scholarly journals Estimation of the dietary requirement for vitamin D in adolescents aged 14–18 y: a dose-response, double-blind, randomized placebo-controlled trial

2016 ◽  
Vol 104 (5) ◽  
pp. 1301-1309 ◽  
Author(s):  
Taryn J Smith ◽  
Laura Tripkovic ◽  
Camilla T Damsgaard ◽  
Christian Mølgaard ◽  
Christian Ritz ◽  
...  
Keyword(s):  
Vitamin D ◽  
Dose Response ◽  
Controlled Trial ◽  
Double Blind ◽  
Dietary Requirement

scholarly journals Estimation of the maternal vitamin D intake that maintains circulating 25-hydroxyvitamin D in late gestation at a concentration sufficient to keep umbilical cord sera ≥25–30 nmol/L: a dose-response, double-blind, randomized placebo-controlled trial in pregnant women at northern latitude

2018 ◽  
Vol 108 (1) ◽  
pp. 77-91 ◽  
Author(s):  
Karen M O'Callaghan ◽  
Áine Hennessy ◽  
George L J Hull ◽  
Karina Healy ◽  
Christian Ritz ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Dose Response ◽  
Controlled Trial ◽  
Late Gestation ◽  
Total Vitamin ◽  
Double Blind ◽  
Hydroxyvitamin D ◽  
Vitamin D Intake ◽  
25 Hydroxyvitamin D

ABSTRACT Background In the absence of dose-response data, Dietary Reference Values for vitamin D in nonpregnant adults are extended to pregnancy. Objective The aim was to estimate vitamin D intake needed to maintain maternal 25-hydroxyvitamin D [25(OH)D] in late gestation at a concentration sufficient to prevent newborn 25(OH)D <25–30 nmol/L, a threshold indicative of increased risk of nutritional rickets. Design We conducted a 3-arm, dose-response, double-blind, randomized placebo-controlled trial in Cork, Ireland (51.9oN). A total of 144 white-skinned pregnant women were assigned to receive 0, 10 (400 IU), or 20 (800 IU) µg vitamin D3/d from ≤18 wk of gestation. Vitamin D metabolites at 14, 24, and 36 wk of gestation and in cord sera, including 25(OH)D3, 3-epi-25(OH)D3, 24,25(OH)2D3, and 25(OH)D2 were quantified by liquid chromatography–tandem mass spectrometry. A curvilinear regression model predicted the total vitamin D intake (from diet and antenatal supplements plus treatment dose) that maintained maternal 25(OH)D in late gestation at a concentration sufficient to maintain cord 25(OH)D at ≥25–30 nmol/L. Results Mean ± SD baseline 25(OH)D was 54.9 ± 10.7 nmol/L. Total vitamin D intakes at the study endpoint (36 wk of gestation) were 12.1 ± 8.0, 21.9 ± 5.3, and 33.7 ± 5.1 µg/d in the placebo and 10-µg and 20-µg vitamin D3 groups, respectively; and 25(OH)D was 24.3 ± 5.8 and 29.2 ± 5.6 nmol/L higher in the 10- and 20-µg groups, respectively, compared with placebo (P < 0.001). For maternal 25(OH)D concentrations ≥50 nmol/L, 95% of cord sera were ≥30 nmol/L and 99% were >25 nmol/L. The estimated vitamin D intake required to maintain serum 25(OH)D at ≥50 nmol/L in 97.5% of women was 28.9 µg/d. Conclusions Thirty micrograms of vitamin D per day safely maintained serum 25(OH)D concentrations at ≥50 nmol/L in almost all white-skinned women during pregnancy at a northern latitude, which kept 25(OH)D at >25 nmol/L in 99% and ≥30 nmol/L in 95% of umbilical cord sera. This trial was registered at www.clinicaltrials.gov as NCT02506439.

scholarly journals Single High-Dose Vitamin D Supplementation as an Approach for Reducing Ultramarathon-Induced Inflammation: A Double-Blind Randomized Controlled Trial

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1280
Author(s):  
Jan Mieszkowski ◽  
Andżelika Borkowska ◽  
Błażej Stankiewicz ◽  
Andrzej Kochanowicz ◽  
Bartłomiej Niespodziński ◽  
...  
Keyword(s):  
Vitamin D ◽  
Inflammatory Marker ◽  
Controlled Trial ◽  
Vitamin D Supplementation ◽  
Oncostatin M ◽  
Control Group ◽  
High Dose ◽  
Double Blind ◽  
Single High Dose ◽  
High Dose Vitamin

Purpose: A growing number of studies indicate the importance of vitamin D supplementation for sports performance. However, the effects of a single high-dose vitamin D supplementation on ultramarathon-induced inflammation have not been investigated. We here analyzed the effect of a single high-dose vitamin D supplementation on the inflammatory marker levels in ultramarathon runners after an ultramarathon run (maximal run 240 km). Methods: In the study, 35 runners (amateurs) were assigned into two groups: single high-dose vitamin D supplementation group, administered vitamin D (150,000 IU) in vegetable oil 24 h before the start of the run (n = 16); and placebo group (n = 19). Blood was collected for analysis 24 h before, immediately after, and 24 h after the run. Results: Serum 25(OH)D levels were significantly increased after the ultramarathon in both groups. The increase was greater in the vitamin D group than in the control group. Based on post-hoc and other analyses, the increase in interleukin 6 and 10, and resistin levels immediately after the run was significantly higher in runners in the control group than that in those in the supplementation group. Leptin, oncostatin M, and metalloproteinase tissue inhibitor levels were significantly decreased in both groups after the run, regardless of the supplementation. Conclusions: Ultramarathon significantly increases the serum 25(OH)D levels. Attenuation of changes in interleukin levels upon vitamin D supplementation confirmed that vitamin D has anti-inflammatory effect on exercise-induced inflammation.

scholarly journals Effects of Vitamin D Supplementation on Surrogate Markers of Fertility in PCOS Women: A Randomized Controlled Trial

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 547
Author(s):  
Elisabeth Lerchbaum ◽  
Verena Theiler-Schwetz ◽  
Martina Kollmann ◽  
Monika Wölfler ◽  
Stefan Pilz ◽  
...  
Keyword(s):  
Vitamin D ◽  
Treatment Effect ◽  
Polycystic Ovary ◽  
Controlled Trial ◽  
Dehydroepiandrosterone Sulfate ◽  
Vitamin D Supplementation ◽  
Double Blind ◽  
Significant Treatment ◽  
Hydroxyvitamin D ◽  
Randomized Controlled

Vitamin D (VD) might play an important role in polycystic ovary syndrome (PCOS) and female fertility. However, evidence from randomized controlled trials (RCT) is sparse. We examined VD effects on anti-Müllerian hormone (AMH) and other endocrine markers in PCOS and non-PCOS women. This is a post hoc analysis of a single-center, double-blind RCT conducted between December 2011 and October 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria. We included 180 PCOS women and 150 non-PCOS women with serum 25-hydroxyvitamin D (25(OH)D) concentrations <75 nmol/L in the trial. We randomized subjects to receive 20,000 IU of VD3/week (119 PCOS, 99 non-PCOS women) or placebo (61 PCOS, 51 non-PCOS women) for 24 weeks. Outcome measures were AMH, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, dehydroepiandrosterone sulfate, and androstenedione. In PCOS women, we observed a significant treatment effect on FSH (mean treatment effect 0.94, 95% confidence interval [CI] 0.087 to 1.799, p = 0.031) and LH/FSH ratio (mean treatment effect −0.335, 95% CI −0.621 to 0.050, p = 0.022), whereas no significant effect was observed in non-PCOS women. In PCOS women, VD treatment for 24 weeks had a significant effect on FSH and LH/FSH ratio but no effect on AMH levels.

scholarly journals Vitamin D-Fortified Bread Is as Effective as Supplement in Improving Vitamin D Status: A Randomized Clinical Trial

2016 ◽  
Vol 101 (6) ◽  
pp. 2511-2519 ◽  
Author(s):  
Bahareh Nikooyeh ◽  
Tirang R. Neyestani ◽  
Maliheh Zahedirad ◽  
Mehrdad Mohammadi ◽  
S. Hedayat Hosseini ◽  
...  
Keyword(s):  
Vitamin D ◽  
Controlled Trial ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Concentration ◽  
Daily Consumption ◽  
Double Blind ◽  
Hydroxyvitamin D ◽  
Group Reduction ◽  
25 Hydroxyvitamin D

Abstract Context: Bread can potentially be a suitable vehicle for fortification with vitamin D. Objective: This study was undertaken to evaluate the following: 1) the bioavailability of vitamin D from the fortified Iranian bread and 2) the possible effects of daily consumption of the fortified bread on certain health aspects. Design, Setting, and Participants: This was a randomized, double-blind, placebo-controlled trial conducted over 8 weeks in 90 healthy subjects aged 20–60 years. Intervention: Subjects were randomly allocated to one of three groups: 1) fortified bread (FP; 50 g bread fortified with 25 μg vitamin D3 plus placebo daily; n = 30); 2) supplement (SP; 50 g plain bread plus 25 μg vitamin D supplement daily; n = 30); and 3) control (CP; 50 g plain bread plus placebo daily; n = 30). Outcome Measures: Initial and final anthropometric and biochemical assessments were performed. Results: The within-group changes of serum 25-hydroxyvitamin D concentrations were 39.0 ± 22.6 (P &lt; .001), 28.9 ± 31.2 (P &lt; .001), and −9.2 ± 12.3 nmol/L in the FP, SP, and CP groups, respectively. Only in FP and SP groups, serum intact PTH concentrations decreased approximately 13.5% and 14.5%, respectively. Visceral fat also showed a significant decrement in FP (−1.05% ± 1.4%; P ≤ .001) and SP (−0.96% ± 1.7%; P = .006). Serum low-density lipoprotein cholesterol concentration showed a within-group reduction in FP (−10.4 ± 11.2 mg/dL; P &lt; .001) and an insignificant decrement in SP (−6.6 ± 20.2 mg/dL; P = .083). Serum high-density lipoprotein increased in both vitamin D-supplemented groups (FP: 9.7 ± 7.6 vs SP: 5.7 ± 6.7 mg/dL; P &lt; .001). Conclusion: Vitamin D-fortified bread could be potentially effective in raising circulating 25-hydroxyvitamin D levels of the population to nearly adequate levels.

scholarly journals Acute Effects of Triiodothyronine on Endothelial Function in Human Subjects

2007 ◽  
Vol 92 (1) ◽  
pp. 250-254 ◽  
Author(s):  
Raffaele Napoli ◽  
Vincenzo Guardasole ◽  
Valentina Angelini ◽  
Emanuela Zarra ◽  
Daniela Terracciano ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Dose Response ◽  
Vascular Reactivity ◽  
Controlled Trial ◽  
University Hospital ◽  
Acute Effects ◽  
Response Curves ◽  
Double Blind ◽  
Low T3 ◽  
Dose Response Curves

Abstract Context: Thyroid hormone regulates several cardiovascular functions, and low T3 levels are frequently associated with cardiovascular diseases. Whether T3 exerts any acute and direct effect on endothelial function in humans is unknown. Objective: Our objective was to clarify whether acute changes in serum T3 concentration affect endothelial function. Design, Setting, and Subjects: Ten healthy subjects (age, 24 ± 1 yr) participated in a double-blind, placebo-controlled trial at a university hospital. Interventions: T3 (or placebo) was infused for 7 h into the brachial artery to raise local T3 to levels observed in moderate hyperthyroidism. Vascular reactivity was tested by intraarterial infusion of vasoactive agents. Main Outcome Measures: We assessed changes in forearm blood flow (FBF) measured by plethysmography. Results: FBF response to the endothelium-dependent vasodilator acetylcholine was enhanced by T3 (P = 0.002 for the interaction between T3 and acetylcholine). The slopes of the dose-response curves were 0.41 ± 0.06 and 0.23 ± 0.04 ml/dl·min/μg in the T3 and placebo study, respectively (P = 0.03). T3 infusion had no effect on the FBF response to sodium nitroprusside. T3 potentiated the vasoconstrictor response to norepinephrine (P = 0.006 for the interaction). Also, the slopes of the dose-response curves were affected by T3 (1.95 ± 0.77 and 3.83 ± 0.35 ml/dl·min/mg in the placebo and T3 study, respectively; P &lt; 0.05). The increase in basal FBF induced by T3 was inhibited by NG-monomethyl-l-arginine. Conclusions: T3 exerts direct and acute effects on the resistance vessels by enhancing endothelial function and norepinephrine-induced vasoconstriction. The data may help clarify the vascular impact of the low T3 syndrome and point to potential therapeutic strategies.

Using Activities of Daily Living Assessments to Measure the Effectiveness of Vitamin D Supplements in Elderly Long-Stay Patients

1987 ◽  
Vol 50 (2) ◽  
pp. 60-62 ◽  
Author(s):  
D Corless ◽  
M Ellis ◽  
E Dawson ◽  
F Fraser ◽  
S Evans ◽  
...  
Keyword(s):  
Vitamin D ◽  
Elderly Patients ◽  
Activities Of Daily Living ◽  
Daily Living ◽  
Controlled Trial ◽  
Double Blind ◽  
Hydroxyvitamin D ◽  
Low Concentrations ◽  
25 Hydroxyvitamin D ◽  
Vitamin D Supplements

Selected activities of daily living were used to measure improvement in independence of long-stay elderly patients known to have low concentrations of plasma 25-hydroxyvitamin D. This was a double-blind random controlled trial lasting between 8 and 40 weeks. No significant changes were found in either group.

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