 20-29 years old. The data were analyzed by ${\chi}^2$ test and multiple logistic regression analysis using weighted composite sample analysis. Vitamin D deficiency was reveled in 84.2% of subjects; 88.6% of women and 79.4% of men showed deficiency. In the multiple logistic regression analysis, the risk for vitamin D deficiency was higher in women (OR 1.84; 95% CI 1.31-2.56), non-married (OR 2.12; 95% CI 1.41-3.19), poor subjective health status (OR 1.94; 95% CI 1.16-3.25), and in the absence of moderate to vigorous physical activity (OR 3.38; 95% CI 1.85-6.16). Continued research on vitamin D levels at this time is needed since vitamin D deficiency among Koreans in their twenties will exacerbate health problems, both individually and socially. In addition, vitamin D has been shown to be closely related to time of exposure to sunlight and physical activity. Therefore, it is thought that long-term and planned efforts should be made at the national level, such as establishing schools and workplaces in which those in their twenties can perform outdoor activities and moderate to vigorous physical activity.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.133-137
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• 2010

Purpose: The main function of vitamin D is the mineralization of the brain by increase of calcium and phosphorus, in case it is insufficient in children, lime deposition on cartilage cannot occur so it leads to rachitis, and in adults, it leads to osteomalacia or osteoporosis. It is also strongly believed in the academic world that vitamin D can restrict the growth of cancer cells and prevent heart diseases, which is also somewhat proven in epidemiological researches. While the right density of vitamin D is still being studied, 20-32 ng/mL is believed to be the most ideal density. Therefore, I wanted analyze how much density of 25-Hydroxyvitamin D3 that Koreans possess. Materials and Methods: From February 20th, 2008 to April 21st, 2009, the collection of 2800 serums, from medical examination treated subjects by Neodin Medical Institute, have been tested. The targets were tested by 25-Hydroxyvitamin D (125I Kit: Diasorin, USA), and were analyzed by dividing into many different categories (gender, age, season, region). Results: The average density of male were 20 ng/mL, female 17.08 ng/mL. Per age groups, the density of males were as follows: 10~20-18 ng/mL, 21~30-17 ng/mL, 31~40-19 ng/mL, 41~50-21 ng/mL, 51~60-22 ng/mL, 61~70-22 ng/mL, 71~80-22 ng/mL and 81~90-19.9 ng/mL. Average density of females per age groups, were as follows: 10~20-16 ng/mL, 20~30-15.26 ng/mL, 30~40-16 ng/mL, 40~50-17 ng/mL, 50~60-19 ng/mL, 60~70-19 ng/mL, 70~80-19 ng/mL, and 80~90-17 ng/mL. Per seasons, From December to May, the subjects showed the density of 15.97 ng/mL, while from June to November, it showed 21.60 ng/mL. On density of males from January to April regionally, Seoul+Gyeonggi-Do-15.52 ng/mL, Gangwon-Do-15.33 ng/mL, Choongchung-Do-18.03 ng/mL, Jeonla-Do-18.68 ng/mL, Gyungsang-Do-18.76 ng/mL and Cheju Do-21.23 ng/mL. Conclusions: The vitamin D of Koreans is has been insufficient compared to the suggested amount. Ultraviolet rays, which is the main source of vitamin D is critical, therefore it is suggested that more outdoor activities can definitely help.

• Journal of Nutrition and Health
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• v.52 no.6
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• pp.552-558
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• 2019

Purpose: Although vitamin D deficiency is common among Korean adolescent girls and young women, few studies have explored the potential health effects of vitamin D deficiency in this vulnerable population. This study examined the association between vitamin D deficiency and anemia in Korean adolescent girls and young women. Methods: The data from the Korea National Health and Nutrition Examination Survey 2008 ~ 2014 were used. A total of 3,643 girls and adult women aged 12 to 29 who provided all the information (including serum 25-hydroxy vitamin D, hemoglobin, and/or serum ferritin) needed for the analysis were included in the analysis. Demographic, lifestyle, and health data were obtained through survey questionnaires. Anemia and iron deficiency anemia were defined according to the World Health Organization cut-offs. Multivariable logistic regression, and restricted cubic spline regression were used in the analysis. Results: In fully adjusted logistic regression models, the vitamin D deficiency was significantly associated with higher prevalences of anemia (odds ratio (OR): 1.61, 95% confidence interval (CI): 1.04 ~ 2.49) and iron deficiency anemia (OR: 1.43, 95% CI: 1.01 ~ 2.03). In a cubic spline regression model, we observed a dose-response relationship between serum 25(OH)D concentration and anemia, and this linear relationship was also clearly observed between serum 25(OH)D concentration and iron deficiency anemia. Conclusion: Vitamin D deficiency may be associated with a higher prevalence of iron deficiency anemia and anemia in adolescent girls and young women. Alternatively, vitamin D deficiency may be a concurrent event for patients with anemia, which we cannot distinguish in this cross-sectional study. Further studies are needed to verify the causality in this population of low vitamin D levels.

• Allergy, Asthma & Respiratory Disease
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• v.6 no.6
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• pp.284-289
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• 2018

Purpose: Vitamin D plays an important role in calcium homeostasis and bone metabolism. It is associated with various diseases such as cardiovascular, immune, allergic and infectious disease. The aim of this study was to investigate the difference in clinical manifestations according to the concentration of vitamin D in mild bronchiolitis. Methods: We performed a retrospective review of medical records of patients with mild bronchiolitis from November 2016 to April 2017 in Daegu Fatima Hospital. Mild bronchiolitis was classified by the modified Tal's score method. Patients were divided into 2 groups according to a 25-hydroxyvitamin D level of 20 ng/mL. We analyzed the clinical characteristics and laboratory data from the 2 groups. Results: Of the 64 patients, 19 were included in the deficiency group and 45 in the normal group. Vitamin D levels were $11.7{\pm}4.9ng/mL$ in the deficiency group and $28.8{\pm}5.0ng/mL$ in the normal group. There were no differences in clinical features between both groups. However, the vitamin D deficiency group had significantly longer hospitalization than the normal group ($6.78{\pm}2.74$ days vs. $5.3{\pm}1.7$ days, P=0.045). In the deficiency group, the incidence of previous respiratory diseases was significantly higher (P=0.001). No significant difference in blood and respiratory virus tests was observed. Conclusion: Low vitamin D levels in mild bronchiolitis were associated with longer hospitalization and prior respiratory disease. Vitamin D may affect the course of mild bronchiolitis.

• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.665-668
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• 2005

"Rickets" is the term applied to impaired mineralization at epiphyseal growth plate, resulting in deformity and impaired linear growth of long bones. Rickets may arise as a result of vitamin D deficiency or abnormality in metabolism. Vitamin D-dependent rickets(VDDR) is rare autosomal recessive disorder in which affected individuals have clinical features of vitamin D deficiency. In 1961, Prader first described this disorder including severe clinical features of rickets, such as hypophosphatemia, hypocalcemia, muscle weakness and seizure. Two distinctive hereditary defects, type I VDDR and type II VDDR have been recognized in vitamin D metabolism. Type I VDDR may be due to congenital defects of renal 1 ${\alpha}$-hydroxylase, the enzyme responsible for conversion of $25(OH)D_3$. These patients have low to detectable $1,25(OH)_2D_3$ in presence of normal to raised $25(OH)D_3$. In type II VDDR, renal production of $1,25(OH)_2D_3$ is intact but $1,25(OH)_2D_3$ is not used effectively and target organ resistant to $1,25(OH)_2D_3$ is respectively derived from the abnormality in the vitamin D receptor. We report a case of a 25 month-old girl with typical clinical features of VDDR type I rickets, hypocalcemia, increased alkaline phosphatase and secondary hyperparathyroidism.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2227-2230
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• 2015

Background: Prostate cancer (PCa) is one of the most commonly diagnosed neoplasms and the second leading cause of cancer death in men in the Western world. Vitamin D (1,25dihydroxy vitamin D) is linked to many biological processes that influence oncogenesis but data on relations between its genetic variants and cancer risk have been inconsistent. The aim of this study was to determine associations between a vitamin D genetic polymorphism and 25-hydroxyvitamin D [25(OH)D] levels and prostate cancer. Materials and Methods: Genomic DNA was extracted from 124 Jordanian prostate cancer patients and 100 healthy volunteers. Ethical approval was granted from the ethical committee at Hashemite University and written consent was given by all patients. PCR was used to amplify the vitamin D receptor Fok1 polymorphism fragment. 25(OH)D serum levels were measured by competitive immunoassay. Results: All genotypes were in Hardy-Weinberg equilibrium. Genotype frequency for Fok1 genotypes FF, Ff and ff was 30.7%, 61.3% and 8.06%, for prostate cancer patients, while frequencies for the control group was 28.0%, 66.0% and 6.0%, respectively, with no significant differences. Vitamin D serum level was significantly lower in prostate cancer patients (mean 7.7 ng/ml) compared to the control group (21.8 ng/ml). No significant association was noted between 25(OH)D and VDR Fok1 gene polymorphism among Jordanians overall, but significant associations were evident among prostate cancer patients (FF, Ff and ff : 25(OH)D levels of 6.2, 8.2 and 9.9) and controls (19.0, 22.5 and 26.3, respectively). An inverse association was noted between 25(OH)D serum level less than 10ng/ml and prostate cancer risk (OR 35.5 and 95% CI 14.3- 88.0). Conclusions: There is strong inverse association between 25(OH)D serum level less than 10ng/ml level and prostate cancer risk.

• Nutrition Research and Practice
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• v.9 no.2
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• pp.158-164
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• 2015

BACKGROUND/OBJECTIVES: Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS: A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and $1,25(OH)_2D$ levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS: Mean 25(OH)D and $1,25(OH)_2D$ levels were $13.5{\pm}5.8ng/ml$ and $20.6{\pm}11.8pg/ml$, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (${\geq}30ng/ml$) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS: Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.