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Vitamin Deficiencies – Diagnosis and Treatment
Published in Jennifer Doley, Mary J. Marian, Adult Malnutrition, 2023
Vitamin D refers to both ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3), which are either consumed in the diet or synthesized in the skin. Vitamin D must undergo two hydroxylations for activation. The first, which occurs in the liver, converts vitamin D to 25-hydroxyvitamin D, also known as calcidiol. The second hydroxylation occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D, also known as calcitriol.4
The dietary requirements of infants
Published in Claire Tuck, Complementary Feeding, 2022
Vitamin D exists in two forms: (1) vitamin D3 or cholecalciferol, which is produced in the skin from 7-dehydrocholesterol by the action of sunlight, and (2) vitamin D2 (ergocalciferol), which is produced by some plants such as fungi and is less bioavailable than vitamin D3. The main factors affecting an infant’s vitamin D status are maternal vitamin D status during pregnancy and the infant’s exposure to ultraviolet radiation; ultraviolet exposure is often low.4The RNI for vitamin D is 8.5 μg per day for infants between 4 and 6 months and 7 μg per day for infants aged 7–12 months.4
Role of Vitamin D and Antioxidants in the Prevention and Treatment of Alzheimer’s Disease
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
Shilia Jacob Kurian, Ruby Benson, Sonal Sekhar Miraj, Mahadev Rao
Vitamin D is fat-soluble secosteroid (steroids with broken ring) with roles not limited to the musculoskeletal system. Its functions extend to metabolic signaling, immunity, and prevention or treatment of cardiovascular disease, autoimmune and inflammatory conditions, and neoplasms (Cherniack and Troen 2016; Japelt and Jakobsen 2013). The two forms of vitamin D are “ergocalciferol” (vitamin D2) and “cholecalciferol” (vitamin D3), which are obtained primarily from plant sources and animal sources, respectively (Umar et al. 2018; Summers et al. 2018). Both of these forms are being used as supplements (Bikle 2018). In the presence of sunlight, ergosterol and 7-dehydrocholesterol (provitamin forms) result in the synthesis of ergocalciferol and cholecalciferol, respectively (Japelt and Jakobsen 2013).
Vitamin D and COVID-19: where are we now?
Published in Postgraduate Medicine, 2023
Victoria Contreras-Bolívar, Beatriz García-Fontana, Cristina García-Fontana, Manuel Muñoz-Torres
An update was published by the National Institute for Health and Care Excellence (NICE): ‘COVID-19 rapid guideline: vitamin D’ that recommended vitamin D supplementation for people in confined spaces, those living in residences, with low sun exposure, or spending more time at home due to the COVID-19 pandemic [124]. The recommended dose is 400 IU/day of cholecalciferol. The recommended period is between October and March (indicated all year round for people without sun exposure during spring and summer). The objective proposed by the authors was to achieve levels of 25(OH)D3 > 10 ng/mL to maintain optimal bone health. The authors indicated that low 25(OH)D3 levels are associated with more severe COVID-19 outcomes. However, they also cautioned that vitamin D supplementation should not be administered solely for the purpose of preventing or treating COVID-19, as clinical trials are necessary to give this recommendation. The US National Academy of Medicine and the European Food Safety Authority recommend achieving 25(OH)D3 levels at least 20 ng/mL. For this purpose, it was indicated that supplementation should be done at 800 IU/day. In addition, in the case of hospital admissions, it is recommended that 25(OH)D3 levels be determined on admission [125].
Cholecalciferol complexation with hydroxypropyl-β-cyclodextrin (HPBCD) and its molecular dynamics simulation
Published in Pharmaceutical Development and Technology, 2022
Fang Wang, Wenbo Yu, Carmen Popescu, Ahmed Ashour Ibrahim, Dongyue Yu, Ryan Pearson, Alexander D. MacKerell, Stephen W. Hoag
Cholecalciferol (vitamin D3) is an essential vitamins, and plays important roles in maintaining human health; for example, it is one of the primary biological regulators of calcium homeostasis (Norman 2008). Cholecalciferol is inactive in our body. It is converted to its active form 25-hydroxycholecalciferol (calcifediol, 25-OH vitamin D3) in the liver, then converted to 1,25-dihydroxycholecalciferol (calcitriol, 1,25-(OH)2vitamin D3) in the kidney. Calcitriol is a steroid hormone and functions by interacting with its cognate vitamin D receptor (VDR) (Feldman et al. 2004; Norman 2008). We know that calcitriol and VDR significantly contribute to good bone health (Vitamin D Fact Sheet for Health Professionals 2021). Thus, vitamin D3 is widely used in the prevention and treatment of diseases such as rickets (Stuart et al. 2009; Joint Formulary Committee 2015), osteomalacia, osteoporosis and hypoparathyroidism (HSDB: Cholecalciferol 2022), and Fanconi syndrome (Stuart et al. 2009; Hamilton 2015). In addition to metabolic disorders, recent evidence suggests that vitamin D3 may have a role in colon cancer, prostate cancer, and breast cancer prevention (HSDB: Cholecalciferol 2022). Vitamin D3 is a fat-soluble vitamin which is practically insoluble in water (1.3 × 10−5 mg/L, 25 °C) (Estimation Program Interface (EPI) Suite 2004), and orally delivered. There is no intramuscular (IM) or intravenous (IV) injection available (Stuart et al. 2009).
Parathormone, bone alkaline phosphatase and 25-hydroxyvitamin D status in a large cohort of 1200 children and teenagers
Published in Acta Clinica Belgica, 2022
Aurélie Ladang, Olivier Rousselle, Loreen Huyghebaert, Anne-Catherine Bekaert, Stéphanie Kovacs, Caroline Le Goff, Etienne Cavalier
Among the factors responsible for impaired skeletal growth, vitamin D deficiency is probably the most frequent [5]. Cholecalciferol is synthesized under the skin after sun exposure. A first hydroxylation in the liver produces 25-Hydroxyvitamin D (25(OH)D) followed by a second hydroxylation by 1-alpha-hydroxylase in the kidney to create the active form 1,25-dihydroxyvitamin D [3]. The dosage of 25(OH)D is commonly accepted as the best marker of vitamin D status although the optimum level of 25(OH)D is still under debate [5]. Some publications are also distinguishing individuals with severe hypovitaminosis D (25(OH)D < 12 ng/mL) who are at high risk of rickets, osteomalacia or fractures from those with mild hypovitaminosis D in whom impacts on bone density are less obvious [6]. Hypovitaminosis D has been largely described in both children and adults [7–10]. Decreased calcium levels due to low vitamin D lead to PTH secretion [3]. This secondary hyperparathyroidism driven by hypovitaminosis D has been described in adults as well as in children worldwide [8,11–17].