Vitamin D3 supplementation using an oral spray solution resolves deficiency but has no effect on VO2 max in Gaelic footballers: results from a randomised, double-blind, placebo-controlled trial Effect of micronutrient supplement on health and nutritional status of schoolchildren: biochemical status. The impact of 1-year vitamin D supplementation on vitamin D status in athletes: a dose–response study The 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D from the Institute of Medicine: What Clinicians Need to Know Vitamin D Insufficiency Among Postmenopausal Women in Urban and Rural Areas in Guilan, Northern Iran A randomized double-blinded placebo controlled trial of ergocalciferol 40,000 versus 100,000 IU per week for vitamin D inadequacy in institutionalized postmenopausal women Factors Affecting Bone Loss in Female Endurance Athletes
Purpose Vitamin D inadequacy is a global health concern in athletes as well as the general population . Whilst the role of vitamin D in skeletal health is well defined , there remains uncertainty over whether vitamin D supplementation has an added benefit beyond bone health . Methods This r and omised placebo-controlled trial in healthy male and female Gaelic footballers ( n = 42 ) investigated the effect of vitamin D3 supplementation [ 3000 IU ( 75 µg ) daily for 12 weeks , via an oral spray solution ] on VO2 max which was the primary outcome measure . Secondary outcomes included skeletal muscle and lung function . Results Supplementation significantly increased total 25-hydroxyvitamin D concentrations compared to the placebo group ( mean ± SD change from baseline , 36.31 ± 32.34 vs. 6.11 ± 23.93 nmol/L , respectively ; P = 0.006 ) . At baseline , 50 and 22 % of footballers presented with vitamin D insufficiency ( 31–49 nmol/L ) and deficiency ( < 30 nmol/L ) , respectively . Total 25-hydroxyvitamin D concentration did not significantly correlate with any measure of physical performance . Analysis of covariance ( ANCOVA ) models demonstrated that vitamin D supplementation over 12 weeks had no significant effect on VO2 max ( P = 0.375 ) , vertical jump height ( P = 0.797 ) , left and right h and grip strength ( P = 0.146 and P = 0.266 , respectively ) , forced vital capacity ( P = 0.573 ) or forced expiratory volume at 1 s ( P = 0.665 ) , after adjusting for confounders . The high prevalence of vitamin D inadequacy observed in this cohort of collegiate Gaelic footballers supports the need for vitamin D supplementation during wintertime to avoid being at risk of poor bone health . Conclusions Twelve-week daily supplementation with 3000 IU ( 75 µg ) vitamin D3 successfully resolved deficiency but did not have any significant effect on VO2 max , skeletal muscle or lung function OBJECTIVE We assessed the effect of a daily intake of a micronutrient-fortified beverage for 14 mo on indicators of biochemical status of important micronutrients in schoolchildren . METHODS A double-blind , placebo-controlled , matched-pair , cluster , r and omization study design was used . Biochemical indicators of micronutrient status were evaluated at baseline and at the end of 14 mo on a sub sample in nine matched pairs . Prevalence ( percentage ) of sub clinical deficiency , mean , and mean increments of each indicator were compared between supplemented and placebo groups . RESULTS Extent of inadequacy at baseline was more or less 100 % for folic acid , 65 % for vitamins B2 and B6 , and 55 % for vitamins C and A. Prevalence of anemia among subjects was 55 % , with inadequacy of vitamin B12 being 40 % and that of vitamin D being 30 % . No subject had inadequacy of iodine based on urinary iodine . Supplementation of a micronutrient-enriched beverage for 14 mo significantly improved the status of many of the nutrients . The effect was significant with respect to vitamins A , B2 , and B12 , folic acid , vitamin D , parathyroid hormone , and thyroid-stimulating hormone in children who received the supplement compared with those who received only placebo .  Hemoglobin status improved only in children who had anemia in the supplemented group . CONCLUSIONS Prevalence of multiple sub clinical micronutrient deficiencies are high in middle-income Indian school children . Daily consumption of a micronutrient-enriched beverage had positive effects that were confined to those nutrients that were inadequate at baseline Background / Objectives : To assess the prevalence of vitamin D deficiency in Dutch athletes and to define the required dosage of vitamin D3 supplementation to prevent vitamin D deficiency over the course of a year . Subjects/ Methods : Blood sample s were collected from 128 highly trained athletes to assess total 25(OH)D concentration . Of these 128 athletes , 54 male and 48 female athletes ( 18–32 years ) were included in a r and omized , double blind , dose – response study . Athletes with either a deficient ( < 50 nmol/l ) or an insufficient ( 50–75 nmol/l ) 25(OH)D concentration were r and omly assigned to take 400 , 1100 or 2200 IU vitamin D3 per day orally for 1 year . Athletes who had a total 25(OH)D concentration above 75 nmol/l at baseline continued with the study protocol without receiving vitamin D supplements  . Serum total 25(OH)D concentration was assessed every 3 months , as well as  dietary vitamin D intake and sunlight exposure . Results : Nearly 70 % of all athletes showed an insufficient ( 50–75 nmol/l ) or a deficient ( < 50 nmol/l ) 25(OH)D concentration at baseline . After 12 months , serum 25(OH)D concentration had increased more in the 2200 IU/day group ( + 50±27 nmol/l ) than the sufficient group receiving no supplements ( + 4±17 nmol/l ; P<0.01 ) and the 1100 IU/day group ( + 25±23 nmol/l ; P<0.05 ) . Supplementation with 2200 IU/day vitamin D result ed in a sufficient 25(OH)D concentration in 80 % of the athletes after 12 months . Conclusions : Vitamin D deficiency is highly prevalent in athletes . Athletes with a deficient or an insufficient 25(OH)D concentration can achieve a sufficient 25(OH)D concentration within 3 months by taking 2200 IU/day This article summarizes the new 2011 report on dietary requirements for calcium and vitamin D from the Institute of Medicine ( IOM ) . An IOM Committee charged with determining the population needs for these nutrients in North America conducted a comprehensive review of the evidence for both skeletal and extraskeletal outcomes . The Committee concluded that available scientific evidence supports a key role of calcium and vitamin D in skeletal health , consistent with a cause- and -effect relationship and providing a sound basis for determination of intake requirements . For extraskeletal outcomes , including cancer , cardiovascular disease , diabetes , and autoimmune disorders , the evidence was inconsistent , inconclusive as to causality , and insufficient to inform nutritional requirements . R and omized clinical trial evidence for extraskeletal outcomes was limited and generally uninformative . Based on bone health , Recommended Dietary Allowances ( RDAs ; covering requirements of ≥97.5 % of the population ) for calcium range from 700 to 1300 mg/d for life-stage groups at least 1 yr of age . For vitamin D , RDAs of 600 IU/d for ages 1–70 yr and 800 IU/d for ages 71 yr and older , corresponding to a serum 25-hydroxyvitamin D level of at least 20 ng/ml ( 50 nmol/liter ) , meet the requirements of at least 97.5 % of the population . RDAs for vitamin D were derived based on conditions of minimal sun exposure due to wide variability in vitamin D synthesis from ultraviolet light and the risks of skin cancer . Higher values were not consistently associated with greater benefit , and for some outcomes U-shaped associations were observed , with risks at both low and high levels . The Committee concluded that the prevalence of vitamin D inadequacy in North America has been overestimated . Urgent research and clinical priorities were identified , including re assessment of laboratory ranges for 25-hydroxyvitamin D , to avoid problems of both undertreatment and overtreatment This study aim ed to describe vitamin D status in postmenopausal women in urban and rural areas in Guilan , northern Iran . Between October 2004 and February 2005 a group of 750 women older than 50 years was r and omly selected from urban and rural areas in Guilan . The participants were interviewed to collect data on age , educational level , body weight , height , employment status , reproductive history , medications , history of illness , and supplement use . Serum 25(OH ) D was measured in 646 women ( 427 in urban areas and 219 women in rural areas ) . Serum 25(OH ) D levels in urban and rural postmenopausal women were 18.5 ± 13.5 ng/ml and 22.9 ± 13.8 ng/ml ( P < 0.0001 ) , respectively . In urban and rural areas , 84.7 % and 79.5 % of the women had serum 25(OH ) D levels less than 30 ng/ml , respectively . In this study , serum vitamin D levels and prevalence of vitamin D insufficiency was related to educational level in urban women . The urban women in the lowest educational level ( < 5 years schooling ) had a better vitamin D status than other educational groups . This study showed that a high proportion of postmenopausal women living in Guilan province  had vitamin D insufficiency . Vitamin D inadequacy was more common in urban areas and especially in the upper social class . Supplement use and national strategies to prevent vitamin D insufficiency are strongly needed in this community Background Vitamin D inadequacy is common in institutionalized post-menopausal women who are at the highest risk for osteoporotic fracture . Aim To evaluate efficacy and safety of ergocalciferol 40,000 versus 100,000 IU per week for 12 weeks for vitamin D inadequacy in institutionalized postmenopausal women . Method A r and omized double-blinded placebo-controlled trial was conducted in 94 institutionalized subjects with baseline 25(OH)D levels < 30 ng/mL. Subjects were r and omized to receive ergocalciferol 40,000 ( st and ard dose ) or ergocalciferol 100,000 IU ( high dose ) per week . Serum 25(OH)D levels , calcium , phosphate , h and grip strength , time up and go ( TUG ) test and quality of life by EQ-5D-5L were measured at baseline and 12 weeks after r and omization . Results Of the 94 subjects enrolled , 85 subjects completed the study . Subjects in the high dose group had higher mean 25(OH)D levels than subjects in the st and ard group ( 51.73 ± 19.35 and 34.5 ± 9.12 , p < 0.001 ) . More subjects in the high dose group ( 90.9 % ) achieved optimal 25(OH)D levels ( > 30 ng/mL ) than those in the st and ard group ( 65.9 % ) , p = 0.007 . In a subgroup analysis of subjects with vitamin D deficiency ( < 20 ng/mL , n = 44 ) and severe vitamin D deficiency ( < 10 ng/mL , n = 9 ) , more subjects in the high dose group achieved optimal 25(OH)D levels than those in the st and ard group ( 88 % and 100 % versus 47.4 % and 16.7 % with p of 0.007 and 0.018 , respectively ) . There were no differences in h and grip strength , TUG , EQ-5D-5L and adverse events between groups . Discussion / conclusions Subjects who received high dose ergocalciferol achieved more optimal 25(OH)D levels than those who received st and ard dose . High dose ergocalciferol is preferred to optimize 25(OH)D levels in subjects with severe vitamin D deficiency Background : Low bone mass leading to stress fractures is a well-known and yet unsolved problem among female athletes . Purpose : To quantify the rate of bone loss in healthy female athletes and investigate the effects of estrogen and vitamin K supplementation on bone loss . Study Design : Prospect i ve cohort study . Methods : We classified 115 female endurance athletes into amenorrheic , eumenorrheic , or estrogen-supplemented groups and r and omized them to receive either placebo or vitamin K1 . The bone mineral densities of the subjects ' femoral neck and lumbar spine were measured at baseline and after 2 years . Results : Bone mineral density in the lumbar spine remained constant , but bone density in the femoral neck had decreased significantly after 2 years in all three subgroups . The decrease was higher in amenorrheic ( —6.5 % ± 4.0 % ) than in eumenorrheic ( —3.2 % ± 4.1 % ) and estrogen-supplemented athletes ( —3.9 % ± 3.1 % ) . Supplementation with vitamin K did not affect the rate of bone loss . Conclusions : The rate of bone loss in all three subgroups of female athletes was unexpectedly high ; neither estrogen nor vitamin K supplementation prevented bone loss . Clinical Relevance : High-intensity training maintained over several years must be regarded in women as a risk factor for osteoporosis , and protocol s for optimal treatment should be developed
Conclusion Despite the limitations of the current evidence , the prevalence of vitamin D inadequacy in athletes is prominent .
The risk significantly increases in higher latitudes , in winter and early spring seasons , and for indoor sport activities .
The prevalence of injuries in athletes is notable but its association with  vitamin D status is unclear .
Background Vitamin D is essential for maintaining optimal bone health .
The prevalence of vitamin D inadequacy in athletes is currently unclear .
Objective The objective of this study is to determine the prevalence of vitamin D inadequacy in athletes .
Serum 25(OH)D is measured to clinical ly determine vitamin D status .