Food composition issues--implications for the development of food-based dietary guidelines.

Sound food composition databases that are both comprehensive and representative of available foods are an essential basic tool to develop Food Based Dietary Guidelines (FBDG). The main drawbacks of current food composition databases available in the European Union are: partial coverage of foods and nutrients, variability of analytical data, lack of accuracy in the description of food items, need for harmonisation of the expression of nutrients. An inappropriate use of these databases could lead to gross errors in the assessment of the nutrient intake levels, in the identification of the major sources of a nutrient, in the comparison of data between countries and in the analysis of time trends. Inadequacy of food composition data is, in part, responsible for the failure to understand some relationships between nutrient intakes and health or disease and for difficulties in establishing quantitative dietary guidelines in terms of nutrients. Recommendations are made for the compilation of future food composition databases and tools are proposed to enhance the quality of existing data. A careful study of the food composition databases is always necessary before nutrition recommendations are given and before trends in nutrient intakes are interpreted.