| Food Composition Data: A User's Perspective (1987) |
|International food composition data|
|Food data in Canada: the Canadian nutrient file|
The reformated file was designed to provide all reliable nutrient data available for the described foods and to include features that would facilitate its use. It was developed for Health and Welfare Canada to calculate nutrient intakes in food consumption surveys and to analyse menus for food-fortification or food-substitution studies. Agriculture Canada also had a need for such data and it was hoped that it would provide a national file on which all Canadian studies could be based. User comments were solicited from the beginning and changes have been made in the format to facilitate use. A major change was from seven conversion factors, described in the user's manual accompanying the tape (in the first two editions), to the four factors described on the present tape.
A National CNF User's Workshop was organized in June 1984 in Toronto, Ontario, to promote the general use of the file and share experiences in using it. Development of software programs requires the skills of both a nutritionist and a computer programmer. Agriculture Canada, with nutritionists, statisticians, and programmers, acquired the tape and has developed a very extensive programme: their nutrient-analysis computer program (AGNAP) has both nutritional and statistical input. Most of the nutritional data in AGNAP come from the CNF, but there is also a cookiny-yield file for "in-house" research information. Six types of reports can be produced: recipe/menu analysis, food ranking by amount of specific nutrient, cost of food per unit of nutrient, apparent nutrient intakes, nutritive value of food purchased, and nutritious foodbasket data manipulations. Statistics Canada provides data for four other reference files: a population file, providing estimates of demographic groups within the Canadian population; a food disappearance data file, outlining the apparent per capita food consumption in Canada between 1960 and 1983 (updated annually); a family food expenditure data file, including the quantities of food purchased by various socioeconomic groups within Canada (derived from a continuing market basket survey); and a retail food prices file, based on Statistics Canada's consumer price index. From these are derived three programs: the Apparent Nutrient Intakes program, the Nutritive Value of Food Purchased program, and the Agriculture Canada Nutritious Food Basket development program. At the other end of the scale, a nutritionist in a rural community, with specific needs for the evaluation of nutrient intakes in hospital food services, nursing homes, and boardinghouses, wrote a program on a microcomputer including nutrient assessment of individuals and menu planning, and now has extended use with a modem connection to a local university to access the entire CNF.
Several users have had special programs written for such projects as a regional hospital foodservices group that supplies prepared frozen foods daily to seven hospitals with a completely computerized program for food purchase, quality control, menu planning, ingredient delivery, assembly, cooking, freezing, and storage prior to delivery. Attached to these programs are nutrient compositions of all foods as delivered. A food-service organization, providing bulk foods to boarding-houses and nursing homes, includes computerized recipes, menus and probable nutrient intakes.
Most users buy a software program, including all or part of the CNF. Services are also available for the submission of data to a university computer centre for computation. As the capacity of microcomputers expands, more and more programs are able to store and access the entire file. Programs are becoming more sophisticated and various user needs are being met. Canadian programmers, using their experience in developing packages for the CNF, are working on software systems for third-world countries.
A further extension of the CNF is in progress with the development of a data file for use in dietetics in Canadian hospitals. Louise Bell, a nutritionist at the Hospital for Sick Children in Toronto, is modifying the file to include imputations of missing values, standard foods, brandname foods including infant formula and enteral feedings, special dietetic products, and vitamin and mineral supplements, with unused foods being deleted. The first issue will have complete data for all foods covering 24 nutrients.
Interest is developing in identifying areas where Canadian data are needed for differences in the foods, and in defining research programmes to fill these gaps. Contracts have been made out by Agriculture Canada for meat  and other analyses, and an ongoing assessment of the Canadian food supply is being conducted by Health and Welfare Canada, in conjunction with the Total Diet Study, regarding specific nutrients where differences from the US data might be expected or where data are now missing (e.g. fat levels in meats and neutral detergent fibre in many foods). The Field Operations Directorate of Health and Welfare Canada already samples and analyses certain selected foods and nutrients each year and provides data that are useful in checking the applicability of the USDA data. Over the years, such research will help to increase the proportion of Canadian data in the CNF.
Data are missing for northern animal, fish, and plant foods. Recommendations to resume consumption of available "land foods" in the north must be supported by data on nutrient content. As only a small part of the population consumes such foods, little research interest exists, and an exchange of data with other northern countries is being sought.
The CNF format is compatible with that of USDA and will form part of the NOAFOODS regional network.