See comment in PubMed Commons belowInt J Vitam Nutr Res Suppl. 1989;30:81-6.High-dose vitamin D therapy: indications, benefits and hazards.Davies M.AbstractThere are two sources of vitamin D available to man: The more important source is the cholecalciferol (vitamin D3), which is produced photochemically in the skin from the provitamin, 7-dehydrocholesterol; vitamin D ingested with food is of secondary importance, but assumes a critical role when an individual is deprived of solar exposure. Vitamin D therefore is not strictly a vitamin. A deficiency of vitamin D ultimately results in osteomalacia in adults and rickets in children, and provision of sunlight or small oral doses of the vitamin can cure this bone condition. There are, however, many less common conditions in which small doses of the vitamin are ineffective, whereas larger doses of vitamin D can achieve healing of the bone disease. These conditions are collectively called vitamin D-resistant diseases and include hypoparathyroidism, genetic and acquired hypophosphataemic osteomalacias, renal osteodystrophy, vitamin D-dependent rickets, and the osteomalacia associated with liver disease and intestinal malabsorption.
Unfortunately, large doses of vitamin D continue to be prescribed for a wide variety of diseases in which there is little scientific evidence of their efficacy. The benefits and dangers of high doses of vitamin D are discussed and the problems arising from inappropriate or poorly supervised treatment with vitamin D presented. The serum concentration of the active metabolite of vitamin D, 1,25 dihydroxyvitamin D is increased in certain disease states, and the pathophysiology of some these diseases are presented. The exciting developments in tumour differentiation and the role of high doses of 1,25 dihydroxyvitamin D for the control of leukaemia and other blood and skin diseases are discussed.PMID: 2507709 [Indexed for MEDLINE] Publication typeReviewMeSH termsHumansVitamin D/administration & dosage*Vitamin D/adverse effectsVitamin D/therapeutic useSubstanceVitamin DMedicalVitamin D - MedlinePlus Health Information[Skip to Content Landing] Sign in to your personal account Institutional sign in: OpenAthens |
Create a free personal account Subscribe to the journal Subscribe to Learning for one year Sign in to download free article PDFs A free personal account provides Free current issues on The JAMA Network Reader Free quizzes on The JAMA Network ChallengeAlert me when new content is published.J Am Geriatr Soc. 2007 Feb;55(2):234-9.Broe KE1, Chen TC, Weinberg J, Bischoff-Ferrari HA, Holick MF, Kiel DP.Author information1Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts 02131, USA. broe@hrca.harvard.eduAbstractOBJECTIVES: To determine the effect of four vitamin D supplement doses on falls risk in elderly nursing home residents.DESIGN: Secondary data analysis of a previously conducted randomized clinical trial.SETTING: Seven hundred twenty-five-bed long-term care facility.PARTICIPANTS: One hundred twenty-four nursing home residents (average age 89).INTERVENTION: Participants were randomly assigned to receive one of four vitamin D supplement doses (200 IU, 400 IU, 600 IU, or 800 IU) or placebo daily for 5 months.
MEASUREMENTS: Number of fallers and number of falls assessed using facility incident tracking database.RESULTS: Over the 5-month study period, the proportion of participants with falls was 44% in the placebo group (11/25), 58% (15/26) in the 200 IU group, 60% (15/25) in the 400 IU group, 60% (15/25) in the 600 IU group, and 20% (5/23) in the 800 IU group. Participants in the 800 IU group had a 72% lower adjusted-incidence rate ratio of falls than those taking placebo over the 5 months (rate ratio=0.28; 95% confidence interval=0.11-0.75). No significant differences were observed for the adjusted fall rates compared to placebo in any of the other supplement groups.CONCLUSION: Nursing home residents in the highest vitamin D group (800 IU) had a lower number of fallers and a lower incidence rate of falls over 5 months than those taking lower doses. Adequate vitamin D supplementation in elderly nursing home residents could reduce the number of falls experienced by this high falls risk group.
PMID: 17302660 DOI: 10.1111/j.1532-5415.2007.01048.x [Indexed for MEDLINE] Publication typesRandomized Controlled TrialResearch Support, N.I.H., ExtramuralMeSH termsAccidental Falls/prevention & control*Accidental Falls/statistics & numerical dataAgedAged, 80 and overDose-Response Relationship, DrugDouble-Blind MethodFemaleHomes for the AgedHumansIncidenceMaleNursing HomesProportional Hazards ModelsTreatment OutcomeVitamin D/administration & dosage*Vitamins/administration & dosage*SubstancesVitaminsVitamin DGrant supportP01 AG004390/AG/NIA NIH HHS/United StatesFull Text SourcesWileyOvid Technologies, Inc.Other Literature SourcesCOS Scholar UniverseMedicalFalls - MedlinePlus Health InformationVitamin D - MedlinePlus Health Information What is vitamin D toxicity, and should I worry about it since I take supplements? Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body.
Vitamin D toxicity is usually caused by megadoses of vitamin D supplements — not by diet or sun exposure. That's because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don't contain large amounts of vitamin D. The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause poor appetite, nausea and vomiting. Weakness, frequent urination and kidney problems also may occur. Treatment includes the stopping of excessive vitamin D intake. Your doctor also may prescribe intravenous fluids and medications, such as corticosteroids or bisphosphonates. Taking 50,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the Recommended Dietary Allowance (RDA) for most adults of 600 IU of vitamin D a day. Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor for a specified time frame.