• The Korean Journal of Physiology and Pharmacology
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• v.17 no.5
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• pp.385-392
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• 2013

Vitamin D deficiency is prevalent, primarily due to limited sun exposure, which may be observed in urban areas, or as a result of modern lifestyles. Common myths about vitamin D persist, including that it is mostly obtained from the diet and is only essential for bone and mineral homeostasis. Nonetheless, advances in biomedical science suggest that vitamin D is a hormone that is integral to numerous physiologic functions in most cells and tissues. Therefore, abnormal vitamin D levels may contribute to health disturbances. A number of recent reports on potential associations between vitamin D deficiency and cardiovascular disease have highlighted its role in this system. A focus over the previous decade has been to better understand the mechanisms behind vitamin D regulation and the pathophysiology associated with suboptimal vitamin D levels. Vitamin D deficiency is highly associated with the incidence of cardiovascular diseases, even when considering other well-known risk factors. In this process, the renin-angiotensin system is disrupted, and hypertension and endothelial dysfunction contribute to the risk of cardiovascular disease. Likewise, clinical outcomes upon the normalization of vitamin D levels have been investigated in different patient populations. It makes sense that vitamin D supplementation to improve vitamin D status among vitamin D-deficient individuals could be useful without requiring a sudden lifestyle change. This manuscript provides a brief overview of vitamin D metabolism and the vitamin D receptor. It also summarizes the current clinical research relating to vitamin D supplementation and its effects on hypertension and endothelial dysfunction in cardiovascular medicine.

• Clinical and Experimental Pediatrics
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• v.60 no.8
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• pp.248-253
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• 2017

Purpose: Vitamin D plays a key role in immune function. Vitamin D deficiency may play a role in the pathogenesis of infections, and low levels of circulating vitamin D are strongly associated with infectious diseases. In this study, we aimed to evaluate the effects of low vitamin D levels in cord blood on neonatal sepsis in preterm infants. Methods: One hundred seventeen premature infants with gestational age of <37 weeks were enrolled. In the present study, severe vitamin D deficiency (group 1) was defined as a 25-hydroxyvitamin D (25(OH)D) concentration <5 ng/mL; vitamin D insufficiency (group 2), 25(OH)D concentration ${\geq}5ng/mL$ and <15 ng/mL; and vitamin D sufficiency (group 3), 25(OH)D concentration ${\geq}15ng/mL$. Results: Sixty-three percent of the infants had deficient levels of cord blood vitamin D (group 1), 24% had insufficient levels (group 2), and 13% were found to have sufficient levels (group 3). The rate of neonatal sepsis was higher in group 2 than in groups 1 and 3. Conclusion: There was no significant relationship between the cord blood vitamin D levels and the risk of neonatal sepsis in premature infants.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.3
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• pp.321-330
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• 2020

Objectives: The purpose of this study was to compare vitamin D levels, sleep quality, and anxiety symptoms between shift workers and daytime workers and analyze the mediating effect of vitamin D and sleep quality between shift work and anxiety symptoms. Methods: The subjects of the study were 6744 people who received a medical examination while working for an electronics manufacturing company in 2016. We evaluated their shift work, vitamin D levels, sleep quality, and anxiety symptoms with blood samples and questionnaires. Chi-square test, t-test and path statistical analysis were performed. Results: The shift workers had significantly higher symptoms of anxiety than the day workers, significantly lower levels of vitamin D in the blood, and significantly poorer quality of sleep. The results of the pathway analysis confirmed that blood vitamin D and sleep quality had a mediating effect between shift work and anxiety symptoms. Conclusions: Shift workers should be constantly paying attention to mental health effects such as anxiety symptoms. Shift workers should also be alerted of the risk of vitamin D deficiency, encouraged about sun exposure and vitamin D intake, and required to undergo training and counseling on sleep hygiene.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.498-506
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• 2015

This paper investigates the association of among alcohol consumption and blood vitamin D and lead concentrations. Subjects to 4,074 with adults over the age of 20 in the 5th Korea National Health and Nutrition Examination Survey, correlation analysis is used to validate the relations between an average daily alcohol consumption and blood vitamin D and lead concentration, and to study the effects of blood vitamin D to the lead concentration is carried out regression analysis. The correlation analysis shows that alcohol consumption has the correlation with blood vitamin D and lead concentration(p<0.01). As the results of regression analysis, age(p<0.01), education(p<0.01), occupation(p<0.05), alcohol consumption(p<0.01), vitamin D(p<0.05) appear significant influence on lead concentration in male. Alcohol consumption increases not only lead concentration but also vitamin D. Blood vitamin D also contributes to the rise in lead concentration, but in the reverse the metabolic activity of blood vitamin D by influence of lead receives a negative effect in our body.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.289-296
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• 1998

A large body of epidemiologic evidence suggests inverse relationships between ischemic heart disease and plasma vitamin C and E concentrations. Smokers have lower plasma concentrations of these vitamins than do nonsmokers. Smokers therefore need antioxidant vitamin supplementation . The purpose of study was to investigate the effect of antioxidant vitamin supplementation on blood composition in smoking college men. 24 subjects were divided into 3 groups of which were the vitamin C supplementation group(n=8), the vitamin E supplementation group(n=8), and the vitamin C+E supplementation group(n=8). The vitamin supplementation group consumed 500mg of ascorbic acid, the vitamin E supplementation group consumed 200IU of D-$\alpha$-tocopherol , and the vitamin C+E supplementation group consumed 500mg of ascorbic acid +200IU of D-$\alpha$-tocopherol for 4 weeks. We examined the blood compositions of the volunteers bofore and after vitamins were supplemented . The results obtained were as follows ; intakes of energy , carbohydrate , fat protein , vitamin C and vitamin E were not significantly affected by vitamin supplementation in all groups. Blood glucose concentrations were not significantly affected by vitamin supplementation in all groups. Concentrations of plasma uric acid and alkaline phosphatase activity were decreased significantly (p<0.05) with vitamin E supplementation. The results of this study show that antioxidant vitamin supplementation in smokers has a tendency to decrease coronary heart disease risk.

• Physical Therapy Rehabilitation Science
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• v.2 no.2
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• pp.63-69
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• 2013

Objective: To assess the effect of vitamin D administration on the skin blood flow response to occlusion and heat. Design: Cross-sectional study. Methods: Twenty age matched subjects; 10 who had diabetes and 10 who were controls were administered 4,000 IU of vitamin D3 for 3 weeks at breakfast. The function of the endothelial cells was evaluated in 2 ways; first, the response to 4 minutes of vascular occlusion of the skin was measured with a laser Doppler flow meter. Second, the skin blood flow response to local heat at 42 degrees C for 6 minutes was examined. Results: The results of the experiments showed that the blood flow response to heat was reduced after 3 weeks administration of vitamin D in the subjects with diabetes and in the control subjects (p<0.05). The response to occlusion was not significantly different within each group before and after vitamin D administration, but the group with diabetes had a significantly lower blood flow response to occlusion than did the controls (p<0.05). Conclusions: Acute doses of vitamin D may impair nitric oxide production and reduce blood flow to tissue during stressors in people with diabetes.

• Animal Bioscience
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• v.36 no.10
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• pp.1536-1545
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• 2023

Objective: The objective was to evaluate the effects of UV-B irradiated vitamin D-enriched yeast supplementation on milk yield, milk composition, vitamin D in milk, milk fatty acids, blood chemistry, and 25(OH)D status in dairy cows. Methods: Six Thai Friesian cows (milk production, 11.2±2.0 kg/d; body weight, 415.0±20.0 kg; and days in milk, 90.0±6.0) were allocated to each treatment in a 3×3 Latin square design, with three treatments and three periods. Each period of the Latin square lasted 49 days consisting of 14 days for diet adaptation and 35 days for sample collection. Dairy cows were randomly assigned to one of three treatments: i) feeding a basal diet without yeast (CON); ii) basal diet + 5 g of live yeast (75 IU/head/d of vitamin D₂; LY); and iii) basal diet + 5 g of UV-B irradiated vitamin D enriched yeast (150,000 IU/head/d of vitamin D₂; VDY). Feed intake and milk production were recorded daily, milk sample collection occurred on days 14 and 35 of each collection period, and blood plasma was collected on days 0, 7, 14, 21, 28, and 35 of each collection period. Results: The results show that after a trial period of 14 and 35 days, the VDY group had significantly higher vitamin D content in milk than the LY and CON groups (376.41 vs 305.15, 302.14 ng/L and 413.46 vs 306.76, 301.12 ng/L, respectively). At days 7, 14, 21, 28, and 35 of the experiment, cows fed the VDY group had significantly higher 25(OH)D₂ status in blood than the CON and LY groups (51.07 vs 47.16, 48.05 ng/mL; 54.96 vs 45.43, 46.91 ng/mL; 56.16 vs 46.87, 47.16 ng/mL; 60.67 vs 44.39, 46.17 ng/mL and 63.91 vs 45.88, 46.88 ng/mL), respectively. Conclusion: In conclusion, UV-B irradiated vitamin D-enriched yeast supplementation could improve vitamin D content in the milk and 25(OH)D status in dairy cows during the lactation period.

• Journal of the Korean Dietetic Association
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• v.23 no.1
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• pp.39-53
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• 2017

Insufficient vitamin D intake is a major health problem around the world. Recently, many studies have suggested that vitamin D intake may influence insulin resistance. However, little is known about the association between vitamin D and diabetes mellitus. The aim of this study was to investigate the association between serum 25-hydroxy vitamin D (25(OH)D) levels and diabetes mellitus in Korean adults. This study was a cross-sectional analysis of 3,686 participants of the Korean National Health and Nutrition Examination Survey (KNHANES) 2013~2014 aged 19 years and higher. The results showed that the mean serum 25-hydroxy vitamin D (25(OH)D) level in Korean adults was 16.77 ng/mL, and 74.2% of them had an insufficient serum 25-hydroxy vitamin D (25(OH)D) level (below 20 ng/mL). In normal and pre-diabetic groups, the serum 25-hydroxy vitamin D (25(OH)D) level significantly increased with age (P<0.001), but there was no significant difference relative to age in the diabetic group. Low vitamin D levels (25-hydroxy vitamin D < 10 ng/mL) were associated with increased fasting blood glucose levels, compared with optimal vitamin D levels (25-hydroxy vitamin D > 30 ng/mL), after adjusting for variables that may affect fasting blood glucose, but this result was not significant. In conclusion, although no significant association was observed between diabetes prevalence and vitamin D levels in this study, further studies are needed because the effect of vitamin D on diabetes remains controversial. This nutrient plays a crucial role in the body, and levels are insufficient in the Korean population.

• Journal of the Korean Society of School Health
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• v.29 no.1
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• pp.22-32
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• 2016

Purpose: This study is intended to analyze factors of metabolic syndrome and vitamin D deficiency with resources obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) V conducted in 2010. Methods: The subjects were 870 adolescents aged from 10 to 18 who participated in the first KNHANES V. Secondary data analysis was done by Chi-square, ANOVA, correlation analysis and simple linear regression. Results: The influencing factors of metabolic syndrome were vitamin D, systolic blood pressure and diastolic blood pressure, which were statistically significant. Simple linear regression was conducted to identify the influence of vitamin D on the factors related to metabolic syndrome, which showed that waist size (t=-1.97, p<.05), systolic blood pressure (t=-2.88, p<.01), and diastolic blood pressure (t=-5.72, p<.001) were influenced by vitamin D. In addition, each factor decreased by .131, .209, and .355, respectively, when vitamin D increased by one unit. Conclusion: Metabolic syndrome is a factor to be considered in order to improve adolescent health and form adolescent health behaviors. Schools, families, and local communities should cooperate with each other on the foundation of a regular health screening process and systematic health education programs. In addition, it is expected enhanced physical activities and sports club participation can prevent metabolic syndrome and increase vitamin D among adolescent.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.3-12
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• 2016

Vitamin D plays a vital role in maintaining blood concentrations of Ca and P. In lipid metabolism, vitamin D is also known to negatively affect the development of adipocytes, but it has received little attention with regard to improve marbling score in beef cattle via restricting its supply. Recently, the method of feeding fat soluble vitamins(including vitamin D)-deficient diets in Korean native cattle (Hanwoo) has been spread by feed companies and TMR plants. But proper guidelines in feeding vitamin D-deficient diets should be provided, otherwise it can adversely affect the health of cattle. To maximize marbling score, a controlled level of vitamin D in blood needs to be maintained and the proper period for feeding vitamin D-deficient diets should be provided. This review was conducted to highlight the regulatory effects of vitamins D on adipocyte differentiation, and provide information on improving beef quality grades in relation to feeding vitamin D-deficient diets in beef cattle.