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Ultraviolet exposure scenarios: risks of erythema from recommendations on cutaneous vitamin D synthesis. Webb AR, Engelsen O. Adv Exp Med Biol. 2008;624:72-85. PMID: 18348448 DOI: 10.1007/978-0-387-77574-6_6

A positive dose-response effect of vitamin D supplementation on site-specific bone mineral augmentation in adolescent girls: a double-blinded randomized placebo-controlled 1-year intervention. Viljakainen HT, Natri AM, Kärkkäinen M, Huttunen MM, Palssa A, Jakobsen J, Cashman KD, Mølgaard C, Lamberg-Allardt C. J Bone Miner Res. 2006 Jun;21(6):836-44. PMID: 16753014 doi: 10.1359/jbmr.060302 We conclude that the current vitamin D recommendation for adolescent girls, at least in the northern latitudes, is too low to ensure sufficient vitamin D status during winter. Intake of vitamin D at rates of 10-15 μg/day aids to maintain stable S-25(OH)D concentrations during winter. Vitamin D induced BMC augmentation by decreasing bone resorption, but not affecting bone formation, which was reflected by the biochemical markers of bone turnover. Optimizing bone mineral gain in adolescence is crucial to the prevention of osteoporosis later in life. Increasing vitamin D intake to 10-15 μg/day aids in attaining this goal.

How much vitamin D3 do the elderly need? Viljakainen HT, Palssa A, Kärkkäinen M, Jakobsen J, Lamberg-Allardt C. J Am Coll Nutr. 2006 Oct;25(5):429-35. PMID: 17031013 Conclusions: A clear dose response was noted in S-25-OHD to different doses of vitamin D3. The recommended dietary intake of 15 µg is adequate to maintain the S-25-OHD concentration around 40-55 nmol/L during winter, but if the optimal S-25-OHD is higher than that even higher vitamin D intakes are needed. Interestingly, subjects with lower vitamin D status at baseline responded more efficiently to supplementation than those with more adequate status

Hypovitaminosis D in medical inpatients. Thomas MK, Lloyd-Jones DM, Thadhani RI, Shaw AC, Deraska DJ, Kitch BT, Vamvakas EC, Dick IM, Prince RL, Finkelstein JS. N Engl J Med. 1998 Mar 19;338(12):777-83. PMID: 9504937 Conclusions Hypovitaminosis D is common in general medical inpatients, including those with vitamin D intakes exceeding the recommended daily amount and those without apparent risk factors for vitamin D deficiency.

Nutrients, endpoints, and the problem of proof. Heaney RP. 2008 W. O. Atwater Memorial Lecture J Nutr. 2008 Sep;138(9):1591-5. PMID: 18716155 To sum up, I think that there would be general agreement to the effect that nutrition is important, despite the fact that the still growing number of failed trials of individual nutrients might suggest that no nutrient actually made much of a difference, a conclusion that is absurd on its face and ought to have alerted us to the possibility that there was something wrong with how we were investigating the matter. To provide the proof needed to sustain revised intake recommendations, we shall have to find a design better suited to nutrients than the randomized controlled trial as currently implemented, and we need to develop a series of global indices, nutrient by nutrient, which better capture the polyvalent nature of most nutrients. Perhaps it would be useful for the ASN, in collaboration with concerned governmental entities such as the USDA, to convene a workshop to address these structural issues. Such deliberation may well be arduous and frustrating, but it is terribly important and, in my view, well worth the effort.

Wintertime vitamin D insufficiency is common in young Canadian women, and their vitamin D intake does not prevent it. Vieth R, Cole DE, Hawker GA, Trang HM, Rubin LA. Eur J Clin Nutr. 2001 Dec;55(12):1091-7. PMID: 11781676 INTERPRETATION: The self-reported vitamin D intake from milk and/or multivitamins does not relate to prevention of low vitamin D nutritional status of young women in winter. Recommended vitamin D intakes are too small to prevent insufficiency. Vitamin D nutrition can only be assessed by measuring serum 25(OH)D concentration.

Vitamin D in preventive medicine: are we ignoring the evidence? Zittermann A. Br J Nutr. 2003 May;89(5):552-72. Review. PMID: 12720576 Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1alpha-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1alpha-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5-15 microg/d.

Pharmacokinetics of a single, large dose of cholecalciferol. Ilahi M, Armas LA, Heaney RP. Am J Clin Nutr. 2008 Mar;87(3):688-91. PMID: 1832660 Conclusions: Cholecalciferol (100 000 IU) is a safe, effective, and simple way to increase calcidiol concentrations. The dosing interval should be ≤2 mo to ensure continuous serum calcidiol concentrations above baseline. Our study highlights that 100 000 IU cholecalciferol is a safe, efficient, and cost-effective means to increase calcidiol concentrations in the elderly. From this study we can safely recommend 100 000 IU cholecalciferol dosed every 2 mo in persons with moderate baseline calcidiol concentrations. However, in those persons with baseline calcidiol concentrations < 20 ng/mL, even this large dose will not adequately raise their calcidiol concentrations.

Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Ginde AA, Liu MC, Camargo CA Jr. Arch Intern Med. 2009 Mar 23;169(6):626-32. PMID: 19307527 Conclusions National data demonstrate a marked decrease in serum 25(OH)D levels from the 1988-1994 to the 2001-2004 NHANES data collections. Racial/ethnic differences have persisted and may have important implications for known health disparities. Current recommendations for vitamin D supplementation are inadequate to address the growing epidemic of vitamin D insufficiency.

Strong correlations have been noted between cardiovascular diseases and low bone density / osteoporosis-connections so strong that the presence of one type of pathology is considered a likely predictor of the other. This potentially causal relationship has led to the hypothesis that these conditions share core mechanisms. Recent advances in our understanding of the complimentary roles played by vitamin D3 and vitamin K2 in vascular and bone health provide support for this hypothesis, along with insight into key metabolic dysfunctions underlying cardiovascular disease and osteoporosis. Part I of this review summarizes current research linking vitamin D deficiency to cardiovascular disease, the physiological mechanisms underlying vitamin D's cardiovascular effects, and leading vitamin D researchers' recommendations for significantly higher supplemental doses of the pro-hormone. Part II reviews the vitamin K connection to cardiovascular disease; the ways in which vitamin D and vitamin K pair up to prevent inflammation, vascular calcification and osteoporosis; and the necessity of providing vitamin K along with vitamin D to preclude adverse effects associated with hypervitaminosis D, which include vascular and other soft tissue calcification.

Now a new and controversial book by an American doctor suggests that taking even higher levels of the vitamin - 10 to 15 times the recommended amounts - can work wonders. Dr James Dowd, who works at the Arthritis Institute of Michigan, has been prescribing vitamin D to people suffering from chronic disorders such as arthritis, back pain and headaches and the result, he claims, is a huge improvement in their symptoms. In his book, The Vitamin D Cure, Dr Dowd describes a number of success stories using this approach. One of his patients, Barbara, for instance, was obese, and suffered from arthritis in one leg as well as high blood pressure. As Dowd explains: "In the past I would have given her anti-inflammatory drugs, pain medication, a pill to lose weight and drug treatment for hypertension."

Opinion of the Scientific Committee on Food on the Tolerable Upper Intake Level of Vitamin D (expressed on 4 December 2002)

In the last post, we talked about the new report on vitamin D and cancer from the International Agency for Research into Cancer (IARC). In this one, we'll summarise what the report has to say on the balance between getting enough vitamin D through sun exposure and reducing the risk of skin cancer by being SunSmart. IARC calls for more trials to really pin down the effects of vitamin D supplements - either positive or negative - depending on how much vitamin D people already have in their system. Until then, they feel that there is no solid basis for changing any existing recommendations about vitamin D.

High prevalence of vitamin D deficiency despite supplementation in premenopausal women with breast cancer undergoing adjuvant chemotherapy. Crew KD, Shane E, Cremers S, McMahon DJ, Irani D, Hershman DL. J Clin Oncol. 2009 May 1;27(13):2151-6. Epub 2009 Apr 6. PMID: 19349547 DOI: 10.1200/JCO.2008.19.6162 Conclusion Vitamin D deficiency is highly prevalent in women with breast cancer. The current recommended dietary allowance of vitamin D is too low to increase serum 25-OHD greater than 30 ng/mL. Optimal dosing for bone health and, possibly, improved survival has yet to be determined.

Clinical Responses to a Mega-dose of Vitamin D3 in Infants and Toddlers With Vitamin D Deficiency Rickets. Soliman AT, El-Dabbagh M, Adel A, Ali MA, Aziz Bedair EM, Elalaily RK. J Trop Pediatr. 2009 Jun 8. [Epub ahead of print] PMID: 19506025 doi:10.1093/tropej/fmp040 Conclusion: An IM injection of a mega dose of cholecalciferol is a safe and effective therapy for treatment of VDD rickets in infants and toddlers with normalization of all the biochemical parameters and healing of radiological manifestations. Measurement of serum 25(OH)D level is highly recommended in all short children with a clear need for a general vitamin D supplementation for all infants and young children in Qatar.

Sunlight, vitamin D and the prevention of cancer: a systematic review of epidemiological studies. Rhee HV, Coebergh JW, Vries ED. Eur J Cancer Prev. 2009 Aug 26. [Epub ahead of print] PMID: 19730382 We, therefore, conclude that there is accumulating evidence for sunlight as a protective factor for several types of cancer. The same conclusion can be made concerning high vitamin D levels and the risk of colorectal cancer. This evidence, however, is not conclusive, because the number of (good quality) studies is still limited and publication biases cannot be excluded. The discrepancies between the epidemiological evidence for a possible preventive effect of sunlight and vitamin D and the question of how to apply the findings on the beneficial effects of sunlight to (public) health recommendations are discussed.

Vitamin D deficiency and bone health in healthy adults in Finland: could this be a concern in other parts of Europe? Lamberg-Allardt CJ, Outila TA, Kärkkainen MU, Rita HJ, Valsta LM. J Bone Miner Res. 2001 Nov;16(11):2066-73. PMID: 11697803 Low vitamin D status was prevalent in these young adults in northern Europe in winter, although the vitamin D intake met the recommendation. This probably is not a local problem for northern Europe, because the natural sources of vitamin D are scarce and fortification is not very common in Europe, and with the exception of the southern part of Europe, sunshine is not very abundant in this part of the world. Thus, the results of this study indicate that more attention should be focused on vitamin D status and the sources of vitamin D in these countries.

Towards an adequate intake of vitamin D. An advisory report of the Health Council of the Netherlands R M Weggemans, G Schaafsma and D Kromhout Eur J Clin Nutr advance online publication, July 22, 2009; doi:10.1038/ejcn.2009.67

Many U.S. teenagers -- including half of African Americans -- would be considered vitamin D-deficient if the definition of deficiency were changed to what many experts recommend, a new study finds. Right now, people are considered to have an overt deficiency in vitamin D when blood levels drop below 11 nanograms per milliliter (ng/mL), but there is debate over how the optimal vitamin D level should be define

According to peer-reviewed clinical research, inadequacies of vitamin D have been linked to chronic musculoskeletal pain of various types, muscle weakness or fatigue, fibromyalgia syndrome, rheumatic disorders, osteoarthritis, hyperesthesia, migraine headaches, and other somatic complaints. It also has been implicated in the mood disturbances of chronic fatigue syndrome and seasonal affective disorder. Current best evidence demonstrates that supplemental vitamin D can help to resolve or alleviate chronic pain and fatigue syndromes in many patients who have been unresponsive to other therapies. Vitamin D therapy is easy for patients to self-administer, is well tolerated, and is very economical. The documents on this page provide detailed background information and practice recommendations.