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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.!

Vitamin D Toxicity Fears Unwarranted Is vitamin D toxic? Not if we take the same amount nature intended when we go out in the sun. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentration, and safety. Am J Clin Nutr. 1999;69:842-56. Vieth attempted to dispel unwarranted fears in medical community of physiological doses of vitamin D in 1999 with his exhaustive and well-written review. D-Lite, Renew, & SunSplash UV/Tanning Systems Sunsplash Tanning System Is toxicity a concern for you? If so, then increase your levels the way nature intended, with ultraviolet B light! His conclusions: fear of vitamin D toxicity is unwarranted, and such unwarranted fear, bordering on hysteria, is rampant in the medical profession. Vieth R, Chan PC, MacFarlane GD. Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level. Am J Clin Nutr. 2001 Feb;73(2):288-94. Even Ian Monroe, the chair of the relevant IOM committee, wrote to the Journal to compliment Vieth's work and to promise his findings will be considered at the time of a future Institute of Medicine review. Munro I. Derivation of tolerable upper intake levels of nutrients. Letter, Am J Clin Nutr. 2001;74:865. That was more than two years ago.

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.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]

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]

Conclusion: Vitamin D3 at doses equivalent to 2000 IU/d for 1 yr is safe in adolescents and results in desirable vitamin D levels. Short- and long-term safety of weekly high-dose vitamin D3 supplementation in school children. Maalouf J, Nabulsi M, Vieth R, Kimball S, El-Rassi R, Mahfoud Z, El-Hajj Fuleihan G. J Clin Endocrinol Metab. 2008 Jul;93(7):2693-701. Epub 2008 Apr 29. PMID: 18445674 doi:10.1210/jc.2007-2530

Safety of vitamin D3 in adults with multiple sclerosis. Kimball SM, Ursell MR, O'Connor P, Vieth R. Am J Clin Nutr. 2007 Sep;86(3):645-51. PMID: 17823429 Conclusions: Patients' serum 25(OH)D concentrations reached twice the top of the physiologic range without eliciting hypercalcemia or hypercalciuria. The data support the feasibility of pharmacologic doses of vitamin D3 for clinical research, and they provide objective evidence that vitamin D intake beyond the current upper limit is safe by a large margin.

Randomized comparison of the effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on biochemical responses and the wellbeing of patients. Vieth R, Kimball S, Hu A, Walfish PG. Nutr J. 2004 Jul 19;3:8. PMID: 15260882 doi:10.1186/1475-2891-3-8 CONCLUSION: The highest AI for vitamin D brought summertime 25(OH)D to >40 nmol/L, lowered PTH, and its use was associated with improved wellbeing. The 100 mcg/day dose produced greater responses. Since it was ethically necessary to provide a meaningful dose of vitamin D to these insufficient patients, we cannot rule out a placebo wellbeing response, particularly for those on the lower dose. This work confirms the safety and efficacy of both 15 and 100 mcg/day vitamin D3 in patients who needed additional vitamin D.

Vitamin D and Cancer Mini-Symposium: The Risk of Additional Vitamin D. Vieth R. Ann Epidemiol. 2009 Apr 11. [Epub ahead of print] PMID: 19364661 doi:10.1016/j.annepidem.2009.01.009   

Evidence from clinical trials shows, with a wide margin of confidence, that a prolonged intake of 10,000IU/d of vitamin D3 poses no risk of adverse effects for adults, even if this is added to a rather high physiologic background level of vitamin D. Vitamin D and cancer mini-symposium: the risk of additional vitamin D. Vieth R.\nAnn Epidemiol. 2009 Jul;19(7):441-5. Epub 2009 Apr 11. PMID: 19364661 doi:10.1016/j.annepidem.2009.01.009

Vitamin D toxicity, policy, and science. Vieth R. J Bone Miner Res. 2007 Dec;22 Suppl 2:V64-8. Review. PMID: 18290725 doi: 10.1359/jbmr.07s221

Unusually prolonged vitamin D intoxication after discontinuation of vitamin D: possible role of primary hyperparathyroidism. Taskapan H, Vieth R, Oreopoulos DG. Int Urol Nephrol. 2008;40(3):801-5. Epub 2008 Jun 5. PMID: 18528779 DOI: 10.1007/s11255-008-9404-1

Vitamin D poisoning by table sugar. Vieth R, Pinto TR, Reen BS, Wong MM. Lancet. 2002 Feb 23;359(9307):672. PMID: 11879864 doi:10.1016/S0140-6736(02)07814-5

Vitamin D and cancer mini-symposium: the risk of additional vitamin D. Vieth R. Ann Epidemiol. 2009 Jul;19(7):441-5. Epub 2009 Apr 11. Review. PMID: 19364661 Conclusion The results of well-conducted trials of vitamin D lead to the conclusion that the current U.S. National Academy of Sciences-Institute of Medicine upper limit for vitamin D intake of 2000IU per day 1, 37 is excessively conservative. That intake would raise serum 25(OH)D by an average of about 50 nmol/L (20 ng/mL), well within the safe range of serum 25(OH)D concentrations that extends to 500 nmol/L (200 ng/mL). Intake of 4,000IU per day would raise serum 25(OH)D by an average of about 100 nmol/L (40 ng/mL). Even prolonged physiologic-replacement intake of 10,000IU per day of vitamin D3 would pose no known risk of adverse effects in virtually all adults.

Long-term effects of giving nursing home residents bread fortified with 125 microg (5000 IU) vitamin D(3) per daily serving. Mocanu V, Stitt PA, Costan AR, Voroniuc O, Zbranca E, Luca V, Vieth R. Am J Clin Nutr. 2009 Apr;89(4):1132-7. Epub 2009 Feb 25. PMID: 19244376 doi:10.3945/ajcn.2008.26890

Hathcock JN, Shao A, Vieth R, Heaney R. \nRisk assessment for vitamin D.\nAm J Clin Nutr. 2007 Jan;85(1):6-18. Review.\nPMID: 17209171 [PubMed - indexed for MEDLINE]

Assessment of dietary vitamin D requirements during pregnancy and lactation. Hollis BW, Wagner CL. Am J Clin Nutr. 2004 May;79(5):717-26. Review. PMID: 15113709 We found that high-dose maternal vitamin D supplementation not only improves the nutritional vitamin D status of breastfeeding infants but also elevates the maternal concentrations into the mid-normal range. Thus, a dual benefit is achieved from high-dose maternal supplementation. It is noteworthy that in the Finnish study, the authors added a disclaimer, "A sufficient supply of vitamin D to the breastfed infant is achieved only by increasing the maternal supplementation up to 2000 IU/d. Such a dose is far higher than the RDA [DRI] for lactating mothers [and therefore] its safety over prolonged periods is not known and should be examined by further study." This point of concern was valid when this study was conducted in 1986 (92); however, on the basis of the current findings of Vieth et al (2) and of Heaney et al (3)-which showed that vitamin D intakes <= 10 000 IU/d (250 µg) are safe for prolonged periods (up to 5 mo)-we believe that it is time to reexamine the understated DRI of vitamin D for lactating mothers. This work is now being conducted in our clinics and laboratory.

A phase 2 trial exploring the effects of high-dose (10,000 IU/day) vitamin D(3) in breast cancer patients with bone metastases. Amir E, Simmons CE, Freedman OC, Dranitsaris G, Cole DE, Vieth R, Ooi WS, Clemons M. Cancer. 2009 Nov 13. [Epub ahead of print] PMID: 19918922 DOI: 10.1002/cncr.24749 METHODS: Patients with bone metastases treated with bisphosphonates were enrolled into this single-arm phase 2 study. Patients received 10,000 IU of vitamin D3 and 1000 mg of calcium supplementation each day for 4 months. The effect of this treatment on palliation, bone resorption markers, calcium metabolism, and toxicity were evaluated at baseline and monthly thereafter. CONCLUSIONS: Daily doses of 10,000 IU vitamin D3 for 4 months appear safe in patients without comorbid conditions causing hypersensitivity to vitamin D. Treatment reduced inappropriately elevated parathyroid hormone levels, presumably caused by long-term bisphosphonate use. There did not appear to be a significant palliative benefit nor any significant change in bone resorption. Cancer 2010. © 2009 American Cancer Society.