Vitamin D Supplementation and Physical Performance in Adolescent Swimmers

Author(s):  
Gal Dubnov-Raz ◽  
Netachen Livne ◽  
Raanan Raz ◽  
Avner H. Cohen ◽  
Naama W. Constantini

It is hypothesized that vitamin D insufficiency in athletes might negatively affect sport performance. The objective of this study was to examine the effect of vitamin D3 supplementation on physical performance of adolescent swimmers with vitamin D insufficiency. Fifty-three adolescent competitive swimmers with vitamin D insufficiency (serum 25-hydroxyvitamin-D concentrations (25(OH)D)<30ng/ml, mean 24.2 ± 4.8ng/ml) were randomized to receive 2,000IU/day of vitamin D3 or placebo for 12 weeks. Swimming performance at several speeds, arm-grip strength, and one-legged balance, were measured before and after supplementation. The age-adjusted changes in performance variables during the study were compared between groups. 25(OH) D concentrations at study end were significantly higher in the vitamin group compared with the placebo group (29.6 ± 6.5ng/ml vs. 20.3 ± 4.2ng/ml, p < .001), yet only 48% of the vitamin group became vitamin D sufficient with this dosing. No between-group differences were found in the changes of the performance variables tested. No significant differences in performance were found between participants that became vitamin D sufficient, and those who did not. No significant correlation was found between the change in serum 25(OH)D and ageadjusted balance, strength or swimming performance at study end. Vitamin D3 supplementation that raised serum 25(OH)D concentrations by a mean of 9.3ng/ml above placebo in adolescent swimmers with vitamin D insufficiency, did not improve physical performance more than placebo.

2015 ◽  
Vol 18 (02) ◽  
pp. 1550008 ◽  
Author(s):  
Negin Masoudi Alavi ◽  
Mahla Madani ◽  
Mohsen Taghizadeh ◽  
Mohammad Reza Sharif

Purpose: To investigate the effect of weekly single high dose vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D], and non-specific musculoskeletal pain in female nurses. Methods: In this prospective study in Kashan/Iran, from April 1, 2014, through September 30, 2014, the 150 nurses with vitamin D deficiency received the weekly pearls of 50,000 units of vitamin D3 for 10 weeks. The serum level of 25(OH)D was measured before and after supplement therapy. The subjects were also asked to complete the Extended Nordic Musculoskeletal Questionnaire. All analyses were conducted with SPSS version 16. Results: After 10 weeks of intervention there was [Formula: see text][Formula: see text]ng/mL increase in 25(OH)D. The 82 nurses (54.7%) had 25(OH)D in normal range, while the 68 nurses (45.3%) were still vitamin D deficient. Weight could explain 15.4% increase in 25(OH)D. Before intervention 135 (90%), of nurses reported musculoskeletal pain in at least one region, after intervention this number decreased to 72.7%. There was a statistically significant improvement in musculoskeletal pain in neck, shoulders, upper back, lower back, hips/tights, knees, and ankles/feet after intervention. Conclusions: The weekly single high dose of vitamin D for 10 weeks could resolve vitamin D deficiency in about half of the patients. Patients with non-specific musculoskeletal pain might benefit from vitamin D supplementation.


2003 ◽  
Vol 88 (11) ◽  
pp. 5175-5179 ◽  
Author(s):  
Franck Grados ◽  
Michel Brazier ◽  
Saïd Kamel ◽  
Marc Mathieu ◽  
Nathalie Hurtebize ◽  
...  

Abstract The aim of this study was to determine whether early changes in bone markers could predict long-term response in bone mineral density (BMD) after calcium (500 mg) and vitamin D (400 IU) supplementation twice daily in ambulatory elderly women with vitamin D insufficiency (25-hydroxyvitamin D, &lt;12 ng/ml). One hundred and ninety-two women (mean age, 75 ± 7 yr) were randomized to receive either the supplementation (n = 95) or a placebo (n = 97) in a double-blind, controlled clinical trial for 1 yr. In comparison with the placebo group, supplementation significantly increased BMD, normalized 25-hydroxyvitamin D and significantly decreased intact PTH and bone remodeling markers. The initial values of telopeptide cross-links were correlated with improvement in total body BMD [urinary N-telopeptides (NTX), r = 0.38; C-telopeptides (CTX), r = 0.32; serum CTX, r = 0.28], and the 3-month changes in the same markers were correlated with improvement in total body (urinary N-telopeptides, r = −0.29; serum CTX, r = −0.26) and vertebral BMD (CTX, r = −0.26; all P &lt; 0.05). We concluded that short-term changes in bone resorption markers can predict long-term variations in BMD in elderly women with vitamin D insufficiency receiving calcium and vitamin D supplementation.


2013 ◽  
Vol 110 (10) ◽  
pp. 1866-1872 ◽  
Author(s):  
Sara R. Zwart ◽  
Howard Parsons ◽  
Michael Kimlin ◽  
Sheila M. Innis ◽  
James P. Locke ◽  
...  

The risk of vitamin D insufficiency is increased in persons having limited sunlight exposure and dietary vitamin D. Supplementation compliance might be improved with larger doses taken less often, but this may increase the potential for side effects. The objective of the present study was to determine whether a weekly or weekly/monthly regimen of vitamin D supplementation is as effective as daily supplementation without increasing the risk of side effects. Participants were forty-eight healthy adults who were randomly assigned for 3 months to placebo or one of three supplementation regimens: 50 μg/d (2000 IU/d, analysed dose 70 μg/d), 250 μg/week (10 000 IU/week, analysed dose 331 μg/week) or 1250 μg/week (50 000 IU/week, analysed dose 1544 μg/week) for 4 weeks and then 1250 μg/month for 2 months. Daily and weekly doses were equally effective at increasing serum 25-hydroxyvitamin D, which was significantly greater than baseline in all the supplemented groups after 30 d of treatment. Subjects in the 1250 μg treatment group, who had a BMI >26 kg/m2, had a steady increase in urinary Ca in the first 3 weeks of supplementation, and, overall, the relative risk of hypercalciuria was higher in the 1250 μg group than in the placebo group (P= 0·01). Although vitamin D supplementation remains a controversial issue, these data document that supplementing with ≤ 250 μg/week ( ≤ 10 000 IU/week) can improve or maintain vitamin D status in healthy populations without the risk of hypercalciuria, but 24 h urinary Ca excretion should be evaluated in healthy persons receiving vitamin D3 supplementation in weekly single doses of 1250 μg (50 000 IU).


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Recep Bentli ◽  
Hulya Taskapan ◽  
Halil Toktaş ◽  
Ozkan Ulutas ◽  
Adnan Ozkahraman ◽  
...  

Aims. Kidney disease was found to be a major risk factor for vitamin D deficiency in a population study of patients hospitalized. The aims of the study were to describe the prevalence of vitamin D deficiency inpatients and outpatients in a nephrology department during fall and to evaluate effect of assessing serum 25-hydroxyvitamin D (25(OH)D) levels and previous supplementation of cholecalciferol on vitamin D status.Methods. We studied 280 subjects in total, between October and January. The subjects were recruited from the following two groups: (a) inpatients and (b) outpatients in nephrology unit. We examined previous documentary evidence of vitamin D supplementation of the patients.Results. The prevalence of vitamin D deficiency among these 280 patients was 62,1% (174 patients). Fifty-three patients (18.9%) had severe vitamin D deficiency, 121 patients (43.2%) moderate vitamin D deficiency, and 66 patients (23.6%) vitamin D insufficiency. In logistic regression analysis female gender, not having vitamin D supplementation history, low serum albumin, and low blood urea nitrogen levels were significant independent predictors of vitamin D deficiency while no association of vitamin D deficiency with diabetes mellitus, serum creatinine, eGFR, and being hospitalized was found.Conclusion. Vitamin D deficiency, seems to be an important problem in both inpatients and outpatients of nephrology. Monitoring serum 25(OH)D concentrations regularly and replacement of vitamin D are important. Women in Turkey are at more risk of deficiency and may therefore need to consume higher doses of vitamin D.


2013 ◽  
Vol 09 (02) ◽  
pp. 146
Author(s):  
Rebecca L Thomson ◽  

The incidence of vitamin D deficiency is increasing and 25-hydroxyvitamin D (25OHD) levels, which are inversely associated with measures of obesity, are lower in overweight and obese populations. There have been several studies that have investigated the effect of vitamin D supplementation on weight loss, and studies combining weight loss interventions with increased vitamin D intake, either through supplementation or foods fortified with vitamin D. 25OHD levels have also been measured before and after weight loss to see if they improve and if the changes in 25OHD levels are related to the degree of weight loss. Some studies have suggested that vitamin D status is associated with weight loss success, with supplementation resulting in weight loss, or higher baseline 25OHD or greater increases in 25OHD levels associated with greater weight loss, although this has not been shown in all studies.


2011 ◽  
Vol 71 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Ilkka Laaksi

Vitamin D insufficiency is a global issue that has significant implications for health. The classical role of vitamin D in bone mineralisation is well known; vitamin D deficiency leads to rickets, osteomalacia or osteoporosis. The role of vitamin D in an immune system is less known. Vitamin D is not an actual vitamin but a secosteroid hormone produced in the skin from 7-dehydrocholesterol after exposure to sunlight UVB radiation. Nutrition and supplements are main sources of vitamin D in wintertime in northern countries as sunlight exposure is inadequate for the production. For activation vitamin D needs to be hydroxylated in liver to form 25-hydroxyvitamin D and in kidney to 1,25-dihydroxyvitamin D, the most active hormone in Ca absorption in the gut. For determination of vitamin D status serum 25-hydroxyvitamin D level, the major circulating form of the hormone is to be measured. Vitamin D regulates gene expression through binding with vitamin D receptors, which dimerises with retinoid X receptor. This complex binds to vitamin D-responsive elements inside the promoter regions of vitamin D-responsive genes. Vitamin D has a key role in innate immunity activation; the production of antimicrobial peptides (cathelicidin and defensins) following Toll-like receptor stimulation by pathogen lipopeptides is dependent on sufficient level of 25-hydroxyvitamin D. Clinically, there is evidence of the association of vitamin D insufficiency and respiratory tract infections. There is also some evidence of the prevention of infections by vitamin D supplementation. Randomised controlled trials are warranted to explore this preventive effect.


2021 ◽  
pp. 1-7
Author(s):  
Naomi Vather-Wu ◽  
Matthew D. Krasowski ◽  
Katherine D. Mathews ◽  
Amal Shibli-Rahhal

Background: Expert guidelines recommend annual monitoring of 25-hydroxyvitamin D (25-OHD) and maintaining 25-OHD ≥30 ng/ml in patients with dystrophinopathies. Objective: We hypothesized that 25-OHD remains stable and requires less frequent monitoring in patients taking stable maintenance doses of vitamin D. Methods: We performed a retrospective cohort study, using the electronic health record to identify 26 patients with dystrophinopathies with a baseline 25-OHD ≥30 ng/mL and at least one additional 25-OHD measurement. These patients had received a stable dose of vitamin D for ≥3 months prior to their baseline 25-OHD measurement and throughout follow-up. The main outcome measured was the mean duration time the subjects spent with a 25-OHD ≥30 ng/mL. Results: Only 19% of patients dropped their 25-OHD to <  30 ng/ml, with a mean time to drop of 33 months and a median nadir 25-OHD of 28 ng/mL. Conclusions: These results suggest that measurement of 25-OHD every 2–2.5 years may be sufficient in patients with a baseline 25-OHD ≥30 ng/mL and who are on a stable maintenance dose of vitamin D. Other patients may require more frequent assessments.


Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2443
Author(s):  
Wojciech Stefan Zgliczyński ◽  
Olga Maria Rostkowska ◽  
Beata Sarecka-Hujar

Background Vitamin D deficiency occurs in as much as 90–95% of the Polish population, although this condition is known to cause negative long-term health implications. The role of medical doctors in advising proper supplementation, monitoring and correcting the levels of 25-hydroxyvitamin D in individuals is of great importance and should be used to help mitigate its common deficits. The aim of this study was to evaluate knowledge, attitudes and practices of Polish physicians regarding vitamin D supplementation in order to identify areas for improvement and determinants for the knowledge gaps. Methods The study group comprised 701 medical doctors aged 32.1 ± 5.3 years on average, mostly women (71.61%). An original survey questionnaire was developed for the purpose of the study. Results The mean vitamin D knowledge score was 6.8 ± 2.3 (in a scale 0–13) and was related to gender (p < 0.001), type of specialization (p = 0.032), D3 supplements use (p < 0.001), recommending supplementation to patients (p = 0.005), to relatives and friends (p < 0.001) and to healthy adults (p < 0.001). In terms of self-administration, 14% of respondents take vitamin D all-year-round while 24% only in autumn and winter. 25% of respondents monitor their vitamin D (25-hydroxyvitamin D) serum concentration. Most participants (61%) did not recommend supplementing vitamin D to their patients on a regular basis. Conclusions The study indicates that medical doctors in Poland need to have more training and education on vitamin D supplementation in order to better address the problem of its deficits in the population.


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