Food Standards Agency
Friday 3 July 2009
Safer food better business banner
AZ-Directory
What's NewRSS
What is RSS?Listen
Listen to this siteThursday 23 September 2004
This research project describes the development and use of probabilistic models to look at patterns of food consumption and intakes of food chemicals.
Study Duration : April 1999 to Ocober 2001
When there is a risk of chemical contaminants being found in food, e.g. mycotoxins or pesticide residues, it is important to know how frequently and in what amounts a person might be consuming that food. There is a need to develop a model that can estimate long-term intake from short-term data available, with a view for assessment of when it becomes likely that individuals may consume contaminants to a potentially hazardous level.
This project did not consider contaminant levels in food but includes data on the consumption of Vitamin A (which is available in the Dietary and Nutritional Survey of British adults (1990)).
The classical approach to estimate the within-individual and the between-individual components of variation separately is the analysis of variance (ANOVA) method used by Beaton. A more sophisticated procedure by Nusser can manage different types of statistical variability, intake values and between-person intake variability ranges and is able to process an array of distributions within the data. These two models were applied using data from different food groups: those whose consumption is fairly evenly distributed; those where it is slightly skewed; and those where consumption is very skewed. The project also considered whether 4-day food diary data could be used effectively rather than 7-day data.
This project applied two different statistical procedures to a data set containing a variety of consumption distributions, with a view to assessing their usefulness in estimation of food consumption patterns.
Analysis of the available food diary survey revealed that energy intake showed a normal distribution across the population. The consumption of meat within a group of meat-eaters was variable over the time of the survey, so resulted in a skewed distribution, and the variability in consumption of cruciferous vegetables was heavily skewed within the data set. The simpler Beaton method was successfully applied for the estimation of usual intake for variables with a normal distribution. However, for skewed data and accounting for large variations of consumption on a day-to-day basis, the more complex Nusser approach was required to gain a more accurate estimation of intake.
A comparison of the average intake of meat and nutrients using a 4-day record versus a 7-day record did not show any significant differences, offering potential for easier data collection by means of shorter studies in the future.
Estimation of the likely effects of changes in food composition or consumption habits may be available in the future. The FSA is considering options for incorporating such techniques into intake calculations.
Final report is available from the FSA Library and Information centre.
To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency ( tel: 020 7276 8181/8182 or email:
library&info@foodstandards.gsi.gov.uk
).
Contact
: For any enquiries concerning this research project, please contact the relevant Programme contact or email:
science@foodstandards.gsi.gov.uk
Find out what our other sites have to offer