Group items tagged

Defining Adequate Vitamin D Intake : Cross-sectional and Intervention Studies Viljakainen, Heli Tuulikki University of Helsinki 2008-05-23 Doctoral dissertation (article-based) Vitamin D is required for normal bone growth and maintenance of the skeleton throughout life. In Finland, like in many other Western countries, the population suffers from inadequate or deficient vitamin D status, especially during winter, which is thought to increase the risk of osteoporosis. New strategies to prevent osteoporosis are actively being sought. The main objective of this thesis was to determine whether vitamin D is feasible in the primary prevention of osteoporosis; does it affect bone mineral accrual during the growth period? A second goal was to ascertain whether seasonal variation in calcitropic hormones affects bone remodelling, and to elucidate the vitamin D intake needed to overcome this variation in different age groups. In summary, vitamin D intake remains inadequate among the target groups of this thesis, as reflected by seasonal variation in calcitropic hormones and bone metabolism. Dietary intake of vitamin D should be increased to achieve at least an adequate vitamin D status (S-25-OHD>50 nmol/l) and possibly an optimal vitamin D status (S-25-OHD>80 nmol/l) throughout the year. This could be accomplished by introducing new vitamin D-fortified foods to the market."

"Vitamin D may be more important to colon cancer prevention than previously believed, according to a study published in the Journal of the American Medical Association (Vol. 290, No. 22: 2959-2967). The study examined people with no symptoms of colon cancer to determine what role diet, exercise, smoking, and other behaviors played in the development or not of colon polyps, small growths in the colon that can turn into cancer if they aren't removed."

"Researchers at Johns Hopkins are reporting what is believed to be the first conclusive evidence in men that the long-term ill effects of vitamin D deficiency are amplified by lower levels of the key sex hormone estrogen, but not testosterone. In a national study in 1010 men, to be presented Nov. 15 at the American Heart Association's (AHA) annual Scientific Sessions in Orlando, researchers say the new findings build on previous studies showing that deficiencies in vitamin D and low levels of estrogen, found naturally in differing amounts in men and women, were independent risk factors for hardened and narrowed arteries and weakened bones. Vitamin D is an essential part to keeping the body healthy, and can be obtained from fortified foods, such as milk and cereals, and by exposure to sunlight.

"April 28, 2009 (Seattle) -- High doses of vitamin D dramatically cut the relapse rate in people with multiple sclerosis, a study shows. Sixteen percent of 25 people with multiple sclerosis (MS) given an average of 14,000 international units (IU) of vitamin D a day for a year suffered relapses, says Jodie Burton, MD, a neurologist at the University of Toronto. In contrast, close to 40% of 24 MS patients who took an average of 1,000 IU a day -- the amount recommended by many MS specialists -- relapsed, she says. Also, people taking high-dose vitamin D suffered 41% fewer relapses than the year before the study began, compared with 17% of those taking typical doses. People taking high doses of vitamin D did not suffer any significant side effects, Burton tells WebMD."

"(NaturalNews) Treatment with vitamin D supplements may slow the progress of , according to a study published in the journal BJU International. In the United States, prostate cancer is the second leading cause of cancer death among men, after lung cancer. Approximately 240,000 new cases are diagnosed every year, leading to 30,000 deaths. Researchers have suspected for nearly two decades that the so-called "sunshine vitamin" may play a role in the risk and progression of prostate cancer, but no studies have previously been conducted on its usefulness as a treatment."

Association of vitamin D deficiency with cognitive impairment in older women. Cross-sectional study. Annweiler C, Schott AM, Allali G, Bridenbaugh SA, Kressig RW, Allain P, Herrmann FR, Beauchet O. Neurology. 2009 Sep 30. [Epub ahead of print] PMID: 19794127 doi:10.1212/WNL.0b013e3181beecd3 Conclusions: 25-Hydroxyvitamin D deficiency was associated with cognitive impairment in this cohort of community-dwelling older women.

Effect of vitamin D deficiency and replacement on endothelial function in asymptomatic subjects. Tarcin O, Yavuz DG, Ozben B, Telli A, Velioglu Ogunc A, Yuksel M, Toprak A, Yazici D, Sancak S, Deyneli O, Akalin S. J Clin Endocrinol Metab. 2009 Jul 7. [Epub ahead of print] PMID: 19584181 doi:10.1210/jc.2008-1212 Conclusions: This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D associated endothelial dysfunction may predispose to higher cardiovascular disease in the winter.

Effects of Atorvastatin on vitamin D levels in patients with acute ischemic heart disease. Pérez-Castrillón JL, Vega G, Abad L, Sanz A, Chaves J, Hernandez G, Dueñas A. Am J Cardiol. 2007 Apr 1;99(7):903-5. Epub 2007 Feb 8. PMID: 17398180 In conclusion, atorvastatin increases vitamin D levels. This increase could explain some of the beneficial effects of atorvastatin at the cardiovascular level that are unrelated to cholesterol levels. The mechanism by which atorvastatin increases vitamin D levels is related to inhibition of 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) reductase. Cholesterol is synthesized from 7-dehydrocholesterol, which is also a precursor of vitamin D3. For this reason, we initially observed a statistically significant relation between total cholesterol and vitamin D. HMG-CoA enzyme reductase is key to the synthesis of cholesterol, whereas ultraviolet radiation causes the formation of 25-hydroxyvitamin D. Inhibition of the enzyme may increase levels of 7-dehydrocholesterol and increase the synthesis of 25-hydroxycholecalciferol, thereby increasing vitamin D levels,10 although we observed no relation between lower cholesterol and increased vitamin D. In addition, 25-hydroxyvitamin D has been shown to inhibit HMG-CoA enzyme reductase activity in in vitro studies.11 A greater concentration of vitamin D could increase enzymatic inhibition, acting in synergy with the statin in decreasing total cholesterol.

Age-related changes in the 25-hydroxyvitamin D versus parathyroid hormone relationship suggest a different reason why older adults require more vitamin D. Vieth R, Ladak Y, Walfish PG. J Clin Endocrinol Metab. 2003 Jan;88(1):185-91. PMID: 12519850 This study shows that all age groups exhibit a high prevalence of 25(OH)D insufficiency and secondary hyperparathyroidism. Older adults are just as efficient in maintaining 25(OH)D, but they need more vitamin D to produce the higher 25(OH)D concentrations required to overcome the hyperparathyroidism associated with their diminishing renal function

Geographic variation in breast cancer mortality in the United States: a hypothesis involving exposure to solar radiation. Garland FC, Garland CF, Gorham ED, Young JF. Prev Med. 1990 Nov;19(6):614-22. PMID: 2263572 doi:10.1016/0091-7435(90)90058-R Vitamin D from sunlight exposure may be associated with low risk for fatal breast cancer, and differences in ultraviolet light reaching the United States population may account for the striking regional differences in breast cancer mortality. The ecological nature of this study is emphasized, and the possibility that an indirect association with dietary and socioeconomic factors could explain these findings is discussed.

Supplementation with cholecalciferol does not improve glycaemic control in diabetic subjects with normal serum 25-hydroxyvitamin D levels. Jorde R, Figenschau Y. Eur J Nutr. 2009 Apr 16. [Epub ahead of print] PMID: 19370371 10.1007/s00394-009-0020-3 Conclusions We were not able to demonstrate that vitamin D supplementation had a significant effect on glucose metabolism in subjects with type 2 diabetes but without vitamin D deficiency. Further studies are needed in larger groups of subjects with type 2 diabetes or impaired glucose tolerance, who also exhibit low serum 25-hydroxyvitamin D levels.

Vitamin D deficiency and risk of cardiovascular disease. Wang TJ, Pencina MJ, Booth SL, Jacques PF, Ingelsson E, Lanier K, Benjamin EJ, D'Agostino RB, Wolf M, Vasan RS. Circulation. 2008 Jan 29;117(4):503-11. Epub 2008 Jan 7. PMID: 18180395 doi: 10.1161/CIRCULATIONAHA.107.706127 Conclusions- Vitamin D deficiency is associated with incident cardiovascular disease. Further clinical and experimental studies may be warranted to determine whether correction of vitamin D deficiency could contribute to the prevention of cardiovascular disease.

The dependency of vitamin D status on body mass index, gender, age and season. Lagunova Z, Porojnicu AC, Lindberg F, Hexeberg S, Moan J. Anticancer Res. 2009 Sep;29(9):3713-20. PMID: 19667169 CONCLUSION: The 25(OH)D3 level, as well as its seasonal variation and the prevalence of vitamin D deficiency, are all dependent on BMI, and age separately. The results of the study suggest that 1 in 3 women and 1 in 2 men with BMI > or = 40 are vitamin D deficient.

Optimal vitamin D status attenuates the age-associated increase in systolic blood pressure in white Americans: results from the third National Health and Nutrition Examination Survey. Judd SE, Nanes MS, Ziegler TR, Wilson PW, Tangpricha V. Am J Clin Nutr. 2008 Jan;87(1):136-41. PMID: 18175747 Conclusions: SBP is inversely associated with serum vitamin D concentrations in nonhypertensive white persons in the United States. This observation provides a rationale for studies on the potential effects of vitamin D supplementation as a method to reduce SBP in persons at risk of hypertension.

Stress fractures in the Israeli defense forces from 1995 to 1996. Givon U, Friedman E, Reiner A, Vered I, Finestone A, Shemer J. Clin Orthop Relat Res. 2000 Apr;(373):227-32. PMID: 10810481 Serum levels of bone specific alkaline phosphatase and osteocalcin were elevated in patients with high grade stress fractures compared with control subjects with no symptoms: 37.6 versus 26.2 units/L, and 10.8 versus 8.8 ng/mL, respectively. Levels of 25-hydroxy vitamin D were lower in patients with high grade stress fractures (25.3 ng/mL) than in control subjects (29.8 ng/mL). This study revealed that several parameters can distinguish soldiers with high grade stress fractures, but their predictive value and precise pathogenetic role remain unclear.

Hypovitaminosis D is associated with insulin resistance and beta cell dysfunction. Chiu KC, Chu A, Go VL, Saad MF. Am J Clin Nutr. 2004 May;79(5):820-5. PMID: 15113720 Conclusions: The data show a positive correlation of 25(OH)D concentration with insulin sensitivity and a negative effect of hypovitaminosis D on ß cell function. Subjects with hypovitaminosis D are at higher risk of insulin resistance and the metabolic syndrome. Further studies are required to explore the underlying mechanisms.

25-hydroxyvitamin D, IGF-1, and metabolic syndrome at 45 years of age: a cross-sectional study in the 1958 British Birth Cohort. Hyppönen E, Boucher BJ, Berry DJ, Power C. Diabetes. 2008 Feb;57(2):298-305. Epub 2007 Nov 14. PMID: 18003755 doi: 10.2337/db07-1122 CONCLUSIONS-Serum 25(OH)D is inversely associated with metabolic syndrome, whereas the inverse association with IGF-1 was found only among those without hypovitaminosis D. These results suggest that metabolic syndrome prevalence is the lowest when both 25(OH)D and IGF-1 are high.

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.

Relation of body fat indexes to vitamin D status and deficiency among obese adolescents. Lenders CM, Feldman HA, Von Scheven E, Merewood A, Sweeney C, Wilson DM, Lee PD, Abrams SH, Gitelman SE, Wertz MS, Klish WJ, Taylor GA, Chen TC, Holick MF; Elizabeth Glaser Pediatric Research Network Obesity Study Group. Am J Clin Nutr. 2009 Sep;90(3):459-67. Epub 2009 Jul 29. PMID: 19640956 RESULTS: The mean (+/-SD) age of the adolescents was 14.9 +/- 1.4 y; 38 (66%) were female, and 8 (14%) were black. The mean (+/-SD) body mass index (in kg/m(2)) was 36 +/- 5, FM was 40.0 +/- 5.5%, and VAT was 12.4 +/- 4.3%. Seventeen of the adolescents were vitamin D deficient, but none had elevated PTH concentrations. Bone mineral content and bone mineral density were within 2 SDs of national standards. In a multivariate analysis, 25(OH)D decreased by 0.46 +/- 0.22 ng/mL per 1% increment in FM (beta +/- SE, P = 0.05), whereas PTH decreased by 0.78 +/- 0.29 pg/mL per 1% increment in VAT (P = 0.01). CONCLUSIONS: To the best of our knowledge, our results show for the first time that obese adolescents with 25(OH)D deficiency, but without elevated PTH concentrations, have a bone mass within the range of national standards (+/-2 SD). The findings provide initial evidence that the distribution of fat may be associated with vitamin D status, but this relation may be dependent on metabolic factors

Vitamin D treatment in multiple sclerosis. Myhr KM. J Neurol Sci. 2009 Jun 22. [Epub ahead of print] PMID: 19549608 doi:10.1016/j.jns.2009.05.002 Epidemiological evidence combined with clinical and laboratory analyses, and experimental animal models, suggest a possible influence of vitamin D on MS susceptibility as well as clinical disease activity. Supplement with vitamin D may reduce the risk of developing MS. An intervention may also reduce the risk of conversion from a first clinical event suggestive of MS to clinical definite MS, as well as reduce the relapse rate among patients with relapsing remitting MS. More studies are, however, needed to determine optimal dose and serum level for vitamin D, as well as target populations and optimal timing for intervention.