Protein
In comparison to the previously studied children, intake of energy from protein in the studied 6-year-olds was lower than in Belgian 4.5-6-year-olds [
9], French 5-11-year-olds [
15] and Greek children [
11,
40], and much lower than in Spanish 6-7-year-olds [
12,
13], Spanish 6-9-year-olds [
14], Portuguese 7-9-year-olds [
34] and Vietnamese 4-5-year-olds [
41]. However, it was higher than in British [
7] and Polish [
6] 4-6-year-olds, and similar to energy from protein in the diets of American children aged 6–11 years and less than 6 years [
16]. Intake of protein per kg of body weight in the studied 6-year-olds was lower than in Belgian 4.5-6-year-olds [
10] and protein density was lower than in Cretan children [
11].
Total protein intake in the studied 6-year-olds poses little risk of deficiency. However, there were substantial percentages of girls and boys whose intake of energy from total protein was above the recommended. Nevertheless, these percentages were much lower than in Belgian 4.5-6-year-olds (50.0% of girls and 56.5% of boys) [
9].
Intake of animal protein (% of total protein) in the studied 6-year-olds was similar to that observed in the previously studied Polish 4-6-year-olds [
6], Belgian 4–6.5-year-olds [
10] and Vietnamese 4-5-year-olds [
41]. It is recommended to reduce the intake of animal protein since its high intake is related to an increased diabetes risk [
42], as well as to earlier pubertal onset which may contribute to a higher risk of breast cancer [
43]. Moreover, it causes reduced intake of plant protein which is inversely related to the risk of ischaemic heart disease [
44]. It is surprising that although the studied children attended preschools promoting health, their intake of total, animal and plant protein did not differ much from the intakes observed in other children.
Fat
Total fat intake in the studied 6-year-olds exceeded the recommendations and should be lowered. Former concerns that lowering energy from fat in children’s diets may cause decreased intakes and deficiencies of essential nutrients, and thus poor growth [
45], have been dispelled by the results of many intervention and longitudinal studies on children of various age [
46‐
49]. On the contrary, it is emphasised that energy from fat in children’s diets should not exceed 30% because of the benefits to lipid profile [
47,
50] as well as reduced risk of cardiovascular diseases and cancer, not only in the short term but also in adulthood [
51].
Although the studied 6-year-olds exceeded the recommendations on fat intake, energy from fat was the lowest compared to children from other European countries: France [
15], Great Britain [
7,
8,
33], Greece [
11,
40], Portugal [
34] and Spain [
12‐
14]. It is important to note that intake of energy from fat was the highest in Greek children [
40] and Cretan children [
11], as well as Spanish 6-7-year-olds [
12,
13], reaching 40% and more energy from this macronutrient. Only in Belgian 4–6.5-year-olds [
9] and Polish 4-6-year-olds [
6], intake of energy from fat was lower than in the studied 6-year-olds, but only Belgian children met the recommendations [
9]. In comparison to children from outside Europe, intake of energy from fat in the studied children was similar to the intake observed in American children aged 6–11 years and less than 6 years [
16], but it was much lower than in Vietnamese 4-5-year-olds [
41].
The structure of fatty acid intake was also unfavourable. It was characterised by excessive intake of saturated fatty acids, higher even than monounsaturated fatty acid intake, along with inadequate intake of polyunsaturated fatty acids. It is especially disconcerting in case of boys, since it is well recognised that males are at higher risk for atherosclerosis than females and the studied boys’ intakes of both total fat and saturated fatty acids (g, % of energy, g/1000 kcal) were significantly higher in comparison to girls. Moreover, inadequate intake of polyunsaturated fatty acids observed in almost all of the studied 6-year-olds may have adverse effect on their neurodevelopment [
52].
Intakes of fatty acids in children of various age from other countries were usually similar to those observed in the current study. Excessive intake of energy from saturated fatty acids was observed also in the diets of children in Belgium [
9], France [
15], Great Britain [
7,
8,
33], Greece [
11,
40], Portugal [
34], Spain [
12,
14] and the United States [
16], as well as in the previously studied Polish children [
6]. Intake of energy from polyunsaturated fatty acids was lower than the recommended also in the diets of Belgian 4–6.5-year-olds [
9], British children [
8,
33], Cretan children [
11], Polish 4-6-year-olds [
6], Portuguese 7-9-year-olds [
34] and Spanish 6-9-year-olds [
14], and adequate only in the diets of Spanish 6-7-year-olds [
12]. Intake of energy from monounsaturated fatty acids in the studied 6-year-olds was much lower than in Cretan children [
11], Spanish 6-7-year-olds [
12] and Spanish 6-9-year-olds [
14], lower than in Polish 4-6-year-olds [
6] and Portuguese 7-9-year-olds [
34], similar to British children [
8,
33], but higher than in Belgian 4–6.5-year-olds [
9]. Nutrient densities of fatty acids in the studied children’s diets were lower than in Cretan children [
11], especially for saturated and monounsaturated fatty acids.
Although cholesterol intake in the studied 6-year-olds was in accordance with the recommendations, it was higher than in American children aged 6-11-years and less than 6 years [
16] and in Polish 4-6-year-olds [
6], and much higher than in Belgian 4–6.5-year-olds [
9]. However, it was lower than in Spanish 6-7-year-olds [
12] and Spanish 6-9-year-olds [
14] who exceeded the recommendations. Cholesterol density was higher than in Cretan children [
11], but lower than in Spanish 6-7-year-olds [
12].
Despite not exceeding the recommendations on cholesterol intake by the studied children, density of this nutrient, along with the adverse structure of fatty acid intake, need urgent intervention. Otherwise, unfavourable structure of fatty acid intake will soon be accompanied by excessive cholesterol intake due to the inevitable increase of energy intake as children grow. It is surprising that although the children attended preschools aimed at promoting health, their intakes of energy from fat and fatty acids were so unfavourable. These findings confirm unfavourable food habits observed in the previous studies on Polish preschoolers [
53,
54]. Moreover, these findings are similar to those obtained in other populations of children in Europe and show the need to work out a common educational programme to improve nutrition in young European children taking into account food habits which are specific to the tradition or food supply of each country.
Carbohydrates
Intake of available carbohydrates in the studied 6-year-olds was below the recommended. However, it is worth noting that carbohydrate content of foods in Polish food composition tables [
20] was calculated by difference, that is by subtracting the content of moisture, protein, fat, ash and alcohol from the total weight of the food [
21]. Intake of carbohydrates was reported to be 14% higher when measured by difference compared to carbohydrates measured directly (direct analysis of carbohydrate components and summation to obtain a total carbohydrate value) [
21]. Therefore, it is probable that intake of carbohydrates in the studied 6-year-olds was in fact even more below the recommendations than it can be observed from the obtained results.
Due to the differences in methodology, it is difficult to compare the results with the results of other studies. For sure, intake of energy from carbohydrates in the studied 6-year-olds was lower than in Polish 4-6-year-old children studied by Szponar et al. [
6] who used the same method of carbohydrate determination. In comparison to British 4-6-year-olds [
7], British 4-10-year-olds [
8], British 7-year-olds [
33] and French 5-11-year-olds [
15], intake of energy from carbohydrate in the studied 6-year-olds was higher. However, the aforementioned studies on British and French children used McCance and Widdowson’s ‘The Composition of Foods’ in which carbohydrate content was obtained by direct analysis [
21]. Therefore, if in case of French 5-11-year-olds [
15] the difference in energy from carbohydrates is 11.3% compared to the studied 6-year-olds, the observed difference is mainly due to different methodology and so the intake is similar. And if in case of British children this difference is from 2.3% [
8] to 4.0% [
33], it is probable that the intake of energy from carbohydrates by the studied 6-year-olds was in fact lower than in British children. Surely, intake of energy from carbohydrates in the studied 6-year-olds was lower than in Belgian 4–6.5-year-olds [
9] whose intake was 54.87% in girls and 54.19% in boys and was determined using McCance and Widdowson’s The Composition of Foods. The lowest intake of energy from carbohydrates was reported in Spanish 6-7-year-olds [
12,
13], only 38.3%, however, the method of carbohydrate determination in Spanish food composition tables was not available to the author.
Intake of sucrose in the studied 6-year-olds seems to be high. It is recommended to reduce intake of all monosaccharides and disaccharides, that is also sucrose, added to foods by the manufacturer, cook or consumer, as well as sugars naturally present in honey, syrups and fruit juices to less than 10% of energy [
25]. In the studied 6-year-olds the intake of energy only from sucrose was almost twice higher than the WHO recommendations for all added monosaccharides and disaccharides. These findings reflect the adverse habit of adding a lot of sugar to tea and other beverages, which is very popular in the studied region, as well as the adverse habit of snacking on sweets between the main meals. A study on Polish 5-6-year-olds showed that more than 50% of the children snacked on sweets twice or more times a day [
53]. Besides, it is well recognised that preferences for sweet taste are innate and typical of infants and young children irrespective of gender [
55,
56] and probably this was also an important factor of high intake of sucrose in the studied 6-year-olds.
High intake of sucrose in the studied 6-year-olds is very unfavourable. The studies showed that an increase in sucrose intake increases triacylglycerol concentration [
57] which is the risk factor for atherosclerosis. Moreover, high intake of added sugars in children is associated with lower intakes of micronutrients [
58‐
61] and with lower intakes of important food groups such as grains, vegetables, fruits, and dairy [
58,
60,
61]. Most of the staff who worked in the studied preschools and most of the studied children’s parents knew that high sucrose intake increases dental caries [
62,
63] and that sugar intake should be limited because it does not provide any additional nutrients in children’s diets [
64,
65]. Therefore, it is surprising to find high sucrose intake in children who attended preschools aimed at promoting health. Most probably food habits were stronger than knowledge.
It is interesting that intake of sucrose (% of energy, g/1000 kcal) in the studied girls was significantly higher than in boys. This seems to reflect female higher preferences for sweet taste which are typical in teenagers and adult women [
66‐
68].
In other studies, intake of sucrose was not analysed. In British 4-10-year-old children [
8] and British 7-year-olds [
33], intake of non-milk extrinsic sugars was reported to exceed the recommendations. In the study on Belgian 4–6.5-year-olds [
9], Spanish 6-7-year-olds [
12,
13] and Portuguese 7-9-year-olds [
34], intake of energy from simple carbohydrates was reported to be high, however, only Moreira et al. [
34] defined the term ‘simple carbohydrates’ as all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, as well as sugars naturally present in honey, syrups and fruit juices.
No recommendations on starch intake are available. Intake of energy from this macronutrient in the studied 6-year-olds was similar to that reported in British 7-year-olds [
33] and slightly lower than in British 4-10-year-olds [
8]. In other studies, intake of energy from complex carbohydrates was reported. In French 5-11-year-olds [
15], it was similar to intake of energy from starch in the studied 6-year-olds, whereas it was slightly lower in Belgian 4–6.5-year-olds [
9]. Very low intake of energy from complex carbohydrates was found in Spanish 6-7-year-olds, only 17.8% [
13].
Dietary fibre intake in most of the studied 6-year-olds was in accordance with the recommendations and was similar to the intake reported in Polish 4-6-year-olds [
6], in Belgian 4–6.5-year-olds [
9] and in Spanish 6-9-year-olds [
14] but it was lower than in Spanish 6-7-year-olds [
13] and Portuguese 7-9-year-olds [
34]. Dietary fibre density in the studied children’s diets was higher than in Cretan children [
11] but similar to dietary fibre density in the diets of Belgian 4–6.5-year-olds [
9]. In British 4-10-year-olds [
8] and British 7-year-olds [
33], intake of non-starch polysaccharides was analysed so the comparison is not possible.