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Vitamin D status predicts physical performance and its decline in older persons. Wicherts IS, van Schoor NM, Boeke AJ, Visser M, Deeg DJ, Smit J, Knol DL, Lips P. J Clin Endocrinol Metab. 2007 Jun;92(6):2058-65. Epub 2007 Mar 6. PMID: 17341569 doi:10.1210/jc.2006-1525 ONCLUSIONS: Serum 25-OHD concentrations below 20 ng/ml are associated with poorer physical performance and a greater decline in physical performance in older men and women. Because almost 50% of the population had serum 25-OHD below 20 ng/ml, public health strategies should be aimed at this group.

Athletic performance and vitamin D. Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ. Med Sci Sports Exerc. 2009 May;41(5):1102-10. Review. PMID: 19346976 doi: 10.1249/MSS.0b013e3181930c2b Conclusions: Vitamin D may improve athletic performance in vitamin D-deficient athletes. Peak athletic performance may occur when 25(OH)D levels approach those obtained by natural, full-body, summer sun exposure, which is at least 50 ng·mL-1. Such 25(OH)D levels may also protect the athlete from several acute and chronic medical conditions.

Vitamin D-Related Changes in Physical Performance: A Systematic Review. Annweiler C, Schott AM, Berrut G, Fantino B, Beauchet O. J Nutr Health Aging. 2009;13(10):893-898. PMID: 19924350 Conclusions: The findings show that the association between vitamin D and physical performance remains controversial. Observational studies and clinical trials yielded divergent results, which highlights the complex and to date still poorly understood association between serum vitamin D concentration or vitamin D supplementation and physical performance.

Vitamin D deficiency is associated with worse cognitive performance and lower bone density in older African Americans. Wilkins CH, Birge SJ, Sheline YI, Morris JC. J Natl Med Assoc. 2009 Apr;101(4):349-54. PMID: 19397226 CONCLUSIONS: Vitamin D deficiency in older African Americans was associated with worse cognitive performance and lower BMD of the hip

Effects of vitamin D supplementation on strength, physical performance, and falls in older persons: a systematic review. Latham NK, Anderson CS, Reid IR. J Am Geriatr Soc. 2003 Sep;51(9):1219-26. Review. PMID: 12919233 DOI: 10.1046/j.1532-5415.2003.51405. Conclusion: Although there is insufficient evidence that vitamin D supplementation alone improves physical performance in older people, some data suggest a benefit from vitamin D combined with calcium supplementation, but this requires confirmation in large, well-designed trials.

Vitamin D and cognitive performance in adults: a systematic review. Annweiler C, Allali G, Allain P, Bridenbaugh S, Schott AM, Kressig RW, Beauchet O. Eur J Neurol. 2009 Oct;16(10):1083-9. Epub 2009 Jul 29. PMID: 19659751 DOI: 10.1111/j.1468-1331.2009.02755.x This systematic review shows that the association between serum 25OHD concentrations and cognitive performance is not yet clearly established. The inconclusive results of the reviewed studies could be due to methodology, types of the cognitive tasks used and/or the cellular mechanisms of vitamin D.

Association between 25-hydroxyvitamin D levels and cognitive performance in middle-aged and older European men. Lee DM, Tajar A, Ulubaev A, Pendleton N, O'Neill TW, O'Connor DB, Bartfai G, Boonen S, Bouillon R, Casanueva FF, Finn JD, Forti G, Giwercman A, Han TS, Huhtaniemi IT, Kula K, Lean ME, Punab M, Silman AJ, Vanderschueren D, Wu FC; EMAS study group. J Neurol Neurosurg Psychiatry. 2009 Jul;80(7):722-9. Epub 2009 May 21. PMID: 19460797 doi:10.1136/jnnp.2008.165720 Conclusion: In this study, lower 25(OH)D levels were associated with poorer performance on the DSST. Further research is warranted to determine whether vitamin D sufficiency might have a role in preserving cognitive function in older adults.

Circulating vitamin D3 and 25-hydroxyvitamin D in humans: An important tool to define adequate nutritional vitamin D status. Hollis BW, Wagner CL, Drezner MK, Binkley NC. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):631-4. Epub 2007 Jan 10. PMID: 17218096 In the present study, we sought to investigate what circulating 25(OH)D levels would result in populations exhibiting no substrate limitations to the vitamin D-25-hydroxylase. To perform this, we chose two distinct populations. The first were individuals from a year-found sunny environment who spent a good deal of time outdoors. The second were a group of lactating women receiving a substantial daily oral dose of vitamin D3. Surprisingly, a study such as this previously had not been undertaken. There are several reasons for this. First, finding a group of sun-exposed individuals is not an easy task; in fact, we had to go to Hawaii to find them. Secondly, very few studies have been performed where subjects actually received adequate vitamin D3 supplementation to make them replete. Finally, it is very difficult and costly to measure circulating vitamin D3 and relate it to circulating 25(OH)D. The results of our study are far-reaching. This study also demonstrates that individuals can be vitamin D deficient with significant sun exposure if the skin area exposed is limited as was suggested several years ago (19). Finally, whether one receives their vitamin D3 orally or through UV exposure, the vitamin D-25-hydroxylase appears to handle it in an equivalent fashion with respect to maintaining circulating 25(OH)D levels. Thus, we believe that the relationship between circulating vitamin D and 25(OH)D may define adequate nutritional vitamin D status.

Association between vitamin D status and physical performance: the InCHIANTI study.\nHouston DK, Cesari M, Ferrucci L, Cherubini A, Maggio D, Bartali B, Johnson MA, Schwartz GG, Kritchevsky SB.\nJ Gerontol A Biol Sci Med Sci. 2007 Apr;62(4):440-6.\nPMID: 17452740

Wicherts IS, van Schoor NM, Boeke AJ, Visser M, Deeg DJ, Smit J, Knol DL, Lips P. Vitamin D status predicts physical performance and its decline in older persons. J Clin Endocrinol Metab. 2007 Jun;92(6):2058-65. Epub 2007 Mar 6. PMID: 17341569 [PubMed

Houston DK, Cesari M, Ferrucci L, Cherubini A, Maggio D, Bartali B, Johnson MA, Schwartz GG, Kritchevsky SB. Association between vitamin D status and physical performance: the InCHIANTI study. J Gerontol A Biol Sci Med Sci. 2007 Apr;62(4):440-6. PMID:

"In 1927 a controversy arose in the athletic world. The German Swimmers' Association had decided to use a sunlamp on their athletes to boost performance. Some felt this ultraviolet irradiation constituted "athletic unfairness." In other words, doping."

Podiatrists provide medical and surgical care for people suffering foot, ankle, and lower leg problems. They diagnose illnesses, treat injuries, and perform surgery.

Vitamin D supplementation improves neuromuscular function in older people who fall. Dhesi JK, Jackson SH, Bearne LM, Moniz C, Hurley MV, Swift CG, Allain TJ. Age Ageing. 2004 Nov;33(6):589-95. PMID: 15501836 doi:10.1093/ageing/afh20 9 CONCLUSIONS: vitamin D supplementation, in fallers with vitamin D insufficiency, has a significant beneficial effect on functional performance, reaction time and balance, but not muscle strength. This suggests that vitamin D supplementation improves neuromuscular or neuroprotective function, which may in part explain the mechanism whereby vitamin D reduces falls and fractures.

Vitamin D and its role in skeletal muscle. Ceglia L. Curr Opin Clin Nutr Metab Care. 2009 Sep 18. [Epub ahead of print] PMID: 19770647 SUMMARY: Further studies are needed to fully characterize the underlying mechanisms of vitamin D action in human muscle tissue, to understand how these actions translate into changes in muscle cell morphology and improvements in physical performance, and to define the 25-hydroxyvitamin D level at which to achieve these beneficial effects in muscle.

Summary of evidence-based review on vitamin D efficacy and safety in relation to bone health. Cranney A, Weiler HA, O'Donnell S, Puil L. Am J Clin Nutr. 2008 Aug;88(2):513S-519S. Review. PMID: 18689393 We found inconsistent evidence of an association between serum 25-hydroxyvitamin D [25(OH)D] concentration and bone mineral content in infants and fair evidence of an association with bone mineral content or density in older children and older adults. The evidence of an association between serum 25(OH)D concentration and some clinical outcomes (fractures, performance measures) in postmenopausal women and older men was inconsistent, and the evidence of an association with falls was fair. We found good evidence of a positive effect of consuming vitamin D-fortified foods on 25(OH)D concentrations. The evidence for a benefit of vitamin D on falls and fractures varied. We found fair evidence that adults tolerated vitamin D at doses above current dietary reference intake levels, but we had no data on the association between long-term harms and higher doses of vitamin D.

An international comparison of serum 25-hydroxyvitamin D measurements. Lips P, Chapuy MC, Dawson-Hughes B, Pols HA, Holick MF. Osteoporos Int. 1999;9(5):394-7. PMID: 10550457 DOI: 10.1007/s001980050162 The results show that 25(OH)D values from different laboratories can not be assumed to be comparable unless a careful cross-calibration has been performed.

In 1939, Dr. Abraham Myerson measured initial levels of circulating testosterone in men and exposed their various body parts to UVB light. After five days of chest exposure sufficient to cause reddening, circulating testosterone increased by 120%. After eight days without additional UV exposure, testosterone returned to initial levels. When the genital area was exposed, testosterone levels increased by 200%!

NEW YORK (Reuters Health) - New research suggests that low vitamin D levels in the body are associated with thinking or "cognitive" impairments in older men, but whether vitamin D supplements can help is not yet known. In the study, an investigation of European men, subjects with low levels of vitamin D scored worse on a standard test of cognitive ability than did their peers with normal levels, Dr. David M. Lee, from the University of Manchester, UK, and co-researchers found. Although, the authors emphasize, the difference in scores was not that great.