GENESIS OF VITAMIN D IN THE BODY BY ULTRAVIOLET IRRADIATION

1931 ◽  
Vol 97 (6) ◽  
pp. 392

1975 ◽  
Vol 13 (8) ◽  
pp. 29-31

Natural vitamin D (D3, cholecalciferol) reaches the body from animal sources in the diet and from endogenous skin synthesis by the action of solar ultraviolet irradiation. Vitamin D2 (ergocalciferol) is used for fortifying proprietary foods such as margarine (and milk in the USA and Canada). These compounds have equal potency in man. A regular intake of 2.5 micrograms (100 i.u.) daily for adults and about 10 micrograms (400 i.u.) daily for children under 5 years old is usually recommended to prevent nutritional osteomalacia and rickets.



2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
Suaad Muhssen Ghazi ◽  
Fatin Shallal Farhan

Vitamin D deficiency is common in women with polycystic ovarian syndrome. Vitamin D plays an important physiologic role in reproductive functions of ovarian follicular development and luteinization through altering anti-müllerian hormone signaling, follicular stimulating hormone activity and progesterone production in human granulose cells. Vitamin D is precipitated in adipose fat tissues, making it notable to be used for the body as a result; obese people with high body mass index are already highly expected to have low levels of serum vitamin D.



Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1408
Author(s):  
Hermann Brenner ◽  
Sabine Kuznia ◽  
Clarissa Laetsch ◽  
Tobias Niedermaier ◽  
Ben Schöttker

Meta-analyses of randomized controlled trials (RCTs) have demonstrated a protective effect of vitamin D3 (cholecalciferol) supplementation against cancer mortality. In the VITAL study, a RCT including 25,871 men ≥ 50 years and women ≥ 55 years, protective effects of vitamin D3 supplementation (2000 IU/day over a median of 5.3 years) with respect to incidence of any cancer and of advanced cancer (metastatic cancer or cancer death) were seen for normal-weight participants but not for overweight or obese participants. We aimed to explore potential reasons for this apparent variation of vitamin D effects by body mass index. We conducted complementary analyses of published data from the VITAL study on the association of body weight with cancer outcomes, stratified by vitamin D3 supplementation. Significantly increased risks of any cancer and of advanced cancer were seen among normal-weight participants compared to obese participants in the control group (relative risk (RR), 1.27; 95% confidence interval (CI), 1.07–1.52, and RR, 1.44; 95% CI, 1.04–1.97, respectively). No such patterns were seen in the intervention group. Among those with incident cancer, vitamin D3 supplementation was associated with a significantly reduced risk of advanced cancer (RR, 0.86; 95% CI, 0.74–0.99). The observed patterns point to pre-diagnostic weight loss of cancer patients and preventive effects of vitamin D3 supplementation from cancer progression as plausible explanations for the body mass index (BMI)—intervention interactions. Further research, including RCTs more comprehensively exploring the potential of adjuvant vitamin D therapy for cancer patients, should be pursued with priority.



Author(s):  
Maryam Mosavat ◽  
Aisling Smyth ◽  
Diana Arabiat ◽  
Lisa Whitehead

AbstractVitamin D contributes to numerous physiological processes within the body but primarily calcium and bone homeostasis. Emerging evidence highlights a novel role for vitamin D in maintaining and regulating optimal sleep. Sleep is a known regulator of bone health, highlighting the interconnectedness between vitamin D concentrations, sleep duration and bone metabolism. It is possible that the relationship between sleep length and vitamin D is bidirectional, with vitamin D playing a role in sleep health and conversely, sleep affecting vitamin D levels. Nevertheless, limited information on the direction of the interaction is available, and much remains to be learned concerning the complex relationship between insufficient sleep duration and vitamin D deficiency. Given the potential to implement interventions to improve sleep and vitamin D supplementation, understanding this relationship further could represent a novel way to support and improve health.



2021 ◽  
Vol 22 (10) ◽  
pp. 5251
Author(s):  
Ming-Yieh Peng ◽  
Wen-Chih Liu ◽  
Jing-Quan Zheng ◽  
Chien-Lin Lu ◽  
Yi-Chou Hou ◽  
...  

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is still an ongoing global health crisis. Immediately after the inhalation of SARS-CoV-2 viral particles, alveolar type II epithelial cells harbor and initiate local innate immunity. These particles can infect circulating macrophages, which then present the coronavirus antigens to T cells. Subsequently, the activation and differentiation of various types of T cells, as well as uncontrollable cytokine release (also known as cytokine storms), result in tissue destruction and amplification of the immune response. Vitamin D enhances the innate immunity required for combating COVID-19 by activating toll-like receptor 2. It also enhances antimicrobial peptide synthesis, such as through the promotion of the expression and secretion of cathelicidin and β-defensin; promotes autophagy through autophagosome formation; and increases the synthesis of lysosomal degradation enzymes within macrophages. Regarding adaptive immunity, vitamin D enhances CD4+ T cells, suppresses T helper 17 cells, and promotes the production of virus-specific antibodies by activating T cell-dependent B cells. Moreover, vitamin D attenuates the release of pro-inflammatory cytokines by CD4+ T cells through nuclear factor κB signaling, thereby inhibiting the development of a cytokine storm. SARS-CoV-2 enters cells after its spike proteins are bound to angiotensin-converting enzyme 2 (ACE2) receptors. Vitamin D increases the bioavailability and expression of ACE2, which may be responsible for trapping and inactivating the virus. Activation of the renin–angiotensin–aldosterone system (RAS) is responsible for tissue destruction, inflammation, and organ failure related to SARS-CoV-2. Vitamin D inhibits renin expression and serves as a negative RAS regulator. In conclusion, vitamin D defends the body against SARS-CoV-2 through a novel complex mechanism that operates through interactions between the activation of both innate and adaptive immunity, ACE2 expression, and inhibition of the RAS system. Multiple observation studies have shown that serum concentrations of 25 hydroxyvitamin D are inversely correlated with the incidence or severity of COVID-19. The evidence gathered thus far, generally meets Hill’s causality criteria in a biological system, although experimental verification is not sufficient. We speculated that adequate vitamin D supplementation may be essential for mitigating the progression and severity of COVID-19. Future studies are warranted to determine the dosage and effectiveness of vitamin D supplementation among different populations of individuals with COVID-19.



Author(s):  
Matthew F Warren ◽  
Kimberly A Livingston

Abstract The risk of vitamin D insufficiency in humans is a global problem that requires improving ways to increase vitamin D intake. Supplements are a primary means for increasing vitamin D intake, but without a clear consensus on what constitutes vitamin D sufficiency, there is toxicity risk with taking supplements. Chickens have been used in many vitamin D-related research studies, especially studies involving vitamin D supplementation. Our state-of-the-art review evaluates vitamin D metabolism and how the different hydroxylated forms are synthesized. We provide an overview with how vitamin D is absorbed, transported, excreted, and what tissues in the body store vitamin D metabolites. We also discuss a number of studies involving vitamin D supplementation with broilers and laying hens. Vitamin D deficiency and toxicity are also described and how they can be caused. The vitamin D receptor (VDR) is important for vitamin D metabolism. However, there is much more that can be understood with VDR in chickens. Potential research aims involving vitamin D and chickens should explore VDR mechanisms which could lead to newer insights with VDR. Utilizing chickens in future research to help with elucidating vitamin D mechanisms has great potential to advance human nutrition. Finding ways to increase vitamin D intake will be necessary because the coronavirus 2019 disease (COVID-19) pandemic is leading to increased risk of vitamin D deficiency in many populations. Chickens can provide a dual purpose with addressing pandemic-caused vitamin D deficiency: 1) vitamin D supplementation gives chickens added value with possibly leading to vitamin D-enriched meat and egg products; and 2) chickens’ use in research provides data for translational research. Expanding vitamin D-related research in chickens to include more nutritional aims in vitamin D status has great implications with developing better strategies to improve human health.



Author(s):  
Marius Baranauskas ◽  
Valerija Jablonskienė ◽  
Jonas Algis Abaravičius ◽  
Rimantas Stukas

There are about 466 million people with hearing impairments in the world. The scientific literature does not provide sufficient data on the actual nutrition and other variables of professional deaf athletes. The objectives of this study were to investigate and evaluate the body composition, the physical working capacity, the nutrition intake, and the blood parameters of iron and vitamin D in the Lithuanian high-performance deaf women’s basketball team players. The female athletes (n = 14) of the Lithuanian deaf basketball team aged 26.4 ± 4.5 years were recruited for an observational cross-sectional study. A 7-day food recall survey method was used to investigate their actual diet. The measurements of the body composition were performed using the BIA (bioelectrical impedance analysis) tetra-polar electrodes. In order to assess the cardiorespiratory and aerobic fitness levels of athletes, ergo-spirometry (on a cycle ergometer) was used to measure the peak oxygen uptake (VO2peak) and the physical working capacity at a heart rate of 170 beats per minute (PWC170). The athletes’ blood tests were taken to investigate the red blood cells, hemoglobin, 25-hydroxyvitamin D, ferritin, transferrin, iron concentrations, and total iron-binding capacity (TIBC). The consideration of the VO2peak (55.9 ± 6.1 mL/min/kg of body weight, 95% CI: 51.8, 58.9) and the low VO2peak (56–60 mL/min/kg of body weight) (p = 0.966) in the deaf women’s basketball team players revealed no differences. For the deaf female athletes, the PWC170 was equal to 20.3 ± 2.0 kgm/min/kg of body weight and represented only the average aerobic fitness level. The carbohydrate and protein intakes (5.0 ± 1.3 and 1.3 ± 0.3 g/kg of body weight, respectively) met only the minimum levels recommended for athletes. The fat content of the diet (38.1 ± 4.1% of energy intake) exceeded the maximum recommended content (35% of energy intake) (p = 0.012). The mean blood serum concentrations of 25(OH)D and ferritin (24.1 ± 6.6 nmol/L and 11.0 ± 4.1 µg/L, respectively) predicted vitamin D and iron deficits in athletes. Female athletes had an increased risk of vitamin D and iron deficiencies. Regardless of iron deficiency in the body, the better cardiorespiratory fitness of the deaf female athletes was essentially correlated with the higher skeletal muscle mass (in terms of size) (r = 0.61, p = 0.023), the lower percentage of body fat mass (r = −0.53, p = 0.049), and the reduced intake of fat (r = −0.57, p = 0.040).



Author(s):  
Katarzyna Zadka ◽  
Ewelina Pałkowska-Goździk ◽  
Danuta Rosołowska-Huszcz

The percentage of children with vitamin D deficiency in Poland is alarming. The aim of the study was to assess the knowledge about sources of food and the function of vitamin D, as well as the frequency of its supplementation. A survey was conducted among the parents of children from Central Poland attending primary schools, and a questionnaire containing mainly open-ended questions was used to collect the data. Most mothers knew at least one of the functions of vitamin D in the body but had a low level of knowledge about its dietary sources. Only a small group of respondents supplemented themselves and their children with vitamin D. Statistically significant influences on the level of knowledge about the functions and sources of vitamin D were place of residence (i.e., better knowledge in the countryside) and mothers’ level of education (i.e., the better educated, the greater knowledge). In the case of monthly income level, such impact was observed only in relation to the knowledge of vitamin D functions. Concerning the frequency of supplementation, only maternal level of education had a statistically significant effect (i.e., the higher the education level, the higher the frequency of supplementation). In addition, mothers who were aware of functions of vitamin D and nutritional sources, significantly more frequently supplemented vitamin D.



2021 ◽  
Vol 100 (3) ◽  
pp. 295-300
Author(s):  
N.B. Gomboeva ◽  
◽  
E.I. Grigoryeva ◽  

The proven relationship between the frequency of influenza and acute respiratory infections in children with vitamin D deficiency and the data on the relationship between a high mortality rate from SARS-CoV-2 in patients with low levels of vitamin D in the body under conditions of a forced sharp decrease in the level of insolation in the period from March 11, 2020 dictated the relevance assessing the vitamin D supply of children and adolescents in educational organizations of the city of Ulan-Ude. Purpose of the study: to assess the vitamin D supply of children and adolescents living in the city of Ulan-Ude. Methods: in a non-randomized, single-center, transverse (one-stage) uncontrolled comparative study, the concentration of 25(OH) vitamin D – 25(OH)D – in the blood serum of children and adolescents in Ulan-Ude was studied from May 22 to May 24, 2020. Moderate vitamin D deficiency (deficiency) was determined when the content of 25(OH)D was in the range of 20–30 ng/ml, the deficiency was within the limits, and the severe deficiency was <10 ng/ml. Results: assessment of vitamin D provision was carried out in 60 children aged 10 to 17 years (15 [11; 16] years), of which 19 boys, 41 girls. Children were divided into 2 groups depending on age: 10–11 years old (grade 5) (n=27) and 15–17 years old (grades 9–11) (n=33). Deficiency of vitamin D was found in 4 (15%), 11 (33%); deficit – in 19 (70%), 18 (55%); severe deficiency – in 2 (7%), 4 (12%), respectively. Along with low indicators of the provision of children and adolescents in the city of Ulan-Ude, an even lower provision of children and adolescents of Buryats was noted. The concentration of vitamin D in Buryat children and adolescents below normal (less than 30 ng/ml) was found in 35 (100%) children and adolescents, deficiency – in 8 (23%) children, vitamin D deficiency – in 21 (60%) children and severe deficiency – in 6 (17%). A statistically significant difference in the content of 25(OH)D between children and adolescents of Russian nationality and Buryats was revealed (p=0,0056). Evaluation of the diet showed that the frequency of consumption of fish as a source of vitamin D by children and adolescents is low. Conclusion: there is a high incidence of vitamin D deficiency and deficiency, which amounted to 97% in the examined children and adolescents living in the city of Ulan-Ude, more pronounced in Buryat children and adolescents, which requires organizational measures to replenish the vitamin D deficiency.



2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Samuel Asamoah Sakyi ◽  
Maxwell Hubert Antwi ◽  
Linda Ahenkorah Fondjo ◽  
Edwin Ferguson Laing ◽  
Richard K. Dadzie Ephraim ◽  
...  

Background. Vitamin D is a steroid hormone important for the normal functioning of the body. It is produced through skin exposure to sunlight and from the diet. Although Ghana is located in the tropics where sunlight is abundant, factors like culture, diet, skin pigmentation, variation in the ozone layer, and geographical area influence the optimization of vitamin D concentration. It is imperative to evaluate the interplay between sunshine exposure, proinflammatory cytokines, and mediators of vitamin D metabolism and their relationship to vitamin D status in three geographical sections among apparent healthy Ghanaians. Methods and Results. In a cross-sectional study, a total of five hundred (500) healthy blood donors from three geographical areas in Ghana were enrolled. Their age ranged from 17 to 55 years with a mean age of 27.97 ± 8.87 years. The overall prevalence rate of vitamin D deficiency was 43.6% (218/500), with 41.2% (91/221), 45.3% (63/139), and 45.7% (64/140) of vitamin D deficiency being recorded in participants from the Northern Sector (NS), Middle Belt (MB), and Southern Sector (SS), respectively. However, there were no significant differences in the proportions of vitamin D deficiency across various geographical sectors. The median 25-hydroxyvitamin D serum levels were compared among geographical areas (NS, MB, and SS) and there were no significant differences ( P = 0.275 ) after adjusting for confounding factors. 25-Hydroxyvitamin D correlated positively with corrected ionized calcium (rs = 0.622, P ≤ 0.001 ) and phosphorus (rs = 0.299, P ≤ 0.001 ) and negatively correlated with SBP (rs = −0.092, P = 0.039 ), vitamin D binding protein (VDBP) (rs = −0.421, P ≤ 0.001 ), intact parathyroid hormone (iPTH) (rs = −0.0568, rs ≤ 0.001), IFN-gamma (rs = −0.684, P ≤ 0.001 ), and TNF-alpha (rs = −0.600, P ≤ 0.001 ). After adjusting for possible confounders, not having knowledge about vitamin D foods, taking fewer vitamin D foods, and higher levels of IF-γ and IL-10 were associated with a higher risk of having vitamin D deficiency. Conclusion. The prevalence of 25-hydroxyvitamin D deficiency is high among the general adult population in Ghana despite the abundance of sunlight. Increasing knowledge on vitamin D diet coupled with a daily intake of vitamin D dietary supplements is likely to reduce the risk of developing 25-hydroxyvitamin D deficiency.



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