1. Introduction
Nutritional problems are still a serious and vital issue (Taki, 2018). Malnutrition is the cause of one-third of child deaths in the world (WHO team, 2020). Undernutrition and overnutrition are still problems that must be addressed (Huizar, Arena, and Laddu, 2021). Nutrition is a significant and fundamental issue in human life. Malnutrition can cause health problems (morbidity, mortality, and disability) and reduce the quality of human resources of a nation (Saunders and Smith, 2010). Nutritional problems are different from disease problems, meaning that the state of malnutrition does not occur suddenly. A healthy child’s status to malnutrition takes a minimum of 3 to 6 months, characterized by insufficient weight gain. Several factors can affect nutritional status, including physical conditions (Shrestha et al., 2020), disease or infection (Suchdev et al., 2014), medication (Fisher and Swift, 2015), nutritional intake (Galgamuwa et al., 2017), physical activity (Akdemir, Donmez, and Polat, 2017), the role of cadres (Community Health Workers), parenting patterns, and parents’ feeding styles (Hidayat, Marini and Tyas, 2020).
The establishment of good eating practices that begins in infancy will impact lifelong nutritional habits and overall health. Children acquire the motor skills needed to feed themselves and develop preferences that influence their food choices during this period. Classifications for the low weight (also called stunted growth or failure to thrive) and overweight are based on the World Health Organization (WHO) child growth standards for children under two years of age and growth charts by the CDC (the Centers for Disease Control and Prevention) for children two years and older (Riley, Rupert, and Boucher, 2018).
Parenting plays a role in the nutritional status of children. One of the parenting patterns related to the nutritional status of children is the pattern of feeding. Children’s feeding patterns are always related to feeding activities which will ultimately contribute to their nutritional status. The practice of feeding children has a decisive role in child nutrition. Feeding children and eating habits in the family have a considerable impact, and children usually follow what their parents and siblings eat (Istiany, 2019).
Food parenting refers to specific behaviors, or rules parents use to control what, how much, or when their child eats, whereas parent feeding styles are defined as general parent-child interactions across food-related situations (Hersch et al., 2014). Parents are responsible for modeling healthy food choices and dietary practices, shaping children’s food preferences and eating behaviors. Parents should avoid practices that lead to overeating in toddlers (e.g., feeding to calm or put the child to sleep, giving excessive portions, encouraging the child to “clean his plate,” punishing with food, force-feeding, allowing frequent snacking). Generally, parents should use approaches such as “parents provide, the child decides,” where parents provide healthy food choices, and children choose which foods to eat and how much (Riley, et al., 2018).
Increasing parents’ knowledge and awareness of nutritional assistance for toddlers are essential because they play an essential role in meeting the nutritional needs of their children and preventing the risk of malnutrition. Thus, parents should be provided with appropriate educational intervention. Several studies have been conducted regarding the model of parental education as the most responsible party for meeting the nutritional needs of toddlers. This review explored effective education models applied to increase parents’ knowledge and awareness of nutritional assistance for toddlers through published articles.

2. Materials and Methods
Review protocol 
This systematic review was conducted using PRISMA (the Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement (Moher et al., 2009) in the time frame between January 2010 to December 2021 and sought to answer the question of “which educational models increase parents’ knowledge and awareness of nutritional assistance to toddlers?” PICO format (Patient, Intervention, Comparison, Outcome) was used to ask a focused question in quantitative studies. 

Sources of information and search strategies
International electronic databases, including PubMed, ScienceDirect, Web of Science, Cochrane, and Wiley online library, were searched for articles published from 2021 to 2010. The keywords were selected based on the Medical Subject Headings (MeSH) standard. Boolean operators and a combination of keywords were used, including (“parenting education”[MeSH Terms] OR “parents”[MeSH Terms] AND (“nutritional intakes”[MeSH Terms] OR “nutrition disorder, infant”[MeSH Terms] OR “infant nutrition”). These keywords are mainly used in PubMed. Meanwhile, for search on ScienceDirect and Cochrane, the keywords were “Improving,” “Parent Knowledge,” and “Infant Nutrition Assistance.” 

Eligibility criteria
The selected articles (quantitative and qualitative) met the following criteria: 1) they were performed on parents of infants, 2) evaluated the structured form of education for child nutrition assistance, 3) quasi-experimental studies that presented the results of structured interventions, 4) explored the concept of parental education for child nutrition, 5) were in English, and 6) had a sample of more than 20 participants. In addition, review articles, editorials, comments, full texts, case reports, and meta-analytical or systematic review articles were excluded from this review study. Eligibility criteria were according to PICOS (population, intervention, comparison, outcome, and study design). 
Population: Parents of toddlers with a minimum sample of 20. Studies with a sample below 20 were excluded from the study.
Intervention: interventions on nutrition, healthy eating/diet, dietary intake, anemia, fruits, and vegetables were included in the study. 
Comparison: A comparison group with no intervention or other trial interventions was included (for experimental studies). 
Outcome: Studies with knowledge or attitude or practice or awareness as the study outcome were included. 
Study design: Quasi-experimental, randomized controlled trials/clustered randomized control trials, correlational studies, and qualitative studies were included. Studies that did not mention these designs were excluded.
Studies with irrelevant titles, not available (only abstract), literature reviews, systemic reviews, books, conference proceedings, reports, thesis, and case studies were excluded from this review. 

Data extraction and quality assessment
The two authors (RM, EN) independently extracted the data from studies that met the inclusion criteria. The obtained data were synthesized in two ways: 1) research design and intervention strategies were presented, and 2) the findings of each study were analyzed qualitatively by collecting the main findings with the design and intervention applied. Furthermore, data extraction was carried out to provide a brief description of the articles’ substance, such as the characteristics of the respondents and the characteristics of the study. The extracted data included author, year, location, sample population, study design, and the intervention method (Table 1).

The researchers then examined each extracted study, and any discrepancies were discussed until a consensus was reached.
The quality of the included quantitative articles was measured using an assessment tool for the Effective Public Healthcare Panacea Project (EPHPP), which allows experts to apply this tool to articles on any public health topic. This tool uses strong, moderate, and weak categorizations based on the assessment results of eight components: selection bias, study design, confounders, blinding, data collection methods, withdrawals, dropouts, intervention integrity, and analyses. Articles in the strong category are the articles that gained four strong components from the EPHPP components without any weak component; the category is considered moderate if four components are rated strong and one component weak, and the weak category is given if two or more components reach a weak value (Berghs et al. 2016) (Table 2).

Critical appraisal of qualitative studies was performed using the McMaster Critical Review Form for qualitative studies (v2.0) (Letts L. et al., 2007) (Table 3).

3. Results
Search results 
Search results from five databases yielded 842 articles according to the keywords applied. Duplicates (563 articles) were eliminated, leaving 279 articles. The screening stage was carried out on the remaining articles. Next, 253 articles were excluded because they did not discuss the parents’ nutritional assistance for the toddler. At the end of the screening, seven articles met the inclusion criteria (Figure 1).

These articles were included in the moderate and strong categories based on the EPHPP assessment tool for article quality assessment. The process of identifying and screening articles was done using the Mendeley Reference Manager to eliminate duplicate articles. 

Study characteristics
The articles reviewed in this study were conducted in several countries such as Indonesia (Sukandar et al., 2015; Mitra et al., 2020), the USA (Reznar et al., 2014; Whiteside-Mansell and Swindle, 2017), Uganda (Moon et al., 2020), Tanzania (Kulwa et al., 2014), and Turkey (Göbel et al., 2021). The study designs used by the included articles were quasi-experimental (Sukandar et al., 2015; Mitra et al., 2020; Moon et al., 2020; Göbel et al., 2021), randomized control trial (Kulwa et al., 2014), cross-sectional (Whiteside-Mansell and Swindle, 2017), and qualitative (Reznar et al., 2014).

Intervention Characteristics
In this review, the articles used different educational methods, such as lectures (Kulwa et al., 2014; Sukandar et al., 2015; Mitra et al., 2020; Moon et al., 2020; Göbel et al., 2021), playing cards (Mitra et al., 2020), counseling (Kulwa et al., 2014), role playing (Mitra et al., 2020), social media (a Facebook group) (Whiteside-Mansell and Swindle, 2017), and Booklet (Reznar et al., 2014). The duration of the intervention varied from 2 weeks to 9 months. The educational session took 10 to 180 minutes in the included articles.
Topics in the articles were not only about nutritional education, and some articles expanded the topics to breathing and respiratory problems, family planning, HIV, diarrhea (Moon et al., 2020), home food environment, food modeling, praise and encouragement, making mealtime fun, and how to handle difficult behaviors (Reznar et al., 2014), growth and development, exclusive breastfeeding (Mitra et al., 2020), breastfeeding, complementary feeding, selection and preparation of locally available foods, feeding during illness, healthcare-seeking, hygiene, and home environment sanitation (Kulwa et al., 2014), parenting tips, and cost savings idea (Whiteside-Mansell and Swindle, 2017), malnutrition problems (Sukandar et al., 2015), and healthy eating (Göbel et al., 2021).

Evaluation strategy and outcomes
The studies’ evaluation of the effectiveness of parent education programs was carried out using various measures, both qualitatively and quantitatively, which had been adapted to the features and processes of the program (e.g., pretest and posttest based on questionnaires and interviews). Regardless of the outcome measures, there were positive gains and improvements for parents in various functions such as parenting competence and post-program nutritional problem-solving skills. Several evaluation methods were carried out, including pretest and or posttest using a questionnaire (Reznar et al., 2014; Sukandar et al., 2015; Mitra et al., 2020; Moon et al., 2020; Göbel et al., 2021), supervision (Kulwa et al., 2014), and posting responses (e.g., views, comments, and like) (Whiteside-Mansell and Swindle, 2017).
Among the outcomes of the studies were knowledge (Reznar et al., 2014; Mitra et al., 2020; Moon et al., 2020; Göbel et al., 2021), KAP (knowledge, attitude, practice) (Kulwa et al., 2014; Sukandar et al., 2015), and perception (Whiteside-Mansell and Swindle, 2017).

4. Discussion
The present systematic review identified the interventions designed to improve parents’ knowledge and awareness in assisting the nutritional status of toddlers and determined whether some strategies were more effective than others.
In a previous review, Peters et al. (2012) highlighted a dearth of quality intervention research with parents of preschoolers that attempt to address and promote specific parenting practices and skills that may optimize healthy diets in young children. In particular, intervention design should focus on implementing and evaluating specific parenting practices that may complement nutrition education and empower children to develop and instill healthy eating habits. Our review focused on the studies that reported strategies to improve the knowledge and awareness of parents as a basis for good practice in their children’s nutritional status. This review provided an overview of the studies carried out in both high and lower-middle income countries. The results of this review can provide answers to previous review studies that focused only on developed countries (Charles Shapu et al., 2020), as well as previous review studies that focused on developing countries only (Salam et al., 2014). The effectiveness of the intervention in this review also concurs with other health education interventions regarding the knowledge, attitudes, and practices regarding the health of the mother and infants (Imdad, Yakoob, and Bhutta, 2011).  
Insufficient knowledge and non-nutritional behavior of families directly influence the feeding of preschool-age children and toddlers and lead to problems such as obesity, weakness, and developmental retardation (Şanlıer, 2013). At this age, most children undergo preschool education, which is an opportunity to develop age-specific nutritional behavior. A meta-analysis concluded that school-based nutrition education interventions effectively reduce the body mass index (BMI) of children and adolescents (da Silveira et al., 2013). Nurses and other health professionals working with parents of young children should discuss with the parents the importance of healthy food choices and appropriate eating environments. Parents need knowledge about feeding toddlers healthily, such as appropriate serving sizes and the need to taste a new food often. Parents should understand that a child-size portion is much smaller than the amounts served to adults. 
Limited access to several primary databases was a significant obstacle that affected the literature search results. It is suggested that future research explore more extended time frames using more databases.

5. Conclusion
Health and nutrition education interventions to increase parents’ knowledge and awareness of nutritional assistance for toddlers demonstrated variable success. The evidence presented in this review has identified characteristics that may contribute to the effectiveness of interventions in increasing parents’ knowledge and awareness of nutritional assistance for toddlers. The overall evidence from this review reveals the need to improve the standards and procedures in intervention design in randomized controlled trials to improve their effectiveness.

Ethical Considerations
Compliance with ethical guidelines
All listed authors have made a valuable contribution to the process and approved the final manuscript. ‘Guest authorship’ and ‘ghost authorship’ were avoided. Redundant (duplicate) publications were excluded. Data were extracted independently by two authors, and any discrepancies were resolved. Also, the decision on which data to include is agreed upon by all authors.

Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Authors' contributions
Conceptualization and Investigation: Rusmimpong Rusmimpong, Asni Johari, Intan Intan, Guspiyanto Guspiyanto; Data collection: Rusmimpong Rusmimpong, Asni Johari; Writing-original draft: Asni Johari, Guspiyanto Guspiyanto; Writing – review & editing: All authors.

Conflict of interest
The authors declared no competing interests.

Acknowledgments
We express our gratitude to the director of Jambi University for support in implementing this research and to the President of Jambi University, Indonesia.


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