Promoting adequate and healthy food in early childhood education: a systematic review

Abstract Objectives: to identify and describe the characteristics of studies that address the promotion of adequate and healthy food in early childhood education units and their repercussions on the school community. Methods: the search and selection were performed according to the PRISMA recommendations in the Medline databases via OVID, EMBASE and LILACS. Data extraction took placeusing a table developed by the authors. The evaluation of the quality of the evidence of the studies was carried out through the risk of bias using an adapted scale. Result: twelve articles that met the eligibility criteria were selected. All studies were applied in public or private educational institutions with a median of 236 participants. In the analysis of food and nutrition education activities, the most adopted with preschoolers were playful; with the parents it was the meetings and counseling; and with the professionals it was the training. The methodological qualification of the studies was considered low, which may be related to their limitations included in this review, mainly due to the types of designs adopted, the time and lack of continuity of interventions and sample size. Conclusion: food and nutrition education activities seem to be a promising strategy in knowledge, adoption of healthy eating practices and transmission of values in the school community.


Introduction
The nutrition of a child starts with breastfeeding (BF), as preconized by the World Health Organization, exclusive within the first semester of life, and, after this period, complemented with other foods until at least 2 years of age. 1,2][5][6][7] Considering that the Early Childhood is a stage of intense infant development and formation of habits, the introduction of complementary feeding needs to be offered also in the perspective of adequate and healthy feeding (AHF).This should be done in a regular manner, respecting schedules and particularities of children, with the introduction of varied foods, in natura and minimally processed, in a sensorially attractive way and promoting meals together with the family. 2,8he infant education units (IEU) are configured as a support network, complementing the family's action, in order to help with the formation of citizens and habits, among them, eating habits.Such units play a determinant role in the dissemination of knowledge and collective, transdisciplinary and intersectoral work, including actions of health promotion.They are considered privileged spaces that allow direct contact with children and their guardians, favoring the development of health education actions. 9indergartens, nurseries and pre-schools are examples of IEU, which may shelter children from birth until six years of age, a stage defined as Early Childhood, depending on the type of organizational management. 10,11hese institutions are adequate environments for the improvement of healthy eating habits since they are facilities in which preschoolers spend a large amount of time and receive up to 40% of their nutritional needs. 9,12,13ood and nutrition education (FNE) in infant education (IE) have, among their objectives, to influence healthy eating practices, including the valorization of breastfeeding and healthy complementary feeding, and the development of autonomy.FNE is a permanent process, which considers the exchange of knowledge, individuality and cultural eating habits by means of complex and active approaches and educational processes that favor communication with individuals and their population groups, considering all life stages. 9,14n this perspective, it is also worth highlighting the importance of ludic, a word with Latin origin that means "play" and "games".By means of ludic, an educational action may contribute to a better usage of FNE activities, since it favors the learning, making it more interactive, fun and having an intention, objective and conscience of actions in relation to infant development and learning. 15,16t is considered the hypothesis that IEUs that develop FNE activities, by means of promoting AHF, have the potential of positively affect knowledge on feeding and the adoption of healthy eating practices by school community. 9,14However, it is not yet present in the literature a collection of findings concerning the influences of these practices in this educational stage.
In the face of the above, the present study aimed to identify and describe the characteristics of surveys that attempted to promote AHF in IEUs and their repercussions in the school community.

Methods
The present systematic review was conducted according to the protocol Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). 17With the guiding question "Do IEUs (nurseries and preschools) that develop FNE activities focused on the school community, as a way of promoting AHF, have the potential of positively influence the adoption of healthy eating practices by the school community?" This was elaborated by means of the strategy of searching for the PICO 18 acronym: "P" (population) refers to the IEU; "I" (intervention) concerns the promotion of AHF by means of FNE; "C" (comparison) is related to the comparison of the group with itself before and after intervention; and "O" (outcome/result) deals with the knowledge acquired about AHF and adoption of healthy eating practices by the school community.
The research was conducted after registration in the International Prospective Register of Systematic Reviews (PROSPERO) platform, under registry: CRD 42021253335, between October, 2020 and August, 2021, and the searches were performed in the following databases: Medical Literature Analysis and Retrieval System Online (MEDLINE), consulted with the OVID; ExcerptaMedica Database (EMBASE) and Latin American and Caribbean Health Sciences Literature (LILACS), using the descriptors "Child", "Preschool child", according suggested by MeSH (Medical Subject Headings) and the alternative terms "Children", "Preschool Children" and the descriptor "Food and Nutrition Education", being used the Boolean operators "and" and "or" in order to help with the combination -child (ab.ti)OR preschool child (ab.ti) AND food and nutrition education (ab.ti); child (ab.ti)OR preschool (ab.ti)AND food and nutrition education (ab.ti); child (ab.ti)OR preschool children (ab.ti)AND food and nutrition education (ab.ti); children (ab.ti)OR preschool (ab.ti)AND food and nutrition education (ab.ti).In the LILACS database, the search was also performed with terms in Portuguese and Spanish.
Duplicate articles found in the different databases were excluded, both manually and with the Mendeley software.The study selection analysis was performed by means of the reading of titles and abstracts.The selected articles for full reading were those that presented as intervention FNE activities with IEU preschoolers.
The following inclusion criteria were considered for the selection of articles: studies conducted in IEUs that promote FNE activities focused on the school community (students from 0 to 6 years old, parents and professionals); published in Portuguese, English and Spanish, and without period delimitation.Exclusion criteria were: studies that did not present defined methodology; reviews; case reports; descriptive studies; qualitative studies; those with impossibility of access to the printed or online versions, as well as the article that declared conflicts of interest.
Data extraction was performed by means of a table, previously conceived by the authors, in which the following information was highlighted: 1) identification: title and author's name; responsible researcher; year of publication; reference, and location; 2) eligibility: inclusion criteria and reasons for exclusion; 3) method: design; duration; participants (number, age, sex and sociodemographic characteristics); information on bias; ethical registry; consent of participation; intervention (number of groups, FNE activities types, time of execution of the activity, frequency, material, existence of protocol and duration of intervention; funding source, and conflict of interests; 4) results: number of participants (before and after intervention); type of statistical analysis; estimate of effect (confidence interval and/or p-value); outcome, and main conclusions.
Data synthesis consisted in the analysis of information extracted concerning the obtained results from the individual studies that were included in this review, which were resumed in a table to produce logical and valid observations.Therefore, it was considered whether the results of all included studies were clearly available; if the observed effects were consistent among the studies and if there were possible reasons for any inconsistencies.
The evaluation of the evidence quality of the studies was performed by means of risk of bias, using an adapted scale.0][21] However, this classification did not attempt to exclude studies, but to provide the discussion of different results with elements that would base it.
The discussion was performed by means of a planned narrative approach of results.All stages were executed by two reviewers, independently.In case of discrepancy, the opinion of specialists was considered.The authors declared no conflicts of interest.

Results
The entire selection process, from identification, screening and eligibility steps until the inclusion of articles in the systematic review are demonstrated in Figure 1.The initial search identified 2732 studies in the databases, excluding duplicates.Only 12 articles met the eligibility criteria and were included in the systematic review for analysis.Data synthesis of the selected articles was described in Table 1.
The selected studies demonstrated a variation between 26 and 781 participants, with a median of 236 participants.Of these, four articles were executed with preschoolers; [22][23][24][25] four with preschoolers, parents and professionals; [28][29] two with preschoolers and professionals; 30,31 one with preschoolers and parents; 32 and one with parents and professionals. 31here was a time variability between the studies of 10 to 392 days, with a median of 238 days.Most articles (nine) with applying of FNE activities in public IEUs; 22,23,24,26,27,28,30,31,33 one in public and private units; 29 one only in private institutions, 25 and one did not define the type of institution in which the study was carried out. 32ach article presented one or more FNE activities with strategies focused on the assessment of knowledge on AHF and/or changes of eating habits.It was observed that the most adopted activities with preschoolers were the ludic ones, which included painting workshops, 32 theater plays, 24, puppets, 31 sticker albums, 24 plays, 24,31,32 , songs, 29 games 27,29,31,32 and building of thematic stories about nutrition that used fictional characters. 24,25,32The activity of vegetable gardens was applied in only one study. 29This activity consisted in: lead the children to care agricultural plants and prepare the soil (sowing and irrigating) and, finally, the vegetables were harvested and consumed in the school and in their homes.
Of the FNE activities performed with the parents, those that promoted reunions and counseling were the most frequent, having as a theme the principles of healthy feeding in childhood. 31,33and basic nutritional advisement. 27,32On the other hand, the delivery of educational booklets with information on AHF in order to substantiate knowledge, was the least executed. 28,32oncerning the professionals, teachers and collaborators group, the qualification that instructed the correct preparation and portioning of foods, 24,30,31 as well Articles that are not applicable after analysis of titles and abstracts (n=2,694) Articles selected for full reading and verification of eligibility criteria (n=43) Flowchart of the processof selection of articles in the systematic review concerning the promotion of adequate and healthy feeding in infant education, 2021.IG = professionals -received the same information than the CG and participated in bimonthly reunions concerning complementary healthy feeding.
Application of an adapted questionnaire concerning breastfeeding and complementary feeding before and after activities.After intervention, there was a significant result indicating that it is possible to increase the average number of correct answers given by the IG (12.2 vs. 10.7;p= 0.001).
Besides, there were improvements between **IG parents concerning beliefs (soups and broths do not feed my child: p=0.012), attitudes (to offer meat as of the sixth month: p= 0.032) and intentions (do not offer soups and broths: p=0.003; to offer vegetables: p=0.018; to offer meat: p< 0.001).Previously, the professionals presented knowledge on breastfeeding and complementary feeding, although it was insufficient for the adequate care of babies, after the intervention, the CG and IG evolved positively.IG was the group with the highest learning.
In relation to parents, in the IG there was a significant improvement of the rate in some assessed parameters, however with a very low adhesion.In the CG, no change was observed with regard to beliefs, attitudes and intentions after intervention.
A comparison between CG and IG demonstrated that written guidelines, isolated, without reunions, lead to few effective results.an intervention of nutritional education in which children were taught to identify and categorize foods, according to their rate of consumption, as "sometimes" (that is, unhealthy) or "anytime" (that is, healthy).
In order to select snacks, the PSS tool was used -which include cards with printed pictures of foods and drinks in pairs of high contrast the easiest (ex: carrots and donuts) and pairs of low contrastthe hardest (golden fish and French fries) to assess their ability to classify food items with more details in differences of nutrients.The preschoolers saw pairs of foods and were asked to identify the snacks.The researchers registered each answer as 0 (incorrect) or 1 (correct).When a food was incorrectly identified, the researchers provided the correct answer.
The TSG was also used: an online tool with which teachers could follow the progress of preschoolers within the year in order to assess the progress in the socioemotional, physical, language, cognitive, literacy and mathematics subscales.Lectures were performed with each preschooler, exposing their opinion to researchers and their teachers, regarding their experiences with the Garden, reinforcing their knowledge on nutritional value of each vegetable.
Games and songs related to each vegetable were part of these activities.Pre-test was elaborated to be performed in one session, in order to determine the habits standard related to vegetable consumption of both preschoolers and their mothers.
The post-test was started immediately after VEGAPRO conclusion, also in an attempt to determine eating attitudes related to the consumption of vegetables.
Both researchers and kindergarten teachers registered their opinions and observations in camp notes.Preschoolers that participated in the VEGAPRO increased the number of daily meals and the frequency of vegetable intake (p<0.02).Mothers from the IG significantly increased the number of daily meals in which they consumed vegetables.(p<0.01)The findings corroborate the hypothesis that preschoolers enrolled in VEGAPRO increased the number of daily meals and the frequency of vegetable intake, as well as the number of vegetables that they like to eat and mothers experienced positive changes in their eating habits under the influence of their children.Parents and Teachers -Reunions approaching principles of healthy feeding in the childhood.
The children were submitted to anthropometric and dietetic measurements, before and after intervention with works of nutritional education.
The consumption of foods by the children in nurseries was assessed by means of the direct weighing of foods during 2 days of the week.Meals prepared at home were evaluated with the foods registry method, directed for parents or guardians, during 1 day of the weekend.
The evaluation of the available amount of food for the per capita intake of sodium (salt and spices), sugar and cooking oil was performed by means of data collection in the scholar feeding area.
To assess the quality of diet, the DQI-R was used.It was observed that the average availability of sugar decreased from 20.30g to 14.88g after the nutritional intervention, although this reduction did not significantly affect in the prevalence of inadequacy of consumption (p=0.14).It was observed a significant decrease of the prevalence of cooking oil inadequacy, however, without a significant difference in the available amount for consumption.
Such an outcome is due to the fact that 35.64% of children, during the study period, changed their age groups and thus, were included in another range of recommendation.
It was also assessed, the per capita intake of sodium during the study period, and it was 12.87% of inadequacy.It was not possible to evaluate the sodium intake before and after the intervention period, since the period of salt and spice delivery was annual.
It was observed a significant improvement in fruits consumption and significant reduction in the iron, cereals and legumes intake.The diets of all children were classified as "need modifications", before and after nutritional intervention.In face of this, it was verified the importance of continuity of nutritional education activities, in order to promote healthy eating habits among preschoolers.Food handlers were qualified to execute the new menu.
In order to measure the incorporation of knowledge and the acceptance of preparations with foods rich in iron and Vitamin c, an educational booklet was used.
The analysis of satisfaction in relation to the menus was performed by means of the hedonic scale fulfilled by the responsible teacher, observing the child during meals in 3 moments: before and after intervention and at the maintenance stage (of positive reinforcers).Most (62.74%) answered correctly about how to fight anemia, mentioning educational approaches used during intervention.
The low initial acceptance of meals decreased significantly (p<0.05).The acceptance index concerning the encouraged foods quintupled after intervention (14.7% to 76%).The use of a ludic methodology associated to super-heroes and positive reinforcers demonstrate a considerable impact in the assimilation of knowledge on healthy feeding and its effect in preschooler children's health, promoting changes in acceptance and eating habits towards the consumption of more varied foods, mainly fruits and vegetables, as well as foods rich in iron.
Rev. Bras.Saúde Mater.Infant., Recife, 23: e20220238 The curriculum of the 4 thematic sessions was sent to the teachers and nutrition professionals' team in a total of 3 qualification sessions of 30 minutes.
CG= All key-concepts of the nutrition sessions were equally offered to the control group after the follow-up of 10 weeks.
In the beginning of the study, parents were asked about the general characteristics of their children.as good personal hygiene practices and handling of foods, were the most executed FNE activities. 31The placement of posters 33 in workplaces to build knowledge on BF, consistency of foods, new offer of rejected foods, AHF and foods to be avoided was the least explored.
Concerning the evaluation of FNE activities implemented in school community, the most used tool was the applying of questionnaires before and after intervention, aiming to know about BF, 33 complementary feeding, 33 knowledge and preferences of snacks, 26 food frequency, 27,28,32 eating attitudes related to the consumption of vegetables 29 and about sociodemographic data 28,32 to associate the population profile with other questionnaires.On the other hand, only one study applied the revisited diet quality index (IQD-R -Portuguese acronym), 31 which measures several dietetic risk factors for chronic diseases, allowing, simultaneously, to assess and monitor diet at population or individual levels.
A methodological qualification analysis was executed in the selected surveys without the perspective of excluding any study.This analysis indicated low evidence quality in these, which obtained a score between 10 and 20 points (Table 2).

Discussion
This review found positive associations among FNE activities, as a manner to promote AHF in IEUs.Piziak et al., 27 in one of the included studies, brought an activity of intervention structurally ludic, following a bingo game model, with positive impact on the vegetables intake outside the educational environment.Similarly, the article of Ferreira et al. 34 presented a bingo game activity with students of the fifth grade of the elementary school, which also contributed to the improvement of teaching and learning of the different types of foods and their nutritional characteristics.
FNE activities that involve preschoolers in an active manner make it possible to practice the transmitted knowledge.In this way, they provide both cognitive development, which allows the received information to make sense, and affective development, which encourages the preschooler to interact, remember and understand the informational in a personal and emotional way. 35t is worth highlighting that, according to the National Curricular Guidelines for IE and the Common Curricular National Base, the structural axes of pedagogic practices in this step are the interactions and games.Such axes are presented as potentials to the integral development of children, playing an active role in environments and helping with the learning.These instances reinforce the importance of using the ludic as a manner of establishing any type of educational activity. 36,37her authors of the selected studies, such as Rosa et al. 24 and Kim et al., 25 brought a FNE activity based in tales with fictional characters.In both of them, after intervention, there was a significant increase in the intake of foods that were encouraged during the educational activity.Whilst in the first one it was also noticed the expansion of knowledge with citations of the preschoolers concerning educational approaches, the second study highlighted an increase in the fast food consumption in the control group.Such findings corroborate with the reports of Drewnowski 38 and Millen et al. 39 regarding the adoption of an eating standard with high energy density, rich in sugars and fats and a sedentary lifestyle in modern and industrialized societies.
The least used FNE activity between the analyzed studies was the food garden, although the study of Miguel et al. 29 demonstrates evidence on the significant increase in the vegetables intake.The lower implementation of this kind of project is probably due to factors such as low adhesion of voluntary teachers and of the community school, overload of tasks and the need for daily care with the food garden and material resources. 40n the nutrition education process, the involvement of the entire school community should be encouraged, since the family has its responsibilities, such as the transmission of ethical, moral and human values. 41,42It should be noticed that reunions and counseling were the most applied ways of parental inclusion since they were direct manners of communication.
Cândido et al., 33 Baskale et al., 32 Piziak et al. 27 and Andrade et al., 31 when executing reunions and counseling with parents, attempted to demonstrate the activities conducted with preschoolers and to expand the knowledge of adults about the theme.This is because children under five years old depend on their parents for the consumption of food, being a reflection of the family environment. 43esides, according to Paro, 44 present and participative parents encourage their children, stimulating them to a better interaction and school performance.
A FNE activity focused on the guardians of children that were less frequently used was the use of educational booklets, such as was observed in the studies of Baskale et al. 32 and Larsen et al. 28 Moreira 45 points that in this kind of strategy there is no attribution of personal meanings, which leads knowledge to be only stored and reproduced in a mechanic manner.
Another pillar of the community school is represented by professionals that act in these teaching institutions.It was observed that they were included in several FNE activities, being the qualification activities the most frequent ones.This was observed in the study carried out by Andrade et al., 31 which implemented qualification courses that approached the themes: "Good

Table 2
The evaluation of evidence quality of the selected studies in the systematic review concerning the promotion of adequate and healthy feeding in child education, 2021.Type of study: intervention= 5; cohort= 4; case-con-trol= 3; cross-sectional= 2; case study= 1 practices of personal hygiene and food handling" and "Adequate preparation and portioning of foods".In the studies conducted by Rosa et al. 24 and Santos et al., 30 the qualification was implemented not only as a reinforcement of the knowledge on the theme, but also for the learning of modifications done in the school menu.Professional qualification optimizes the execution of tasks, improves the productivity and consolidates the role of professionals as educators. 46he FNE activity with professionals using posters was described only in the study of Cândido et al. 33 The limitation of this kind of approach may be related to the low attention directed to information contained in such materials, which lead to few effective results.The authors recommend the usage of complementary FNE activity, such as reunions.33 Among all the FNE activities mentioned in the selected studies, the ones with higher repercussion were those who dealt with interaction directly with children, since they emphasize the active process that make a permanent involvement between theory and practice possible.14 The interaction, according to Dal Soto, 47 pervades the comprehension of the child as an active being and involves the possibility of discovery, transformation and production of knowledge in these educational spaces.Brigatto et al. 48indicate that it is possible to comprehend that children's games act as a transition between absolute dependence of the immediate situation, which characterizes the first years of life, and the possibility of the free thinking of real situations, which constitutes a late achievement of human development.

Scoring of quality criteria
In order to verify the effectiveness of the applied FNE activities, the questionnaires were the most frequent method of assessment, applied before and after intervention, except Baskale et al., 32 which also applied it one year after the project's execution.Nevertheless, Bizzo et al. 49 points out that in order to achieve the effectiveness of nutritional education, the child must be submitted to a constant evaluation of his/her practices and effective health indicators, during the educational process.Another aspect to be valorized would be the replanning for improvement, since a global assessment, compromised with the learning, presupposes the care, being aware of the long-term transformation. 49t was noticed that the questionnaires applied in the selected studies did not have a pattern of formulation and common structure, and, mostly, were not validated.According to Gil 50 , the questionnaire is limiting and leads to highly critical results in relation to objectivity, since the items may have different meanings for each subject and bring uncertainties about the veracity of information.Vargas et al. 51 highlights that this method should not be used in an isolated manner, since it does not provide a follow-up which is closer to the respondent.In this context, there is the possibility of the results to be underestimated or overestimated.Such fact reinforces the idea that more adequate methods to assess the FNE process should be developed and used, according to the particularities of the target public. 51he least used method was the IDQ-R found in the study conducted by Andrade et al. 31 Although IDQ-R is an effective evaluation method, it only can be applied in an intervention with diet quantification, which demands time, data tabulation, qualified professionals and resources that impair its applicability. 52t was also observed a high variability of duration in FNE activities developed in studies.However, all results were punctual and did not have reported continuity after the interventions, which may represent a limitation in this review.Another limitation of this study was the low number of included articles, due to the majority of FNE activities being applied with both preschoolers and regular students and do not present analyses separated for each population.In the face of this limitation, it is known that systematic reviews conducted with few articles and with low quality of evidence may generate an overestimated effect. 53he fact that the methodological qualification of studies was considered low may be related to the limitation of the studies included in this review, such as the design types of studies adopted by the authors, the time and lack of continuity of interventions, as well as the sample size.The mentioned limitations signal the need for investments in the execution of studies that focus on the assessment of the repercussions of FNE activities in the long-term, in the school community.
In this context, it is necessary the investment in validation of tools that allow the conduction of more robust studies in FNE assessment as a way to promote health in IE.In this manner, it will be possible the replication of these studies and their comparability, favoring the building of a consistent and elucidative theoretical framework.

Figure 1
Figure 1 Flowchart of the processof selection of articles in the systematic review concerning the promotion of adequate and healthy feeding in infant education, 2021.

1
Scale of generalization of results: any location of the world= 5; continents= 4; same country= 3; same geographic region= 2; specific population= when information was not specified within the text or did not meet the defined criteria.Source: Adapted from Vieira et al., 19 Parry et al. 20 and Taylor et al.21

Table 1
Data synthesis of the selected articles in the systematic review concerning adequate and healthy diet, 2021.