• Title, Summary, Keyword: vitamin D

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Effects of Vitamin D on Blood Pressure and Endothelial Function

  • Min, Bokyung
    • 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.

Vitamin D status and childhood health

  • Shin, Youn Ho;Shin, Hye Jung;Lee, Yong-Jae
    • Korean Journal of Pediatrics
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    • v.56 no.10
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    • pp.417-423
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    • 2013
  • Vitamin D is an essential component of bone and mineral metabolism; its deficiency causes growth retardation and skeletal deformities in children and osteomalacia and osteoporosis in adults. Hypovitaminosis D (vitamin D insufficiency or deficiency) is observed not only in adults but also in infants, children, and adolescents. Previous studies suggest that sufficient serum vitamin D levels should be maintained in order to enhance normal calcification of the growth plate and bone mineralization. Moreover, emerging evidence supports an association between 25-hydroxyvitamin D (25[OH]D) levels and immune function, respiratory diseases, obesity, metabolic syndrome, insulin resistance, infection, allergy, cancers, and cardiovascular diseases in pediatric and adolescent populations. The risk factors for vitamin D insufficiency or deficiency in the pediatric population are season (winter), insufficient time spent outdoors, ethnicity (non-white), older age, more advanced stage of puberty, obesity, low milk consumption, low socioeconomic status, and female gender. It is recommended that all infants, children, and adolescents have a minimum daily intake of 400 IU ($10{\mu}g$) of vitamin D. Since the vitamin D status of the newborn is highly related to maternal vitamin D levels, optimal vitamin D levels in the mother during pregnancy should be maintained. In conclusion, given the important role of vitamin D in childhood health, more time spent in outdoor activity (for sunlight exposure) and vitamin D supplementation may be necessary for optimal health in infants, children, and adolescents.

Association of Diabetes with Serum Vitamin D in Korean Adults : Analysis of the Korea National Health and Nutrition Examination Survey (2013~2014) (한국 성인 남녀에서 당뇨병 유병률과 혈중 비타민 D 농도와의 관련성 : 제6기 국민건강영양조사(2013~2014)에 근거하여)

  • Kim, Arang;Yun, Jung-Mi
    • 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.

Vitamin D and Metabolic Diseases: Growing Roles of Vitamin D

  • Park, Jung Eun;Pichiah, Tirupathi;Cha, Youn-Soo
    • Journal of Obesity & Metabolic Syndrome
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    • v.27 no.4
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    • pp.223-232
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    • 2018
  • Vitamin D, a free sunshine vitamin available for mankind from nature, is capable to avert many health-related critical circumstances. Vitamin D is no more regarded as a nutrient involved in bone metabolism alone. The presence of vitamin D receptor in a number of tissues implies that vitamin D has various physiological roles apart from calcium and phosphorus metabolism. Low serum vitamin D has been found to be associated with various types of metabolic illness such as obesity, diabetes mellitus, insulin resistance, cardiovascular diseases including hypertension. Various studies reported that vitamin D insufficiency or deficiency in linked with metabolic syndrome risk. This review focuses on various metabolic diseases and its relationship with serum vitamin D status.

Serum Fat Soluble Vitamins in Bile Duct Ligated Rats (담도 결찰한 백서에 있어서 담즙산 및 UDCA 투여에 따른 혈중 지용성 비타민의 농도 변화에 관한 연구)

  • Sim, Jay-Geon;O, Myung-Ho;Kim, Kee-Hyuck
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.2 no.1
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    • pp.59-64
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    • 1999
  • Purpose: The aims of this study are to measure the serum levels of fat soluble vitamins (vitamin A and D) from bile duct ligated rats, and to evaluate the effect of oral bile acids administration to facilitate absorption of fat soluble vitamins. Methods: We measured serum ALT, total bilirubin, vitamin A, and vitamin D of Sprague-Dawley rats 1 week before and 4 weeks after experimental bile duct ligation. Rats were consisted with 3 groups. Group 2 had been fed bile acids and group 3 ursodeoxycholic acid after operation for 4 weeks. Multi-vitamin was given to all groups. Results: 1) Base line (mean value before duct ligation): ALT 74.2 IU, total bilirubin 0.26 mg/dL; vitamin D 13.01 ng/mL vitamin A $0.87\;{\mu}g/mL$, total bile acids $25.16\;{\mu}mol/L$. 2) Four weeks after ligation: ALT 100.7 IU, total bilirubin 2.58 mg/dL; vitamin D 7.89 ng/mL vitamin A $1.37{\mu}g/mL$, total bile acids $278.22\;{\mu}mol/L$. 3) 4 weeks after ligation, each group (group 1, group 2 and group 3) showed vitamin D (7.62, 8.10 and 7.99) ng/mL, vitamin A (1.68, 1.06 and 1.33) ${\mu}g/mL$, total bile acids (233.17, 345.80 and 268.57) ${\mu}mol/L$, which were statistically not significant. Conclusion: Serum level of vitamin A is increased after bile duct ligation although vitamin D is decreased. Oral administration of bile acids does not affect the serum levels of vitamin A and D in bile duct ligated rats.

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Enrichment of Vitamins $D_3$, K and Iron in Eggs of Laying Hens

  • Park, S.W.;Namkung, H.;Ahn, H.J.;Paik, I.K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.2
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    • pp.226-229
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    • 2005
  • An experiment was conducted to produce eggs enriched with vitamins $D_3$, K and iron in eggs. Six hundred 97-wk-old ISA Brown force molted hens were allocated to completely randomized block arrangement of six dietary treatments: T1; control (C), T2; C+4,000 IU vitamin $D_3$+2.5 mg vitamin K+100 ppm Fe, T3; C+8,000 IU vitamin $D_3$+5.0 mg vitamin K+100 ppm Fe, T4; C+12,000 IU vitamin $D_3$+7.5 mg vitamin K+100 ppm Fe, T5; C+16,000 IU vitamin $D_3$+10.0 mg vitamin K+100 ppm Fe, T6; C+20,000 IU vitamin $D_3$+12.5 mg vitamin K+100 ppm Fe. Fe was supplemented with Fe-methionine. Each treatment consisted of five replicates of ten cages with two birds per cage. Egg production and egg weight were highest in T2 and incidence of soft and broken egg was highest in T6. Haugh unit was not different among treatments although it tended to be increased as dietary vitamins $D_3$ and K increased. Eggshell strength was not different among treatment. Concentrations of vitamin $D_3$ and K in egg yolk increased and plateaued approximately 20 days after feeding supplemented diets. The level of these vitamins peaked at 12,000 IU/kg vitamin $D_3$ and 7.5 mg/kg vitamin K supplementation and then decreased at the higher than these supplementation levels. The peak concentrations of vitamin $D_3$ and vitamin K were 4.6 times and 4.8 times greater than the control, respectively. Supplementary Fe also increased Fe content in egg yolk. It is concluded that vitamin $D_3$ and K in eggs can be effectively enriched by proper supplementation time and level of these vitamins.

Subclinical Vitamin D Insufficiency in Korean School-aged Children

  • Han, Sang Woo;Kang, Ha Ra;Kim, Han Gyum;Kim, Joo Hyun;Uhm, Ji Hyun;Seo, Ji Young
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.16 no.4
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    • pp.254-260
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    • 2013
  • Purpose: Recently, vitamin D insufficiency has increased and has been correlated to growth and puberty in children. This study was conducted to find the prevalence of subclinical vitamin D insufficiency and its influence on school-aged children in Korea. Methods: The subjects of this study were 397 children aged 7 to 15 years who had been tested for 25-OH vitamin D3 among the outpatients of the Department of Pediatrics in Eulji General Hospital from March 2007 to February 2011. Data for age, sex, comorbidities, serum 25-OH vitamin D3, height, weight, body mass index (BMI), and sunlight exposure time were collected before and after 3 months of vitamin D administration, retrospectively. Results: Vitamin D insufficiency was present in 343 (86%) of the subjects. In the vitamin D insufficient group, chronological age was $8.96{\pm}1.72$ years, mean height (z-score [z]) was $0.51{\pm}1.26$, mean BMI (z) was $0.81{\pm}2.20$, and bone age was $10.26{\pm}1.75$ years. In the vitamin D sufficient group, chronological age was $9.61{\pm}1.77$ years, mean height (z) was -$0.66{\pm}0.98$, mean BMI (z) was -$0.01{\pm}1.16$, and bone age was $9.44{\pm}2.12$ years. A paired t-test showed that three months after vitamin D administration, the mean 25-OH vitamin D3 level in the insufficient group increased to $24.38{\pm}10.03$ ng/mL and mean BMI (z) decreased to $0.67{\pm}1.06$. Conclusion: In Korean school-aged children, vitamin D insufficiency were relatively higher and may be closely related with higher BMI. Insufficient rise of the level of vitamin D after supplementation suggest the new supplementation guidelines, especially for Korean children.

Vitamin D dependent rickets type I

  • Kim, Chan-Jong
    • Korean Journal of Pediatrics
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    • v.54 no.2
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    • pp.51-54
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    • 2011
  • Vitamin D is present in two forms, ergocalciferol (vitamin $D_2$) produced by plants and cholecalciferol (vitamin $D_3$) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 $[1,25(OH)_2D]$, plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of $1,25(OH)_2D$ from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the $1{\alpha}$-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D $1{\alpha}$-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of $1,25(OH)_2D$ despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human $1{\alpha}$-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and $1{\alpha}$-hydroxylase mutations with clinical findings.

The Role of Vitamin D in the Pathogenesis of Adolescent Idiopathic Scoliosis

  • Ng, Shu-Yan;Bettany-Saltikov, Josette;Cheung, Irene Yuen Kwan;Chan, Karen Kar Yin
    • Asian Spine Journal
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    • v.12 no.6
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    • pp.1127-1145
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    • 2018
  • Several theories have been proposed to explain the etiology of adolescent idiopathic scoliosis (AIS) until present. However, limited data are available regarding the impact of vitamin D insufficiency or deficiency on scoliosis. Previous studies have shown that vitamin D deficiency and insufficiency are prevalent in adolescents, including AIS patients. A series of studies conducted in Hong Kong have shown that as many as 30% of these patients have osteopenia. The 25-hydroxyvitamin D3 level has been found to positively correlate with bone mineral density (BMD) in healthy adolescents and negatively with Cobb angle in AIS patients; therefore, vitamin D deficiency is believed to play a role in AIS pathogenesis. This study attempts to review the relevant literature on AIS etiology to examine the association of vitamin D and various current theories. Our review suggested that vitamin D deficiency is associated with several current etiological theories of AIS. We postulate that vitamin D deficiency and/or insufficiency affects AIS development by its effect on the regulation of fibrosis, postural control, and BMD. Subclinical deficiency of vitamin K2, a fat-soluble vitamin, is also prevalent in adolescents; therefore, it is possible that the high prevalence of vitamin D deficiency is related to decreased fat intake. Further studies are required to elucidate the possible role of vitamin D in the pathogenesis and clinical management of AIS.

Effects of cord blood vitamin D levels on the risk of neonatal sepsis in premature infants

  • Say, Birgul;Uras, Nurdan;Sahin, Suzan;Degirmencioglu, Halil;Oguz, Serife Suna;Canpolat, Fuat Emre
    • Korean Journal of 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.