Mr. Speaker, in reponse to a)i) In late 2008, the Canadian and US governments contracted with the US Institute of Medicine, IOM, to convene a multi-disciplinary panel of Canadian and U.S. experts, the expert committee, to undertake a study to reassess current relevant data and to update as appropriate the dietary reference intakes, DRIs, for vitamin D and calcium, last published in 1997. This will result in the delivery of a detailed report that is peer-reviewed according to the protocols of the Institute of Medicine and the U.S. National Research Council.
In response to a)ii) The report from IOM is expected to be publicly available in the fall 2010. It is planned that the implementation process for government programs, policies, guidelines and information will take place in 2011.
In response to a)iii) Health Canada supported the IOM review in a number of ways. Health Canada provided publicly available data on usual distributions of vitamin D intake, based on the 2004 Canadian Community Health Survey. Health Canada also worked jointly with Statistics Canada on a preliminary public release of blood 25-OH vitamin D results from the 2007- 2009 Canadian Health Measures Survey. These results were essential for the IOM expert committee to take into consideration the Canadian vitamin D status in their deliberations. In addition, Health Canada, the Public Health Agency of Canada, the US Office of Dietary Supplements/National Institutes of Health and the US Food and Drug Administration funded the Agency for Healthcare Research and Quality (AHRQ) to prepare the report “Vitamin D and Calcium: A Systematic Review of Health Outcomes”, which was published in August 2009. The purpose of this review was to systematically summarize the evidence on the relationship between vitamin D, calcium, and a combination of both nutrients on a wide range of health outcomes.
In response to b) The review of DRIs for vitamin D and calcium is being conducted by a 14-member expert committee appointed through standard procedures of the national academies. Expertise includes, but is not necessarily limited to the following areas: nutrition, infant nutrition, reproductive nutrition, pregnancy and lactation, dermatology, gerontology, epidemiology, biostatistics, bone and skeletal health, cardiovascular health, immunology, oncology, cellular metabolism, toxicology, genetics, factors affecting intensity of UVB radiation, and population monitoring methodology.
In response to c) An AHRQ report published in August 2007 entitled “Effectiveness and Safety of Vitamin D in Relation to Bone Health” did examine the question of whether intakes of vitamin D above current reference intakes lead to toxicities. A total of 22 trials reported data on toxicity-related outcomes, 21 of which used doses above current reference intakes.
Overall, there was fair evidence from adult trials that vitamin D supplementation above current reference intakes, with or without calcium supplementation, was well tolerated. However, there were challenges in conducting this part of the review because harms are often secondary outcomes and may not be reported completely, especially if they are not significant. Most of the trials were not designed to evaluate harms, were of small sample size, and had short duration of exposure to vitamin D. There is also a lack of data on toxicity outcomes in infants, children, and specific ethnic groups.
In response to d) As part of its review of the evidence, the IOM expert committee will try to set a tolerable upper intake level, UL, defined as the highest level of daily nutrient intake that is likely to pose no risk of adverse effects for almost all individuals in the general population. The UL is based on an evaluation conducted by using the methodology for risk assessment of nutrients.
Until the recommendations for vitamin D have been updated, Health Canada continues to recommend that Canadians follow the existing tolerable upper intake level, which for anyone over one year of age is 50 micrograms, 2000 IU, vitamin D per day from all sources, including milk and supplements.
In response to e) According to the dietary reference intakes, DRIs, for vitamin D and calcium published in 1997, the adverse effects of excess vitamin D are probably largely mediated by increasing calcium levels in the blood, and limited scientific evidence suggests that direct effects of high concentrations of vitamin D may be expressed in various organ systems, including kidney, bone, central nervous system and cardiovascular system. Human case reports of pharmacologic doses of vitamin D over many years describe severe effects at intake levels of 250 to 1250 micrograms per day, 10,000 to 50,000 IU/day.
The IOM expert committee is looking at more recent clinical scientific data with regard to amounts of vitamin D that may be considered harmful and the indicators of adverse effects.
In response to f) The full set of studies used will be made available in fall 2010 in the IOM report.