|Compiling Data for Food Composition Data Bases (UNU, 1991, 68 pages)|
|Part II Gathering the data|
|4. Data from other sources|
Potential sources of nutrient data include published food composition tables and data bases, journal articles, books and book chapters, proceedings from meetings, project reports, unpublished laboratory reports, university theses, reports from food producers, and materials produced for consumers. Data are generated and compiled by international and national agencies, academic groups, clinical/medical groups, food industries, trade associations, and private groups, usually for specific studies relating to the nutritional properties of foods or as part of efforts to create food composition data bases, either reference or special-purpose. (See Schakel et al. .)
International agencies, such as the FAO,collect food composition data in order to judge the quality of international food trade, and the potential needs and resources of various areas of the world. Government agencies conduct food composition analyses for regulatory purposes (e.g., to determine the nutritional quality of foods and to determine compliance with label claims), to develop data bases for use in dietary surveys evaluating the dietary status of population groups, and frequently to provide food composition data to professional groups and consumers. Academic groups generate food composition data as part of research efforts in food science and nutrition, while clinical/medical groups generate food composition data for analyses of patient diets and for nutrition intervention studies. The food industry analyses its products to determine their nutritional quality and to develop nutritional labelling claims. Trade associations generate food composition data to provide information for constituents and consumers. Private laboratories generate food composition data under commission for other groups.
Schakel et al.  provide a detailed listing of various sources of food composition data. The Nutrient Data Bank Directory , Computer Programs and Databases in the Field of Nutrition , and the INFOODS International Directory of Food Composition Tables  list many of the major tables and data bases in existence, and provide first steps for finding already compiled data. Journal, book, and proceedings references may be researched through computer retrieval, using keywords for titles, to assist in locating appropriate references. Food industries and trade organizations can be contacted directly, by post or by telephone. Listings of these industries and organizations (e.g., in the United States: the Thomas Register , the Million Dollar Directory , and the Trade Names Dictionary ) may be found in some libraries. It is more difficult to obtain project reports and unpublished laboratory data. Contact with individuals known to be involved with such work, as well as with government agencies, may give access to some of this information. INFOODS and its various regional liaison groups are also good potential sources of such information.
In some countries certain information about nutrients can be found on food labels, provided by food packagers and manufacturers. Nutrition information on food labels is generally under the regulation of a government agency seeking to ensure the safety and quality of the food supply. National laws may indicate that some label information is mandatory and some is voluntary, with the form and content of the mandatory information often being quite rigidly defined. As a result, the specific information provided by a food label usually varies both between and within countries.
In dealing with label information, manufacturers should be contacted to determine the specifics of the information, for example, if the values are based on analyses done by the manufacturer or if they are derived from a data base. It should be noted that label data for multi-ingredient foods may be calculated by the manufacturer from data base values of ingredients, and that label values may represent upper or lower estimates or be variously manipulated to be in compliance with national laws. Original data should be requested from the manufacturer with as much documentation as possible. If original data cannot be obtained, label data may be used as a "last resort" and subsequently updated or replaced when "better" data become available.
Label information is especially useful for identifying foods, describing foods, determining weight and other measures of serving sizes, identifying ingredients of multi-ingredient foods, and estimating nutrient values. Additionally, label information for multi-ingredient foods can sometimes be used to reconstruct recipes, and from this information the levels of nutrients not included on the label can be estimated. (See chapter 6.)