Vitamin D

[Michael Scally MD]

Vitamin D and Calcium Supplementation, Skeletal Muscle Strength and Serum Testosterone in Young Healthy Adult Males

Background: Cholecalciferol and/or calcium supplementation might increase skeletal-muscle strength and serum testosterone in young adult males.

Objective: We performed a randomized-control-trial assessing the effect of cholecalciferol/calcium on skeletal-muscle strength and serum testosterone in vitamin-D deficient young males.

Design: Two-by-two factorial RCT.

Subject and Intervention: Two-hundred and twenty-eight young males were block-randomized to
1) double-placebo,
2) calcium/placebo,
3) cholecalciferol/placebo, and
4) cholecalciferol/calcium.

Doses for cholecalciferol was 60,000 IU/wk for eight-weeks followed by 60,000 IU/fortnightly and for elemental calcium was 500 mg/twice daily for six-months. 180 subjects completed the study protocol. Their mean age, body-mass-index, and baseline 25(OH)D were 20.2 ± 2.2 years, 23.0 ± 3.6 kg/m2, and 21.5 ± 9.5 nmol/l, respectively.

Measurements: Handgrip (primary outcome), pinch-grip strength, distance walked in six-minutes, dyspnoea-score, quality of life by Short-Form-36, serum 25(OH)D, 1,25(OH)2D, iPTH, total testosterone and free-androgen-index (FAI).

Results: After intervention, mean serum 25(OH)D was > 75.0 nmol/l in cholecalciferol groups. However, the handgrip strength (29.7 ± 4.4, 29.3 ± 4.6, 30.6 ± 5.0, and 28.8 ± 4.3 kg, P = 0.28) were comparable in the four groups. Subgroups analysis among subjects with baseline serum 25OH)D < 25.0 and < 12.0 nmol/l showed similar results.

The mean serum testosterone decreased significantly at six-months; however, delta change was similar in four groups.

Change in handgrip strength and other outcomes were similar in four groups with and without adjustment for delta testosterone and FAI.

Conclusions: Six-months of cholecalciferol/calcium supplementation had no significant effect on skeletal-muscle strength and serum testosterone in young adult males.

Saha S, Goswami R, Ramakrishnan L, et al. Vitamin D and calcium supplementation, skeletal muscle strength and serum testosterone in young healthy adult males: Randomized Control Trial. Clinical Endocrinology. Vitamin D and calcium supplementation, skeletal muscle strength and serum testosterone in young healthy adult males: Randomized Control Trial

 

[Michael Scally MD]

Owens DJ, Allison R, Close GL. Vitamin D and the Athlete: Current Perspectives and New Challenges. Sports Medicine 2018;48:3-16. Vitamin D and the Athlete: Current Perspectives and New Challenges

The last decade has seen a dramatic increase in general interest in and research into vitamin D, with many athletes now taking vitamin D supplements as part of their everyday dietary regimen. The most recognized role of vitamin D is its regulation of calcium homeostasis; there is a strong relationship between vitamin D and bone health in non-athletic individuals. In contrast, data have consistently failed to demonstrate any relationship between serum 25[OH]D and bone health, which may in part be due to the osteogenic stimulus of exercise.

Vitamin D may interact with extra-skeletal tissues such as muscle and the immune system to modulate recovery from damaging exercise and infection risk. Given that many athletes now engage in supplementation, often consuming extreme doses of vitamin D, it is important to assess whether excessive vitamin D can be detrimental to health. It has been argued that toxic effects only occur when serum 25[OH]D concentrations are greater than 180 nmol·l−1, but data from our laboratory have suggested high-dose supplementation could be problematic.

Finally, there is a paradoxical relationship between serum 25[OH]D concentration, ethnicity, and markers of bone health: Black athletes often present with low serum 25[OH]D without physiological consequences. One explanation for this could be genetic differences in vitamin D binding protein due to ethnicity, resulting in greater concentrations of bioavailable (or free) vitamin D in some ethnic groups. In the absence of any pathology, screening may be unnecessary and could result in incorrect supplementation. Data must now be re-examined, taking into consideration bioavailable or “free” vitamin D in ethnically diverse groups to enable new thresholds and target concentrations to be established; perhaps, for now, it is time to “set vitamin D free”.

 

[Michael Scally MD]

[OA] Vitamin D, PCOS and Androgens in Men

Background: Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the reproductive system in both genders. Aim: The aim of this review was to provide an overview on the effects of vitamin D on polycystic ovary syndrome (PCOS) in women and androgen metabolism in men.

Methods: We performed a systematic literature search in Pubmed for relevant English language publications published from January 2012 until July 2017.

Results and Discussion: The vitamin D receptor and vitamin D metabolizing enzymes are found in reproductive tissues of women and men. In women, vitamin D status has been associated with several features of PCOS. In detail, cross-sectional data suggest a regulatory role of vitamin D in PCOS-related aspects such as ovulatory dysfunction, insulin resistance as well as hyperandrogenism. Moreover, results from randomized controlled trials (RCTs) suggest that vitamin D supplementation may be beneficial for metabolic, endocrine and fertility aspects in PCOS.

In men, vitamin D status has been associated with androgen levels and hypogonadism. Further, there is some evidence for a favourable effect of vitamin D supplementation on testosterone concentrations, although others failed to show a significant effect on testosterone levels.

Conclusion: In summary, vitamin D deficiency is associated with adverse fertility outcomes including PCOS and hypogonadism, but the evidence is insufficient to establish causality. High quality RCTs are needed to further evaluate the effects of vitamin D supplementation in PCOS women as well as on androgen levels in men.

Trummer C, Pilz S, Schwetz V, Obermayer-Pietsch BR, Lerchbaum E. Vitamin D, PCOS and androgens in men: a systematic review. Endocrine Connections 2018. http://www.endocrineconnections.com/content/early/2018/02/15/EC-18-0009.abstract

 

[Michael Scally MD]

A Review of The Growing Risk of Vitamin D Toxicity From Inappropriate Practice

Vitamin D is a particularly important sterol hormone with evidence emerging of its beneficial effects well beyond bone. In consequence of this and increased global recognition of vitamin D deficiency in the general population, there has been a resurgence in treatment with vitamin D preparations.

However, the increasing use of vitamin D treatments has also seen a substantial increase in the numbers of reports of vitamin D intoxication with the majority (75%) of reports published since 2010. Many of these cases are a consequence of inappropriate prescribing, the use of high dose over-the-counter preparations or unlicensed preparations.

This review highlights that the majority of cases were preventable and discusses the inappropriate use of poorly formulated, and unlicensed vitamin D preparations.

Taylor PN, Davies JS. A review of the growing risk of vitamin D toxicity from inappropriate practice. British journal of clinical pharmacology 2018. A review of the growing risk of vitamin D toxicity from inappropriate practice

 

[LOVEMe89]

This is why it's always a good excuse to tan. Just put it aside as a bodybuilding job for "the aesthetic" and get the health benefits chucked in

 

[Michael Scally MD]

Plasma 25-Hydroxyvitamin D Concentration and Risk of Type 2 Diabetes and Pre-Diabetes

Background It has been reported that higher plasma 25-hydroxyvitamin D is associated with lower risk of type 2 diabetes. However the results to date have been mixed and no adequate data based on a cohort are available for the high end of the normal range, above approximately 32 ng/ml or 80 nmol/L.

Methods We performed a cohort study of 903 adults who were known to be free of diabetes or pre-diabetes during a 1997–1999 visit to a NIH Lipid Research Centers clinic. Plasma 25(OH)D was measured at Visit 8 in 1977–1979. The mean age was 74 years. The visit also included fasting plasma glucose and oral glucose tolerance testing. Follow-up continued through 2009.

Results There were 47 cases of diabetes and 337 cases of pre-diabetes. Higher 25(OH)D concentrations (> 30 ng/ml) were associated with lower hazard ratios (HR) for diabetes: 30–39 ng/ml or 75–98 nmol/L: HR = 0.31, 95% CI = 0.14–0.70; for 40–49 ng/ml or 100–122 nmol/L: HR = 0.29, CI = 0.12–0.68; for > 50 ng/ml or 125 nmol/L: HR = 0.19, CI = 0.06–0.56. All HRs are compared to < 30 ng/ml or 75 nmol/L.

There was an inverse dose-response gradient between 25(OH)D concentration and risk of diabetes with a p for trend of 0.005. Each 10 ng/mL or 25 nmol/L higher 25(OH)D concentration was associated with a HR of 0.64, CI = 0.48–0.86. 25(OH)D concentrations were more weakly inversely associated with pre-diabetes risk, and the trend was not significant.

Conclusion Further research is needed on whether high 25(OH)D might prevent type 2 diabetes or transition of prediabetes to diabetes.

Park SK, Garland CF, Gorham ED, BuDoff L, Barrett-Connor E. Plasma 25-hydroxyvitamin D concentration and risk of type 2 diabetes and pre-diabetes: 12-year cohort study. PloS one 2018;13:e0193070. Plasma 25-hydroxyvitamin D concentration and risk of type 2 diabetes and pre-diabetes: 12-year cohort study

 

[ICD-HardThings]

This is why it's always a good excuse to tan. Just put it aside as a bodybuilding job for "the aesthetic" and get the health benefits chucked in

I just recently found out for some reason my body doesn't produce enough Vitamin D from the sun. I'm now taking 50,000iu a week to make up for what my body don't produce.

 

[LOVEMe89]

I just recently found out for some reason my body doesn't produce enough Vitamin D from the sun. I'm now taking 50,000iu a week to make up for what my body don't produce.

Damm that´s interesting and i´m sorry to hear that

 

[ICD-HardThings]

Damm that´s interesting and i´m sorry to hear that

I just found out in talking with my sister that she recently found out the same thing about herself. I have a way better feeling of well being taking a supplement for it.

 

[Michael Scally MD]

Galior K, Ketha H, Grebe S, Singh RJ. 10 years of 25-hydroxyvitamin-D testing by LC-MS/MS-trends in vitamin-D deficiency and sufficiency. Bone Reports. 2018;8:268-273. 10 years of 25-hydroxyvitamin-D testing by LC-MS/MS-trends in vitamin-D deficiency and sufficiency

In early 2000's vitamin-D deficiency was shown to be prevalent in several countries including the United States (US). Studies exploring the role of vitamin-D metabolism in diverse disease pathways generated an increased demand for vitamin-D supplementation and an immense public interest in measurement of vitamin-D metabolite levels.

In this report, we review the role of vitamin-D metabolism in disease processes, clinical utility of measuring vitamin-D metabolites including 25-hydroxyvitamin-D (25(OH)D), 1,25-dihydroxyvitamin-D and 24,25-dihydroxyvitamin-D and discuss vitamin-D assay methodologies including immunoassays and liquid chromatography mass spectrometry (LC-MS/MS) assays.

We also provide examples of vitamin-D toxicity and insight into the trends in serum 25(OH)D levels in the US population based on 10 years of data from on serum 25(OH)D values from ~5,000,000 patients who were tested at the Mayo Medical Laboratories between February 2007–February 2017.

 

[Michael Scally MD]

[OA] Effects of Vitamin D Supplementation on Androgens in Men With Low Testosterone Levels

PURPOSE: It has been hypothesized that vitamin D is associated with androgen levels in men. We, therefore, aimed to evaluate whether vitamin D supplementation increases serum total testosterone (TT) levels in men with low TT levels at baseline.

METHODS: The Graz Vitamin D&TT-RCT is a single-center, double-blind, randomized placebo-controlled trial conducted between March 2013 and November 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria.

One-hundred healthy men with serum TT levels < 10.4 nmol/l and 25-hydroxyvitamin D [25(OH)D] levels < 75 nmol/l participated in the trial. Subjects were randomized to receive 20,000 IU of vitamin D3/week (n = 50) or placebo (n = 50) for 12 weeks.

Primary outcome was TT measured using mass spectrometry. Secondary outcomes were free testosterone, free androgen index, sex hormone-binding globulin, estradiol, follicle-stimulating hormone, luteinizing hormone, metabolic characteristics, and body composition.

RESULTS: Ninety-four men [mean age and 25(OH)D: 47 (+/- 12) years and 56.3 (+/- 18.3) nmol/l, respectively] completed the study. We found no significant treatment effect on serum TT or on the remaining secondary outcome variables.

CONCLUSION: Vitamin D treatment had no effect on serum TT levels in middle-aged healthy men with low TT levels.

Lerchbaum E, Trummer C, Theiler-Schwetz V, et al. Effects of vitamin D supplementation on androgens in men with low testosterone levels: a randomized controlled trial. European journal of nutrition 2018. Effects of vitamin D supplementation on androgens in men with low testosterone levels: a randomized controlled trial

 

[Michael Scally MD]

[OA] Does testosterone mediate the relationship between vitamin D and prostate cancer?

BACKGROUND: Evidence from studies on prostate cancer progression have identified vitamin D to be a potentially important nutrient. However, the World Cancer Research Fund and American Institute for Cancer Research have reported the quality of this evidence to be limited and warrant further investigation.

We plan to use the recently developed WCRF International/University of Bristol mechanistic systematic review framework to determine whether the observed association between vitamin D and prostate cancer exists through a plausible biological pathway.

METHODS: This protocol sets out how we will perform a systematic review of the literature in human and animal studies. We will search the electronic databases MEDLINE, EMBASE, PubMed, and BIOSIS Citation Index without restrictions on year of publication or language.

We will extract data from observational and experimental studies examining two inter-linked pathways in the relationship between vitamin D and prostate cancer progression:
(1) vitamin D and testosterone, and
(2) testosterone and prostate cancer progression.

We focus on testosterone as its actions form a potentially novel intermediate mechanism that was identified via our online literature mining tools. The outcomes of interest include incidence or prevalence of prostate cancer, measures of prostate cancer progression (including biochemical recurrence, local, or distal metastases), and prostate cancer-specific mortality.

We will assess study quality and the level of certainty of the evidence. We will analyse data where possible, using meta-analysis with forest plots or albatross plots; otherwise, a narrative synthesis will be performed.

DISCUSSION: To our knowledge, this will be the first systematic synthesis of the evidence underpinning the vitamin D-testosterone-prostate cancer mechanistic pathway. The results of the review may inform future research, intervention trials, and public health messages.

Robles LA, Dawe K, Martin RM, Higgins JPT, Lewis SJ. Does testosterone mediate the relationship between vitamin D and prostate cancer? A systematic review and meta-analysis protocol. Systematic reviews 2019;8:52. Does testosterone mediate the relationship between vitamin D and prostate cancer? A systematic review and meta-analysis protocol

 

[Michael Scally MD]

Causal Link Between Vitamin D and Total Testosterone

CONTEXT: Low circulating vitamin D levels have been associated with lower total testosterone. These epidemiological associations, if true, would have public health importance, since vitamin D deficiency is common and correctable. We aimed to test whether genetically lowered vitamin D levels were associated with lower total testosterone (T), using Mendelian randomization (MR) methodology.

DESIGN AND SETTING: 4,254 men were enrolled from the SPECT-China study, which was performed in 23 sites in East China during 2014 to 2016. Using four single-nucleotide polymorphisms (SNPs) strongly associated with 25-hydroxyvitamin D (25(OH)D) levels, we created a genetic risk score (GRS) as instrumental variable (IV) to estimate the effect of genetically lowered 25(OH)D on total T.

MAIN OUTCOME MEASURE: Total T was detected by chemiluminescenceassay.

RESULTS: Lower measured 25(OH)D levels were associated with lower total T (B 0.40, 95%CI 0.23, 0.58) after multivariable adjustment. In addition, per SD increase in the VD_GRS was significantly associated with 25(OH)D (B -1.64, 95%CI -2.04, -1.24) and with total T (B -0.19, 95%CI -0.37, -0.02). Using VD_GRS as IV in the MR analysis, the causal regression coefficient (betaIV) of genetically determined per SD increase for 25(OH)D on total T was 0.12 (95%CI 0.02, 0.22).

CONCLUSIONS: The study provided evidence for the biologically plausible causal effects of 25(OH)D on total T using MR analysis. Whether vitamin D supplementation can raise androgen levels merits further investigation in long-term randomized controlled trials.

Chen C, Zhai H, Cheng J, et al. Causal link between vitamin D and total testosterone in men: A mendelian randomization analysis. The Journal of clinical endocrinology and metabolism 2019. Causal link between vitamin D and total testosterone in men: A mendelian randomization analysis

 

[Michael Scally MD]

Auguste BL, Avila-Casado C, Bargman JM. Use of vitamin D drops leading to kidney failure in a 54-year-old man. Canadian Medical Association Journal 2019;191:E390. Use of vitamin D drops leading to kidney failure in a 54-year-old man

KEY POINTS
· Vitamin D toxicity is rare, but clinicians must be aware of the risks of vitamin D use to limit complications related to hypercalcemia.
· Calcium levels may get worse before getting better in patients even after cessation of supplements, as vitamin D is fat soluble.
· Observational data and expert opinion suggest that glucocorticoids, ketoconazole and hydroxychloroquine are reasonable options to treat hypercalcemia related to vitamin D toxicity by decreasing the “active” 1, 25 dihydroxyvitamin D3 levels.

 

[Michael Scally MD]

The Effect of Vitamin D Supplementation on The Androgenic Profile

The aim of this systematic review and meta-analysis was to evaluate the effect of vitamin D supplementation on total testosterone (TT) and sex hormone-binding globulin (SHBG) in men.

We searched PubMed, Scopus and Web of Science for randomized, controlled trials of vitamin D supplementation in men >/=18 years old up to September 2018, without language restrictions. Meta-analysis was based on a random effects model. The systematic review was registered as CRD42018094498.

We identified 3,402 articles, of which eight studies with 10 effect sizes met the inclusion criteria. Vitamin D daily dose equivalents ranged from 600 to 4,000 per day to 60,000 IU per week; duration was 6 weeks to 36 months.

In general, vitamin D supplementation had no significant effect on TT (MD = 0.20, 95% CI: -0.20, 0.60, p = 0.336) and SHBG (MD = 1.56, 95% CI: -0.85, 3.97, p = 0.204). Subgroup analysis conducted with duration of prescription, type (daily or weekly), dosing frequency and baseline vitamin D and TT concentration showed that vitamin D did not significantly affect TT.

The present study did not find any evidence to support beneficial effect of vitamin D supplementation on TT and SHBG in men. Thus, further large-scale randomised controlled trials are required to evaluate the effects of vitamin D supplementation on androgen in men.

Hosseini Marnani E, Mollahosseini M, Gheflati A, Ghadiri-Anari A, Nadjarzadeh A. The effect of vitamin D supplementation on the androgenic profile in men: A systematic review and meta-analysis of clinical trials. Andrologia 2019:e13343. Error - Cookies Turned Off

 

[Michael Scally MD]

Vitamin D in Physiological and Pathological Aging: Lesson from Centenarians

Vitamin D is a secosteroid hormone that exerts a pleiotropic action on a wide spectrum of tissues, apparatuses and systems. Thus, vitamin D has assumed an increasingly dominant role as a key determinant of biological mechanisms and specific clinical conditions.

Older people frequently present vitamin D deficiency, a status potentially influencing several mechanisms responsible for different age-related diseases. Centenarians symbolize the ideal model for investigating the peculiar traits of longevity, as they have reached an age close to the estimated limit of the human lifespan.

Interestingly, despite the profound heterogeneity of centenarians in terms of health status, all these people share the same condition of severe vitamin D deficiency, suggesting that they may have implemented a number of adaptive strategies to cope with the age-related physiological derangement of vitamin D metabolism.

The lesson deriving from centenarians' experience suggests that:

i) severe vitamin D deficiency does not preclude the possibility of reaching extreme longevity,

ii) strategies to prevent hypovitaminosis D may be useful to slow down the processes of "fragilization" occurring in aged people,

iii) beneficial effects of vitamin D supplementation need to be confirmed regarding longevity.

Ferri E, Casati M, Cesari M, Vitale G, Arosio B. Vitamin D in physiological and pathological aging: Lesson from centenarians. Reviews in endocrine & metabolic disorders 2019. Vitamin D in physiological and pathological aging: Lesson from centenarians

 

[Michael Scally MD]

Vitamin D and Sex Steroid Production

Highlights

· Young men with vitamin D deficiency have lower testosterone/estradiol ratio

· Men with impaired Leydig cell function and vitamin D deficient are less sensitive to hCG stimulation

· Testicular tissue culture exposed to calcitriol induces a significant increase in testosterone

· Vitamin D may have a stimulatory role on androgen production in men

Production of testosterone is under tight control by human chorion gonadotropin (hCG) during fetal life and luteinizing hormone (LH) in adulthood. Several animal and human studies have linked vitamin D status with sex steroid production although it is not clear whether there exist a direct or indirect involvement in androgen production. Few studies have investigated this crosslink in young healthy men and putative direct or synergistic effect of activated vitamin D (1,25(OH)2D3) and LH/hCG on sex steroid production in vitro.

Here, we present cross-sectional data from 300 young men and 41 hCG-stimulated men with impaired Leydig cell function combined with data from an ex vivo culture of human testicular tissue exposed to 1,25(OH)2D3 alone or in combination with hCG. Serum 25-OHD was positively associated with SHBG (β:0.002; p = 0.023) and testosterone/estradiol-ratio (β:0.001; p = 0.039), and inversely associated with free testosterone (%) (free testosterone/total testosterone) (β:-0.002; p = 0.016) in young men.

Vitamin D deficient men had higher total and free estradiol concentrations than men with higher vitamin D status (19% and 18%, respectively; p < 0.01). Interestingly, men with impaired Leydig cell function and vitamin D deficiency had a significantly lower hCG-mediated increase in total and free testosterone compared with vitamin D sufficient men (p < 0.05). Accordingly, testicular tissue exposed to 0.1 µM 1,25(OH)2D3 had a 15% higher testosterone release into the media compared with vehicle treated specimens (p = 0.030).

In conclusion, vitamin D deficiency is associated with lower testosterone/estradiol ratio in young men and lower Leydig cell sensitivity after hCG-stimulation in men with impaired gonadal function. The significant effect of 1,25(OH)2D3 on testosterone production in a human testis model supports that the stimulatory effect at least in part may be direct. Larger placebo-controlled studies are needed to determine whether vitamin D supplementation can influence testosterone production.

Holt R, Mortensen LJ, Harpelunde Poulsen K, et al. Vitamin D and sex steroid production in men with normal or impaired Leydig cell function. The Journal of Steroid Biochemistry and Molecular Biology 2020:105589. Vitamin D and sex steroid production in men with normal or impaired Leydig cell function - ScienceDirect

 

[Michael Scally MD]

[OA] Serum Vitamin D Content Is Associated with Semen Parameters and Serum Testosterone Levels

The present study aimed to evaluate the influence of serum vitamin D levels on semen quality and testosterone levels. This is a cross-sectional study conducted at Androscience, Science and Innovation Center in Andrology and High-Complex Clinical and Andrology Laboratory in Sao Paulo, Brazil, with 508 male patients, aged 18-60 years, from 2007 to 2017.

Seminal parameters and serum sexual hormones were correlated with serum vitamin D concentrations in 260 men selected by strict selection criteria. Patients were divided into normozoospermic group (NZG, n = 124) and a group with seminal abnormalities (SAG, n = 136).

Evaluation included complete physical examination, past medical history, habits and lifestyle factors, two complete seminal analysis with sperm functional tests, serum levels of 25-hydroxy-vitamin D3(25(OH)VD3), total and free testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), sex hormone-binding globulin (SHBG), total cholesterol, homeostatic model assessment of insulin resistance (HOMA-IR) index, and karyotype.

The mean concentration of 25(OH)VD3 was significantly lower in the SAG (P < 0.001) and positively correlated with all baseline seminal parameters and total testosterone levels. In addition, serum vitamin D3 concentration was found to be positively correlated with sperm concentration (β= 2.103; P < 0.001), total number of spermatozoa with progressive motility (β = 2.069; P = 0.003), total number of motile spermatozoa (β = 2.571; P = 0.015), and strict morphology (β = 0.056; P = 0.006), regardless of other variables.

This is the first comparative study to address the issue of serum vitamin D3content between normozoospermic patients and those with sperm abnormalities. It clearly demonstrates a direct and positive relationship between serum vitamin D level and overall semen quality, male reproductive potential, and testosterone levels.

Ciccone IM, Costa EM, Pariz JR, et al. Serum vitamin D content is associated with semen parameters and serum testosterone levels in men [published online ahead of print, 2020 Apr 28]. Asian J Androl. 2020;10.4103/aja.aja_9_20. doi:10.4103/aja.aja_9_20 Serum vitamin D content is associated with semen parameters and serum testosterone levels in men Ciccone IM, Costa EM, Pariz JR, Teixeira TA, Drevet JR, Gharagozloo P, Aitken RJ, Hallak J, - Asian J Androl

 

[Michael Scally MD]

Reviewing the Evidence on Vitamin D Supplementation in the Management of Testosterone Status and Its Effects on Male Reproductive System

Purpose: Vitamin D supplementation has been suggested to increase testosterone levels. The primary purpose of this literature review was to critically assess the physiologic effects of vitamin D supplementation on serum testosterone concentrations in men and the secondary purpose was to evaluate the feasibility of vitamin D status toward urologic health (testis and prostate).

Methods: A structured literature review was performed using the Cochrane, MEDLINE, and Web of Science databases. The literature search encompassed studies published between 2011 and 2019.

Findings: Observational studies suggest an association between higher testosterone and serum vitamin D concentrations. Conversely, most randomized clinical trials that investigated the effect of vitamin D administration on testosterone levels have failed to detect any significant effect. Physiologically, vitamin D is engaging in spermatogenesis, but it remains unclear whether vitamin D is a determinant of fertility. With prostate support, the management of vitamin D status has been associated with a decreased prevalence of benign prostatic hyperplasia and symptoms (ie, lower urinary tract symptoms). However, with prostate cancer, there is a paucity of evidence pertaining to vitamin D supplementation.

Implications: Mechanistically, vitamin D exhibits essential roles in the testis and prostate; otherwise, there is no apparent evidence to support the use of vitamin D supplementation to increase testosterone levels and to improve clinical outcomes related to the male reproductive system.

Santos HO, Howell S, Nichols K, Teixeira FJ. Reviewing the Evidence on Vitamin D Supplementation in the Management of Testosterone Status and Its Effects on Male Reproductive System (Testis and Prostate): Mechanistically Dazzling but Clinically Disappointing [published online ahead of print, 2020 May 20]. Clin Ther. 2020;S0149-2918(20)30183-1. doi:10.1016/j.clinthera.2020.03.016 https://www.clinicaltherapeutics.com/article/S0149-2918(20)30183-1/pdf

 

[Michael Scally MD]

[OA] Role of Vitamin D in Athletes and Their Performance

We are currently experiencing a vitamin D (VITD) deficiency pandemic across the world. Athletes have the same predisposition to low levels of vitamin D, the majority of its concentrations being below 20 ng/mL in a wide range of sports, especially in the winter months.

Vitamin D is important in bone health, but recent research also points out its essential role in extraskeletal functions, including skeletal muscle growth, immune and cardiopulmonary functions and inflammatory modulation, which influence athletic performance. Vitamin D can also interact with extraskeletal tissues to modulate injury recovery and also influence the risk of infection.

The data presented in this paper has triggered investigations in relation to the importance of maintaining adequate levels of vitamin D and to the possible positive influence supplementation has on immune and musculoskeletal functions in athletes, benefiting their performance and preventing future injuries.

The objective of this review is to describe the latest research conducted on the epidemiology of vitamin D deficiency and its effects on sports performance and musculoskeletal health.

de la Puente Yagüe M, Collado Yurrita L, Ciudad Cabañas MJ, Cuadrado Cenzual MA. Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends. Nutrients. 2020;12(2):579. Published 2020 Feb 23. doi:10.3390/nu12020579 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071499/