Food Composition
Data
Foods
are chemically analyzed for a variety of purposes. Food composition
databases rely on nutritional
and toxicological analyses conducted by government, academia and industry to determine
the potential contributions of foods to the diet, and to determine compliance with
regulations concerning composition, quality, safety and labeling. Foods may also be analyzed for the purpose of ongoing monitoring
of the food supply. The estimation of nutrient intake from
food consumption requires reliable data on food composition. These data are
also the fundamentals of food-based dietary guidelines for healthy nutrition,
containing the necessary information on food sources for different nutrients.
Furthermore, food composition tables can provide information on chemical forms
of nutrients and the presence and amounts of interacting components, and thus
provide information on their bioavailability. For some nutrients such as
vitamin A, vitamin E and niacin, the concept of equivalence has been introduced
to account for differences in the availability and biological activity of
different chemical forms.
Impact of Food Composition Data for Food Safety
Levels
of certain nutrients, additives and contaminants in foods are monitored for several reasons. Some nutrients, for example,
may react adversely under particular processing conditions, producing poor sensory
quality or affecting the safety of the food (e.g. trans fatty acids). Labeling regulations
also require prescribed levels of nutrients in specific foods (e.g. vitamins and
minerals in fortified foods, polyunsaturated fat levels in margarine). Certain toxic
substances are limited to prescribed levels and are monitored by government, industry
and other laboratories. The nutrient content of manufactured foods is rarely made
available in electronic format to compilers, and care must be exercised when compiling
databases using information provided
on food labels.
Although most food
composition tables focus on energy, macro and micronutrients, interest in
non-nutritive components is increasing. Considering the beneficial effects of
biologically active secondary plant cell compounds such as polyphenols and
carotenoids, more data on these areas are needed. On the other hand, there are
a number of naturally occurring or 'man-made' non-nutritive substances with
negative effects, and to control exposure, the main dietary sources must be
known. Another aspect is contaminants, which could have detrimental effects on
consumers' health. Among these are agrochemicals, industrial pollutants
reaching the food chain and substances formed during food preparation. A valid
risk assessment requires data on exposure, and thus on the contents of
contaminants in foods. However, these data are highly variable and may
significantly differ even within narrowly confined regions.
Contaminants
Contaminants
include mycotoxins, heavy metals and residues of pesticides, herbicides and animal growth promoters.
The distribution of contaminants in foods is such that the concept of representative
values for contaminants differs from that for nutrients. It may be misleading to
list contaminant values in the same record as nutrients.
Bioactive substances
There
has been a growing interest in the range of dietary phytochemicals in recent years,
particularly in view of their possible protective action against cardiovascular
diseases and certain cancers. These include isothiocyanates, polyphenols, flavonoids,
isoflavones, lignans, saponins and coumestrol (AICR, 1996; Pennington, 2002). Consequently,
there is a parallel interest in the inclusion of phytochemicals in food composition
databases (Ziegler, 2001).
Anti-nutrients and toxicants
Some
constituents have undesirable physiological effects, for example, goitrogens, haemagglutinins,
antivitamin factors, trypsin inhibitors, oxalic acid and phytic acid. Data for these
components should be included for the relevant foods. Other important natural toxicants include solanine,
cyanides, glucosinolates, lathyrogens, mimosine and nitrosamines.
Additives
Many additives are measured, in whole or in part,
during the course of nutrient analyses. Salts, for example, are included in analyses
for various cations and anions; protein additives are determined in nitrogen analysis;
and some emulsifiers and thickeners are included in analyses for nitrogen, starch
and unavailable carbohydrates. Clearly, specific analyses are preferable. However,
the need for data on additives and other non-nutrient components of foods may relate
to priorities regarding food safety and not necessarily to nutritional priorities.
Miscellaneous
The
data exist for other compounds of interest, such as caffeine, theophylline, theobromine,
tannins and other bioactive compounds (carnosine, carnitine and creatinine), they
should be listed in the database at least up to the reference level.
Benefits of Food Composition Data
In
agriculture, factors such as disease resistance and yield, rather than nutritional
value,
have tended to dominate
decision-making regarding policies and programmes. Similarly, in food technology
economic considerations such as consumer appeal and profitability have been the
major influences on product development. Attitudes are changing, however, and nutritional
quality is now one of the factors considered in cultivar selection and the development
of processed foods. The production, handling, processing
and preparation of foods profoundly affect their nutritional quality. Extensive
literature covers agricultural practices (climate, geochemistry, husbandry, post-harvest
treatments); processing methods (freezing, canning, drying, extrusion); and stages
in food preparation (holding, cutting, cooking). Most nutritional studies in these
areas, however, cover a limited range of nutrients (notably labile vitamins); very
little information is provided on the broad range of nutrients (Henry and Chapman,
2002; Harris and Karmas, 1988;
Bender, 1978; Rechigl, 1982).
In many countries, government
agencies often assess diets at the population level, through national food
consumption surveys, in order to monitor trends in nutritional status and to
evaluate the impact of nutrition policy. FCD are also widely used in the
development of recipes, meals and menus for therapeutic diets, institutional
catering and the commercial foodservice industry. Dietitians and clinicians
need to design therapeutic diets for patients with specific nutritional
requirements associated with their condition (e.g. metabolic disorders,
diabetes). FCD are also an important tool in planning menus in care homes,
hospitals and prisons to ensure adequate nutrient content. There is also a move
towards the provision of point-of-sale nutritional information in foodservice
outlets, which has increased the application of food composition data in the
foodservice industry. The demand for point-of-purchase information on nutrient
content has also been a driving force behind the inclusion of nutritional information
on food labels. This is in the form of nutrition panels and, increasingly,
front-of-pack or ‘signpost’ labeling, which provides information for consumers
in a simplified format. Nutrient profiling, a tool for categorizing foods on
the basis of their nutrient content, is a relatively new application of FCD. It
will help assess the eligibility of foods to bear nutrition and health claims
under new EU regulations. Other uses of food composition data in relation to
food manufacturing include optimization of product composition when developing
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FCD are also used to help identify
the needs of nutrition education and health promotion and to implement
appropriate strategies, such as targeted interventions. They form an integral
part of, and an educational resource for, food and nutrition training in
schools, tertiary education and, increasingly, in workplace settings. They also
have more general applications in agriculture and trade. For example, FCD can
be used to monitor the nutrient content, safety and authenticity of foods.
Improvements to the food supply, such as plant breeding, and new methods of
cultivation, harvesting and preservation can be assessed using FCD. Finally,
they form part of the evidence base in support of initiatives on nutrition and
biodiversity.
Reference
http://www.fao.org/fileadmin/templates/food_composition/images/FCD.pdf
http://www.eurofir.org/?page_id=17
http://www.ncbi.nlm.nih.gov/pubmed/21045848
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