Canadian Exposure Assessment for Acrylamide in Food
Acrylamide has been measured in selected foods available in Canada by Health Canada scientists. The results are consistent with the levels that have been found in foods available in other countries.
Health Canada has conducted a preliminary assessment of Canadian exposure to acrylamide in food. These calculations are based on the acrylamide levels measured in foods by Health Canada and on information about the dietary habits of Canadians.
Preliminary calculations suggest that the average exposure of adults to acrylamide in food is between 0.3 and 0.4 micrograms per kilogram of body weight per day (μg/kg bw/day). A microgram (μg) is one-millionth of a gram. For young children 6-11 years of age, the average exposure is roughly twice the adult exposure. This is largely due to the fact that children consume more food than adults on a "per body weight basis." These estimations of Canadian exposure to acrylamide are consistent with exposures that have been calculated in other countries. For example, the average daily intake of acrylamide in Sweden has been estimated to be 0.5 μg/kg bw/day (Svensson et al., 2003, Food and Chemical Toxicology, Vol. 41, pp. 1581-1586). The United States Food and Drug Administration has estimated an average daily intake of 0.4 μg/kg bw/day.
What these levels of exposure mean in terms of degree of risk is not yet well characterised. The 64th meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) was held in February 2005. JECFA determined that there may be a human health concern at current levels of exposure to acrylamide. However, a more precise determination of the risk to human health could not be made based on the available scientific information.
The results of ongoing studies on carcinogenicity as well as long-term neurotoxicity studies will allow a better understanding of the risks of exposure to low levels of acrylamide in food.
How Canadian exposure to acrylamide was calculated
Exposure to any chemical in food is affected by (1) the concentration of the chemical in food; and (2) the amount of the food consumed. Therefore, both the chemical concentration and the amount of food consumed by an individual are needed to estimate exposure, which is usually expressed on a body weight basis. For example, a 60 kg adult (132 lb) who consumes 24 μg acrylamide per day, based on the types and amounts of foods typically eaten, would have an exposure to acrylamide of 0.4 μg per kg body weight per day.
For the calculation of average exposure to acrylamide, the acrylamide concentrations from Health Canada's surveillance activities were used. The amounts of various foods consumed by adults on average were based on provincial surveys of individuals that were conducted in the 1990's. An adult body weight of 60 kg and a child (6-11 years) body weight of 26 kg were used.
It is important to note that only the average exposure to acrylamide was calculated. An average value provides information about those with average eating habits and average body weights but it does not provide a complete picture of the full range of exposures that would be found in a diverse population. Depending on their dietary habits, some people will have higher than average exposures, and others will have lower than average exposures to acrylamide.
Current data on food intakes among Canadians were recently gathered by Statistics Canada as part of the Canadian Community Health Survey (CCHS). In addition, Health Canada has committed to generating more recent Canadian occurrence data as part of its Acrylamide Monitoring Program. These data will be used for the purposes of an updated food-related health risk assessment.
Detailed example - Adult exposure to acrylamide
The following table summarises the calculations of exposure of adults to acrylamide through selected foods. Possible exposure in occupational settings or through smoking were not considered. Similar calculations (not shown) were carried out for young children 6-11 years of age, resulting in an average exposure that is roughly twice the adult exposure.
With respect to the food consumption values, which are listed in the third column of the table, AP or "all persons" indicates that the data from every individual who participated in the food consumption survey were used to calculate the consumption value for each particular food. Using bread as an example, suppose that 600 people were surveyed. This would result in 600 values for the amount of bread consumed in the 24-hour period covered by the survey. Some of these values would be "0" grams (for those individuals who did not consume bread during the 24-hour period) and the remainder would be values above zero (indicative of individuals who had consumed bread during that 24-hour survey period). All 600 values can be averaged to obtain a value that serves as an estimate of average daily bread consumption for the population. "All persons" consumption values are normally used to estimate exposure to chemicals with "chronic" (long-term) health effects, such as acrylamide.
The "all persons" acrylamide intake values (column 4) for each food were added together to estimate a total average intake of acrylamide from the foods analysed. Because only one exposure value is being calculated for the population, rather than a range of values, the exposure assessment is called a "deterministic exposure assessment."
This "deterministic" exposure assessment is considered preliminary. A more detailed "probabilistic" exposure assessment will be conducted when the results of the most recent food consumption survey are available. Probabilistic exposure assessments provide more information about the range of exposures in the population and the proportions of the population with low, average, and high acrylamide intakes.
|Food Group||Average Acrylamide concentration (ppb)Table 1 footnote 1||Average adult "AP" Consumption (g/day)Table 1 footnote 2||Average acrylamide intake by adults (μg/kg bw/day)|
Table 1 footnotes
|Coffee substitute (as consumed)||62||Table 1 footnote 3|||
|Soft bread (untoasted)||26||43||0.019|
|Roasted sunflower seeds||66||0.3||0.0004|
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