Understanding the dietary intake of a population requires the investigation of the intake of individual nutrients, but also of foods and contributions of foods to nutrient intakes. Since this is the first study to provide a detailed list of principal food sources of energy and macronutrient intakes in Flemish preschoolers, it can be used to formulate suggestions in order to increase the compliance of nutrient and food intakes with the current recommendations.
Bread, sweet snacks, flavoured milk drinks, milk, and meat products were the top five sources of energy intake among Flemish preschoolers. However, for the bread group, it is noteworthy that this group also contains rolls and croissants, which were often consumed by preschoolers and partly responsible for the important contribution of the bread group to energy, SFA and cholesterol intakes. Also, sweet snacks were major sources of total fat and SFA, and the third important source of simple carbohydrate intakes after flavoured milk drinks and fruit juices.
While spreadable margarine for bread was underconsumed in comparison with the FBDG, it was still the main source of PUFA intakes. Although spreadable fat is an item that might be more prone to underreporting in diaries, the results from the FFQ confirmed that more than one-third of the children never consumed spreadable fat on their bread .
Food sources and nutrient and food adequacy: a basis for evaluating dietary guidelines
When comparing tables 4 & 5, while taking into account the main food sources for those nutrients discussed above (tables 2 & 3), interesting recommendations/guidelines could be formulated in order to pursue the designated nutritional goals. Insufficient nutrient intakes in Flemish preschoolers, should be increased by enhancing the intake of food(group)s that highly contribute to these particular nutrients, but are underconsumed in comparison with the FBDG. In the same way, excessive nutrient intakes should be decreased by reducing the consumption of food(group)s with high contributions to those particular nutrients, though overconsumed in this population.
When looking at the food groups that are underconsumed in comparison with the FBDG (table 4) and taking into account the contributions of these foods to the nutrients being inadequately consumed, it can be concluded that higher intakes of non-sugared beverages (mainly water) could contribute importantly to the increase in water intake. Although an increase in milk intake can contribute to higher fluid intakes, it would also increase the intake of many other nutrients like SFA. Enhancing the daily amount of spreadable margarine for preschoolers' bread and increasing fish intake could contribute importantly to the increase of PUFA intakes.
When looking at the food groups that are overconsumed in comparison with the FBDG (table 5) and taking into account the contributions of these foods to nutrients that exceed the upper intake level, it can be concluded that lower intakes of sweet snacks would lower importantly the SFA and simple carbohydrate intakes among Flemish preschoolers. Also, a decrease in the consumption of sugared drinks and fruit juices would significantly decrease simple carbohydrate intakes. Replacement of flavoured milk drinks by natural milk should for instance be encouraged. The current consumptions of sweet spreads (like jam and chocolate spread) are only a case of concern with regard to the intake of simple sugars, though their contribution to simple sugars is still lower than that from flavoured milk drinks, fruit juices, soft drinks, and sweet snacks. Furthermore, it could be concluded from tables 2 and 3 that a lower consumption of fat-rich cold cuts could help to decrease SFA intakes, given its high contribution and its high consumption in comparison with other products from the 'meat group'. At last, a lower consumption of hard cheese or replacement by low-fat types or cottage cheese could also reduce SFA intakes.
Some limitations should be considered when interpreting or using these results. First of all, it should be underlined that the information collected from these Flemish preschoolers relies upon parents and/or other proxies' capabilities of recall. However, several steps were undertaken in this study to increase the validity of the information (e.g. school staff was involved in the reporting of snacks and lunches consumed during school-time, and great efforts were done to motivate the parents). Nevertheless, it should be noted that the underrepresentation of lower educated parents could result in participation bias warranting caution in generalisation of the current findings.
Second, decisions about food grouping were based on the food groups in our Flemish FBDG and on the judgement of the investigators, which might have implications for the findings. For example, rolls and croissants were classified under bread products according to the main food group classification, however, within the bread food group it is considered as a food item from the residual group. Also, decisions regarding the disaggregating of mixed foods might have consequences for the present results. For example, disaggregating pizza would have given a more realistic estimate of how cheese contributes to nutrient intakes but does not allow for knowing how pizza itself contributes.
Since all days of the week were included in the study, the effect of day of the week could be removed. Unfortunately, it was impossible to correct for seasonal variations, because data was collected during autumn and wintertime. However, in the Belgian National Food Consumption Survey performed in 2004, it was concluded that seasonal variation was limited for nutrient intakes . A possible explanation might be the widespread availability of most foods all year round.
Differences in methodology and ways of grouping foods hamper comparisons with other studies. However, an essential finding that was comparable with other studies investigating the major sources of energy and nutrient intakes among children was the important contribution of fortified foods to children's diets [7, 24].
Finally, caution is necessary when interpreting these results since food composition data do not consider bio-availability of nutrient sources.
Suggestions for future dietary guidelines and policies
From previous studies investigating nutrient and food group adequacies in Flemish preschoolers [3, 4], it could be concluded that preschoolers in Flanders should be recommended a different dietary pattern in order to pursue the designated nutritional goals. More specifically, fibre, iron and vitamin D intakes were well below recommendations, while sodium and saturated fatty acid intakes exceeded tolerable upper intake levels . Furthermore, the percentage of children complying with FBDGs was for most food groups extremely low (ranging from 4% for fluids and vegetables up to 99% for potato intakes) . The current study investigating nutrient sources, additionally revealed some important recommendations in order to increase nutrient and food intake compliances with the current recommendations. However, this study also raised concern about some of the current dietary guidelines, which are discussed below.
Given the fact that whole fat milk is still recommended for children younger than four years old and considering the high SFA contributions of milk products, it could be suggested to replace whole fat milk by half-fat varieties in FBDG for preschoolers. Supply of fat-soluble vitamins could then be compensated by use of margarine on children's bread, which is currently being underconsumed in comparison with the recommendations and which, at the same time, would contribute to higher PUFA intakes. Accordingly, nutritional policies targeted at replacing whole fat milk with another low-fat (e.g. semi-skimmed) variety, should be implemented as key strategy for achieving recommended SFA intake levels in this age group [25, 26].
Furthermore, it should be noted that excessive consumption of fruit juice in infants and children has typically been related to carbohydrate malabsorption , dental caries, and gastrointestinal symptoms such as bloating, diarrhoea, and cramping . More recently, fruit juices have also been blamed as possible contributors to the current childhood obesity epidemic in the US where fruit juices were seen as healthy and convenient replacements of fresh fruits . Therefore, it should be stressed to parents and caregivers that fruit juices should not be used as a replacement for fresh fruits. More importantly, FBDG compilers should re-evaluate fruit juice's grouping as a food that can be consumed with moderation. In the present study, fruit juice consumption is the second highest contributor of simple carbohydrate intakes in preschoolers, therefore, fruit juice should be categorised as a food item from the residual group.
The high intake of fortified biscuits seen in Flemish preschoolers results in an increase of energy, SFA, and simple carbohydrates, all counteradvised in the prevention of certain chronic diseases. Furthermore, a 'habit' of eating biscuits/cakes that is formed during childhood is likely to continue into adulthood [30, 31]. Therefore, children should be recommended to replace sweet snacks by more healthy foods like bread with margarine (combined with low-fat cold cuts or cottage cheese), fruits or certain vegetables (e.g. baby carrots) in order to decrease SFA and simple carbohydrate intakes.
Since this study includes the first comprehensive examination of food sources of nutrients in Flemish preschoolers, it can be used for establishing/revising guidelines for Flemish preschoolers. Though, as the food supply changes, these data will need to be continually updated.