High-Dose Cholecalciferol Booster Therapy is Associated with a Reduced Risk of Mortality in Patients with COVID-19: A Cross-Sectional Multi-Centre Observational Study

The worldwide pandemic of 2019 novel coronavirus disease (COVID-19) has posed the most substantial and severe public health issue for several generations, and therapeutic options have not yet been optimised. Vitamin D (in its “parent” form, cholecalciferol) has been proposed in the pharmacological management of COVID-19 by various sources. We aimed to determine whether COVID-19 mortality was affected by serum 25-hydroxyvitamin D (25(OH)D) levels, vitamin D status, or cholecalciferol therapy, and to elucidate any other predictors of COVID-19 mortality. Patients hospitalised with COVID-19 were opportunistically recruited from three UK hospitals, and their data were collected retrospectively. Logistic regression was used to determine any relationships between COVID-19 mortality and potential predictors, including 25(OH)D levels and cholecalciferol booster therapy. A total of 986 participants with COVID-19 were studied, of whom 151 (16.0%) received cholecalciferol booster therapy. In the primary cohort of 444 patients, cholecalciferol booster therapy was associated with a reduced risk of COVID-19 mortality, following adjustment for potential confounders (OR_adj 0.13, 95% CI 0.05–0.35, p < 0.001). This finding was replicated in a validation cohort of 541 patients (OR_adj 0.38, 95% CI 0.17–0.84, p = 0.018). In this observational study, treatment with cholecalciferol booster therapy, regardless of baseline serum 25(OH)D levels, appears to be associated with a reduced risk of mortality in acute in-patients admitted with COVID-19. Further work with large population studies needs to be carried out to determine adequate serum 25(OH)D levels, as well as multi-dose clinical trials of cholecalciferol therapy to assess maximum efficacy.     

Fasting and Exercise Induce Changes in Serum Vitamin D Metabolites in Healthy Men

Background: Vitamin D plays pleiotropic roles in the body and hence, changes in its metabolism and distribution during starvation could play an important role in the adaptive response to famine. We aimed to identify the responses of some vitamin D metabolites to 8 d of fasting and exercise. Methods: A repeated-measures design was implemented, in which 14 male volunteers fasted for 8 d and performed an exercise test before and after fasting. Serum samples were collected on day 1 after night fasting and after 8 d of complete food restriction, before and 1 h and 3 h after exercise. Results: After 8 d of fasting, compared with baseline values, serum 24,25(OH)₂D₃ and 3-epi-25(OH)D₃ levels significantly increased; those of 25(OH)D₃ and 1,25(OH)₂D₃ were unaffected; and those of 25(OH)D₂ decreased. Exercise on the first day of fasting induced an increase in serum 3-epi-25(OH)D₃ levels, while exercise performed after 8 d of fasting induced an increase in 25(OH)D₃, 24,25(OH)₂D₃, 25(OH)D₂, and 3-epi-25(OH)D₃ levels. Conclusion: Increases in 24,25(OH)₂D₃ and 3-epi-25(OH)D₃ levels imply that fasting stimulates vitamin D metabolism. The effects of exercise on serum vitamin D metabolites, which are most pronounced after fasting and in subjects with serum 25(OH)D₃ above 25 ng/mL, support the notion that fasting and exercise augment vitamin D metabolism.     

Food fortification and biofortification as potential strategies for prevention of vitamin D deficiency

Hypovitaminosis D (vitamin D deficiency) is widespread throughout the world. The cutaneous production of vitamin D through sunlight can be limited by several factors (e.g. skin pigmentation, sunscreen usage and, increasingly, indoor lifestyle). Thus, diet has become an important strategy to increase vitamin D intake and status {blood 25‐hydroxyvitamin D [25(OH)D]}. However, there are a limited number of foods that naturally contain vitamin D, and concentrations can vary significantly between and within species. The need for vitamin D‐fortified foods (including via direct fortification and biofortification) to support the adequacy of vitamin D status is a corollary of several limitations to synthesise vitamin D from sunlight. Ergocalciferol (vitamin D₂) and cholecalciferol (vitamin D₃) can be found in some mushrooms and animal‐derived foods, respectively. Evidence has shown vitamin D₃ is more effective than vitamin D₂ at raising 25(OH)D blood concentrations. The vitamin D metabolite, 25(OH)D_3, is present in animal‐derived foods (e.g. meat, eggs and fish), and several intervention trials have shown 25(OH)D₃ to be more effective at raising blood 25(OH)D concentrations than vitamin D₃. In addition, 25(OH)D₃ supplements may prove to be preferable to vitamin D₃ for patients with certain clinical conditions. However, there is limited evidence on the effects of 25(OH)D₃‐fortified foods on human vitamin D status and health, both in the general population and patients with certain conditions, and long‐term randomised controlled trials are needed in this area.     

Single high-dose vitamin D at birth corrects vitamin D deficiency in infants in Mexico

Abstract

This study examined the prevalence of vitamin D deficiency in mothers and infants in Tijuana, Mexico and determined the effect of a single oral dose of 50?000?IU vitamin D₃ at birth on 25-hydroxyvitamin D (25[OH]D) levels during infancy. Healthy infants were randomized to receive vitamin D₃ or placebo at birth. At birth 23% of infants were vitamin D deficient and 77% had vitamin D insufficiency (mean 25[OH]D level 18.9?ng/ml); 10% of mothers were vitamin D deficient and 61% were insufficient. Infants receiving vitamin D₃ had higher 25(OH)D levels at two months (N?=?29; 33.9 versus 24.2?ng/ml) and six months (N?=?21; 36.5 versus 27.4?ng/ml). Exclusively breastfed infants had lower 25(OH)D levels at two months (14.9 versus 33.4?ng/ml). Vitamin D deficiency is common in infants and mothers in Tijuana, Mexico. A single dose of vitamin D₃ at birth was safe and significantly increased 25(OH)D levels during infancy.     

Relationship of very low serum 25-hydroxyvitamin D<Subscript>3</Subscript> levels with long-term survival in a large cohort of colorectal cancer patients from Germany

To investigate the association of serum 25-hydroxyvitamin D (25(OH)D₃) with survival in a large prospective cohort study of colorectal cancer (CRC) patients. The study population consisted of 2,910 patients diagnosed with CRC between 2003 and 2010 who participated in the DACHS study, a multicenter study from Germany with comprehensive long-term follow-up. 25(OH)D₃ was determined in serum samples collected shortly after cancer diagnosis by High Performance Liquid Chromatography-Electro Spray Ionization-Mass Spectrometry. Analyses of survival outcomes were performed using Cox regression with comprehensive adjustment for relevant confounders. The majority (59%) of CRC patients were vitamin D deficient (serum 25(OH)D₃ levels <30 nmol/L). During a median follow-up of 4.8 years, 787 deaths occurred, 573 of which were due to CRC. Compared to patients in the highest 25(OH)D₃ quintile (>45.20 nmol/L), those in the lowest 25(OH)D₃ quintile (<11.83 nmol/L) had a strongly increased mortality. Adjusted hazard ratios (95% Confidence Interval) were 1.78 (1.39–2.27), 1.65 (1.24–2.21), 1.32 (1.03–1.71) and 1.48 (1.18–1.85) for all-cause mortality, CRC-specific mortality, recurrence-free and disease-free survival, respectively. Subgroup analyses did not show any significant effect modification across strata defined by sex, age, stage, body mass index, or the late entry. Dose–response analyses showed a strong inverse relationship between serum 25(OH)D₃ levels and survival endpoints at 25(OH)D₃ levels <30 nmol/L, and no association with mortality at higher 25(OH)D₃ levels. Vitamin D deficiency is highly prevalent in CRC patients and a strong independent predictor of poor prognosis. The possibility of enhancing CRC prognosis by vitamin D supplementation, ideally combined with outdoor physical activity, should be evaluated by randomized controlled trials focusing on patients with vitamin D deficiency.     

Abstracts on Calcium and Bone Metabolism

Objective: Vitamin D supplementation may be required for certain subgroups in the United States in whom status and intake are inadequate, but the impact of various doses, and whether calcium administration jointly or independently influences vitamin D metabolite levels, is unclear.

Methods: In a pilot chemoprevention trial of biomarkers of risk for colorectal adenoma, we measured the impact of vitamin D supplementation and/or calcium supplementation on plasma vitamin D metabolite concentrations. Ninety-two adult men and women living in the southeastern United States were randomized to 800 IU vitamin D₃, 2000 mg elemental calcium, both, or placebo daily for 6 months. We examined vitamin D status at baseline and postintervention and compared the change in plasma 25-hydroxyvitamin D (25(OH)D) and 1,25(OH)₂D levels by intervention group using general linear models.

Results: Eighty-two percent of the study population had insufficient plasma 25(OH)D concentrations (<75 nmol/L) at baseline, with the lowest levels observed among African American participants. Vitamin D supplements, with or without calcium supplementation, raised plasma 25(OH)D concentrations, on average, by 25 to 26 nmol/L. Half of the study participants were classified as having sufficient 25(OH)D status after 6 months of 800 IU of vitamin D₃ daily. Calcium alone did not influence 25(OH)D concentrations.

Conclusion: In this southeastern U.S. population, half of the study participants receiving 800 IU vitamin D₃ daily had blood 25(OH)D concentrations of ≤75 nmol/L after a 6-month intervention period, supporting higher vitamin D dose requirements estimated by some groups. More research is needed to identify the optimal vitamin D dose to improve 25(OH)D status in various at-risk populations.     

Serum Vitamin D Affected Type 2 Diabetes though Altering Lipid Profile and Modified the Effects of Testosterone on Diabetes Status

Numerous studies have investigated the associations between serum vitamin D or testosterone and diabetes; however, inconsistencies are observed. Whether there is an interaction between vitamin D and testosterone and whether the lipid profile (total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)) mediates the association between vitamin D and diabetes is unclear. To investigate the effect of vitamin D and testosterone on impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM), 2659 participants from the Henan Rural Cohort were included in the case-control study. Generalized linear models were utilized to estimate associations of vitamin D with IFG or T2DM and interactive effects of vitamin D and testosterone on IFG or T2DM. Principal component analysis (PCA) and mediation analysis were used to estimate whether the lipid profile mediated the association of vitamin D with IFG or T2DM. Serum 25(OH)D₃, 25(OH)D₂, and total 25(OH)D levels were negatively correlated with IFG (odds ratios (ORs) (95% confidence intervals (CIs)): 0.99 (0.97, 1.00), 0.85 (0.82, 0.88), and 0.97 (0.96, 0.98), respectively). Similarity results for associations between serum 25(OH)D₂ and total 25(OH)D with T2DM (ORs (95%CIs): 0.84 (0.81, 0.88) and 0.97 (0.96, 0.99)) were observed, whereas serum 25(OH)D₃ was negatively correlated to T2DM only in the quartile 2 (Q2) and Q3 groups (both p < 0.05). The lipid profile, mainly TC and TG, partly mediated the relationship between 25(OH)D₂ or total 25(OH)D and IFG or T2DM and the proportion explained was from 2.74 to 17.46%. Furthermore, interactive effects of serum 25(OH)D₂, total 25(OH)D, and testosterone on T2DM were observed in females (both p for interactive <0.05), implying that the positive association between serum testosterone and T2DM was vanished when 25(OH)D₂ was higher than 10.04 ng/mL or total 25(OH)D was higher than 40.04 ng/mL. Therefore, ensuring adequate vitamin D levels could reduce the prevalence of IFG and T2DM, especially in females with high levels of testosterone.     

Vitamin D Metabolites and Clinical Outcome in Hospitalized COVID-19 Patients

(1) Background: Vitamin D, a well-established regulator of calcium and phosphate metabolism, also has immune-modulatory functions. An uncontrolled immune response and cytokine storm are tightly linked to fatal courses of COVID-19. The present retrospective study aimed to inves-tigate vitamin D status markers and vitamin D degradation products in a mixed cohort of 148 hospitalized COVID-19 patients with various clinical courses of COVID-19. (2) Methods: The serum concentrations of 25(OH)D₃, 25(OH)D₂, 24,25(OH)₂D₃, and 25,26(OH)₂D₃ were determined by a validated liquid-chromatography tandem mass-spectrometry method in leftover serum samples from 148 COVID-19 patients that were admitted to the University Hospital of the Medical Uni-versity of Graz between April and November 2020. Anthropometric and clinical data, as well as outcomes were obtained from the laboratory and hospital information systems. (3) Results: From the 148 patients, 34 (23%) died within 30 days after admission. The frequency of fatal outcomes did not differ between males and females. Non-survivors were significantly older than survivors, had higher peak concentrations of IL-6 and CRP, and required mechanical ventilation more frequently. The serum concentrations of all vitamin D metabolites and the vitamin D metabolite ratio (VMR) did not differ significantly between survivors and non-survivors. Additionally, the need for res-piratory support was unrelated to the serum concentrations of 25(OH)D vitamin D and the two vitamin D catabolites, as well as the VMR. (4) Conclusion: The present results do not support a relevant role of vitamin D for the course and outcome of COVID-19.     

Prevalence and Correlates of Vitamin D Deficiency among Young South African Infants: A Birth Cohort Study

Early-life vitamin D deficiency is associated with adverse child health outcomes, but the prevalence of vitamin D deficiency and its correlates in infants remains underexplored, particularly in sub-Saharan Africa. We aimed to investigate the prevalence of vitamin D deficiency and its correlates among young infants in South Africa. This study included 744 infants, aged 6–10 weeks from the Drakenstein Child Health Study, a population-based birth cohort. Infants were categorized into distinct categories based on serum 25(OH)D concentration level including deficient (<50 nmol/L), insufficient (50–74 nmol/L), and sufficient (≥75 nmol/L). Using multivariable Tobit and logistic regression models, we examined the correlates of serum 25(OH)D₃ levels. The overall prevalence of vitamin D deficiency was 81% (95% confidence intervals (CI]) 78–83). Multivariable regression analysis showed that serum 25(OH)D₃ concentration was independently associated with study site, socioeconomic status, and sex. Birth in winter and breastfeeding were the strongest predictors of lower serum 25(OH)D₃ concentration levels. Compared to non-breastfed children, children breastfed were at higher risk of vitamin D deficiency (AOR, 1.96; 95% CI, 1.04–3.67) and breastfeeding for more than one month was associated with greater likelihood of vitamin D deficiency (AOR, 5.40; 95% CI, 2.37–12.32) and lower vitamin D concentrations (−16.22 nmol/L; 95% CI, −21.06, −11.39). Vitamin D deficiency in infants is ubiquitous, under-recognised, and strongly associated with season of birth and breastfeeding in this setting. Nutritional interventions with vitamin D supplementation in national health programs in low- and middle-income countries are urgently needed to improve early-life vitamin D status in infants.     

Dietary vitamin D intake is not associated with 25-hydroxyvitamin D3 or parathyroid hormone in elderly subjects,whereas the calcium-to-phosphate ratio affects parathyroid hormone

This cross-sectional study investigates whether serum 25-hydroxyvitamin D₃ [25(OH)D₃] and intact parathyroid hormone (iPTH) are affected by vitamin D, calcium, or phosphate intake in 140 independently living elderly subjects from Germany (99 women and 41 men; age, 66-96 years). We hypothesized that habitual dietary intakes of vitamin D, calcium, and phosphate are not associated with 25(OH)D₃ or iPTH and that body mass index confounds these associations. Serum 25(OH)D₃ and iPTH were measured by an electrochemiluminescence immunoassay. Dietary intake was determined using a 3-day estimated dietary record. The median dietary intake levels of vitamin D, calcium, and phosphate were 3 μg/d, 999 mg/d, and 1250 mg/d, respectively. Multiple regression analyses confirmed that dietary vitamin D and calcium did not affect 25(OH)D₃ or iPTH; however, supplemental intakes of vitamin D and calcium were associated with 25(OH)D₃ after adjustment for age, sex, body composition, sun exposure, physical activity, and smoking. In addition, phosphate intake and the calcium-to-phosphate ratio were associated with iPTH after multiple adjustments. In a subgroup analysis, calcium and vitamin D supplements, as well as phosphate intake, were associated with 25(OH)D₃ and/or iPTH in normal-weight subjects only. Our results indicate that habitual dietary vitamin D and calcium intakes have no independent effects on 25(OH)D₃ or iPTH in elderly subjects without vitamin D deficiency, whereas phosphate intake and the calcium-to-phosphate ratio affect iPTH. However, vitamin D and calcium supplements may increase 25(OH)D₃ and decrease iPTH, even during the summer, but the impact of supplements may depend on body mass index.     

Effects of Vitamin D3 and Calcium Supplementation on Serum Levels of Tocopherols,Retinol, and Specific Vitamin D Metabolites

γ-Tocopherol (γT) protects against DNA-damaging effects of nitrogen oxides, yet its physiologic regulation in vivo is unknown. Observational studies indicate inverse associations of 25[OH]-vitamin D with γT and leptin. To determine whether vitamin D₃ supplementation alters levels of lipid-soluble micronutrients, serum samples (N = 85 subjects) from a randomized, double-blind, placebo-controlled clinical trial of vitamin D₃ (800 IU) and calcium (2 g), alone and in combination, were analyzed for lipid micronutrients and specific vitamin D metabolites at baseline and after 6 mo of supplementation. Serum 25[OH]-vitaminD₃ levels increased 55% (P < 0.0001) and 48% (P = 0.0005), whereas 25[OH]-vitaminD₂ levels were lower by 48% (P = 0.26) and 21% (P = 0.36) in the vitamin D₃ and vitamin D₃ plus calcium groups, respectively. At baseline, γT levels were inversely associated with 25[OH]D (r = ?0.31, P = 0.004). With vitamin D₃ plus calcium treatment, serum α-tocopherol decreased 14% (P = 0.04), whereas similar changes in γT (19% lower, P = 0.14) were observed. No significant effects were observed for D₃ supplementation on leptin or retinol levels. These results are consistent with the hypothesis that vitamin D₃ ± calcium affects serum tocopherol and 25[OH]D₂ levels; however, studies using larger, more homogeneous populations are warranted.     

Low vitamin D status in preschool children in Greece

Vitamin D status in humans depends on the amount of sun exposure and vitamin D intake. Recent reports suggest that hypovitaminosis D (as defined by serum 25-hydroxyvitamin D [25(OH)D] <10 ng/mL) is reemerging in developed countries and in the Middle East, pointing out the significance of dietary and cultural practices. In the line of prevention, we determined vitamin D status in 393 healthy preschool children randomly selected from 7 day care centers in the Municipality of Athens in October. The data for the analysis were collected from a questionnaire regarding their actual dietary practices, voluntary sun exposure, and lifestyle conditions; clinical investigation for the determination of the skin phototype; and blood sampling for the determination of serum 25(OH)D, parathyroid hormone, and osteocalcin levels. Of the 393 children, 49 were immigrants. According to our results, 6.6% of our population had serum 25(OH)D less than 10 ng/mL. Multilinear analysis showed that the amount of sun exposure and vitamin D intake were the direct determinants of vitamin D status. Immigrant children presented lower serum 25(OH)D levels associated with lower vitamin D intake and lower socioeconomic class when compared with the Greek children. No relationship was found between 25(OH)D concentration and skin phototype, whereas 93.3% of children used topical sunscreen. We suggest that abundant sunlight exposure in Athens is not sufficient to prevent hypovitaminosis D in preschool children. The extensive use of topical sunscreens and environmental factors such as air pollution would account for inadequate sunlight exposure and the need for dietary intake of vitamin D.     

Determination of vitamin D3 and 25-hydroxyvitamin D3 in foodstuffs by HPLC UV-DAD and LC–MS/MS

In order to generate new data for vitamin D content for the Canadian Nutrient File, a method for the quantification of vitamin D₃ and 25(OH)D₃ in foodstuffs has been modified and improved. Vitamin D₃ was quantified using reverse phase liquid chromatography (LC) with UV-diode array detector (UV-DAD), while 25(OH)D₃ was measured by triple quadrupole mass spectrometry (APCI MS/MS). Quantification was by internal standards (IS) using vitamin D₂ and 25(OH)D₂. A Certified Reference Material (CRM-421 containing vitamin D₃) and a control sample (internally generated reference material of ground pork containing both vitamin D₃ and 25(OH)D₃) were used as validation and quality control tools. Limit of detection for both compounds was 0.04 μg/100 g. Accuracy for vitamin D in the CRM-421 was 99% (0.142 mg/kg for a target of 0.143, n = 10). Recovery of vitamin D₃ in ground pork was 97% (88% absolute recovery). For 25(OH)D₃, a recovery of 94% (73% absolute recovery) was obtained. Using this method, data for vitamin D₃ and 25(OH)D₃ content in a variety of foods (pork, beef, eggs, poultry, fish, and dinners) have been generated.     

Effects of sun exposure and dietary vitamin D intake on serum 25-hydroxyvitamin D status in hemodialysis patients

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 ± 5.8 ng/ml and 20.6 ± 11.8 pg/ml, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (≥ 30 ng/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.     

Vitamin D Status and Severity of Clostridium difficile Infections

Background: Clostridium difficile is the most common cause of nosocomial diarrhea, affecting up to 10% of hospitalized patients. Preliminary studies suggest an association between vitamin D status and C difficile infections (CDIs). Our goal was to investigate whether serum 25‐hydroxyvitamin D (25(OH)D) levels are associated with CDI severity. Methods: We prospectively enrolled patients diagnosed with CDI and divided them into 2 severity groups: group A (positive toxin A/B enzyme immunoassay only) and group B (positive toxin A/B enzyme immunoassay with abdominal computed tomography scan findings consistent with colitis). Serum 25(OH)D levels (25(OH)D₃, 25(OH)D₂, and total 25(OH)D) were measured on all patients after diagnosis of CDI. We performed multivariable logistic regression analyses to investigate the association between 25(OH)D levels and CDI severity, while adjusting for age, Deyo‐Charlson Comorbidity Index, recent hospitalization, and vitamin D supplementation. Results: One hundred patients were enrolled between July 2011 and February 2013. The mean (standard deviation) cohort age and Deyo‐Charlson Comorbidity Index were 62 (19) years and 4 (3), respectively; 54% of patients were male. Mean serum total 25(OH)D level was 22 (10) ng/mL. Mean 25(OH)D₃ level was significantly higher in group A (n = 71) than in group B (n = 29): 21 (1) vs 15 (2) ng/mL, respectively (P = .005). There was no observed difference in mean 25(OH)D₂ levels and total 25(OH)D levels between the 2 groups. Multivariable logistic regression analysis demonstrated an association between 25(OH)D₃ levels and CDI severity (adjusted odds ratio, 0.92; 95% confidence interval, 0.87–0.98). Conclusions: We found a significant inverse association between 25(OH)D₃ levels and CDI severity. Further studies are needed to determine whether vitamin D supplementation can improve outcomes in patients with CDI.     

Ultra-Marathon-Induced Increase in Serum Levels of Vitamin D Metabolites: A Double-Blind Randomized Controlled Trial

Purpose: While an increasing number of studies demonstrate the importance of vitamin D for athletic performance, the effects of any type of exercise on vitamin D metabolism are poorly characterized. We aimed to identify the responses of some vitamin D metabolites to ultra-marathon runs. Methods: A repeated-measures design was implemented, in which 27 amateur runners were assigned into two groups: those who received a single dose of vitamin D₃ (150,000 IU) 24 h before the start of the marathon (n = 13) and those (n = 14) who received a placebo. Blood samples were collected 24 h before, immediately after, and 24 h after the run. Results: In both groups of runners, serum 25(OH)D₃, 24,25(OH)₂D₃, and 3-epi-25(OH)D₃ levels significantly increased by 83%, 63%, and 182% after the ultra-marathon, respectively. The increase was most pronounced in the vitamin D group. Body mass and fat mass significantly decreased after the run in both groups. Conclusions: Ultra-marathon induces the mobilization of vitamin D into the blood. Furthermore, the 24,25(OH)₂D₃ and 3-epi-25(OH)D₃ increases imply that the exercise stimulates vitamin D metabolism.     

Vitamin D status among adults in the Aegean region of Turkey

Background  

Vitamin D is a lipid-soluble hormone found in certain foods and synthesized from precursors in the skin when exposed to ultraviolet light. Vitamin D plays a critical role in bone metabolism and many cellular and immunological processes and low levels have been associated with several chronic and infectious diseases. Vitamin D status is assessed by measuring the concentration of serum 25-hydroxyvitamin D [25(OH)D]. Vitamin D deficiency is reported to be common worldwide, but little has been reported about the vitamin D status of adults in Turkey. In this cross-sectional study, we determined the prevalence of 25(OH)D deficiency in adults residing in a city in the Aegean region of Turkey.     

Clinical Trial of Vitamin D2 vs D3 Supplementation in Critically Ill Pediatric Burn Patients

Background: Hypovitaminosis D exists postburn. However, evidence‐based guidelines for vitamin D repletion are unknown. This investigation examined differences between D₂ and D₃ supplementation on outcome in children with burn injuries. Methods: Fifty patients with total body surface area burn of 55.7% ± 2.6% and full‐thickness injury of 40.8% ± 3.8% were enrolled, ranging in age from 0.7–18.4 years. All participants received multivitamin supplementation per standardized clinical protocol. In addition, 100 IU/kg D₂, D₃, or placebo was administered daily during hospitalization using a randomized, double‐blinded study design. Assay of total 25‐hydroxyvitamin D (D25), 1,25‐dihydroxyvitamin D (D1,25), 25‐hydroxyvitamin D₂ (25‐OH‐D₂), 25‐hydroxyvitamin D₃ (25‐OH‐D₃), and parathyroid hormone (PTH) was performed at 4 preplanned time intervals (baseline, midpoint, discharge, and 1 year postburn). Differences in vitamin D status were compared over time and at each specific study interval. Results: There were no significant differences in serum vitamin D levels between groups, but >10% of patients had low D25 at discharge, and percent deficiency worsened by the 1‐year follow up for the placebo (75%), D₂ (56%), and D₃ (25%) groups. There were no statistical differences in PTH or clinical outcomes between treatment groups, although vitamin D supplementation demonstrated nonsignificant but clinically relevant decreases in exogenous insulin requirements, sepsis, and scar formation. Conclusions: The high incidence of low serum D25 levels 1 year following serious thermal injury indicates prolonged compromise. Continued treatment with vitamin D₃ beyond the acute phase postburn is recommended to counteract the trajectory of abnormal serum levels and associated morbidity.     

Differences in the Concentration of Vitamin D Metabolites in Plasma Due to the Low-Carbohydrate-High-Fat Diet and the Eastern European Diet—A Pilot Study

Vitamin D deficiency is a global problem with many health consequences, and it is currently recommended to supplement vitamin D. Change of diet should also be considered to ensure adequate vitamin D in the human body. The aim of this study was to assess the concentration of vitamin D metabolites in two different groups: one group on the low-carbohydrate-high-fat (LCHF) diet and the other group on the Eastern European (EE) diet. In the first stage, 817 participants declaring traditional EE diet or LCHF diet were investigated. Nutrition (self-reported 3-day estimated food record) and basic anthropometric parameters were assessed. After extra screening, 67 participants on the EE diet and 41 on the LCHF diet were qualified for the second stage. Plasma 25-hydroxycholecalciferol (25(OH)D₃) and (25(OH)D₂) concentration was measured by the validated HPLC—MS/MS method. Plasma 25(OH)D₃ concentration was significantly higher in the group on the LCHF diet (34.9 ± 15.9 ng/mL) than in the group on the EE diet (22.6 ± 12.1 ng/mL). No statistical differences were observed in plasma 25(OH)D₂ concentration between the study groups (p > 0.05). Women had a higher plasma 25(OH)D₂ concentration than men regardless of diet type. The LCHF diet had a positive influence on plasma vitamin D concentration. However, long-term use of the LCHF diet remains contentious due to the high risk of cardiovascular disease. This study confirmed that the type of diet influences the concentration of vitamin D metabolites in the plasma.     

Is a daily supplementation with 40 microgram vitamin D3 sufficient? A randomised controlled trial

Purpose

The effect of 40?μg (1,600?IU) per day of vitamin D₃ on serum 25-hydroxyvitamin D (25(OH)D) and markers of bone and mineral metabolism was evaluated.

Methods

This intervention study was designed as a double-blind randomised controlled trial. Forty-five community-dwelling subjects (32 females), age 55–84?years, at 58° North latitude were supplemented for 1?year with 40?μg vitamin D₃ plus 1,000?mg calcium per day, or with 1,000?mg calcium per day for controls. Safety parameters and 25(OH)D, intact parathyroid hormone (PTH), ionized calcium, bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase isoform 5b (TRACP5b) were measured over the study period.

Results

All subjects supplemented with vitamin D₃ reached a 25(OH)D level above 50?nmol/L. Mean (SD) serum 25(OH)D increased from 50.4 (13.5) nmol/L to 84.2 (17.5) nmol/L, range 55.0–125.0?nmol/L in the vitamin D₃ supplemented group and the corresponding levels for the control group were 47.3 (14.1) nmol/L and 45.7 (13.4) nmol/L, range 26.0–73.0?nmol/L. No serious adverse event was recorded and the highest 25(OH)D level reached, 125.0?nmol/L, is well below toxic levels. BALP and TRACP5b did not change significantly over the study period.

Conclusions

This trial suggests that a daily supplementation with 40?μg vitamin D₃ is sufficient to secure a 25(OH)D level of 50?nmol/L. No side effects were observed in the study group.