| Food Composition Data: A User's Perspective (1987) |
|Report and recommendations of the conference|
The users and their needs
The Users of Food Composition Data
Data on the composition of foods are used by a wide selection of individuals and organizations, ranging from the Food and Agriculture Organization of the United Nations, which calculates food balance sheets for countries around the world and advises them on the global allocation of foods and other resources, to individual shoppers reading labels in the supermarket in an attempt to plan the nutritional value of their next meal. The following list of examples illustrates the range and variety of users (see also the extended list in paper 13).
International Users (e.g. paper 15)
International agencies dealing with food aid are responsible for acquiring large quantities of food and transporting it to different locations in the world, often to meet the specific nutritional needs of populations. Here there is a strong need to know the constituents of the foodstuffs available around the world and, at the same time, the relevant nutrient situation within each country, in order to match the food supply to human physiological needs.
Governments need to know the composition of the foods that are imported in order to plan for satisfying the nutritional requirements of their populations and to protect these populations from contaminant and toxicologically active constituents.
Food industries that compete on the international market need to know the components of the local food with which they are competing, and also the nutrient content of potential ingredients for their products - ingredients which may come from widely separated parts of the world.
Epidemiologists have long realized that food is one of the most important components of an individual's environment. Studies of global disease patterns must be accompanied by data on global food and nutrient consumption patterns (see papers 4, 5, and 6).
National Users (e.g. papers 16 and 17)
National governments regulate what is produced within the country as well as what is imported in order to protect and guarantee the health of their populations . Their activities include the setting of regulations and the monitoring of adherence to those regulations. They must also assess the nutritional status of their populations (papers 7 and 20); one important aspect of this is to determine what is being consumed and how this compares with established dietary requirements and allowances. All of these activities require the availability of reliable and extensive data on the composition of foods.
National programmes of feeding, such as in schools or in the military, require up-todate information on the nutrient content of foods so that nutritionally adequate diets can be formulated.
University teachers and researchers require reliable and current food tables for a broad spectrum of activities that involve the relationship between health and disease and what people consume [2,14] (papers 8 and 14).
Below the national level, there are many activities concerned with the preparation and recommendation of healthy diets, in institutions such as hospitals and factories as well as in special segments of society such as the elderly.
Food industries regulate the quality of their foods by routinely analysing the components of their products, using available food tables. New formulations must adhere to nutritional and safety standards and food tables are used initially to select preparations for investigation (paper 9).
The diet and nutrition clinics which continue to increase in number in technically developed regions rely heavily on food tables for individual counselling. These clinics complement the activities of individual dietitians and physicians dealing with patients ranging from those with metabolic disorders to those who are over- and underweight.
Finally, the most extensive use of food composition data by the individual is, of course, the individual shopper scanning the ingredients list, nutrient contents, and percentages of requirements fulfilled on the labels of packaged foods.
Some Generalizations about Users
The extent and diversity of the users of food composition data are underlying problems of the field. These various users' groups not only make very different uses of the data, but also have different expectations and requirements. Thus it is important to identify the common threads that would permit the organization of users into groups who have similar needs and make similar demands on any food composition data system:
- System requirements are quite different for the user concerned with a limited set of foods that can be fairly well defined, such as those in a restricted geographic region or those suitable for a very specific diet, and for the user concerned with extensive, perhaps open-ended, sets of foods, with often a global distribution. The former group of users is usually able to define its needs and knows the questions it will ask of a data base, which can thus be embedded in a fairly rigid system, while the latter requires much more flexibility in its interactions with the data.
- The degree of precision or specific level of detail required divides users into a spectrum of groups, with some needing accurate data, some only approximate data or ranges, and others only an indication as to the presence or absence of components. - Many users need to know the constituents of specific foods (e.g. diet evaluation) while others are interested in the foods that contain certain components (recipe or menu development). This distinction divides the users into two groups with quite different search and retrieval requirements.
- The distinction between whether the user is interested in a specific individual, for example for diet or menu planning, or in a group of individuals, for example to determine the nutritional intake of the population of a region, is essential in order to design a system to properly estimate various statistical quantities, such as confidence regions.
- Some users need only representative values for specific nutrients in specific foods. Others are interested in the extremes that a nutrient can attain (at a certain probability level), while others want to know how certain nutrients (and foods) correlate with one another. Each of these classes of users asks different questions, requires different amounts and types of data, and needs systems for usage which are superficially quite different.
The Needs of Food Composition Users
The basic needs of the users are: (a) high-quality data on foods and components, (b) ancillary data, and (c) facility of access and manipulation of these data to give the information desired.
The most obvious need of the users is for data that represents the foods and components with which they are concerned. These data must be as precise as the particular usage requires, unambiguously identified, and easily accessible (see section 3 below).
For most users, the amount of a specific nutrient in a given specific food is not sufficient for their task (paper 2). Necessary ancillary data range from usual serving sizes to household consumption and individual nutrient requirements. The following list includes some of the major types of additional information that often may be needed:
- data describing the food composition data - where they came from, their quality, etc.;
- descriptions of representative serving portions, including weight/portion equivalents;
- brand names and identifications; recipes and ingredient lists;
- effects of processing and preparation; fortification rules;
- food/nutrient interactions; food/drug interactions;
- contaminants, toxicants, and allergenic compounds; dietary standards and nutrient requirements;
- food production and consumption; geographic distribution of disease.
The mere existence of food composition and associated data is not sufficient for carrying out the tasks of most users. These data need to be acquired, merged, and manipulated in order to be turned into information. Thus the users require many of the tools of data-base management, with their use-specific tasks ranging from recipe calculations to grouping and imputation; these are discussed more fully in section 4 below. It is especially important to note that, with the ever widening usages of food composition data, and with the increasing availability of those data, it is essential that there be consistency in the way these tasks are performed.