Food-based dietary guidelines: some assumptions tested for the Netherlands

Recently, the concept of food-based dietary guidelines has been introduced by WHO and FAO. For this concept, several assumptions were necessary. The validity and potential consequences of some of these assumptions are discussed in this paper on the basis of the Dutch National Food Consumption Surveys. The topics were interrelationships among dietary characteristics, nutrient density, diets in accordance with the guidelines, and food variety. To obtain insight into overall diet quality, a dietary quality index based on nutrients and a food-based quality index based on food groups were created and tested. As expected the results showed that a higher dietary quality index was associated with an improved intake of the nutrients included in the index, in particular a lower intake of total fat and cholesterol. This was related to a lower consumption of cheese, fats and oils, meat and meat products, and a higher consumption of fruit and vegetables. The information obtained with a dietary quality index can be used to assess the feasibility of a particular goal in combination with other relevant goals and to obtain clues or confirmation for recommendations regarding food consumption. The food-based quality index created showed that a combination of several food-based goals (formulated in quantitative terms) was associated with an increase in food consumption, without a clear relevance for the dietary quality. Therefore, the formulation of food-based guidelines should be based on explicitly stated dietary goals. The findings regarding nutrient density were in the direction of what was assumed, namely a positive association between density and absolute intake, although the expected effects were not completely found. The results regarding the association between variety and dietary intake were characterized mainly by differences in quantity rather than dietary quality. The data indicate that energy intake may be an important pitfall in implementing food-based dietary guidelines, that 'eat a variety of food' can be an empty slogan and that nutrient density is positively related to the absolute intake of specific micronutrients. Further, the 'absence' of interrelationships among risk nutrients indicates that a selection process has to be applied.