Relative effectiveness of oral 25-hydroxyvitamin D3 and vitamin D3 in raising wintertime serum 25-hydroxyvitamin D in older adults

Effects of alendronate and calcifediol compared to alendronate and cholecalciferol in osteoporotic patients

BACKGROUND

Several formulations of vitamin D and alendronate are available for the treatment of osteoporosis. The objective of this study was to examine efficacy and safety of calcifediol (25(OH)D) compared to cholecalciferol (vitamin D3) and also the relationship between different formulations of alendronate and adverse reactions.

METHODS

We observed a population of women diagnosed with postmenopausal osteoporosis or osteopenia treated with alendronate 70 mg weekly associated to vitamin D3 or 25(OH)D at monthly total dose of 625 µg. Data collected both at baseline (T0) and at follow-up after at least 12 months of therapy (T1) were: demographic characteristics, BMI, full medical history, lumbar T-score, femur T-score, calcium, osteocalcin, alkaline phosphatase, PTH and vitamin D blood level.

RESULTS

A total of 362 patients were enrolled in the study. Alendronate 70 mg + calcifediol (A+25(OH)D) group consisted of 202 patients while 160 patients were treated with alendronate 70 mg + cholecalciferol (A+D3). In the A+25(OH)D group, we observed a significant increase in lumbar T-score value (0.26±0.35 vs. 0.13±0.3) and serum vitamin D (20.64±20.71 vs. 6.07±7.61 ng/mL) levels compared to the A+D3 group (P<0.05). The lowest incidence of gastrointestinal adverse reactions was observed among patients taking alendronate 70 mg in drinkable solution form (P<0.05).

CONCLUSIONS

Alendronate 70 mg with calcifediol gives a better outcome in the treatment of osteoporosis according to lumbar T-score and vitamin D serum level observed at one-year follow-up compared to alendronate 70 mg with cholecalciferol. Both vitamin D formulations did not show to cause hypercalcemia in this study. Alendronate 70 mg in drinkable solution form is also associated with lowest incidence of gastrointestinal adverse reactions.

Supplemental 25-Hydroxycholecalciferol Is More Effective than Cholecalciferol in Raising Serum 25-Hydroxyvitamin D Concentrations in Older Adults

BACKGROUND

There are few studies directly comparing the pharmacokinetics of 25-hydroxycholecalciferol [25(OH)D3] to cholecalciferol (D3).

OBJECTIVES

The primary objectives were to compare the effectiveness of D3 and 25(OH)D3 in raising 25-hydroxyvitamin D [25(OH)D] serum concentrations and achieving steady state.

METHODS

This was a randomized, double-blind, active comparator trial of 91 participants (53 females, 38 males), aged 63.3 ± 7.9 y. 25(OH)D3 (10, 15, and 20 µg) and D3 (20 µg) were dosed daily for 6 mo followed by 6 mo of washout. Frequent measurements of serum 25(OH)D were performed. Pharmacokinetic parameters were fitted for each individual and the treatment average was modeled with linear regression using the individual baseline level, sex, and gender as covariates.

RESULTS

Mean baseline 25(OH)D was similar in all groups (47.1-49.5 nmol/L). Increases in 25(OH)D to steady state were higher in the 25(OH)D3 groups than in the D3 group [least squares (LS) means (95% CI): 50.1 (43.3-58.0), 72.5 (64.3-81.7), 97.4 (86.6-109.6) nmol/L in 10, 15, and 20 µg/d and 38.7 (33.1-45.2) nmol/L in the D3 group; P = 0.0173, P < 0.0001, P < 0.0001]. The rate to reach steady state was similar in all groups, but the time to reach 25(OH)D concentrations of 75 nmol/L was faster in the higher-dosed 25(OH)D3 groups than in the D3 group (7 and 10 d compared with 40 d, P < 0.0001 and P < 0.0001 for 15 and 20 µg/d). The rate of elimination was 59-109% higher in the 25(OH)D3 groups than in the D3 group. The area under the curve (AUC)/µg dose demonstrated that 25(OH)D3 was 3 times as effective as D3 at raising 25(OH)D concentrations.

CONCLUSIONS

25(OH)D3 is ∼3 times as effective as D3 at raising 25(OH)D concentrations. Once supplementation is discontinued, the elimination rate of 25(OH)D3 is faster than D3. This trial was registered at clinicaltrials.gov as NCT02333682.

Feasibility of artificial light regimes to increase the vitamin D content in indoor-laid eggs

Vitamin D insufficiency is prevalent worldwide. Recently, we showed that exposure of laying hens to sunlight or artificial ultraviolet B (UVB) light is an efficient strategy to increase the vitamin D content in eggs. In the current study, using 2 different chicken genotypes and stocking densities, we addressed the question of whether different UVB-emitting regimes work under real indoor housing conditions in a floor system or in furnished cages. Here, we found a 3.7-fold increase in the egg vitamin D content in Lohmann Selected Leghorn hens and a 4.2-fold increase in Lohmann Brown hens after UVB exposure for 6 h/d. The data further reveal that UVB exposure under high stocking density is equally effective compared to that at low stocking density. The different light regimes were not associated with changes in the behavior of these animals. To conclude, artificial UVB-emitting light regimes are a practical strategy to increase the vitamin D content in indoor-laid eggs.

Current opinion on dietary advice in order to preserve fat-free mass during a low-calorie diet

OBJECTIVES

The loss of fat-free mass (FFM) that occurs during weight loss secondary to low-calorie diet can lead to numerous and deleterious consequences. We performed a review to evaluate the state of the art on metabolic and nutritional correlates of loss of fat free mass during low calorie diet and treatment for maintaining fat free mass.

METHODS

This review included 44 eligible studies. There are various diet strategies to maintain FFM during a low-calorie diet, including adoption of a very low carbohydrate ketogenic diet (VLCKD) and taking an adequate amount of specific nutrients (vitamin D, leucine, whey protein).

RESULTS

Regarding the numerous and various low-calorie diet proposals for achieving weight loss, the comparison of VLCKD with prudent low-calorie diet found that FFM was practically unaffected by VLCKD. There are numerous possible mechanisms for this, involving insulin and the insulin-like growth factor-1-growth hormone axis, which acts by stimulating protein synthesis.

CONCLUSIONS

Considering protein and amino acids intake, an adequate daily intake of leucine (4 g/d) and whey protein (20 g/d) is recommended. Regarding vitamin D, if the blood vitamin D has low values (<30 ng/mL), it is mandatory that adequate supplementation is provided, specifically calcifediol, because in the obese patient this form is recommended to avoid seizure in the adipose tissue; 3 to 4 drops/d or 20 to 30 drops/wk of calcifediol are generally adequate to restore normal 25(OH)D plasma levels in obese patients.

Effects of Weekly Supplementation of Cholecalciferol and Calcifediol Among the Oldest-Old People: Findings From a Randomized Pragmatic Clinical Trial

Vitamin D inadequacy is pervasive in the oldest-old. Many vitamin D metabolites are available for supplementation, their effects on the recovery of adequate serum levels remain unknown. We investigate the effects of supplementation with cholecalciferol (D3) and calcifediol (25D3) on serum levels of 25(OH)D, 1-25(OH)D, bone and inflammatory markers, ultimately identifying clinical predictors of successful treatment. Sixty-seven oldest-old individuals were randomized to weekly administration of 150 mcg of 25D3 or D3, from hospital admission to 7 months after discharge. Supplementation of 25D3 and D3 were associated with increasing serum levels of 25(OH)D (p < 0.001) and 1-25(OH)D (p = 0.01). Participants on 25D3 experienced a steeper rise than those on D3 (group*time interaction p = 0.01), after adjustment for intact parathyroid hormone (iPTH) levels the differences disappeared (intervention*iPTH interaction p = 0.04). Vitamin D supplementation was associated with a decreasing trend of iPTH and C-reactive protein (CRP) (p < 0.001). Polypharmacy and low handgrip strength were predictors of failure of intervention, independent of vitamin D metabolites. In conclusion, D3 and 25D3 supplementation significantly increase vitamin D serum levels in the oldest-old individuals, with a tendency of 25D3 to show a faster recovery of acceptable iPTH levels than D3. Polypharmacy and low muscle strength weaken the recovery of adequate vitamin D serum levels.

Maternal 25-hydroxycholecalciferol during lactation improves intestinal calcium absorption and bone properties in sow-suckling piglet pairs

Lower maternal vitamin D status during lactation is a common health problem. The objectives of this study were to investigate the effects of maternal 25-hydroxycholecalciferol (25-OH-D₃) supplementation during lactation on maternal and neonatal bone health in a sow model. 32 Large White × Landrace sows were assigned randomly to one of two diets supplemented with 2000 IU/kg vitamin D₃ (ND) or 50 μg/kg 25-OH-D₃ (25-D). The experiment began on day 107 of gestation and continued until weaning on day 21 of lactation. Maternal 25-OH-D₃ supplementation significantly decreased milk n-6:n-3 PUFA ratio, which supported bone formation of piglets. Supplementation with 25-OH-D₃ altered bone turnover rate of sows and piglets, as evidenced by higher bone-specific alkaline phosphatase (BALP) concentration in serum. 25-D sows had significantly higher bone density and mechanical properties of tibias and femurs than ND sows. Calcium (Ca) absorption rate was higher in 25-D sows than ND sows, which was caused partially by the increased mRNA expressions of renal 1α-hydroxylase (CYP27B1) and duodenal vitamin D receptor (VDR), transient receptor potential vanilloid 6 (TRPV6), and calcium-binding protein D9k (CaBP-D9k). Maternal 25-OH-D₃ supplementation increased tibial and femoral Ca content by up-regulating Ca-related gene expression in kidney (CYP27B1), ileum (VDR and claudin-2), and colon (VDR and CaBP-D9k), thus, activating 1,25-dihydroxyvitamin D₃ [1,25-(OH)₂-D₃]-dependent Ca transport in piglets. In conclusion, improved milk fatty acids and higher mRNA expressions of calcitropic genes triggered by maternal 25-OH-D₃ supplementation would be the potential mechanism underlying the positive effects of 25-OH-D₃ on maternal and neonatal bone health.

Challenges to Quantify Total Vitamin Activity: How to Combine the Contribution of Diverse Vitamers?

This state-of-the-art review aims to highlight the challenges in quantifying vitamin activity in foods that contain several vitamers of a group, using as examples the fat-soluble vitamins A and D as well as the water-soluble folate. The absorption, metabolism, and physiology of these examples are described along with the current analytical methodology, with an emphasis on approaches to standardization. Moreover, the major food sources for the vitamins are numerated. The article focuses particularly on outlining the so-called SLAMENGHI factors influencing a vitamer's' ability to act as a vitamin, that is, molecular species, linkage, amount, matrix, effectors of absorption, nutrition status, genetics, host-related factors, and the interaction of these. After summarizing the current approaches to estimating the total content of each vitamin group, the review concludes by outlining the research gaps and future perspectives in vitamin analysis. There are no standardized methods for the quantification of the vitamers of vitamin A, vitamin D, and folate in foods. For folate and β-carotene, a difference in vitamer activity between foods and supplements has been confirmed, whereas no difference has been observed for vitamin D. For differences in vitamer activity between provitamin A carotenoids and retinol, and between 25-hydroxyvitamin D and vitamin D, international consensus is lacking. The challenges facing each of the specific vitamin communities are the gaps in knowledge about bioaccessibility and bioavailability for each of the various vitamers. The differences between the vitamins make it difficult to formulate a common strategy for assessing the quantitative differences between the vitamers. In the future, optimized stationary digestive models and the more advanced dynamic digestive models combined with in vitro models for bioavailability could more closely resemble in vivo results. New knowledge will enable us to transfer nutrient recommendations into improved dietary advice to increase public health throughout the human life cycle.

Effects of dietary calcium and phosphorus levels and supplementation of 25-hydroxycholecalciferol on performance and bone properties of broiler starters

To investigate effects of dietary calcium (Ca) and phosphorus (P) levels and 25-hydroxycholecalciferol (25OHD₃) supplementation on performance and bone properties of broiler starters, 224 male Arbor Acre broilers were used in a 21-d trial. Broilers were allotted to one of four treatments in a 2 × 2 factorial arrangement including diets either normal or low in Ca and P, which were further supplemented or not with 69 μg 25OHD₃/kg feed. Feeding low Ca and P diets significantly reduced performance of boilers and decreased ash, Ca, P and hydroxyproline contents in tibias and femurs (p < 0.05). Ultimate load, bending moment, stiffness and energy to fail were decreased (p < 0.05) in broilers fed diets deficient in Ca and P. Addition of 25OHD₃ did not influence performance but significantly increased serum 25OHD₃ levels. Furthermore, the addition of 25OHD₃ caused an increased tibial and femoral bone density and femoral hydroxyproline content (p < 0.05), increased bending moment in tibias (p < 0.05), and enhanced ultimate load and bending moment in femurs (p < 0.05). No significant interactions were observed for bone properties. Overall, feeding 25OHD₃ at 69 μg/kg feed to broilers had no effect on growth performance but partly improved bone biochemical and biomechanical properties of broiler starters.

First proposal of quality indicators and standards and recommendations to improve the healthcare in the Spanish National Registry of Hip Fracture

BACKGROUND

The Spanish National Hip Fracture Registry (or Registro Nacional de Fractura de Cadera, RNFC) is a database of hip fracture patients admitted to Spanish hospitals. Its goals include assessment and continuous improvement of the care process.

OBJECTIVES

To (1) establish a series of indicators, (2) evaluate their initial fulfillment, (3) propose quality standards, (4) suggest recommendations to facilitate standards compliance, and (5) monitor the indicators.

METHOD

The indicators fulfilled the criteria of (1) evaluating the process or outcome, (2) being clinically relevant for patients, (3) being modifiable through changes in healthcare practice, and (4) being considered important by the RNFC participants. The first quartile obtained by the group of hospitals in each of the respective variables was proposed as the standard. The Indicators Advisory Committee (IAC) elaborated a list of recommendations for each indicator, based on the available evidence.

RESULTS

Seven indicators were chosen. These indicators (its baseline compliance vs. the standard to be reached, respectively) were: the proportion of patients receiving surgery within 48h (44% vs. 63%), mobilized the first postoperative day (56% vs. 86%), with antiosteoporotic medication at discharge (32% vs. 61%), with calcium supplements at discharge (46% vs. 77%), with vitamin D supplements at discharge (67% vs. 92%), who developed pressure ulcers during hospitalization (7.2% vs. 2.1%) and with independent mobility at 30 days (58% vs. 70%). The IAC has established 25 recommendations for improving care.

CONCLUSION

The indicators and standards chosen are presented, as well as the list of recommendations. This process completes the first step to improve quality of care. The results will be evaluated 6 months after implementing the recommendations.

Effects of maternal 25-hydroxycholecalciferol on nutrient digestibility, milk composition and fatty-acid profile of lactating sows and gut bacterial metabolites in the hindgut of suckling piglets

To investigate the effects of maternal 25-hydroxycholecalciferol (25OHD₃) supplementation during lactation on nutrient digestibility and milk composition of sows and gut bacterial metabolites and their metabolites in the hindgut of suckling piglets, 24 Large White × Landrace sows were assigned randomly to one of two dietary treatments (Diet ND: 2000 IU vitamin D₃/kg feed; Diet 25-D: 50 μg 25OHD₃/kg feed). The experiment began on d 107 of gestation and continued until weaning on d 21 of lactation. Maternal 25OHD₃ supplementation increased (p < 0.05) total litter weight gain during lactation. Milk fat content, immunoglobulin G level on d 21 of lactation and 25OHD₃ concentration on d 7, 14, and 21 of lactation were higher (p < 0.05) in sows fed with 25OHD₃. Apparent total tract digestibility of dietary calcium was higher (p < 0.05) in 25-D sows than ND sows. With respect to fatty-acid profile, C16:0 and saturated fatty acids in milk were higher (p < 0.05), but C20:4n-6, the ratios of monounsaturated fatty acids to saturated fatty acids and polyunsaturated fatty acids to saturated fatty acids were lower (p < 0.05) in 25-D sows than ND sows. 25OHD₃ supplementation increased the mRNA expressions of acetyl-CoA carboxylase α and fatty-acid synthase in the mammary gland of lactating sows. For gut bacterial metabolites, concentration of butyrate in the caecal digesta was higher (p < 0.05) in piglets suckling 25-D sows than piglets suckling ND sows. In conclusion, 25OHD₃ supplementation in maternal diets changed dietary calcium digestibility, milk composition and milk fatty-acid profile of lactating sows and altered gut bacterial metabolites in the hindgut of suckling piglets.

Vitamin D Status and Components of Metabolic Syndrome in Older Subjects from Northern Finland (Latitude 65°North)

INTRODUCTION

Vitamin D deficiency has been linked to the increased risk of several chronic diseases, especially in people living in the Northern Latitudes. The aim of this study was to assess the vitamin D status in older subjects born in 1945 in Northern Finland (latitude 65°North), and to examine its associations to components of metabolic syndrome (MetS).

METHODS

In this cross-sectional study, we invited 904 subjects born in 1945 from the Oulu region (Oulu45 cohort), out of an original cohort of 1332 subjects. In the cohort, plasma 25 hydroxyvitamin D (25OHD) levels were determined by an enzyme immunoassay of 263 men and 373 women, with a mean age baseline of 69±0.5 years old. We assessed the participants' usage of vitamin D supplements, as well as their lifestyle factors, using a questionnaire.

RESULTS

Nearly 80% of the subjects had low vitamin D levels [either vitamin D deficient (<50 nmol/L) or insufficient (50 - 75 nmol/L)], and only 20% of the participants had sufficient vitamin D levels (>75 nmol/L) (based on the American Endocrine Society guidelines). The low vitamin D status was associated with a high prevalence of MetS; a significantly higher number of subjects with MetS (41%) had low vitamin D levels in comparison to the non-MetS subjects (38%) (p ≤ 0.05). The subjects under vitamin D supplementation had a significantly lower incidence of MetS (42.6% vs 57.4%) and its components in comparison to the non-supplemented subjects (p ≤ 0.05).

CONCLUSIONS

Low vitamin D levels are a risk factor for MetS amongst other lifestyle factors, such as dietary habits and physical inactivity, among older subjects in the Northern Latitudes (65°North). Optimal supplementation of vitamin D, along with rich dietary sources of vitamin D, are highly recommended for older subjects as a means to positively affect, e.g., hypertension, insulin resistance, and obesity, as components of the MetS.

Hypovitaminosis D: Is It Time to Consider the Use of Calcifediol?

Hypovitaminosis D is becoming a notable health problem worldwide. A consensus exists among several different medical societies as to the need for adequate levels of vitamin D for bone and general health. The correct method by which to restore normal vitamin D levels is still a matter of debate. Although cholecalciferol remains the most commonly distributed form of vitamin D supplementation worldwide, several drugs with vitamin D activity are available for clinical use, and making the correct selection for the individual patient may be challenging. In this narrative review, we aim to contribute to the current knowledge base on the possible and appropriate use of calcifediol-the 25-alpha-hydroxylated metabolite-in relation to its chemical characteristics, its biological properties, and its pathophysiological aspects. Furthermore, we examine the trials that have aimed to evaluate the effect of calcifediol on the restoration of normal vitamin D levels. Calcifediol is more soluble than cholecalciferol in organic solvents, due to its high polarity. Good intestinal absorption and high affinity for the vitamin-D-binding protein positively affect the bioavailability of calcifediol compared with cholecalciferol. In particular, orally administered calcifediol shows a much shorter half-life than oral cholecalciferol. Most findings suggest that oral calcifediol is about three- to five-fold more powerful than oral cholecalciferol, and that it has a higher rate of intestinal absorption. Accordingly, calcifediol can be particularly useful in treating diseases associated with decreased intestinal absorption, as well as obesity (given its lower trapping in the adipose tissue) and potentially neurological diseases treated with drugs that interfere with the hepatic cytochrome P-450 enzyme system, resulting in decreased synthesis of calcifediol. Up to now, there has not been enough clinical evidence for its use in the context of osteoporosis treatment.

Obesity and hypovitaminosis D: causality or casualty?

Epidemiological studies reported that vitamin D deficiency represents an increasingly widespread phenomenon in various populations. Vitamin D deficiency is considered a clinical syndrome determined by low circulating levels of 25-hydroxyvitamin D (25(OH)D), which is the biologically-inactive intermediate and represents the predominant circulating form. Different mechanisms have been hypothesized to explain the association between hypovitaminosis D and obesity, including lower dietary intake of vitamin D, lesser skin exposure to sunlight, due to less outdoor physical activity, decreased intestinal absorption, impaired hydroxylation in adipose tissue and 25(OH)D accumulation in fat. However, several studies speculated that vitamin D deficiency itself could cause obesity or prevent weight loss. The fat-solubility of vitamin D leads to the hypothesis that a sequestration process occurs in body fat depots, resulting in a lower bioavailability in the obese state. After investigating the clinical aspects of vitamin D deficiency and the proposed mechanisms for low 25(OH)D in obesity, in this manuscript we discuss the possible role of vitamin D replacement treatment, with different formulations, to restore normal levels in individuals affected by obesity, and evaluate potential positive effects on obesity itself and its metabolic consequences. Food-based prevention strategies for enhancement of vitamin D status and, therefore, lowering skeletal and extra-skeletal diseases risk have been widely proposed in the past decades; however pharmacological supplementation, namely cholecalciferol and calcifediol, is required in the treatment of vitamin D insufficiency and its comorbidities. In individuals affected by obesity, high doses of vitamin D are required to normalize serum vitamin D levels, but the different liposolubility of different supplements should be taken into account. Although the results are inconsistent, some studies reported that vitamin D supplementation may have some beneficial effects in people with obesity.

The effects of maternal dietary supplementation of cholecalciferol (vitamin D3) and 25(OH)D3 on sow and progeny performance

A total of 69 sows (DNA Line 200 × 400) and their progeny were used to determine if feeding a combination of vitamin D₃ and 25(OH)D₃ influences neonatal and sow vitamin D status, muscle fiber morphometrics at birth and weaning, and subsequent growth performance. Within 3 d of breeding, sows were allotted to one of three dietary treatments fortified with 1,500 IU/kg vitamin D₃ (CON), 500 IU/kg vitamin D₃ + 25 μg/kg 25(OH)D₃ (DL), or 1,500 IU/kg vitamin D₃ + 50 μg/kg 25(OH)D₃ (DH). When pigs were sacrificed at birth, there were no treatment effects for all fiber morphometric measures (P > 0.170), except primary fiber number and the ratio of secondary to primary muscle fibers (P < 0.016). Pigs from CON fed sows had fewer primary fibers than pigs from sows fed the DH treatment (P = 0.014), with pigs from sows fed DL treatment not differing from either (P > 0.104). Pigs from CON and DL fed sows had a greater secondary to primary muscle fiber ratio compared to pigs from DH sows (P < 0.022) but did not differ from each other (P = 0.994). There were treatment × time interactions for all sow and pig serum metabolites (P < 0.001). Therefore, treatment means were compared within the time period. At all time periods, sow serum 25(OH)D₃ concentrations differed for all treatments with the magnitude of difference largest at weaning (P < 0.011), where serum 25(OH)D₃ concentration was always the greatest when sows were fed the DH diet. At birth, piglets from DH fed sows had greater serum 25(OH)D₃ concentrations than piglets from sows fed the DL treatment (P = 0.003), with piglets from sows fed CON treatment not differing from either (P > 0.061). At weaning, serum concentrations of 25(OH)D₃ in piglets from all sow treatments were different (P < 0.001), with the greatest concentration in piglets from DH sows, followed by CON, and followed by DL. There were no treatment × time interactions for any of the metabolites measured in milk and no treatment or time main effects for 24,25(OH)₂D₃ concentration (P > 0.068). Colostrum collected within 12 h of parturition contained less (P = 0.001) 25(OH)D₃ than milk collected on day 21 of lactation. Regardless of time, concentrations of 25(OH)D₃ in milk were different (P < 0.030), with the largest 25(OH)D₃ concentration from DH fed sows, followed by DL, and then CON. In conclusion, combining vitamin D₃ and 25(OH)D₃ in the maternal diet improves the vitamin D status of the dam and progeny and it increases primary muscle fiber number at birth.

Higher Non-processed Red Meat Consumption Is Associated With a Reduced Risk of Central Nervous System Demyelination

The evidence associating red meat consumption and risk of multiple sclerosis is inconclusive. We tested associations between red meat consumption and risk of a first clinical diagnosis of central nervous system demyelination (FCD), often presaging a diagnosis of multiple sclerosis. We used food frequency questionnaire data from the 2003–2006 Ausimmune Study, an incident, matched, case-control study examining environmental risk factors for FCD. We calculated non-processed and processed red meat density (g/1,000 kcal/day). Conditional logistic regression models (with participants matched on age, sex, and study region) were used to estimate odds ratios (ORs), 95% confidence intervals (95% CI) and p-values for associations between non-processed (n = 689, 250 cases, 439 controls) and processed (n = 683, 248 cases, 435 controls) red meat density and risk of FCD. Models were adjusted for history of infectious mononucleosis, serum 25-hydroxyvitamin D concentrations, smoking, race, education, body mass index and dietary misreporting. A one standard deviation increase in non-processed red meat density (22 g/1,000 kcal/day) was associated with a 19% reduced risk of FCD (AOR = 0.81; 95%CI 0.68, 0.97; p = 0.02). When stratified by sex, higher non-processed red meat density (per 22 g/1,000 kcal/day) was associated with a 26% reduced risk of FCD in females (n = 519; AOR = 0.74; 95%CI 0.60, 0.92; p = 0.01). There was no statistically significant association between non-processed red meat density and risk of FCD in males (n = 170). We found no statistically significant association between processed red meat density and risk of FCD. Further investigation is warranted to understand the important components of a diet that includes non-processed red meat for lower FCD risk.

Low 25-hydroxyvitamin D levels are more prevalent in Canadians of South Asian than European ancestry inhabiting the National Capital Region of Canada

The US Institute of Medicine defined serum 25-hydroxyvitamin D (25OHD) cut point values of 30 nmol/L and 40 nmol/L were used to assess the vitamin D status of South Asian and European Canadians of self-identified ancestry living in the National Capital Region of Canada. Serum 25OHD values were measured in the spring and fall of 2012 to represent status during the winter and summer months, respectively. A total of 1238 measurements were obtained from 669 participants (49% South Asian ancestry): some participants were measured only once (spring or fall). Median 25OHD values were significantly higher in participants of European ancestry: 70.8 nmol/L (68.1, 73.5; 95% CI) versus South Asian ancestry: 42.7 nmol/L (40.5, 45.0; P<0.001). Spring vs. fall differences were small for each ethnic group and significant only for those of European ancestry (2.9, CI: 1.0–4.9 nmol/L; P = 0.01). Among participants of South Asian ancestry, 27.3% (fall) and 29.1% (spring) of females had values <40 nmol/L while the percentages for males were considerably higher (36.5% and 44.2%, respectively). The corresponding values for participants of European ancestry were ≤10%, showing that the South Asian participants were less likely to achieve the 25OHD concentrations established by the IOM for optimum bone health. Investigation of the factors related to serum 25OHD levels showed that supplement intake and ethnic background were associated with the biggest differences. Skin color was not a major factor, suggesting that genetic factors are responsible for the observed differences between participants of different ethnic backgrounds.

Is calcifediol better than cholecalciferol for vitamin D supplementation?

Modest and even severe vitamin D deficiency is widely prevalent around the world. There is consensus that a good vitamin D status is necessary for bone and general health. Similarly, a better vitamin D status is essential for optimal efficacy of antiresorptive treatments. Supplementation of food with vitamin D or using vitamin D supplements is the most widely used strategy to improve the vitamin status. Cholecalciferol (vitamin D₃) and ergocalciferol (vitamin D₂) are the most widely used compounds and the relative use of both products depends on historical or practical reasons. Oral intake of calcifediol (25OHD₃) rather than vitamin D itself should also be considered for oral supplementation. We reviewed all publications dealing with a comparison of oral cholecalciferol with oral calcifediol as to define the relative efficacy of both compounds for improving the vitamin D status. First, oral calcifediol results in a more rapid increase in serum 25OHD compared to oral cholecalciferol. Second, oral calcifediol is more potent than cholecalciferol, so that lower dosages are needed. Based on the results of nine RCTs comparing physiologic doses of oral cholecalciferol with oral calcifediol, calcifediol was 3.2-fold more potent than oral cholecalciferol. Indeed, when using dosages ≤ 25 μg/day, serum 25OHD increased by 1.5 ± 0.9 nmol/l for each 1 μg cholecalciferol, whereas this was 4.8 ± 1.2 nmol/l for oral calcifediol_. Third, oral calcifediol has a higher rate of intestinal absorption and this may have important advantages in case of decreased intestinal absorption capacity due to a variety of diseases. A potential additional advantage of oral calcifediol is a linear dose-response curve, irrespective of baseline serum 25OHD, whereas the rise in serum 25OHD is lower after oral cholecalciferol, when baseline serum 25OHD is higher. Finally, intermittent intake of calcifediol results in fairly stable serum 25OHD compared with greater fluctuations after intermittent oral cholecalciferol.

Vitamin D Content of Australian Native Food Plants and Australian-Grown Edible Seaweed

Vitamin D has previously been quantified in some plants and algae, particularly in leaves of the Solanaceae family. We measured the vitamin D content of Australian native food plants and Australian-grown edible seaweed. Using liquid chromatography with triple quadrupole mass spectrometry, 13 samples (including leaf, fruit, and seed) were analyzed in duplicate for vitamin D₂, vitamin D₃, 25-hydroxyvitamin D₂, and 25-hydroxyvitamin D₃. Five samples contained vitamin D₂: raw wattleseed (Acacia victoriae) (0.03 µg/100 g dry weight (DW)); fresh and dried lemon myrtle (Backhousia citriodora) leaves (0.03 and 0.24 µg/100 g DW, respectively); and dried leaves and berries of Tasmanian mountain pepper (Tasmannia lanceolata) (0.67 and 0.05 µg/100 g DW, respectively). Fresh kombu (Lessonia corrugata) contained vitamin D₃ (0.01 µg/100 g DW). Detected amounts were low; however, it is possible that exposure to ultraviolet radiation may increase the vitamin D content of plants and algae if vitamin D precursors are present.

Cholecalciferol or 25-Hydroxycholecalciferol Supplementation Does Not Affect Muscle Strength and Physical Performance in Prefrail and Frail Older Adults

Background

Vitamin D supplementation is proposed as a potential treatment strategy to counteract functional decline in older adults. However, data from randomized trials are either limited or inconsistent.

Objective

This study investigated the effect of daily supplementation with 25-hydroxycholecalciferol [25(OH)D3] or cholecalciferol (vitamin D3) on muscle strength and physical performance in older adults.

Methods

This was a randomized, double-blind, placebo-controlled trial of 6 mo including 78 prefrail or frail (according to the Fried criteria), community-dwelling older adults (n = 43 men) aged ≥65 y, with a baseline 25-hydroxyvitamin D [25(OH)D] concentration between 20 and 50 nmol/L. Participants were supplemented daily with 10 µg 25(OH)D3, 20 µg vitamin D3, or a placebo capsule. Serum 25(OH)D was measured by liquid chromatography-tandem mass spectrometry. The primary outcome was maximal isometric knee-extension strength (Biodex System 4); secondary outcomes included knee-flexion and hand grip strength, Short-Physical Performance Battery score, Timed Up and Go score, postural sway, muscle mass (dual-energy X-ray absorptiometry), and muscle fiber type and size.

Results

The mean baseline serum 25(OH)D concentration was 37.7 nmol/L (95% CI: 35.4, 39.9 nmol/L). After 6 mo of supplementation, concentrations increased to 98.7 nmol/L (95% CI: 93.1, 104.4 nmol/L) in the 25(OH)D3 group and to 72.0 nmol/L (95% CI: 66.1, 77.8 nmol/L) in the vitamin D3 group, compared with 47.5 nmol/L (95% CI: 41.8, 53.3 nmol/L) in the placebo group (P-interaction < 0.01). Knee-extension strength did not significantly change in the 25(OH)D3 group (5.9 Nm; 95% CI: -6.2, 18.0 Nm), in the vitamin D3 group (5.5 Nm; 95% CI: -6.8, 17.8 Nm), or in the placebo group (1.8 Nm; 95% CI: -10.7, 14.4 Nm) (P-interaction = 0.74). Furthermore, mean changes in physical performance tests, muscle mass, and muscle fiber type and size did not differ between the groups.

Conclusion

Increasing the serum 25(OH)D concentration over a period of 6 mo did not significantly change muscle strength and physical performance in prefrail and frail older adults. This trial was registered at www.clinicaltrials.gov as NCT02349282.

Italian Association of Clinical Endocrinologists (AME) and Italian Chapter of the American Association of Clinical Endocrinologists (AACE) Position Statement: Clinical Management of Vitamin D Deficiency in Adults

Vitamin D deficiency is very common and prescriptions of both assay and supplementation are increasing more and more. Health expenditure is exponentially increasing, thus it is timely and appropriate to establish rules. The Italian Association of Clinical Endocrinologists appointed a task force to review literature about vitamin D deficiency in adults. Four topics were identified as worthy for the practicing clinicians. For each topic recommendations based on scientific evidence and clinical practice were issued according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) System. (1) What cut-off defines vitamin D deficiency: even though 20 ng/mL (50 nmol/L) can be considered appropriate in the general population, we recommend to maintain levels above 30 ng/mL (75 nmol/L) in categories at risk. (2) Whom, when, and how to perform screening for vitamin D deficiency: categories at risk (patients with bone, liver, kidney diseases, obesity, malabsorption, during pregnancy and lactation, some elderly) but not healthy people should be screened by the 25-hydroxy-vitamin D assay. (3) Whom and how to treat vitamin D deficiency: beyond healthy lifestyle (mostly sun exposure), we recommend oral vitamin D (vitamin D2 or vitamin D3) supplementation in patients treated with bone active drugs and in those with demonstrated deficiency. Dosages, molecules and modalities of administration can be profitably individually tailored. (4) How to monitor the efficacy of treatment with vitamin D: no routine monitoring is suggested during vitamin D treatment due to its large therapeutic index. In particular conditions, 25-hydroxy-vitamin D can be assayed after at least a 6-month treatment. We are confident that this document will help practicing clinicians in their daily clinical practice.

The use of synthetic and natural vitamin D sources in pig diets to improve meat quality and vitamin D content

This study investigated the effects of synthetic and natural sources of vitamin D biofortification in pig diets on pork vitamin D activity and pork quality. One hundred and twenty pigs (60 male, 60 female) were assigned to one of four dietary treatments for a 55 d feeding period. The dietary treatments were (1)50 μg vitamin D₃/kg of feed; (2)50 μg of 25-hydroxvitamin D₃/kg of feed (25-OH-D₃); (3)50 μg vitamin D₂/kg of feed; (4)50 μg vitamin D₂-enriched mushrooms/kg of feed (Mushroom D₂). The pigs offered the 25-OH-D₃ diet exhibited the highest (P < 0.001) serum total 25-hydroxyvitamin D concentration and subsequently exhibited the highest (P < 0.05) Longissimus thoracis (LT) total vitamin D activity. Mushroom D₂ and 25-OH-D₃ supplementation increased pork antioxidant status. The vitamin D₂-enriched mushrooms improved (P < 0.05) pig performance, carcass weight and LT colour. In conclusion, 25-OH-D₃ is the most successful source for increasing pork vitamin D activity, while Mushroom D₂ may be a new avenue to improve animal performance and pork quality.

Ocular Pharmacokinetics of 25-Hydroxyvitamin D3 After Weekly Supplementation in Rabbits Using Ultra Performance Liquid Chromatography-Tandem Mass Spectrometer

BACKGROUND AND OBJECTIVES

The protective role of vitamin D supplementation has recently been shown to be present in various ocular inflammatory diseases. The oral supplementation of vitamin D may take time to achieve adequate levels in intraocular fluids. Therefore, the present study was performed to understand the ocular pharmacokinetics of 25-hydroxyvitamin D3 (25D3) in aqueous humor after weekly supplementation of 25D3 in rabbits.

METHODS

A total of 21 rabbits were fed orally with 25D3 (7.22 µg/kg/week) for 8 weeks and 9th dose was given at the end of 8 weeks. The blood and aqueous humor samples were collected from ear vein and though anterior chamber paracentesis, respectively. The serum and aqueous humor samples were spiked with deuterium labeled internal standard and were extracted using liquid extraction method. Furthermore, the samples were derivatized and 25D3 estimation was performed using ultra performance liquid chromatography-tandem mass spectrometer (UHPLC-MS/MS).

RESULTS

The 25D3 supplementation significantly increased the 25D3 levels in serum (78.5 ± 21.6 ng/ml) (mean ± SD) (p < 0.0001) and in aqueous humor (991.3 ± 180.6 pg/ml) (mean ± SD) (p < 0.0001) compared to baseline levels. The maximum concentration was achieved in serum after the 10th hour of supplementation of 1st and 9th dose, while the same was observed at the 24th hour in aqueous humor.

CONCLUSION

The oral supplementation of 25D3 was found to significantly increase 25D3 levels in aqueous humor; however, the time required to achieve 25D3 concentration in aqueous humor was higher as compared to that in serum. Therefore, weekly oral supplementation of 25D3 may have a beneficial role in ocular diseases.

Vitamin D-biofortified beef: A comparison of cholecalciferol with synthetic versus UVB-mushroom-derived ergosterol as feed source

This study investigates dietary fortification of heifer feeds with cholecalciferol and ergocalciferol sources and effects on beef total vitamin D activity, vitamer, respective 25-hydroxymetabolite contents, and meat quality. Thirty heifers were allocated to one of three dietary treatments [(1) basal diet + 4000 IU of vitamin D₃ (Vit D₃); (2) basal diet + 4000 IU of vitamin D₂ (Vit D₂); and (3) basal diet + 4000 IU of vitamin D₂-enriched mushrooms (Mushroom D₂)] for a 30 day pre-slaughter period. Supplementation of heifer diets with Vit D₃ yielded higher (p < 0.001) Longissimus thoracis (LT) total vitamin D activity (by 38-56%; p < 0.05) and serum 25-OH-D concentration (by 20-36%; p < 0.05), compared to that from Vit D₂ and Mushroom D₂ supplemented animals. Irrespective of vitamin D source, carcass characteristics, sensory and meat quality parameter were unaffected (p > 0.05) by the dietary treatments. In conclusion, vitamin D₃ biofortification of cattle diets is the most efficacious way to enhance total beef vitamin D activity.

Effect of dietary vitamin D3 and 25-hydroxyvitamin D3 supplementation on plasma and milk 25-hydroxyvitamin D3 concentration in dairy cows

Milk enriched with vitamin D by supplementing dairy cow diets could provide a valuable dietary source of vitamin D, but information on the feasibility of this approach is limited. In the current study, the effects of supplementing dairy cows with either vitamin D₃ or 25(OH)D₃ over the transition/early lactation period on plasma and milk vitamin D concentrations were compared. Sixty dairy cows were randomly allocated to 1 of 4 dietary treatments from 14 d precalving to 56 d postcalving. Treatments were a control diet (control) for both precalving and postcalving periods containing 0.625 mg/d of vitamin D₃; a precalving diet supplemented with 6 mg of 25(OH)D₃/d, but with a postcalving diet matching that of the control diet [25(OH)D₃ precalving]; the control diet precalving but with the postcalving diet supplemented with 2 mg of vitamin D₃/d (D₃max), and the control diet precalving but with the postcalving diet supplemented with 1.5 mg of 25(OH)D₃/d [25(OH)D₃ postcalving]. No treatment effect on milk yield, composition or 25(OH)D₃ concentration was observed. However, an interaction was observed of treatment and time for plasma 25(OH)D₃ concentration; this increased within 2 wk of supplementation for the 25(OH)D₃ precalving treatment (peaking just after calving, 202 ng/mL), whereas that of the 25(OH)D₃ postcalving group had a slower response following supplementation, continuing to increase at 56 d. Correlations were observed between plasma and milk 25(OH)D₃ concentrations at d 4 and 14 of lactation, but not at later sampling times. The D₃max treatment did not increase 25(OH)D₃ concentration in plasma or milk. Overall, results from this study indicate that supplemental 25(OH)D₃ is an effective means of enhancing dairy cow plasma 25(OH)D₃ concentrations compared with vitamin D₃ supplementation, but not necessarily milk concentrations.

Evolution of Serum 25OHD in Response to Vitamin D3-Fortified Yogurts Consumed by Healthy Menopausal Women: A 6-Month Randomized Controlled Trial Assessing the Interactions between Doses, Baseline Vitamin D Status, and Seasonality

BACKGROUND

Adequate vitamin D status contributes to bone fragility risk reduction and possibly other pathological conditions that occur with aging. In response to pharmaceutical vitamin D3 supplements, several studies have documented the influence of doses, baseline status, and seasonality on serum 25-hydroyvitamin D (s25OHD).

OBJECTIVE

Using fortified yogurt, we investigated in one randomized controlled trial how both baseline status, as assessed by measuring s25OHD prior the onset of the trial, and the season of enrollment quantitatively influenced the response to the supplemented (Suppl.) of vitamin D3 (VitD3) in healthy community-dwelling women.

METHODS

A 24-week controlled trial was conducted in menopausal women (mean age: 61.5). Participants were randomized into 3 groups (Gr): Gr.Suppl.0, time controls maintaining dietary habits; Gr.Suppl.5 and Gr.Suppl.10 consuming one and two 125-g servings of VitD3-fortified yogurts with 5- and 10-µg daily doses, respectively. The 16 intervention weeks lasted from early January to mid-August, the 8 follow-up weeks, without product, from late August to mid-October. Before enrollment, subjects were randomized into 2 s25OHD strata: low stratum (LoStr): 25-50 nmol/L; high stratum (HiStr): >50-75 nmol/L.

RESULTS

All enrolled participants adhered to the protocol throughout the 24-week study: Gr.Suppl.0 (n = 45), Gr.Suppl.5 (n = 44), and Gr.Suppl.10 (n = 44). Over the 16 intervention and 8 follow-up weeks, s25OHD increased in both supplemented groups, more in Gr.Suppl.10 than in Gr.Suppl.5. At the end of the intervention, the subject proportion with s25OHD ≥ 50 nmol/L was 37.8, 54.5, and 63.6% in Gr.Suppl.0, Gr.Suppl.5, and Gr.Suppl.10, respectively. The constant rate of s25OHD per supplemental VitD3 microgram was greater in LoStr than HiStr. The s25OHD increase was greater with late (mid-March) than early (mid-January) inclusion.

CONCLUSION

This randomized trial demonstrates (1) a dose-dependent s25OHD improvement related to fortified yogurt consumption; (2) an inversely baseline-dependent increase in s25OHD; and (3) a seasonal effect that highlights the importance of VitD3-fortified foods during winter, even at 5 µg/d, in healthy menopausal women.

Vitamin D Vitamers Affect Vitamin D Status Differently in Young Healthy Males

Dietary intake of vitamin D includes vitamin D3 (vitD3), 25-hydroxyvitamin D3 (25OH-D3), and vitamin D2 (vitD2). However, the bioactivity of the different species has not been scientifically established. The hypothesis in this study was that vitD3, 25OH-D3, and vitD2 have an equal effect on 25-hydroxyvitamin D in serum (vitamin D status). To test our hypothesis, we performed a randomized, crossover study. Twelve young males consumed 10 µg/day vitD3 during a four-week run-in period, followed by 3 × 6 weeks of 10 µg/day vitD3, 10 µg/day 25OH-D3, and 10 µg/day vitD2. The content of vitD3, vitD2, 25OH-D3, and 25-hydroxyvitamin D2 (25OH-D2) in serum was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The hypothesis that the three sources of vitamin D affect vitamin D status equally was rejected. Based on the assumption that 1 µg vitD3/day will show an increase in vitamin D status of 1.96 nmol/L, the results showed that 23 µg vitD2 and 6.8 µg 25OH-D3 was similar to 10 µg vitD3. These results demonstrate that further investigations are necessary to determine how to quantify the total vitamin D activity based on chemical quantification of the individual vitamin D metabolites to replace the total vitamin D activity assessed in biological rat models.

Genetic and Racial Differences in the Vitamin D Endocrine System

Twin studies indicate that genetic factors may explain about 50% of the variation of serum 25-hydroxyvitamin D (25OHD). Polymorphisms of 3 genes, delta-7-sterol-reductase, CYP2R1, and DBP/GC (and maybe CYP24A1) combined, can explain about 5% to 10% of the variation in serum 25OHD. These polymorphisms are found in nearly all populations. The variation in serum 25OHD found in different areas and populations in the world is mainly due to environmental and lifestyle factors, not truly dependent on racial differences. One genetic variant of DBP, (GC2), is associated with a modest (∼10%) decrease in serum DBP and 25OHD concentrations for unexplained reasons.

25(OH)D3-enriched or fortified foods are more efficient at tackling inadequate vitamin D status than vitamin D3

The ability to synthesise sufficient vitamin D through sunlight in human subjects can be limited. Thus, diet has become an important contributor to vitamin D intake and status; however, there are only a few foods (e.g. egg yolk, oily fish) naturally rich in vitamin D. Therefore, vitamin D-enriched foods via supplementing the animals' diet with vitamin D or vitamin D fortification of foods have been proposed as strategies to increase vitamin D intake. Evidence that cholecalciferol (vitamin D3) and calcifediol (25(OH)D3) content of eggs, fish and milk increased in response to vitamin D3 supplementation of hens, fish or cows' diets was identified when vitamin D-enrichment studies were reviewed. However, evidence from supplementation studies with hens showed only dietary 25(OH)D3, not vitamin D3 supplementation, resulted in a pronounced increase of 25(OH)D3 in the eggs. Furthermore, evidence from randomised controlled trials indicated that a 25(OH)D3 oral supplement could be absorbed faster and more efficiently raise serum 25(OH)D concentration compared with vitamin D3 supplementation. Moreover, evidence showed the relative effectiveness of increasing vitamin D status using 25(OH)D3 varied between 3·13 and 7·14 times that of vitamin D3, probably due to the different characteristics of the investigated subjects or study design. Therefore, vitamin D-enrichment or fortified foods using 25(OH)D3 would appear to have advantages over vitamin D3. Further well-controlled studies are needed to assess the effects of 25(OH)D3 enriched or fortified foods in the general population and clinical patients.

25-Hydroxyvitamin D as a Biomarker of Vitamin D Status and Its Modeling to Inform Strategies for Prevention of Vitamin D Deficiency within the Population

There is substantial evidence that the prevalence of vitamin D deficiency is unacceptably high in the population, and this requires action from a public health perspective. Circulating 25-hydroxyvitamin D [25(OH)D] is a robust and reliable marker of vitamin D status and has been used by numerous agencies in the establishment of vitamin D dietary requirements and for population surveillance of vitamin D deficiency or inadequacy. In a wider context, modeling of serum 25(OH)D data and its contributory sources, namely dietary vitamin D supply and UVB availability, can inform our understanding of population vitamin D status. The aim of this review is to provide the current status of knowledge in relation to modeling of such vitamin D-relevant data. We begin by highlighting the importance of the measurement of 25(OH)D and its standardization, both of which have led to new key data on the prevalence of vitamin D deficiency and inadequacy in North America and Europe. We then overview how state-of-the-art modeling can be used to inform our understanding of the potential effect of ergocalciferol and 25(OH)D on vitamin D intake estimates and how meteorological data on UVB availability, when coupled with other key data, can help predict population serum 25(OH)D concentration, even accounting for seasonal fluctuations, and lastly, how these in silico approaches can help inform policymakers on strategic options on addressing low vitamin D status through food-based approaches and supplementation. The potential of exemplar food-based solutions will be highlighted, as will the possibility of synergies between vitamin D and other dairy food-based micronutrients, in relation to vitamin D status and bone health. Lastly, we will briefly consider the interactions between season and vitamin D supplements on vitamin D status and health.

Correction of vitamin D status by calcidiol: pharmacokinetic profile, safety, and biochemical effects on bone and mineral metabolism of daily and weekly dosage regimens

RATIONALE

Calcidiol can be employed to correct vitamin D deficiency.

MAIN RESULTS

Calcidiol administered at daily and weekly regimens over a period of 3 months was able to successfully raise 25-hydroxyvitamin D levels without altering other markers related to bone and mineral metabolism.

SIGNIFICANCE

Calcidiol supplementation is effective and safe.

INTRODUCTION

The correction of vitamin D status is necessary to maintain an optimal mineral and skeletal homeostasis. Despite cholecalciferol (vitamin D₃) is the most commonly used drug for vitamin D supplementation, the more hydrophilic compound calcidiol (25-hydroxyvitamin D₃) can be employed at daily, weekly, and monthly regimens to reach in the short term the target levels of serum 25-hydroxyvitamin D [25(OH)D]. In the administration of different doses of calcidiol pharmacokinetic study (ADDI-D study), the efficacy and safety of daily and weekly dosages of calcidiol were tested.

METHODS

A total of 87 Caucasian, community-dwelling, postmenopausal women, aged 55 years or older, with vitamin D inadequacy (serum 25(OH)D levels <30 ng/ml, with mean 25(OH)D below 20 ng/ml, namely 16.5 ± 7.5 ng/ml) were randomized to receive three different dosages of calcidiol: 20 μg/day, 40 μg/day, and 125 μg/week for 3 months. The attained level of serum 25(OH)D was selected as primary endpoint to assess efficacy, while other parameters of mineral metabolism, (serum calcium, parathyroid hormone, phosphate, FGF23, urinary calcium, and markers of bone turnover) were assessed as secondary endpoints to establish safety.

RESULTS

In all the three groups, serum 25(OH)D values significantly and promptly rose and plateaued above the 30 ng/ml threshold remaining within safety interval after 14 days of treatment, with similar efficacy for the similar daily and weekly dose regimens. The different dosages were also equally effective in controlling secondary hyperparathyroidism. No significant changes in calcium and phosphate metabolism and in bone turnover markers were observed for any of the treatments, confirming the safety of this compound.

CONCLUSIONS

The results of this study demonstrate the short- and mid-term efficacy and safety on core parameters of mineral metabolism of different daily or weekly dosages of calcidiol when used to treat vitamin D inadequacy or deficiency in postmenopausal women. Further studies are needed to assess falls as primary outcome of calcidiol supplementation.

A 25-Hydroxycholecalciferol-Fortified Dairy Drink Is More Effective at Raising a Marker of Postprandial Vitamin D Status than Cholecalciferol in Men with Suboptimal Vitamin D Status

Background: One strategy for improving population vitamin D status is consumption of fortified foods. However, the effects of dairy products fortified with different vitamin D isoforms on postprandial vitamin D status and metabolic outcomes have not been addressed.Objective: We investigated whether consumption of dairy drinks fortified with either 25-hydroxycholecalciferol [25(OH)D₃] or cholecalciferol (vitamin D₃) had differential effects on 24-h circulating plasma 25(OH)D₃ concentration (a marker of vitamin D status) and cardiometabolic risk markers.Methods: A randomized, controlled, 3-way crossover, double-blind, postprandial study was conducted in 17 men with suboptimal vitamin D status [mean ± SEM age: 49 ± 3 y; body mass index (in kg/m²): 26.4 ± 0.6; and plasma 25(OH)D₃ concentration: 31.7 ± 3.4 nmol/L]. They were randomly assigned to consume 3 different test meals (4.54 MJ, 51 g fat, 125 g carbohydrate, and 23 g protein), which contained either a nonfortified dairy drink (control), 20 μg 25(OH)D₃-fortified (+HyD₃) dairy drink, or 20 μg vitamin D₃-fortified (+D₃) dairy drink with toasted bread and jam on different occasions, separated by a 2-wk washout. Plasma 25(OH)D₃ concentrations and cardiometabolic risk markers, including vascular stiffness, serum lipids, and inflammatory markers, were measured frequently within 8 h postprandially and 24 h after the dairy drink was consumed.Results: Plasma 25(OH)D₃ concentrations (the primary outcome) were significantly higher after the +HyD₃ dairy drink was consumed compared with +D₃ and control (P = 0.019), which was reflected in the 1.5-fold and 1.8-fold greater incremental area under the curve for the 0-8 h response, respectively. The change in plasma 25(OH)D₃ concentrations from baseline to 24 h for the +HyD₃ dairy drink was also 0.9-fold higher than the +D₃ dairy drink and 4.4-fold higher than the control (P < 0.0001), which were not significantly different from each other.Conclusion: The dairy drink fortified with 25(OH)D₃ was more effective at raising plasma 25(OH)D₃ concentrations postprandially than was the dairy drink fortified with vitamin D₃ in men with suboptimal vitamin D status. This trial was registered at clinicaltrials.gov as NCT02535910.

Dietary Whole Egg Consumption Attenuates Body Weight Gain and Is More Effective than Supplemental Cholecalciferol in Maintaining Vitamin D Balance in Type 2 Diabetic Rats

Background: Type 2 diabetes (T2D) is characterized by vitamin D insufficiency owing to excessive urinary loss of 25-hydroxycholecalciferol [25(OH)D]. We previously reported that a diet containing dried whole egg, a rich source of vitamin D, was effective at maintaining circulating 25(OH)D concentrations in rats with T2D. Furthermore, whole egg consumption reduced body weight gain in rats with T2D.Objective: This study was conducted to compare whole egg consumption with supplemental cholecalciferol with respect to vitamin D balance, weight gain, and body composition in rats with T2D.Methods: Male Zucker diabetic fatty (ZDF) rats (n = 24) and their lean controls (n = 24) were obtained at 5 wk of age and randomly assigned to 3 treatment groups: a casein-based diet (CAS), a dried whole egg-based diet (WE), or a casein-based diet containing supplemental cholecalciferol (CAS+D) at the same amount of cholecalciferol provided by WE (37.6 μg/kg diet). Rats were fed their respective diets for 8 wk. Weight gain and food intake were measured daily, circulating 25(OH)D concentrations were measured by ELISA, and body composition was analyzed by dual X-ray absorptiometry.Results: Weight gain and percentage of body fat were reduced by ∼20% and 11%, respectively, in ZDF rats fed WE compared with ZDF rats fed CAS or CAS+D. ZDF rats fed CAS had 21% lower serum 25(OH)D concentrations than lean rats fed CAS. In ZDF rats, WE consumption increased serum 25(OH)D concentrations 130% compared with CAS, whereas consumption of CAS+D increased serum 25(OH)D concentrations 35% compared with CAS.Conclusions: Our data suggest that dietary consumption of whole eggs is more effective than supplemental cholecalciferol in maintaining circulating 25(OH)D concentrations in rats with T2D. Moreover, whole egg consumption attenuated weight gain and reduced percentage of body fat in ZDF rats. These data may support new dietary recommendations targeting the prevention of vitamin D insufficiency in T2D.

Impaired Release of Vitamin D in Dysfunctional Adipose Tissue: New Cues on Vitamin D Supplementation in Obesity

CONTEXT

Vitamin D accumulates in adipose tissue (AT), and vitamin D deficiency is frequent in obesity.

OBJECTIVE

We hypothesize that trafficking of vitamin D is altered in dysfunctional AT.

DESIGN, PATIENTS, SETTINGS

Fifty-four normal-weight and 67 obese males were recruited in a prospective study and randomly assigned to supplementation with 50 µg/wk 25-hydroxyvitamin-D3 or 150 µg/wk vitamin D3 for 1 year, raising dosage by 50% if vitamin D sufficiency [serum 25-hydroxyvitamin-D3 >50 nmol/L], was not achieved at 6 months; 97 subjects completed the study.

METHODS

Vitamin D3 and 25-hydroxyvitamin-D3 were quantified by HPLC-MS in control and insulin-resistant (IR) 3T3-L1 cells and subcutaneous AT (SAT) from lean and obese subjects, incubated with or without adrenaline; expression of 25-hydroxylase (Cyp27a1), 1α-hydroxylase (Cyp27b1), and vitamin D receptor (Vdr) was analyzed by real-time polymerase chain reaction.

RESULTS

In IR adipocytes, uptake of D3 and 25-hydroxyvitamin-D3 was higher, but, after adrenaline stimulation, the decrement in D3 and 25-hydroxyvitamin-D3 was stronger in control cells, which also showed increased expression of Cyp27a1 and Cyp27b1 and higher levels of 25-hydroxyvitamin-D3. In SAT from obese subjects, adrenaline-induced release of D3 and 25-hydroxyvitamin-D3 was blunted; in both IR cells and obese SAT, protein expression of β2-adrenergic receptor was reduced. Supplementation with 25-hydroxyvitamin-D3 was more effective in achieving vitamin D sufficiency in obese, but not in normal weight subjects.

CONCLUSION

Dysfunctional AT shows a reduced catecholamine-induced release of D3 and 25-hydroxyvitamin-D3 and altered activity of vitamin D-metabolizing enzymes; for these reasons supplementation with 25-hydroxyvitamin-D3 is more effective in obese individuals.

Vitamin D₃ and 25-Hydroxyvitamin D₃ Content of Retail White Fish and Eggs in Australia

Dietary vitamin D may compensate for inadequate sun exposure; however, there have been few investigations into the vitamin D content of Australian foods. We measured vitamin D₃ and 25-hydroxyvitamin D₃ (25(OH)D₃) in four species of white fish (barramundi, basa, hoki and king dory), and chicken eggs (cage and free-range), purchased from five Australian cities. Samples included local, imported and wild-caught fish, and eggs of varying size from producers with a range of hen stocking densities. Raw and cooked samples were analysed using high performance liquid chromatography with photodiode array. Limits of reporting were 0.2 and 0.1 μg/100 g for vitamin D₃ and 25(OH)D₃, respectively. The vitamin D₃ content of cooked white fish ranged from <0.1 to 2.3 μg/100 g, and the 25(OH)D₃ content ranged from 0.3 to 0.7 μg/100 g. The vitamin D₃ content of cooked cage eggs ranged from 0.4 to 0.8 μg/100 g, and the 25(OH)D₃ content ranged from 0.4 to 1.2 μg/100 g. The vitamin D₃ content of cooked free-range eggs ranged from 0.3 to 2.2 μg/100 g, and the 25(OH)D₃ content ranged from 0.5 to 0.8 μg/100 g. If, as has been suggested, 25(OH)D₃ has five times greater bioactivity than vitamin D₃, one cooked serve (100 g) of white fish, and one cooked serve of cage or free-range eggs (120 g) may provide 50% or 100%, respectively, of the current guidelines for the adequate intake of vitamin D (5 µg) for Australians aged 1-50 years.

Serum 25-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 concentrations in adult dogs are more substantially increased by oral supplementation of 25-hydroxyvitamin D3 than by vitamin D3

We previously found a weak response in serum 25-hydroxyvitamin D₃ (25(OH)D₃) concentrations when dogs were supplemented with oral vitamin D₃ (D₃). In the present study, we determined the relative potency of oral 25(OH)D₃ compared with D₃ for increasing vitamin D status in dogs with low serum 25(OH)D concentrations. Four male and three female, 4-year-old, intact, lean, genetically related, Chinese-crested/beagle dogs were studied in a randomised, single cross-over trial. After feeding a low-vitamin D diet (<4 IU/100 g) for 30 d, four dogs received daily D₃ supplementation at 2·3 µg/kg body weight^0·75, while three dogs received a molar equivalency as 25(OH)D₃. The supplements, dissolved in ethanol, were applied to a commercial treat for consumption. Serum 25(OH)D₃ and 24R,25-dihydroxyvitamin D₃ (24R,25(OH)₂D₃) were analysed weekly using a validated HPLC method. Both supplementations increased (P ≤ 0·01) serum 25(OH)D₃ concentrations. However, oral 25(OH)D₃ resulted in greater (P < 0·0001) concentrations than D₃ by week 1, with a difference of 173 % (P < 0·0001) by week 2. The supplementation period was limited to 14 d after serum 25(OH)D₃ concentrations were not appearing to plateau. Thereafter, a washout period of 1 month separated the cross-over. Following 25(OH)D₃, but not D₃ supplementation, serum 24R,25(OH)₂D₃ concentrations increased (P ≤ 0·02), 3 to 5 weeks after initiating supplementation. Vitamin D status, as indicated by serum 25(OH)D₃ and 24R,25(OH)₂D₃ concentrations, is more rapidly and efficiently increased in adult dogs by oral supplementation of 25(OH)D₃ than D₃.

Improved Dietary Guidelines for Vitamin D: Application of Individual Participant Data (IPD)-Level Meta-Regression Analyses

Dietary Reference Values (DRVs) for vitamin D have a key role in the prevention of vitamin D deficiency. However, despite adopting similar risk assessment protocols, estimates from authoritative agencies over the last 6 years have been diverse. This may have arisen from diverse approaches to data analysis. Modelling strategies for pooling of individual subject data from cognate vitamin D randomized controlled trials (RCTs) are likely to provide the most appropriate DRV estimates. Thus, the objective of the present work was to undertake the first-ever individual participant data (IPD)-level meta-regression, which is increasingly recognized as best practice, from seven winter-based RCTs (with 882 participants ranging in age from 4 to 90 years) of the vitamin D intake-serum 25-hydroxyvitamin D (25(OH)D) dose-response. Our IPD-derived estimates of vitamin D intakes required to maintain 97.5% of 25(OH)D concentrations >25, 30, and 50 nmol/L across the population are 10, 13, and 26 µg/day, respectively. In contrast, standard meta-regression analyses with aggregate data (as used by several agencies in recent years) from the same RCTs estimated that a vitamin D intake requirement of 14 µg/day would maintain 97.5% of 25(OH)D >50 nmol/L. These first IPD-derived estimates offer improved dietary recommendations for vitamin D because the underpinning modeling captures the between-person variability in response of serum 25(OH)D to vitamin D intake.

25-Hydroxyvitamin D and blood pressure: a plateau effect in adults with African ancestry living at different latitudes

OBJECTIVE

This study examined the association of 25-hydroxyvitamin D [25(OH)D] levels and blood pressure above and below 25(OH)D levels of 20 ng/ml in young adults with African ancestry.

METHODS

This cross-sectional analysis utilized data from a pooled sample of 2242 adults with African ancestry from five different latitudes (403 in the United States, 474 in South Africa, 479 in Ghana, 448 in Jamaica, and 438 in Seychelles). Piecewise linear regression models with a single knot were fitted to determine above and below a 25(OH)D level of 20 ng/ml the slope of SBP and DBP while adjusting for covariates including calcium intake and site.

RESULTS

The mean age was 34.4 (6.1) years, and 46.3% were men. Mean SBP and DBP were 118.1 (15.6) and 73.2 (12.2) mmHg, respectively, and were significantly higher among the United States vs Ghana, Jamaica, and Seychelles groups (P < 0.001 for all comparisons). 25(OH)D levels were significantly lower in the United States vs all other sites (P < 0.001 for all comparisons). When 25(OH)D levels were less than 20 ng/ml, slopes of SBP [-0.33 (95% confidence interval (CI) -0.57, -0.07)] and DBP [-0.21 (95% CI -0.40, -0.02)] were negative and significantly different from zero after adjustment for covariates. In contrast, with 25(OH)D levels above 20 ng/ml, the slopes of SBP [-0.03 (95% CI -0.13, 0.06)] and DBP [-0.04 (-0.11, 0.03)] did not differ significantly from zero.

CONCLUSION

The cross-sectional association of 25(OH)D with blood pressure is strongest when 25(OH)D levels are less than 20 ng/ml in young adults with African ancestry.

Effects of Cholecalciferol vs Calcifediol on Total and Free 25-Hydroxyvitamin D and Parathyroid Hormone

CONTEXT

Vitamin D deficiency disproportionately affects nonwhite individuals. Controversy persists over how to best restore low 25D levels, and how to best define vitamin D status [total (protein bound plus free) vs free 25D].

OBJECTIVE

To assess the effects of vitamin D3 (cholecalciferol, or D3) vs 25-hydroxyvitamin D3 (calcifediol, or 25D3) on total and free 25D in a multiethnic cohort of adults, and whether change in parathyroid hormone (PTH) is more strongly associated with total vs free 25D.

DESIGN

Sixteen-week randomized controlled trial. Biochemistries at 0, 4, 8, and 16 weeks.

SETTING

Academic medical center.

PARTICIPANTS

Thirty-five adults ≥18 years of age with 25D levels <20 ng/mL.

INTERVENTION

Sixty micrograms (2400 IU)/d of D3 or 20 μg/d of 25D3.

MAIN OUTCOME MEASURES

Total and free 25D, and PTH.

RESULTS

Baseline total (16.2 ± 3.7 vs 17.0 ± 2.5 ng/mL; P = 0.4) and free (4.2 ± 0.8 vs 4.7 ± 1.0 pg/mL; P = 0.2) 25D were similar between D3 and 25D3 groups, respectively; 25D3 increased total (+25.5 vs +13.8 ng/mL; P = 0.001) and free (+6.6 vs +3.5 pg/mL; P = 0.03) 25D more than D3. By 4 weeks, 87.5% of 25D3 participants had total 25D levels ≥30 ng/mL, compared with 23.1% of D3 participants (P = 0.001). Change in PTH was associated with both total (P = 0.01) and free 25D (P = 0.04).

CONCLUSIONS

25D3 increased total and free 25D levels more rapidly than D3, regardless of race/ethnicity. Free and total 25D were similarly associated with change in PTH.

Dose-response effects of supplementation with calcifediol on serum 25-hydroxyvitamin D status and its metabolites: A randomized controlled trial in older adults

BACKGROUND & AIMS

Oral supplementation with vitamin D is recommended for older adults to maintain a sufficient 25-hydroxyvitamin D (25(OH)D) status throughout the year. While supplementation with vitamin D₂ or D₃ is most common, alternative treatment regimens exist which require further investigation with respect to increasing 25(OH)D concentration. We investigated the dose-response effects of supplementation with calcifediol compared to vitamin D₃ and assessed the dose which results in mean serum 25(OH)D₃ concentrations between 75 and 100 nmol/L.

METHODS

This randomized, double-blind intervention study included men and women aged ≥65 years (n = 59). Participants received either 5, 10 or 15 μg calcifediol or 20 μg vitamin D₃ per day, for a period of 24 weeks. Blood samples were collected every four weeks to assess response profiles of vitamin D related metabolites; serum vitamin D₃, 25(OH)D₃, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) and 24,25-dihydroxyvitamin D₃ (24,25(OH)₂D₃). Further, serum calcium, plasma parathyroid hormone, and urinary calcium were evaluated.

RESULTS

Supplementation with 20 μg vitamin D₃ increased 25(OH)D₃ concentrations towards 70 nmol/L within 16 weeks. Supplementation with 10 or 15 μg calcifediol increased 25(OH)D₃ levels >75 nmol/L in 8 and 4 weeks, respectively. Steady state was achieved from week 12 onwards with serum 25(OH)D₃ levels stabilizing between 84 and 89 nmol/L in the 10 μg calcifediol group. A significant association was observed between the changes in 25(OH)D₃ and 24,25(OH)₂D₃ (R² = 0.83, P < 0.01), but not between 25(OH)D₃ and 1,25(OH)₂D₃ (R² = 0.04, P = 0.18). No cases of hypercalcemia occurred in any treatment during the study period.

CONCLUSIONS

Calcifediol supplementation rapidly and safely elevates serum 25(OH)D₃ concentrations to improve vitamin D status in older adults. A daily dose of 10 μg calcifediol allows serum 25(OH)D₃ concentrations to be maintained between 75 and 100 nmol/L.

TRIAL REGISTRATION NUMBER

NCT01868945.