Effect of Dietary Supplementation and High-Intensity Motor Learning on Nutritional Status, Body Composition, Muscle Strength, and Motor Skill-Related Physical Fitness in 5-7-Year-Old Children with Moderate Thinness in Ethiopia

Abstract

Background: Despite global efforts, child malnutrition remains a persistent challenge, exacerbating disparities and posing ongoing threats to children and adolescents in developing nations. Malnutrition refers to an inadequate or imbalanced intake of essential nutrients, encompassing both undernutrition and overnutrition. Undernutrition is characterized by an inadequate intake of essential nutrients, resulting in deficiencies. Thinness has been recognized as a more suitable indicator of recent nutritional deprivation, such as insufficient dietary intake of energy, protein, or various micronutrients. Undernutrition is characterized by stunting and thinness. Stunting refers to being short relative to one's age, while underweight is defined in terms of grades of thinness (grades 1–3) and is characterized by rapid weight loss or an inability to gain body mass. Both conditions are linked to poor school attendance and academic performance in mathematics, reading, and writing skills. Additionally, sick or undernourished children often face difficulties with motor function, concentration, problem-solving, and memory recall, all of which contribute to poor academic performance. Undernutrition among schoolchildren in developing countries is a critical global health challenge with far-reaching consequences for their well-being and future opportunities. Nutritional deficiencies during early childhood can lead to poor brain development. Long-term undernutrition can negatively impact academic performance, leading to chronic disorders, hindering cognitive development, and even causing premature death. Addressing both undernutrition and overnutrition among children aged 5–7 presents a significant challenge for the food and nutrition policies in developing countries like Ethiopia. This age group represents a critical developmental stage marked by key growth and developmental milestones and the development of motor skills. Catch-up growth is particularly important for children with moderate thinness (MT), as they may face developmental delays that could impact their long-term health and well-being. This age is also critical for motor skill interventions as it coincides with significant brain development that is closely linked to cognitive and behavioral growth during preschool years. In Ethiopia, however, MT children aged 5-7 are often overlooked due to the absence of specific treatment guidelines for MT. To address this, the management of acute malnutrition should focus on preventing the progression of MT to severe thinness (ST). To effectively manage MT and prevent its progression to ST, appropriate dietary interventions are essential. This includes providing nutrient rich supplementary food or lipid-based Ready-to-Use Supplementary Food (RUSF) tailored to meet the needs of children with MT. In addition to proper nutrition, motor skill training (high-intensity motor learning (HiML)) interventions significantly enhance motor skill development in typically developing children. HiML is very intensive as it is performed daily over an extended period, requiring a minimum of 30–40 hours of training. The focus is on maximizing time spent on the task during training, with a training/rest ratio of at least 70–30%. Active play, which involves repetitive muscle movements that help build strength, speed, and agility, contributes to the development of both gross and fine motor skills. Furthermore, existing literature on active play or goal-oriented play among preschoolers and early school-aged children demonstrates its positive impact on motor skills. Activities such as ball play, balancing exercises, walking, running, and jumping, or hopping have been shown to improve coordination and physical abilities, reinforcing the importance of integrating both nutrition and physical activity in early childhood development programs. Therefore, the main aim of this study was to evaluate the effect of RUSF with(out) HiML compared to no intervention on various outcomes, including weight, height, body composition, muscle strength, and motor skill-related physical fitness of children with MT age 5-7 living in Jimma, South-West Ethiopia. A summary of each chapter of this dissertation is provided below. Chapter 1 is an introduction providing an overview of malnutrition. It begins by defining undernutrition and moderate thinness, discussing their common drivers and consequences. The chapter also presents malnutrition's global, regional, and national status, highlighting its prevalence x and public health significance. Additionally, the chapter identifies gaps or areas that previous studies had not adequately addressed concerning moderate thinness. By providing this comprehensive introduction, the first chapter gives a context for the subsequent chapters of the dissertation, which will dive deeper into specific aspects of moderate thinness and its implications. Chapter 2 outlines the general methods used in the study, including the study design, period, setting, and population, inclusion and exclusion criteria for participant selection, the sampling strategy, and the sample size calculations. Furthermore, it elaborates on the data collection methods and procedures, the specific tools or instruments used, data management procedures including data entry, storage, and quality control measures, and information on statistical tests or analytical techniques used to examine the study variables and assess the outcomes of interest. It also elaborates on the intervention packages implemented in the study, providing an overview of the specific interventions or treatments administered to the participants and key measures or indicators used to assess the outcomes under investigation. Ethical considerations are emphasized in this chapter, highlighting the steps taken to ensure the protection of participants' rights and well-being. Chapter 3 presents the findings of a school-based comparative cross-sectional study carried out in Jimma Town. The study compared the body composition of 5-7-year-old children with MT to that of their well-nourished (WN) peers and identified associated factors. Data were collected from 388 children (194 with MT and 194 with WN). The finding showed that, on average, moderately thin children had significantly lower fat mass and fat-free mass compared to well-nourished children, indicating malnutrition-related loss in both compartments. Body mass index (BMI) for age, age, and sex were significantly associated with both fat-free mass and fat mass. Chapter 4 presents the findings of a study that investigated the relationship between MT and muscle strength in children aged 5-7 years in Jimma Town, Southwest Ethiopia. Conducted as a school based comparative cross-sectional study between June and July 2022, the study assessed children's nutritional status (MT vs. WN) using BMI for age and sex. Muscle strength was evaluated by measuring grip strength with a JAMAR device, and biceps, quadriceps, and gastrocnemius strength were measured using Digital Handheld Dynamometry model (Hoggan MicroFET2™). The result revealed that children with MT had significantly lower muscle strength compared to their WN peers, highlighting the negative functional effect of wasting. These findings underscore the importance of integrating strategies to improve muscle strength into routine health care for children with MT. Chapter 5 presents the result of a systematic review and meta-analysis on the effectiveness of RUSF compared to other dietary interventions or no intervention on functioning at different levels of the International Classification of Functioning, Disability, and Health (ICF) among children with MT between 2 -12 years old. Eight studies were included in the analysis. The use of RUSF intervention shows promise in improving nutritional outcomes and recovery rates in children with MT compared to other dietary interventions. However, the low level of evidence highlights the need for robust randomized controlled trials in MT children to determine the true effect of RUSF. Chapter 6 presents the findings of a cluster-randomized controlled trial that examined the effect of Ready-to-Use Supplementary Food (RUSF), with or without high-intensity motor learning (HiML), on weight, height, body composition, and muscle strength in 5–7-year-old children with MT in Jimma Town, Ethiopia. The study found that RUSF was effective on its own, but when combined with HiML, it had an even greater impact. Both the RUSF and RUSF+HiML interventions led to improvements in body composition, height, weight, and muscle strength of malnourished children. These findings suggest that using RUSF and combining it with HiML could help mitigate the negative effects of malnutrition in Ethiopia. The researchers recommend further exploration of these interventions in a larger community-based study. Chapter 7 presents the results of a cluster-randomized controlled trial that assessed the effect of RUSF with or without HiML on motor skill-related physical fitness in children with MT. A 12-week combination of RUSF + HiML was proven to be safe in children with MT and caused clear improvements in skill-related physical fitness. When the children received RUSF with HiML training, xi similar gains were observed in stepping, side jumping, standing long jump, and jumping and hopping, except for the ball skills, where the HiML training group performed better. Chapter 8 discusses the main findings, strengths, and limitations of the studies and provides conclusions, future research directions, and policy, methodological, and practical implications. It highlights the significance of the findings in relation to the research objectives, addresses the strengths of the methodology, and acknowledges the study's limitations. The chapter also explores potential improvements in research design, sample size, and data collection techniques. Finally, it offers practical recommendations for translating the findings into effective strategies to mitigate moderate thinness and its drivers among children aged 5 to 7 years.