How do children with severe underweight and wasting respond to treatment? A pooled secondary data analysis to inform future intervention studies

Children with weight-for-age z-score (WAZ) <-3 have a high risk of death, yet this indicator is not widely used in nutrition treatment programming. This pooled secondary data analysis of children aged 6-59 months aimed to examine the prevalence, treatment outcomes, and growth trajectories of children with WAZ <-3 versus children with WAZ ≥-3 receiving outpatient treatment for wasting and/or nutritional oedema, to inform future protocols. Binary treatment outcomes between WAZ <-3 and WAZ ≥-3 admissions were compared using logistic regression. Recovery was defined as attaining mid-upper-arm circumference ≥12.5 cm and weight-for-height z-score ≥-2, without oedema, within a period of 17 weeks of admission. Data from 24,829 children from 9 countries drawn from 13 datasets were included. 55% of wasted children had WAZ <-3. Children admitted with WAZ <-3 compared to those with WAZ ≥-3 had lower recovery rates (28.3% vs. 48.7%), higher risk of death (1.8% vs. 0.7%), and higher risk of transfer to inpatient care (6.2% vs. 3.8%). Growth trajectories showed that children with WAZ <-3 had markedly lower anthropometry at the start and end of care, however, their patterns of anthropometric gains were very similar to those with WAZ ≥-3. If moderately wasted children with WAZ <-3 were treated in therapeutic programmes alongside severely wasted children, we estimate caseloads would increase by 32%. Our findings suggest that wasted children with WAZ <-3 are an especially vulnerable group and those with moderate wasting and WAZ <-3 likely require a higher intensity of nutritional support than is currently recommended. Longer or improved treatment may be necessary, and the timeline and definition of recovery likely need review.

Dietary intake of sulfur amino acids and risk of kwashiorkor malnutrition in eastern Democratic Republic of the Congo

BACKGROUND

Kwashiorkor is an often-fatal type of severe acute malnutrition affecting hundreds of thousands of children annually, but whose etiology is still unknown. Evidence suggests inadequate sulfur amino acid (SAA) status may explain many signs of the condition but studies evaluating dietary protein intake in relation to the genesis of kwashiorkor have been conflicting. We know of no studies of kwashiorkor that have measured dietary SAAs.

OBJECTIVES

We aimed to determine whether children in a population previously determined to have high prevalence of kwashiorkor [high-prevalence population (HPP)] have lower dietary intakes of SAAs than children in a low-prevalence population (LPP).

METHODS

A cross-sectional census survey design of 358 children compared 2 previously identified adjacent populations of children 36-59 mo old in North Kivu Province of the Democratic Republic of the Congo. Data collected included urinary thiocyanate (SCN), cyanogens in cassava-based food products, recent history of illness, and a 24-h quantitative diet recall for the child.

RESULTS

The HPP and LPP had kwashiorkor prevalence of 4.5% and 1.7%, respectively. A total of 170 children from 141 households in the LPP and 169 children from 138 households in the HPP completed the study. A higher proportion of HPP children had measurable urinary SCN (44.8% compared with 29.4%, P < 0.01). LPP children were less likely to have been ill recently (26.8% compared with 13.6%, P < 0.01). Median [IQR] intake of SAAs was 32.4 [22.9-49.3] mg/kg for the LPP and 29.6 [18.1-44.3] mg/kg for the HPP (P < 0.05). Methionine was the first limiting amino acid in both populations, with the highest risk of inadequate intake found among HPP children (35.1% compared with 23.6%, P < 0.05).

CONCLUSIONS

Children in a population with a higher prevalence of kwashiorkor have lower dietary intake of SAAs than children in a population with a lower prevalence. Trial interventions to reduce incidence of kwashiorkor should consider increasing SAA intake, paying particular attention to methionine.

Difference between kwashiorkor and marasmus: Comparative meta-analysis of pathogenic characteristics and implications for treatment

Kwashiorkor and marasmus are two clinical syndromes observed in severe acute malnutrition. In this review, we highlighted the differences between these two syndromes by reviewing the data comparing kwashiorkor and marasmus in literature, combined with recent microbiological findings and meta-analysis. Depletion of antioxidants, vitamins and minerals were more severe in kwashiorkor than marasmus. This was consistent with the severe and uncontrolled oxidative stress associated with the depletion of gut anaerobes and the relative proliferation of aerotolerant gut pathogens. This relative proliferation and invasion of gut microbes belonging to the aerotolerant Proteobacteria phylum and pathogens suggested a specific microbial process critical in the pathogenesis of kwashiorkor. Liver mitochondrial and peroxisomal dysfunction could be secondary to toxic microbial compounds produced in the gut such as ethanol, lipopolysaccharides and endotoxins produced by Proteobacteria, particularly Klebsiella pneumoniae, and aflatoxin produced by Aspergillus species. The gut-liver axis alteration is characterized by oedema and a fatty and enlarged liver and was associated with a dramatic depletion of methionine and glutathione, an excessive level of free circulating iron and frequent lethal bacteraemia by enteric pathogens. This was consistent with the fact that antibiotics improved survival only in children with kwashiorkor but not marasmus. The specific pathogenic characteristics of kwashiorkor identified in this review open new avenues to develop more targeted and effective treatments for both marasmus and/or kwashiorkor. Urgent correction of plasma glutathione depletion, alongside supply of specific essential amino acids, particularly methionine and cysteine, early detection of pathogens and an antibiotic more efficient than amoxicillin in supressing gut Proteobacteria including K. pneumoniae, and probiotics to restore the human gut anaerobic mature microbiota could save many more children with kwashiorkor.

Immunometabolism: new insights and lessons from antigen-directed cellular immune responses

Modulation of immune responses by nutrients is an important area of study in cellular biology and clinical sciences in the context of cancer therapies and anti-pathogen-directed immune responses in health and disease. We review metabolic pathways that influence immune cell function and cellular persistence in chronic infections. We also highlight the role of nutrients in altering the tissue microenvironment with lessons from the tumor microenvironment that shapes the quality and quantity of cellular immune responses. Multiple layers of biological networks, including the nature of nutritional supplements, the genetic background, previous exposures, and gut microbiota status have impact on cellular performance and immune competence against molecularly defined targets. We discuss how immune metabolism determines the differentiation pathway of antigen-specific immune cells and how these insights can be explored to devise better strategies to strengthen anti-pathogen-directed immune responses, while curbing unwanted, non-productive inflammation.

Nutrition rehabilitation of children with severe acute malnutrition: Revisiting studies undertaken by the National Institute of Nutrition

Severe acute malnutrition (SAM) in children under five years is an important public health problem due to associated high mortality and long-term health consequences. Research on the dietary causes of SAM, especially the role and relative importance of dietary protein, in the aetiology of oedematous malnutrition, has led to considerable debates and controversies. The present article revisits some of the debates in this field, where the researchers at the National Institute of Nutrition (NIN), Hyderabad, India, with their pioneering work, have contributed to the global literature on the various facets of the disease. Highlighting the importance of energy as a bigger problem than protein malnutrition is a noteworthy contribution of NIN's research. It is, however, important to examine the protein quality of the diets in light of the new information on the lysine requirements. The article argues that the currently dominating hypothesis of free radical theory requires a critical review of the supporting evidence. Over the past few decades, the research has focused on low-cost diets using locally available foods. The article also argues that solutions based on local foods, being acceptable and sustainable, need to be strengthened for their effective delivery through the existing nutrition programmes. Recent evidence shows that the use of ready-to-use therapeutic foods (RUTF) with high micronutrient density may be linked with higher mortality possibly due to the high iron content, which could be counterproductive. There are several unaddressed concerns regarding the potential long-term impact of consumption of RUTF in children with SAM. More evidence and a cautious approach are, therefore, needed before implementing these solutions.

Microbiome, growth retardation and metabolism: are they related?

CONTEXT

Despite an improvement in food security and the delivery of nutritional supplements to children living in impoverished parts of the world, poor growth is still highly prevalent. Given that the microbiome is related to both nutrient absorption, as well as overweight/obesity, it may play a central role in limiting or modifying normal growth processes while contributing to chronic disease risks.

OBJECTIVE

The objective of this paper is to describe normal growth processes, the role of the microbiome in supporting or disrupting normal growth processes, and its potential impact on long-term health.

METHODS

A literature search of relevant human and laboratory research on growth, microbiome and the relationship between poor growth and chronic diseases was conducted. This review focuses on potential mechanisms that implicate the microbiome as a mediator of poor growth and later metabolic outcomes. In this relationship, attention was given to the potential for gastrointestinal infections to disrupt the microbiome.

RESULTS

Based on the studies reviewed, it is clear that exposure to infections disturbs both intestinal functioning as well as normal growth and changes in the microbiome may influence micronutrient availability and metabolic processes.

CONCLUSIONS

The microbiome may play a significant role in limiting human growth, but little is known about changes in the microbiome during periods of undernutrition. Thus, it is of great scientific and public health importance to improve the understanding of how the microbiome changes during nutrient deprivation. To best address the issue of the double burden and poor growth in low-income countries, research is warranted to advance the knowledge of the long-term role of the microbiome in the health of children exposed to undernutrition.

Investigation of the nutrition problems of Central America and Panama

From its earliest years, INCAP gave a high priority to a multidisciplinary effort to learn as much as possible about the dietary habits, nutritional status, and their consequences in the populations of Central America and Panama. Most of the papers in this Special Issue contain some of this information. The first studies were in schoolchildren but were soon extended to preschool children, pregnant and lactating women, and other adults. This paper describes the principal findings of the initial dietary, biochemical, and clinical community-based studies. From 1965-67, very extensive studies were carried out in all six countries including dietary, biochemical, clinical, and anthological studies were carried out in all six countries, the results of which are summarized.

Reflections on the legacy of INCAP

The second Director of the Institute of Nutrition of Central America and Panama (INCAP) reminisces about the productive program of valuable and practical research at the highest level developed with local personnel in a small and poor developing region. The same was true for the world-class advanced training program that contributed many hundreds of professionals, not only to the region, but to all of Latin America and to other countries. The major contributions of INCAP in its first 25 years are cited along with reasons for its success.

INCAP Studies of Nutrition and Infection

As soon as the Institute of Nutrition of Central America and Panama (INCAP) began to study the poor nutritional status and stunting of children in the rural villages of Central America, it was apparent that infections, particularly diarrheas, were also a serious problem. Studies of kwashiorkor indicated that infections precipitated kwashiorkor and anemia in children who were already malnourished. In the 1940s there was almost no suggestion in the literature of a relation between nutrition and infection. INCAP gradually identified the mechanisms by which any infection worsens nutritional status and demonstrated that infections were more severe and more often fatal in malnourished children and adults. These studies ultimately led to the 1968 World Health Organization (WHO) monograph “Interactions of nutrition and infection” and widespread recognition by public health workers of the importance of this relationship for morbidity and mortality in poorly nourished populations.

Diet and Chronic Diseases: INCAP Studies of Atherosclerosis and Coronary Heart Disease

This paper describes early INCAP studies showing that cholesterol and lipoprotein levels were much lower in the low-income populations of Central America than values that were just beginning to emerge from industrialized countries. These led to the collection of aortas and coronary vessels from 14,610 males and 7,906 females from serial autopsies from 12 public general hospitals in developing countries, mostly in Latin America and in New Orleans and Oslo. The severity of atherosclerotic lesions in the samples was evaluated independently by four pathologists after the samples were randomized, who determined that the severity of atherosclerosis progressed so slowly in the developing country samples that it rarely became clinically significant. The strongest correlation with the severity of lesions was the fat content of the diet.