Vitamin D

Discussion in 'Men's Health Forum' started by Michael Scally MD, Jul 27, 2010.

  1. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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
     
  2. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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”.
     
  3. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    [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
     
  4. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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
     
  5. LOVEMe89

    LOVEMe89 Junior Member

    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
     
  6. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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
     
  7. kendallkmw

    kendallkmw Member

    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.
     
  8. LOVEMe89

    LOVEMe89 Junior Member

    Damm that´s interesting and i´m sorry to hear that
     
  9. kendallkmw

    kendallkmw Member

    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.
     
  10. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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.
     
  11. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    [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
     
  12. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    [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
     
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  13. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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
     
  14. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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.
     
  15. Michael Scally MD

    Michael Scally MD Doctor of Medicine

    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