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"So why is Dr Vieth so frustrated? You might think he'd have cause for celebration. But for him and other vitamin D researchers around the world, the good news comes with a bitter aftertaste. They believe they can prove vitamin D could help millions live longer and be healthier and yet they have not been able to convince their own governments. In the US and Canada, official vitamin D policy is set by the Institute of Medicine. And in the opinion of Vieth, the current recommendations - 200 International Units per day for people under 50, 400 for people aged 51-70, and 600 for those 71 and older - are outrageously low. Bruce Hollis, professor of paediatrics at the Medical University of South Carolina, calls 400 IU a day "a joke". That's because the best research suggests that to achieve the higher vitamin D blood levels associated with disease prevention, most adults in the US would need to take 1,000-2,000 IU a day: five to 10 times more than the current official recommendation for adult In 1999, Reinhold Vieth (pictured right) published a review of vitamin D research in response to the IOM conclusions. In it, he argued that there was no evidence that amounts lower than 20,000 IU a day could be toxic. "Throughout my preparation of this review, I was amazed at the lack of evidence supporting statements about the toxicity of moderate doses of vitamin D," Vieth wrote. Studies have since shown 10,000 IU a day of vitamin D to be safe. While any substance will become toxic in excess, vitamin D researchers today accept that the current vitamin D recommendations could be more than quadrupled with no fear of toxicity.!

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

Improved cholecalciferol nutrition in rats is noncalcemic, suppresses parathyroid hormone and increases responsiveness to 1, 25-dihydroxycholecalciferol. Vieth R, Milojevic S, Peltekova V. J Nutr. 2000 Mar;130(3):578-84. PMID: 10702588 We conclude suppression of 1,25(OH)(2)D and PTH, and higher renal VDR mRNA and 24-hydroxylase did not involve higher free 1,25(OH)(2)D concentration or a first pass effect at the gut. Thus, 25(OH)D or a metabolite other than 1,25(OH)(2)D is a physiological, transcriptionally and biochemically active, noncalcemic vitamin D metabolite. When viewed from a perspective that starts with higher vitamin D nutrition, the results indicate that low vitamin D nutrition may bring about a form of resistance to 1,25(OH)2D. This situation would explain why, in humans, nutritional rickets and osteomalacia are commonly associated with normal or increased levels of 1,25(OH)2D (Chesney et al. 1981Citation , Eastwood et al. 1979Citation , Garabedian et al. 1983Citation ,Rasmussen et al. 1980Citation )-these are not like the low hormone levels associated with any other endocrine-deficiency disorder. A connection between lower vitamin D nutrition and vitamin D resistance helps to explain why the supposedly inactive compound 25(OH)D is more relevant in diagnosing nutritional rickets than is the active hormone 1,25(OH)2D. If the features of improved vitamin D nutrition shown here were demonstrated for any newly synthesized compound, the compound would be classified as a noncalcemic 1,25(OH)2D analogue (Brown et al. 1989Citation , Finch et al. 1999Citation , Goff et al. 1993Citation , Koshizuka et al. 1999Citation ). Thus, we contend that 25(OH)D or a metabolite of it other than 1,25(OH)2D exists as a physiological and biologically-active noncalcemic vitamin D metabolite whose effects require further examination, particularly in relationship to studies involving the synthetic analogs of 1,25(OH)2D.

Vieth R, Fraser D. Vitamin D insufficiency: no recommended dietary allowance exists for this nutrient. CMAJ. 2002 Jun 11;166(12):1541-2. PMID: 12074121 In fact, current recommendations for vitamin D are not designed to ensure anything. They are simply based on the old, default strategy for setting a nutritional guideline, which is to recommend an amount of nutrient similar to what healthy people are eating. This approach underlies the circular logic behind a familiar refrain about nutrition: "If you eat a good diet, you won't need supplements." By this logic, the answer to the question, "How much nutrient do you need?" is, "Whatever healthy people happen to be eating." The essential point, lost in the confusing terminology of modern nutrient recommendations, is that a recommended daily allowance (RDA) does not yet exist for vitamin D. Instead, the recommendations for it are referred to as "adequate intake" (AI).12,13 The AI for young adults (5 µg or 200 IU) was chosen to approximate twice the average vitamin D intake reported by 52 young women in a questionnaire-based study reported from Omaha, Neb., in 1997.13,14 Because the available evidence was acknowledged as weak, the Food and Nutrition Board of the US Institute of Medicine called its recommendation an AI.

Vieth R, Chan PC, MacFarlane GD.Efficacy and safety of vitamin D3 intake exceeding the lowest observedadverse effect level.Am J Clin Nutr. 2001 Feb;73(2):288-94.PMID: 11157326 [PubMed - indexed for MEDLINE]

Vieth R. \nCritique of the considerations for establishing the tolerable upper intake level for vitamin D: critical need for revision upwards.\nJ Nutr. 2006 Apr;136(4):1117-22.\nPMID: 16549491 [PubMed - indexed for MEDLINE]

Vieth R, Bischoff-Ferrari H, Boucher BJ, Dawson-Hughes B, Garland CF, Heaney RP, Holick MF, Hollis BW, Lamberg-Allardt C, McGrath JJ, Norman AW, Scragg R, Whiting SJ, Willett WC, Zittermann A. \nThe urgent need to recommend an intake of vitamin D that is

Vieth R.Vitamin D supplementation, 25-hydroxyvitamin D concentrations, andsafety.Am J Clin Nutr. 1999 May;69(5):842-56. Review.PMID: 10232622 [PubMed - indexed for MEDLINE]

Professor Departments of Nutritional Sciences, Laboratory Medicine, and Pathobiology, Bone and Mineral Laboratory, Pathology and Laboratory Medicine, University of Toronto, Toronto, Canada M5S 3E2 Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada

A prospective nested case-control study of vitamin D status and pancreatic cancer risk in male smokers. Stolzenberg-Solomon RZ, Vieth R, Azad A, Pietinen P, Taylor PR, Virtamo J, Albanes D. Cancer Res. 2006 Oct 15;66(20):10213-9. PMID: 17047087 Higher vitamin D concentrations were associated with a 3-fold increased risk for pancreatic cancer (highest versus lowest quintile, >65.5 versus <32.0 nmol/L: OR, 2.92; 95% CI, 1.56-5.48, Ptrend = 0.001) that remained after excluding cases diagnosed early during follow-up. Contrary to expectations, subjects with higher prediagnostic vitamin D status had an increased pancreatic cancer risk compared with those with lower status. Our findings need to be replicated in other populations and caution is warranted in their interpretation and implication. Our results are intriguing and may provide clues that further the understanding of the etiology of this highly fatal cancer. In conclusion, contrary to expectation, subjects with higher 25(OH)D concentrations were at greater risk for pancreatic cancer compared with those with lower concentrations in our prospective study with long-term follow-up. Caution is warranted in the interpretation and implication of our findings, however, as vitamin D inadequacy is an important public health problem and adequate status is desirable to prevent bone and other diseases (5). Our results, however, are intriguing and may provide clues that further the understanding of the etiology of this highly fatal cancer.

Vitamin D from dietary intake and sunlight exposure and the risk of hormone-receptor-defined breast cancer. Blackmore KM, Lesosky M, Barnett H, Raboud JM, Vieth R, Knight JA. Am J Epidemiol. 2008 Oct 15;168(8):915-24. Epub 2008 Aug 27. PMID: 18756015 doi:10.1093/aje/kwn198 This study suggests that vitamin D is associated with a reduced risk of breast cancer regardless of ER/PR status of the tumor. Future studies with a larger number of receptor-negative and mixed tumors are required.

Woo TC, Choo R, Jamieson M, Chander S, Vieth R. Pilot study: potential role of vitamin D (Cholecalciferol) in patients with PSA relapse after definitive therapy.Nutr Cancer. 2005;51(1):32-6.PMID: 15749627 [PubMed - indexed for MEDLINE]

Pilot study: potential role of vitamin D (Cholecalciferol) in patients with PSA relapse after definitive therapy. Woo TC, Choo R, Jamieson M, Chander S, Vieth R. Nutr Cancer. 2005;51(1):32-6. PMID: 15749627

A prospective nested case-control study of vitamin D status and pancreatic cancer risk in male smokers. Stolzenberg-Solomon RZ, Vieth R, Azad A, Pietinen P, Taylor PR, Virtamo J, Albanes D. Cancer Res. 2006 Oct 15;66(20):10213-9. PMID: 17047087 doi: 10.1158/0008-5472.CAN-06-1876 Contrary to expectations, subjects with higher prediagnostic vitamin D status had an increased pancreatic cancer risk compared with those with lower status. Our findings need to be replicated in other populations and caution is warranted in their interpretation and implication. Our results are intriguing and may provide clues that further the understanding of the etiology of this highly fatal cancer.

Knight JA, Lesosky M, Barnett H, Raboud JM, Vieth R. Vitamin D and reduced risk of breast cancer: a population-based case-control study. Cancer Epidemiol Biomarkers Prev. 2007 Mar;16(3):422-9. PMID: 17372236 [PubMed - indexed for MEDLINE]

BACKGROUND: To determine the effect of vitamin D binding protein (DBP) genotypes on 25-hydroxyvitamin D [25(OH)D] changes with vitamin D supplements, we studied 98 adults receiving 600 or 4000 IU/d vitamin D(3) for one year. METHODS: The DBP functional variant, T436K, was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Mean 25(OH)D increases were 97% for TT (n=48), 151% for TK (n=31) and 307% (n=6) for KK genotypes (p=.004). CONCLUSIONS: As with baseline 25(OH)D, T436K genotype predicts 25(OH)D changes after long-term vitamin D supplementation. Common genetic variants of the vitamin D binding protein (DBP) predict differences in response of serum 25-hydroxyvitamin D [25(OH)D] to vitamin D supplementation. Fu L, Yun F, Oczak M, Wong BY, Vieth R, Cole DE. Clin Biochem. 2009 Jul;42(10-11):1174-7. Epub 2009 Mar 18. PMID: 19302999

Vitamin K supplementation in postmenopausal women with osteopenia (ECKO trial): a randomized controlled trial. Cheung AM, Tile L, Lee Y, Tomlinson G, Hawker G, Scher J, Hu H, Vieth R, Thompson L, Jamal S, Josse R. PLoS Med. 2008 Oct 14;5(10):e196. Erratum in: PLoS Med. 2008 Dec;5(12):e247. PMID: 18922041 CONCLUSIONS: Daily 5 mg of vitamin K1 supplementation for 2 to 4 y does not protect against age-related decline in BMD, but may protect against fractures and cancers in postmenopausal women with osteopenia. More studies are needed to further examine the effect of vitamin K on fractures and cancers. Trial registration: ClinicalTrials.gov (#NCT00150969) and Current Controlled Trials (#ISRCTN61708241)

"This website is about Vitamin D and MS Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS), with an uncertain cause. Colleen Hayes and Donald Achaeson have suggested that insufficient sunlight exposure and chronic viral infections might be unrelated environmental risk factors for MS. These risk factors may act synergistically to enable the pathogenic autoimmune response. The prevalence of MS is highest where environmental supplies of vitamin D are lowest. Sunshine enables the production of vitamin D3 (VD3) in the skin. Epidemiological studies have shown that higher vitamin D blood levels are associated with lower risk, less relapses and a slower progression of multiple sclerosis. Higher vitamin D levels can be achieved in part by increased oral intake of VD3. Optimal health requires serum 25 hydroxyvitamin D levels higher than 20 ng/ml (50 nmol/L) P Lips, 40 ng/ml (100 nmol/L) P Heaney or at least 40 ng/ml (100 nmol/L) R Vieth. "

Long-term effects of giving nursing home residents bread fortified with 125 {micro}g (5000 IU) vitamin D3 per daily serving. Mocanu V, Stitt PA, Costan AR, Voroniuc O, Zbranca E, Luca V, Vieth R. Am J Clin Nutr. 2009 Feb 25. [Epub ahead of print] PMID: 19244376

Why "Vitamin D" is not a hormone, and not a synonym for 1,25-dihydroxy-vitamin D, its analogs or deltanoids. Vieth R. J Steroid Biochem Mol Biol. 2004 May;89-90(1-5):571-3. PMID: 15225841 doi:10.1016/j.jsbmb.2004.03.037