Serum 25-hydroxycholecalciferol Concentrations Research Articles

Folate, vitamin B12 and vitamin D status in healthy and active home-dwelling people over 70 years

BackgroundAgeing is characterised by physiological changes that can affect the nutrient availability and requirements. In particular, the status of vitamin D, cobalamin and folate has often been found to be critical in older people living in residential care. However, there is a lack of studies investigating the status of these nutrients in healthy and active home-dwelling elderly people.MethodsThe aim of this cross-sectional study was to assess the status of vitamin D based on serum concentrations of 25-hydroxycholecalciferol [25-(OH)D], cobalamin based on serum concentrations of holotranscobalamin (holoTC) and folate based on red blood cell (RBC) folate in unsupplemented, healthy and active German home-dwelling subjects ≥ 70 years of age (n = 134, mean ± SD: 75.8 ± 4.5 years). Dietary intake was assessed by 3-day food recalls. The study was conducted between March and November of 2021 (during the COVID-19 pandemic).ResultsThe mean 25-(OH)D concentration was high at 85.1 ± 26.0 nmol/L, while the majority of women (92%) and men (94%) had 25-(OH)D concentrations ≥ 50 nmol/L. Less than 10% of men and women had 25-(OH)D concentrations < 50 nmol/L. The mean holoTC concentration was 88.9 ± 33.7 pmol/L (94.8 ± 34.6 pmol/L in women and 73.6 ± 25.6 in men). Only 8% of the women were cobalamin deficient (< 50 pmol/L holoTC) compared to 22% of the men. The mean RBC folate concentration was 831 ± 244 nmol/L, while the prevalence of folate deficiency was 10%. Linear regression analysis showed that only folate equivalent intake was associated with the relevant nutrient status marker.ConclusionOur findings suggest that healthy, independently living older people with high levels of education, physical activity, and health awareness are not necessarily at higher risk of vitamin D, folate and cobalamin deficiency. Further studies are needed to verify these findings and to identify lifestyle and dietary patterns that can predict adequate nutrient status for healthy ageing.Trial registrationThis study is officially recorded in the German Clinical Trials Register (DRKS00021302).

Assessment of the vitamin D status and its determinants in young healthy students from Palestine.

The global prevalence of vitamin D deficiency is high. Poor vitamin D status, especially in women, has been reported in several countries in the Middle East despite adequate year-round sunlight for vitamin D synthesis. However, data on vitamin D status in Palestine are scarce. The aim of this cross-sectional study was to evaluate vitamin D status based on serum concentrations of 25-hydroxycholecalciferol [25-(OH)D] among young healthy Palestinian students (18-27 years) and to assess associations between 25-(OH)D concentrations and several predictors. The mean 25-(OH)D concentration of women (n 151) was 27⋅2 ± 14⋅5 nmol/l, with the majority having insufficient (31⋅1%) or deficient (<60%) 25-(OH)D status. Only 7% of women achieved sufficient or optimal 25-(OH)D status. In contrast, men (n 52) had a mean 25-(OH)D concentration of 58⋅3 ± 14⋅5 nmol/l, with none classified as deficient, and most obtaining sufficient (55⋅8%) or even optimal 25-(OH)D status (11⋅5%). Among women, 98% wore a hijab and 74% regularly used sunscreen. Daily dietary vitamin D intake (3-d 24-h recalls) was 45⋅1 ± 36⋅1 IU in the total group (no sex differences). After adjustment, multiple linear regression models showed significant associations between 25-(OH)D concentrations and the use of supplements (B = 0⋅069; P = 0⋅020) and dietary vitamin D (B = 0⋅001; P = 0⋅028). In gender-stratified analysis, the association between supplement use and 25-(OH)D concentrations was significant in women (B = 0⋅076; P = 0⋅040). The vitamin D status of women in the present cohort is critical and appears to be mainly due to wearing a hijab, regular use of sunscreen and low dietary vitamin D intake. The vitamin D status of the women should be improved by taking vitamin D containing supplements or fortified foods.

Maternal cholecalciferol supplementation during gestation improves antioxidant capacities in gilts and piglets

Various studies have evaluated the relationship between cholecalciferol (vitamin D3) and reproductive performance. This study aimed at investigating the effects of maternal D3 supplementation during gestation on reproductive performance and antioxidant capacities of gilts and their offsprings. Twenty-three Landrace × Yorkshire gilts were randomly allocated into two groups and fed on one of the following two diets during gestation: control diet or D3 supplemented diet. It was found that D3 supplementation had a tendency to increase the number of total born and born alive piglets. Moreover, it elevated serum 25-hydroxycholecalciferol concentrations in gilts and newborn piglets. Besides, D3 supplementation improved the activities of antioxidant enzymes (GSH-Px, T-AOC and T-SOD) in the blood of gilts, umbilical cord and newborn piglets and piglets’ liver, while serum malondialdehyde concentrations of gilts and umbilical cord were reduced in the D3 group. In addition, D3 supplementation upregulated the expression of antioxidant related genes in the placenta and piglets’ liver. In conclusion, D3 supplementation during gestation might improve antioxidant capacities in gilts, placenta and in newborn piglets. Therefore, D3 supplementation has the potential to enhance the reproductive performance of gilts. HIGHLIGHTS D3 supplementation has a significant role in the nutrition of gilts. Maternal D3 supplementation during gestation increased the number of born and born alive piglets. Maternal D3 supplementation during gestation improved the antioxidant capacities of gilts, placenta and newborn piglets.

Lower serum 25-hydroxycholecalciferol is associated with depressive symptoms in older adults in Southern Brazil

BackgroundOlder adults are one of the most susceptible populations to depression, especially those living in low- and middle-income countries. As well, they are also considering a risk group for vitamin D deficiency. Low serum vitamin D has been associated with an increased risk of brain neuropsychiatry disorders. We aimed to investigate the association between serum 25-hydroxycholecalciferol concentrations and depressive symptoms in adults aged 60 years and over from southern Brazil.MethodsA cross-sectional analysis was performed using data collected during 2013–2014 from the populational-based longitudinal EpiFloripa Aging Study (n = 1197). Serum 25-hydroxycholecalciferol concentrations were analyzed and classified according to the Endocrine Society reference values [sufficiency (≥ 30 ng/mL), insufficiency (21–29 ng/mL), and deficiency (≤ 20 ng/mL)]. Depressive symptoms were evaluated using the Geriatric Depression Scale (15-item GDS). Logistic regression was performed to assess depressive symptoms in each vitamin D category. The analysis was adjusted for sex, age, skin color, family income, leisure-time physical activities, social or religious groups attendance, morbidities, cognitive impairment, and dependence in activities of daily living.ResultsA total of 557 participants with complete data for exposure and outcome were enrolled in the analysis. Most of the sample participants were female (63.1%), age-range 60–69 years (42.2%), white skin color (85.1%), and vitamin D serum level samples were collected in autumn (50.7%). Depressive symptoms were present in 15.8% of the participants, and the prevalence was higher in individuals classified as deficient in vitamin D (23.2, 95% confidence interval [CI] = 15.6;32.9) and insufficiency (17.2, 95%CI = 11.0;25.9). The crude analysis showed that vitamin D deficient participants had 3.08 (CI = 1.53;6.20) times higher odds to present depressive symptoms compared to vitamin D sufficiency. After adjusting, the association was maintained [OR 2.27 (95%CI = 1.05;4.94).ConclusionsSerum 25-hydroxycholecalciferol deficiency was positively associated with depressive symptoms in older adults from southern Brazil.

The effects of vitamin D on acute viral respiratory infections: A rapid review

Brief overviewCurrent evidence suggests vitamin D replacement may reduce risk for acute respiratory tract infections (ARTI) in people with deficiency or insufficiency, although the effects of supplementation on incidence and severity of ARTI in the general population remain unknown. Oral vitamin D supplemzentation taken at routine doses appears to be generally safe and well tolerated. VerdictCurrent experimental evidence remains inconclusive regarding the effects of vitamin D supplementation in the general population for the prevention and treatment of acute respiratory tract infections (ARTI). There is also insufficient evidence to draw conclusions regarding the impact of vitamin D supplementation on the severity or duration of ARTI, nor on outcomes related to lung injury or hospitalization from ARTI. Based on this rapid review, sources of significant heterogeneity in published clinical trials include: differences study populations, inconsistent assessment of serum status at baseline, dosing variability, varying routes of administration, and/or inconsistent definitions of outcome measures. Experimental evidence and observations in large cohorts are generally consistent that vitamin D deficiency (<50 nmol/L [<20 ng/mL]) and insufficiency (<75 nmol/L [<30 ng/mL]) of serum 25-hydroxycholecalciferol (25-OHD) concentration is associated with increased risk of ARTI, and supplementation for those with deficiency/insufficiency may lead to clinically meaningful reductions in the incidence of ARTI. In this rapid review, vitamin D was primarily administered as oral supplementation, and findings suggested significant differences in daily oral dosing compared to periodic bolus dosing. Based on the available experimental evidence, vitamin D supplementation appears to have a high margin of safety with very few adverse events reported in children or adults from a variety of dosing strategies. Future clinical trials on vitamin D should consider the sources of heterogeneity in the existing experimental research and design trials that account for baseline status, evaluate the potential for prevention and treatment in at risk populations, standardize dosing strategies, assess product quality, assess outcomes according to gold standard definitions/diagnostic methods, and delineate viral ARTI from other causes when possible. The available mechanistic evidence related to immunological requirements for adequate vitamin D, the availability of observational and experimental evidence suggestive of clinically meaningful benefits (especially in deficient/insufficient participants), and the high margin of safety, should make vitamin D a high priority for additional clinical research during the current COVID-19 pandemic.

Effects of source and level of in ovo-injected vitamin D3 on the hatchability and serum 25-hydroxycholecalciferol concentrations of Ross 708 broilers

Effects of the in ovo injection of vitamin D3 (D3) and 25-hydroxycholecalciferol (25OHD3) on broiler embryo serum 25OHD3 concentrations, hatchability, and hatchling somatic characteristics were determined. Eggs from a 35-wk-old commercial Ross 708 broiler breeder flock were set in a single-stage incubator with 11 treatments represented on each of 8 incubator tray levels (blocks). Each treatment group within a flat on each tray level contained 30 eggs. Control treatments were noninjected and diluent injected. Vitamin treatments were commercial diluent containing 0.6 μg D3, 0.6 μg 25OHD3, 0.6 μg D3 + 0.6 μg 25OHD3, 1.2 μg D3, 1.2 μg 25OHD3, 1.2 μg D3 + 1.2 μg 25OHD3, 2.4 μg D3, 2.4 μg 25OHD3, or 2.4 μg D3 + 2.4 μg 25OHD3. At 432 h of incubation (hoi), 50-μL solution volumes were injected. Blood samples were collected at 462 hoi for serum 25OHD3 analysis, and hatchability of injected live embryonated eggs (HI) was determined at 492 and 516 hoi. At 516 hoi, hatchling yolk-free BW and weights of the liver and yolk sac were determined. Percentage of yolk moisture and dry mater was calculated. At 492 and 516 hoi, HI did not differ between treatments. Embryos that received 1.2 μg or more of either vitamin D3 source alone or in combination had higher serum 25OHD3 concentrations than those that were injected with diluent alone or diluent containing 0.6 μg of D3. Hatchlings that received 1.2 or 2.4 μg of 25OHD3 had higher percentage of yolk dry matter or lower percentage of yolk moisture levels than noninjected controls and those that received D3 alone at any level. These results indicate that the in ovo injection of either vitamin D3 source at levels equal to or higher than 1.2 μg resulted in serum 25OHD3 concentrations that were higher than that of noninjected controls. In addition, the in ovo injection of 1.2 μg or higher of either vitamin D3 source did not negatively affect broiler HI or chick quality.

Expression of vitamin D hydroxylases and bone quality in obese mice consuming saturated or monounsaturated enriched high-fat diets

Obesity induced by high-fat diets (HFDs) is inversely associated with vitamin D status and bone health. However, the associations and effects of excessive fat intake on hepatic and renal vitamin D metabolism have not been addressed. The primary objective was to determine if excessive energy and fat intake, or the type of fat, affects serum 25-hydroxycholecalciferol concentration and whether this can be explained by an alteration of vitamin D–regulating enzymes in older mice. The second objective was a follow up of our recent findings that a high intake of monounsaturated fatty acids (MUFA) is not detrimental to bone in lean mice and whether this is also true under conditions of diet-induced obesity. In the study, twenty-one 8-month-old female C57BL/6 J mice were fed ad libitum for 10 weeks with a 10% normal-fat diet (NFD) or 45% HFD enriched with MUFA or saturated fatty acids (SFA). We found that the HFD, compared with NFD, resulted in greater energy intake, weight gain, total body fat, and liver fat (P < .05). Only the high SFA feeding resulted in higher mRNA but lower protein abundance of hepatic Cyp2r1 and lower renal Cyp24a1 mRNA expression than the NFD group (P < .05). Moreover, although bone mineral density did not differ among groups, the percent difference compared with NFD was significantly lower for SFA (P < .05) but not MUFA. Also, femoral trabecular bone volume fraction was lower (P < .05) only in the SFA compared with the NFD group. In conclusion, high SFA and MUFA feeding differentially affected gene and protein expressions of major vitamin D hydroxylases compared with NFD, but this was unrelated to the lower circulating 25-hydroxycholecalciferol concentration. In addition, only the SFA diet alters vitamin D metabolism and bone changes, indicating the importance of dietary fat composition.

Administration of vitamin D3 by injection or drinking water alters serum 25-hydroxycholecalciferol concentrations of nursery pigs.

ObjectiveTwo experiments were conducted to evaluate vitamin D3 administration to nursery pigs by injection or in drinking water on serum 25-hydroxycholecalciferol (25-OHD3) concentrations.MethodsAt weaning, 51 pigs (27 and 24 pigs in experiments 1 and 2, respectively) were allotted to vitamin D3 treatments. Treatments in experiment 1 were: i) control (CON), no vitamin administration beyond that in the diet, ii) intramuscular (IM) injection of 40,000 IU of vitamin D3 at weaning, and iii) water administration, 5,493 IU of vitamin D3/L drinking water for 14 d postweaning. Treatments in experiment 2 were: i) control (CON), no vitamin administration, and ii) water administration, 92 IU of d-α-tocopherol and 5,493 IU of vitamin D3/L drinking water for 28 d postweaning. The lightest 2 pigs within each pen were IM injected with an additional 1,000 IU of d-α-tocopherol, 100,000 IU of retinyl palmitate, and 100,000 IU of vitamin D3.ResultsIn both experiments, serum 25-OHD3 was changed after vitamin D3 administration (p<0.05). In experiment 1, injection and water groups had greater values than CON group through d 35 and 21 post-administration, respectively (p<0.05). In experiment 2, serum values peaked at d 3 post-administration in the injection groups regardless of water treatments (p<0.05) whereas CON and water-only groups had peaks at d 14 and 28 post-administration, respectively (p<0.05). Even though the injection groups had greater serum 25-OHD3 concentrations than the non-injection groups through d 7 post-administration regardless of water treatments (p<0.05), the water-only group had greater values than the injection-only group from d 21 post-administration onward (p<0.05).ConclusionSerum 25-OHD3 concentrations in pigs increased either by vitamin D3 injection or drinking water administration. Although a single vitamin D3 injection enhanced serum 25-OHD3 concentrations greater than water administration in the initial period post-administration, a continuous supply of vitamin D3 via drinking water could maintain higher serum values than the single injection.

Genetics, Diet, and Season Are Associated with Serum 25-Hydroxycholecalciferol Concentration in a Yup’ik Study Population from Southwestern Alaska

Background: Low blood vitamin D concentration is a concern for people living in circumpolar regions, where sunlight is insufficient for vitamin D synthesis in winter months and the consumption of traditional dietary sources of vitamin D is decreasing.Objective: The objective was to characterize the effects of diet, genetic variation, and season on serum 25-hydroxycholecalciferol [25(OH)D3] concentrations in Yup’ik Alaska Native people living in rural southwest Alaska.Methods: This study was a cross-sectional design that assessed the associations of traditional diet (via a biomarker, the RBC δ15N value), age, gender, body mass index (BMI), community location, and genotype of select single nucleotide polymorphisms (SNPs) in cytochrome P450 family 2, subfamily R, peptide 1 (CYP2R1), 7-dehydrocholesterol reductase (DHCR7), and vitamin D binding protein (GC) with serum 25(OH)D3 concentrations in 743 Yup’ik male and female participants, aged 14–93 y, recruited between September 2009 and December 2013.Results: Yup’ik participants, on average, had adequate concentrations of serum 25(OH)D3 (31.1 ± 1.0 ng/mL). Variations in diet, BMI, age, gender, season of sample collection, and inland or coastal community geography were all significantly associated with serum 25(OH)D3 concentration. In models not adjusting for other covariates, age, diet, and seasonal effects explained 33.7%, 20.7%, and 9.8%, respectively, of variability in serum 25(OH)D3 concentrations. Of the 8 SNPs interrogated in CYP2R1 and DHCR7, only rs11023374 in CYP2R1 was significantly associated with serum 25(OH)D3, explaining 1.5% of variability. The GC haplotype explained an additional 2.8% of variability. Together, age, diet, gender, season of sample collection, BMI, geography of the community, and genotype at rs11023374 explained 52.5% of the variability in serum 25(OH)D3 concentrations.Conclusions: Lower consumption of the traditional diet was associated with lower serum concentrations of 25(OH)D3. Younger adults and youth in this community may be at increased risk of adverse outcomes associated with vitamin D insufficiency compared with older members of the community, especially during seasons of low sunlight exposure, because of lower consumption of dietary sources of vitamin D.

Whole Egg Consumption Prevents Diminished Serum 25-Hydroxycholecalciferol Concentrations in Type 2 Diabetic Rats.

Type 2 diabetes (T2D) is characterized by vitamin D deficiency owing to increased urinary loss of 25-hydroxycholecalciferol (25D). Whole eggs are a rich source of vitamin D, particularly 25D, the circulating form that reflects status. Zucker diabetic (type 2) fatty (ZDF) rats and their lean counterparts were fed casein- or whole egg-based diets for 8 weeks. Whole egg consumption attenuated both hyperglycemia and hypertriglyceridemia, as well as reduced weight gain in ZDF rats compared to casein-fed diabetic rats. Circulating 25D was lower in casein-fed ZDF rats compared to lean controls; however, ZDF rats fed whole egg exhibited the same circulating 25D concentration as casein-fed lean rats. These data suggest that dietary whole egg can attenuate metabolic anomalies, as well as maintain normal circulating 25D concentrations in T2D rats. This finding may support new dietary recommendations targeting vitamin D deficiency prevention in T2D.

Circulating adiponectin concentrations are increased by dietary resistant starch and correlate with serum 25-hydroxycholecalciferol concentrations and kidney function in Zucker diabetic fatty rats

We previously reported that dietary resistant starch (RS) type 2 prevented proteinuria and promoted vitamin D balance in type 2 diabetic (T2D) rats. Here, our primary objective was to identify potential mechanisms that could explain our earlier observations. We hypothesized that RS could promote adiponectin secretion and regulate the renin-angiotensin system activity in the kidney. Lean Zucker rats (n = 5) were fed control diet; Zucker diabetic fatty rats (n = 5/group) were fed either an AIN-93G control diet (DC) or AIN-93G diet containing either 10% RS or 20% RS (HRS) for 6 weeks. Resistant starch had no impact on blood glucose concentrations and hemoglobin A1c percentage, yet circulating adiponectin was 77% higher in HRS-fed rats, compared to DC rats. Adiponectin concentrations strongly correlated with serum 25-hydroxycholecalciferol (r = 0.815; P < .001) and urinary creatinine concentrations (r = 0.818; P < .001) and inversely correlated with proteinuria (r = −0.583; P = .02). Serum angiotensin II concentrations were 44% lower, and expression of the angiotensin II receptor, type 1, was attenuated in RS-fed rats. Moreover, we observed a 14-fold increase in messenger RNA expression of nephrin, which is required for functioning of the renal filtration barrier, in HRS rats. The HRS, but not 10% RS diet, increased circulating 25-hydroxycholecalciferol concentrations and attenuated urinary loss of vitamin D metabolites in Zucker diabetic fatty rats. Taken together, we provide evidence that vitamin D balance in the presence of hyperglycemia is strongly associated with serum adiponectin levels and reduced renal renin-angiotensin system signaling.

Effects of the in ovo injection of 25-hydroxycholecalciferol on the yolk and serum characteristics of male and female broiler embryos ,

Serum concentrations of 25-hydroxycholecalciferol [25(OH)D3] in broiler embryos at 19 d of incubation( doi) have been shown to increase 3 times by the in ovo injection of 0.60 μg 25(OH)D3 on 18 doi. In this trial, effects of the injection of 25(OH)D3 at 18 doi on the yolks and sera of male and female Ross × Ross 708 broiler embryos were assessed. On 18 doi, embryonated eggs that were set in a single stage incubator were assigned to 6 replicate trays within each of 2 injection treatment groups. Treatments included those injected with 100 μL commercial diluent (control) and those injected with 0.60 μg 25(OH)D3 in 100 μL commercial diluent. On 19 doi, embryos and their yolk sacs were extracted for determination of sex, yolk weight, BW, serum CA and phosphorous concentrations, and yolk CA, phosphorous, moisture, dry matter, and lipid concentrations. The weight of female embryos with their attached yolk sacs as a percentage of set egg weight was greater than that of males (P = 0.03). There were treatment × sex interactions for the weight of embryos with their attached yolk sacs relative to 19 doi egg weight (P = 0.05) and for yolk CA concentration (P = 0.004). In eggs that received 25(OH)D3, the weight of female embryos with their attached yolk sacs relative to 19 doi egg weight was higher than that of males (P = 0.005), and percentage yolk CA was higher in control eggs containing female embryos in comparison to those containing males (P = 0.007). An injection of 0.60 μg 25(OH)D3 at 18 doi eliminated yolk CA differences associated with embryo sex, suggesting that 25(OH)D3 may influence sex-related differences in the rate of yolk CA absorption by broiler embryos and may be related to subsequent sex-related differences in posthatch bone strength.

Calcium-phosphate metabolism in patients with multiple sclerosis.

Introduction and objectivesThe purpose of this study was to evaluate the concentration of 25-hydroxycholecalciferol and parameters of calcium–phosphate metabolism at different periods of relapsing–remitting multiple sclerosis (RRMS).Materials and methodsForty-five patients, residents of Poland (49°–50°, N), were enrolled in the study, i.e. 15 immediately after the diagnosis of RRMS, 15 at the early stage and 15 at the advanced stage of RRMS. The results were compared to values obtained in 20 age- and sex-matched controls.ResultsLower serum concentrations of 25-hydroxycholecalciferol and ionised calcium were found in patients compared to the control group. In patients with the disease duration of 5–6 years, concentrations of 25-hydroxycholecalciferol and ionised calcium were lower than in patients in the earlier period of RRMS. The inverse and clearer direction of changes was found in parathormone serum concentration in patients compared to the controls. In patients with a longer disease duration, a significantly lower 25-hydroxycholecalciferol concentration was found in female patients compared to male patients. In patients, more frequent 25-hydroxycholecalciferol and unsaturated fatty acids’ supplementation was observed compared to the controls.ConclusionsIn RRMS patients, calcium–phosphate metabolism is disturbed which increases during disease progression.

Dietary Resistant Starch Prevents Urinary Excretion of Vitamin D Metabolites and Maintains Circulating 25-Hydroxycholecalciferol Concentrations in Zucker Diabetic Fatty Rats

Background:Type 2 diabetes (T2D) is the leading cause of nephropathy in the United States. Renal complications of T2D include proteinuria and suboptimal serum 25-hydroxycholecalciferol (25D) concentrations. 25D is the major circulating form of vitamin D and renal reabsorption of the 25D–vitamin D–binding protein (DBP) complex via megalin-mediated endocytosis is believed to determine whether 25D can be activated to 1,25-dihydroxycholecalciferol (1,25D) or returned to circulation. We previously demonstrated that excessive urinary excretion of 25D–DBP and albuminuria occurred in rats with type 1 diabetes (T1D) and T2D. Moreover, feeding rats with T1D high-amylose maize partially resistant to digestion [resistant starch (RS)] prevented excretion of 25D–DBP without significantly affecting hyperglycemia. Objective:We used Zucker diabetic fatty (ZDF) rats, a model of obesity-related T2D, to determine whether feeding RS could similarly prevent loss of vitamin D and maintain serum 25D concentrations. Methods:Lean control Zucker rats (n = 8) were fed a standard semi-purified diet (AIN-93G) and ZDF rats were fed either the AIN-93G diet (n = 8) or the AIN-93G diet in which cornstarch was replaced with RS (550 g/kg diet; 35% resistant to digestion) (n = 8) for 6 wk. Results:RS attenuated hyperglycemia by 41% (P < 0.01) and prevented urinary DBP excretion and albuminuria, which were elevated 3.0- (P < 0.01) and 3.6-fold (P < 0.01), respectively, in control diet–fed ZDF rats. Additionally, urinary excretion of 25D (P = 0.01) and 1,25D (P = 0.03) was higher (89% and 97%, respectively), whereas serum 25D concentrations were 31% lower (P < 0.001) in ZDF rats fed the control diet compared with RS-fed ZDF rats. Histopathologic scoring of the kidney revealed that RS attenuated diabetes-mediated damage by 21% (P = 0.12) despite an ∼50% decrease in megalin protein abundance. Conclusions:Taken together, these data provide evidence that suggests vitamin D balance can be maintained by dietary RS through nephroprotective actions in T2D, which are independent of vitamin D supplementation and renal expression of megalin.

Association of bone microarchitecture with parathyroid hormone concentration and calcium intake in men: the STRAMBO study

OBJECTVIE: In the elderly, vitamin D deficit, low calcium intake, and impaired bone microarchitecture are associated with higher risk of hip fracture. We assessed the association of bone microarchitecture with calcium intake and serum concentrations of 25-hydroxycholecalciferol (25OHD) and parathyroid hormone (PTH) in men. Cross-sectional analysis was performed in 1064 men aged 20-87 years not taking vitamin D or calcium supplements. Daily calcium intake was assessed using a food frequency questionnaire. Bone microarchitecture was assessed at distal radius and tibia by high-resolution peripheral quantitative computed tomography. We measured serum and urinary levels of biochemical bone turnover markers (BTMs). Statistical models were adjusted for age, weight, height, and glomerular filtration rate. In 500 men aged <65 years, lower 25OHD levels and low calcium intake were associated with lower trabecular volumetric bone mineral density (Dtrab) at the distal tibia, due to lower trabecular number (Tb.N). Low calcium intake was associated with lower cortical thickness (Ct.Th). Higher PTH level was associated with higher BTM levels. In 563 men aged ≥65 years, the highest PTH quartile was associated with lower Ct.Th (tibia), lower Dtrab (both sites), and lower Tb.N (radius) compared with the lowest quartile. Low calcium intake was associated with lower Tb.N and more heterogenous trabecular distribution. BTM positively correlated with the PTH concentration. In older men, elevated PTH concentration is associated with high bone turnover, poor trabecular microarchitecture (radius and tibia), and, at the distal tibia, lower Ct.Th. Low calcium intake is associated with lower Tb.N and more heterogenous trabecular distribution.

Maintenance of Wintertime Vitamin D Status with Cholecalciferol Supplementation Is Not Associated with Alterations in Serum Cytokine Concentrations among Apparently Healthy Younger or Older Adults1–4

AbstractEpidemiological studies have shown that low vitamin D status results in impaired immune function and is associated with the prevalence of autoimmune and inflammatory conditions. Vitamin D supplementation has been shown to reduce circulating concentrations of inflammatory markers in such conditions. However, the possible beneficial effect of vitamin D supplementation in the general population, particularly for those individuals living at high latitudes where hypovitaminosis D is common during wintertime, remains unclear. The aim of this study was to assess the effect of vitamin D supplementation using doses of 5, 10, and 15 g/d cholecalciferol (D3) compared with placebo on cytokine concentrations throughout winter in apparently healthy younger (aged 20–40 y) and older (aged =64 y) adults. A total of 211 younger and 202 older adults completed the 22-wk intervention (from October to March) with >85% compliance. Serum concentrations of 25-hydroxycholecalciferol [25(OH)D3], high sensitivity C-reactive protein, IL-6, IL-10, soluble CD40 ligand, TGF, TNFa, and fibrinogen were measured using ELISA. 25(OH)D3 concentrations significantly decreased in the placebo and 5 and 10/d g D3 groups in the younger cohort and in the placebo group in the older cohort. Whereas 15 g/d D3 supplementation maintained 25(OH)D3 concentrations in the younger cohort (baseline, 75.9 nmol/L; postintervention, 69.0 nmol/L) and significantly increased concentrations in the older cohort (baseline, 55.1 nmol/L; postintervention, 73.9 nmol/L), it had no significant effect on cytokine concentrations (ANCOVA, P > 0.05). The long-term effects of low vitamin D status remain to be elucidated and optimization of vitamin D status in otherwise healthy individuals may potentially have lasting beneficial effects on the immune system.

Bone mineral density and bone markers in patients with a recent low-energy fracture: effect of 1 y of treatment with calcium and vitamin D

Background: Low-energy fractures of the hip, forearm, shoulder, and spine are known consequences of osteoporosis.Objective: We evaluated the effect of 1 y of treatment with calcium and vitamin D on bone mineral density (BMD) and bone markers in patients with a recent low-energy fracture.Design: In a double-blinded design, patients with fracture of the hip (lower-extremity fracture, or LEF) or upper extremity (UEF) were randomly assigned to receive 3000 mg calcium carbonate + 1400 IU cholecalciferol or placebo (200 IU cholecalciferol). BMD of the hip (HBMD) and lumbar spine (LBMD) were evaluated by dual-energy X-ray absorptiometry, and physical performance was assessed by the timed Up & Go test. Serum concentrations of 25-hydroxycholecalciferol, parathyroid hormone (PTH), telepeptide of type I collagen (ICTP), osteocalcin, and N-terminal propeptide of collagen type I were measured.Results: A total of 122 patients were included (84% women; x̄ ± SD age: 70 ± 11 y); 68% completed the study. In an intention-to-treat analysis, LBMD increased in the intervention group and decreased in the placebo group, and the difference between the groups was significant after 12 mo: 0.931 ± 0.211 compared with 0.848 ± 0.194 (P < 0.05). No significant change was shown for HBMD. The effect of treatment was more pronounced in patients aged <70 y. The intervention decreased bone turnover. PTH was significantly lower in the intervention group (P < 0.01) for the LEF patients. ICTP and change in LBMD were significantly related to physical performance.Conclusions: A 1-y intervention with calcium and vitamin D reduced bone turnover, significantly increased BMD in patients younger than 70 y, and decreased bone loss in older patients. The effect of treatment was related to physical performance.

Unusual Case of Osteopenia Associated With Nutritional Calcium and Vitamin D Deficiency in an Adult Dog

A 6-year-old, spayed female rottweiler was presented for facial enlargement from swelling of the maxilla and mandible. The dog was fed a homemade diet deficient in calcium and vitamin D, suggesting that rubber jaw syndrome was a secondary nutritional disorder. Radiographic and tomodensitometric examinations revealed diffuse bone resorption in the skull. The plasma parathormone concentration was high, and serum 25-hydroxycholecalciferol concentration was low. Based on these findings, nutritional calcium and vitamin D deficiency associated with secondary hyperparathyroidism was diagnosed. Dietary correction resulted in clinical and biological improvement, with an increase in skull mineralization.

Vitamin D in Real and Simulated Weightlessness: Implications for Earth

Vitamin D deficiency has reemerged as a public health concern in the United States. It is also a concern for astronauts because spacecraft are shielded from ultraviolet light, leaving diet as the sole source of vitamin D. We report here the findings from four studies: one evaluation of astronauts before and after 4- to 6-month missions to the International Space Station, and the other three from a ground-based analog for space flight, long-term bed rest. For the space flight study, blood samples were collected before the flight and within hours of landing after it. Crewmembers (n = 11) were provided vitamin D supplements (as cholecalciferol (10 g/d) throughout the mission. The average number of vitamin D supplements reported to be consumed per week was 5.7 plus or minus 4.0. The vitamin D status indicator serum 25-hydroxycholecalciferol was 25% less after landing (48 plus or minus 20) than before flight (63 plus or minus 16) (P less than 0.01). A series of three studies was undertaken to evaluate nutritional changes during and after 60 or 90 days of -6 deg. head-down-tilt bed rest. A total of 11 subjects (8 M, 3 F; age 26-55 y) participated in the studies. Blood and urine were collected twice before bed rest and once per month during bed rest. During bed rest the average dietary intake of vitamin D for the three studies was 4.84 plus or minus 0.16 (study 1), 6.24 plus or minus 0.81 (study 2), and 7.16 plus or minus 1.40 (study 3) micrograms/day. In study 1 only, subjects were given a daily supplement of 10 g vitamin D (as ergocalciferol). Data were analyzed using repeated-measures ANOVA. In the first study, 7 days after the end of the bed rest, serum 25-hydroxycholecalciferol was 30% less than it was before bed rest (p less than 0.05). In the second and third studies, during or after bed rest the serum 25-hydroxycholecalciferol concentration was not significantly different from its concentration before bed rest. These data demonstrate that vitamin D intake is critical for individuals not exposed to the sun. Although we studied astronauts and healthy subjects in bed rest, the implications of our results also apply to people living in northern latitudes and others who receive little exposure to sunlight, such as elderly people who seldom go outdoors. The inability of supplements to maintain vitamin D status is also an important finding, and highlights the need for careful food selection to ensure adequate vitamin D intake.

Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol

The cholecalciferol inputs required to achieve or maintain any given serum 25-hydroxycholecalciferol concentration are not known, particularly within ranges comparable to the probable physiologic supply of the vitamin. The objectives were to establish the quantitative relation between steady state cholecalciferol input and the resulting serum 25-hydroxycholecalciferol concentration and to estimate the proportion of the daily requirement during winter that is met by cholecalciferol reserves in body tissue stores. Cholecalciferol was administered daily in controlled oral doses labeled at 0, 25, 125, and 250 micro g cholecalciferol for approximately 20 wk during the winter to 67 men living in Omaha (41.2 degrees N latitude). The time course of serum 25-hydroxycholecalciferol concentration was measured at intervals over the course of treatment. From a mean baseline value of 70.3 nmol/L, equilibrium concentrations of serum 25-hydroxycholecalciferol changed during the winter months in direct proportion to the dose, with a slope of approximately 0.70 nmol/L for each additional 1 micro g cholecalciferol input. The calculated oral input required to sustain the serum 25-hydroxycholecalciferol concentration present before the study (ie, in the autumn) was 12.5 micro g (500 IU)/d, whereas the total amount from all sources (supplement, food, tissue stores) needed to sustain the starting 25-hydroxycholecalciferol concentration was estimated at approximately 96 micro g (approximately 3800 IU)/d. By difference, the tissue stores provided approximately 78-82 micro g/d. Healthy men seem to use 3000-5000 IU cholecalciferol/d, apparently meeting > 80% of their winter cholecalciferol need with cutaneously synthesized accumulations from solar sources during the preceding summer months. Current recommended vitamin D inputs are inadequate to maintain serum 25-hydroxycholecalciferol concentration in the absence of substantial cutaneous production of vitamin D.