Gut Microbiota-Targeted Nutritional Interventions Improving Child Growth in Low- and Middle-Income Countries: A Systematic Review

Cereal-based fermented foods as microbiota-directed products for improved child nutrition and health in sub-Saharan Africa

Several strategies, programs and policies have long been developed and implemented to alleviate child malnutrition in sub-Saharan African countries. However, stunting and wasting still persist at an alarming rate, suggesting that alternative strategies are needed to induce faster progress toward the 2030 SDGs targets of reducing malnutrition. Gut microbiota-directed intervention is now being recognized as an unconventional powerful approach to mitigate malnutrition and improve overall child health. In an African setting, manufactured probiotic and synbiotic foods or supplements may not be successful owing to the non-affordability and high attachment of African populations to their food tradition. This review analyses the potential of indigenous fermented cereal-based products including porridges, doughs, beverages, bread- and yoghurt-like products, to be used as microbiota-directed foods for over 6 months children. The discussion includes relevant strategies to effectively enhance the beneficial effects of these products on gut microbiota composition for improved child health and nutrition in sub-Saharan Africa. Characterization of probiotic features and general safety of food processing in sub-Saharan Africa as well as randomized clinical studies are still lacking to fully ascertain the health effects and suitability of these fermented foods in preventing and treating child malnutrition and diarrhea.

Stunting and Gut Microbiota: A Literature Review

Stunting, a condition characterized by impaired growth and development in children, remains a major public health concern worldwide. Over the past decade, emerging evidence has shed light on the potential role of gut microbiota modulation in stunting. Gut microbiota dysbiosis has been linked to impaired nutrient absorption, chronic inflammation, altered short-chain fatty acid production, and perturbed hormonal and signaling pathways, all of which may hinder optimal growth in children. This review aims to provide a comprehensive analysis of existing research exploring the bidirectional relationship between stunting and the gut microbiota. Although stunting can alter the gut microbial community, microbiota dysbiosis may exacerbate it, forming a vicious cycle that sustains the condition. The need for effective preventive and therapeutic strategies targeting the gut microbiota to combat stunting is also discussed. Nutritional interventions, probiotics, and prebiotics are among the most promising approaches to modulate the gut microbiota and potentially ameliorate stunting outcomes. Ultimately, a better understanding of the gut microbiota-stunting nexus is vital for guiding evidence-based interventions that can improve the growth and development trajectory of children worldwide, making substantial strides toward reducing the burden of stunting in vulnerable populations.

Growth Patterns of 11-29-Month-Old Children Consuming Young Child Formula: Secondary Analysis of a Randomized, Controlled Study

INTRODUCTION

The impact of young child formula (YCF) consumption on children's growth, particularly under suboptimal conditions, has scarcely been studied. In the current study, weight-for-age (WAZ), length-for-age (LAZ), and BMI-for-age (BAZ) z-score development was evaluated in children from five different countries (n = 668) who participated in a double-blind, randomized, controlled trial.

METHODS

The children (1-3 years old) were randomized to one of two intervention YCFs (with presence or absence of prebiotics and n-3 LCPUFAs) during 52 weeks of intervention. Additional stratified analyses evaluated the growth patterns of underweight, overweight, or stunted children.

RESULTS

No apparent differences in anthropometric measurements were observed between the intervention groups. In both YCF intervention groups, mean WAZ, LAZ and BAZ development was indicative of adequate growth during the intervention period. Stratified analyses showed stable WAZ and BAZ development among children with a healthy weight or overweight at baseline. Among underweight and stunted children, normalization in mean weight (∼1 SD) and length (∼0.8 SD) gain, respectively, was observed.

CONCLUSION

The current study suggests that consumption of YCF, either or not containing prebiotics and n-3 LCPUFAs, is associated with adequate growth among young children. This association may depend on the child's baseline nutritional status. Future studies to assess the potential role of YCF in supporting adequate weight/length gain among children at risk for undernutrition are warranted.

Gut Microbiome-Targeted Nutrition Interventions and Growth among Children in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

Background

Childhood malnutrition is a public health challenge of much interest and concern globally. However, a perturbed gut microbiome (GM) may limit some nutrition interventions' effects among healthy children with undernutrition.

Objectives

This review aimed to evaluate the effects of GM-targeted nutrition interventions on growth outcomes among children (0-59 mo) using published studies in low- and middle-income countries.

Methods

The methods were guided by the Cochrane methodology. The literature search was conducted to include articles published from inception to July 2023 in PubMed, Google Scholar, and Cochrane Databases. We identified and included 35 studies among 11,047 children. The analysis was conducted considering various growth parameters in the qualitative synthesis and weight gain (kg) in the meta-analysis.

Results

In the qualitative synthesis, 55.6% of prebiotics, 66.7% of probiotics, 71.4% of synbiotics, and 28.6% of "microbiome complementary feed" studies had significant effects on growth outcomes. Also, prebiotics had more studies with significant effects among healthy children, whereas probiotics, synbiotics, and "microbiome complementary feeds" had more studies with significant effects among children with undernutrition. Nineteen studies were included in the meta-analyses, of which 7 (36.8%) measured GM outcomes. The meta-analysis showed that prebiotics exhibited heterogeneity but had significant effects on weight in the intervention as compared with the control (mean difference [MD]: 0.14 kg; 95% CI: 0.02, 0.25; I2 = 63%, P = 0.02; 4 studies, n = 932). Probiotics had significant effects on weight in the intervention (MD: 0.15 kg; 95% CI: 0.06, 0.25; I2 = 42%, P = 0.05; 8 studies, n = 2437) as compared to the control. However, synbiotics (MD: 0.26 kg; 95% CI: -0.04, 0.56; I2 = 41%, P = 0.17; 4 studies, n = 1896] and "microbiome complementary feed" (MD: -0.03 kg; 95% CI: -0.18, 0.11; I2 = 0%, P = 0.60; 3 studies, n = 733] had no significant effects on weight in the intervention as compared with control.

Conclusions

Although probiotics and synbiotics may be effective at enhancing growth among children, the selection of interventions should be contingent upon health status.This trial was registered at www.crd.york.ac.uk/prospero/ as CRD42023434109.

The Effects of Yogurt Supplementation and Nutritional Education on Malnourished Infants: A Pilot RCT in Dhaka's Slums

Our objective was to quantify the effects of yogurt supplementation and nutrition education over three months on the linear growth of infants at risk of stunting. We conducted a three-arm pilot randomized controlled trial: (1) nutrition education for mothers; (2) nutrition education plus a daily yogurt supplement (50 g) for the index child; and (3) usual care (control). Dyads of children aged 4-6 months and at risk of stunting [length-for-age z-score (LAZ) ≤ -1 SD and >-2 SD] and their mothers with ≤10 years of education were eligible for the study. Participants were recruited from five slum areas in Dhaka, Bangladesh. Intention-to-treat (N = 162) and complete-case analyses (N = 127) showed no between-group statistically significant differences in LAZ or weight-for-age (WAZ). However, the yogurt group showed greater change in linear growth compared to the control (LAZ: mean difference 0.20, 95% CI: -0.06, 0.47, p-value 0.13), which was also slightly greater than the education-only group. Children in the yogurt plus group were five times (95% CI: 0.80, 31.80, p-value 0.09) more likely to meet the minimum dietary diversity (MDD) score compared to the control. A 3-month follow-up of this pilot study did not demonstrate that yogurt was beneficial to linear growth. However, there were encouraging trends that merit replication of the intervention with larger samples and longer follow-ups.

Dietary Component-Induced Inflammation and Its Amelioration by Prebiotics, Probiotics, and Synbiotics

A balanced diet with many dietary components maintains immune homeostasis directly by interacting with innate and adaptive immune components or indirectly through gut microbiota and their metabolites. Dietary components may inhibit pro-inflammatory mediators and promote anti-inflammatory functions or vice versa. Western diets with imbalanced dietary components skew the immune balance toward pro-inflammation and induce intestinal inflammation, consequently leading to many intestinal and systemic inflammatory diseases like ulcerative colitis, Crohn's disease, irritable bowel syndrome, cardiovascular problems, obesity, and diabetes. The dietary component-induced inflammation is usually chronic in nature and frequently caused or accompanied by alterations in gut microbiota. Therefore, microbiome-targeted therapies such as probiotics, prebiotics and synbiotics hold great potentials to amend immune dysregulation and gut dysbiosis, preventing and treating intestinal and systemic inflammatory diseases. Probiotics, prebiotics and synbioitcs are progressively being added to foods and beverages, with claims of health benefits. However, the underlining mechanisms of these interventions for preventing and treating dietary component-induced inflammation are still not very clear. In addition, possibly ineffective or negative consequences of some probiotics, prebiotics and synbiotics call for stringent testing and regulation. Here, we will first briefly review inflammation, in terms of its types and the relationship between different dietary components and immune responses. Then, we focus on current knowledge about the direct and indirect effects of probiotics, prebiotics and synbiotics on intestinal and systemic inflammation. Understanding how probiotics, prebiotics and synbiotics modulate the immune system and gut microbiota will improve our strategies for preventing and treating dietary component-induced intestinal inflammation and inflammatory diseases.