Taking our vitamins

Stephanie Atkinson

doi:10.1503/cmaj.1031096

I commend Eric Wooltorton1 for alerting Canadian physicians to the potential of health risks with excessive consumption of some vitamins and minerals. However, the recommended intakes listed in Table 1 of that article do not reflect dietary reference intake (DRI) values,2 which should be used as the dietary standards for Canadians. Furthermore, there is no mention of tolerable upper level (TUL) intakes, which have been developed as part of the DRI initiative (a collaborative project involving Health Canada and the Food and Nutrition Board of the US Institute of Medicine).3^,4^,5 The TUL is “the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population.”6 The TUL values can serve as guides for health care professionals in educating patients about the possible health risks of excessive consumption of specific nutrients.

Stephanie Atkinson Department of Pediatrics Faculty of Health Sciences McMaster University Hamilton, Ont.

References

1.↵
Wooltorton E. Too much of a good thing? Toxic effects of vitamin and mineral supplements. CMAJ 2003;169(1):47-8.
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2.↵
Office of Nutrition Policy and Promotion. Dietary reference intakes [online]. Ottawa: Health Canada; updated 2004 Feb 13. Available: www.hc-sc.gc.ca/hpfb-dgpsa/onpp-bppn/diet_ref_e.html (accessed 2004 Feb 26).
3.↵
Institute of Medicine. Dietary reference intakes for calcium, phosphorus, magnesium, vitamin D and fluoride. Washington: National Academy Press; 1997.
4.↵
Institute of Medicine. Dietary reference intakes for vitamin C, vitamin E, selenium and carotenoids. Washington: National Academy Press; 2000.
5.↵
Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium and zinc. Washington: National Academy Press; 2000.
6.↵
Institute of Medicine. Food and Nutrition Board. DRI — a risk assessment model for establishing upper intake levels for nutrients. Washington: National Academy of Sciences; 1998.