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Upper Limit 2000 IU - July 2010

From US Govt fact Sheet on Vitamin D http://ods.od.nih.gov/factsheets/vitamind.asp

Long-term intakes above the UL increase the risk of adverse health effects [4] (Table 4). Substantially larger doses administered for a short time or periodically (e.g., 50,000 IU/week for 8 weeks) do not cause toxicity. Rather, the excess is stored and used as needed to maintain normal serum 25(OH)D concentrations when vitamin D intakes or sun exposure are limited [11,92].

Table 4: Tolerable Upper Intake Levels (ULs) for Vitamin D [4]

Age Males Females Pregnancy Lactation
0-12 months 25 mcg
(1,000 IU)
25 mcg
(1,000 IU)
   
1-13 years 50 mcg
(2,000 IU)
50 mcg
(2,000 IU)
   
14+ years 50 mcg
(2,000 IU)
50 mcg
(2,000 IU)
50 mcg
(2,000 IU)
50 mcg
(2,000 IU)

Several nutrition scientists recently challenged these ULs, first published in 1997 [92]. They point to newer clinical trials conducted in healthy adults and conclude that the data support a UL as high as 10,000 IU/day. Although vitamin D supplements above recommended levels given in clinical trials have not shown harm, most trials were not adequately designed to assess harm [5]. Evidence is not sufficient to determine the potential risks of excess vitamin D in infants, children, and women of reproductive age.

As noted earlier, the FNB is currently reviewing data to determine whether updates to the DRIs (including the ULs) for vitamin D are appropriate [4].

4 Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press, 1997.

5Cranney C, Horsely T, O'Donnell S, Weiler H, Ooi D, Atkinson S, et al. Effectiveness and safety of vitamin D. Evidence Report/Technology Assessment No. 158 prepared by the University of Ottawa Evidence-based Practice Center under Contract No. 290-02.0021. AHRQ Publication No. 07-E013. Rockville, MD: Agency for Healthcare Research and Quality, 2007. [PubMed abstract]

Upper Limit 2000 IU - July 2010        
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