75 years of Kwashiorkor in Africa

Mechanisms of Kwashiorkor-Associated Immune Suppression: Insights From Human, Mouse, and Pig Studies

Malnutrition refers to inadequate energy and/or nutrient intake. Malnutrition exhibits a bidirectional relationship with infections whereby malnutrition increases risk of infections that further aggravates malnutrition. Severe malnutrition (SM) is the main cause of secondary immune deficiency and mortality among children in developing countries. SM can manifest as marasmus (non-edematous), observed most often (68.6% of all malnutrition cases), kwashiorkor (edematous), detected in 23.8% of cases, and marasmic kwashiorkor, identified in ~7.6% of SM cases. Marasmus and kwashiorkor occur due to calorie-energy and protein-calorie deficiency (PCD), respectively. Kwashiorkor and marasmic kwashiorkor present with reduced protein levels, protein catabolism rates, and altered levels of micronutrients leading to uncontrolled oxidative stress, exhaustion of anaerobic commensals, and proliferation of pathobionts. Due to these alterations, kwashiorkor children present with profoundly impaired immune function, compromised intestinal barrier, and secondary micronutrient deficiencies. Kwashiorkor-induced alterations contribute to growth stunting and reduced efficacy of oral vaccines. SM is treated with antibiotics and ready-to-use therapeutic foods with variable efficacy. Kwashiorkor has been extensively investigated in gnotobiotic (Gn) mice and piglet models to understand its multiple immediate and long-term effects on children health. Due to numerous physiological and immunological similarities between pigs and humans, pig represents a highly relevant model to study kwashiorkor pathophysiology and immunology. Here we summarize the impact of kwashiorkor on children's health, immunity, and gut functions and review the relevant findings from human and animal studies. We also discuss the reciprocal interactions between PCD and rotavirus-a highly prevalent enteric childhood pathogen due to which pathogenesis and immunity are affected by childhood SM.

The impact of malnutrition on childhood infections

Purpose of review

Almost half of all childhood deaths worldwide occur in children with malnutrition, predominantly in sub-Saharan Africa and South Asia. This review summarizes the mechanisms by which malnutrition and serious infections interact with each other and with children's environments.

Recent findings

It has become clear that whilst malnutrition results in increased incidence, severity and case fatality of common infections, risks continue beyond acute episodes resulting in significant postdischarge mortality. A well established concept of a ‘vicious-cycle’ between nutrition and infection has now evolving to encompass dysbiosis and pathogen colonization as precursors to infection; enteric dysfunction constituting malabsorption, dysregulation of nutrients and metabolism, inflammation and bacterial translocation. All of these interact with a child's diet and environment. Published trials aiming to break this cycle using antimicrobial prophylaxis or water, sanitation and hygiene interventions have not demonstrated public health benefit so far.

Summary

As further trials are planned, key gaps in knowledge can be filled by applying new tools to re-examine old questions relating to immune competence during and after infection events and changes in nutritional status; and how to characterize overt and subclinical infection, intestinal permeability to bacteria and the role of antimicrobial resistance using specific biomarkers.

Gut microbiota alterations and dietary modulation in childhood malnutrition - The role of short chain fatty acids

The gut microbiome affects the health status of the host through different mechanisms and is associated with a wide variety of diseases. Both childhood undernutrition and obesity are linked to alterations in composition and functionality of the gut microbiome. One of the possible mechanisms underlying the interplay between microbiota and host metabolism is through appetite-regulating hormones (including leptin, ghrelin, glucagon-like peptide-1). Short chain fatty acids, the end product of bacterial fermentation of non-digestible carbohydrates, might be able to alter energy harvest and metabolism through enteroendocrine cell signaling, adipogenesis and insulin-like growth factor-1 production. Elucidating these mechanisms may lead to development of new modulation practices of the gut microbiota as a potential prevention and treatment strategy for childhood malnutrition. The present overview will briefly outline the gut microbiota development in the early life, gut microbiota alterations in childhood undernutrition and obesity, and whether this relationship is causal. Further we will discuss possible underlying mechanisms in relation to the gut-brain axis and short chain fatty acids, and the potential of probiotics, prebiotics and synbiotics for modulating the gut microbiota during childhood as a prevention and treatment strategy against undernutrition and obesity.

Milk products in the dietary management of childhood undernutrition - a historical review

The present narrative review outlines the use of milk products in infant and young child feeding from early history until today and illustrates how research findings and technical innovations contributed to the evolution of milk-based strategies to combat undernutrition in children below the age of 5 years. From the onset of social welfare initiatives, dairy products were provided by maternal and child health services to improve nutrition. During the last century, a number of aetiological theories on oedematous forms of undernutrition were developed and until the 1970s the dogma of protein deficiency was dominant. Thereafter, a multifactorial concept gained acceptance and protein quality was emphasised. During the last decades, research findings demonstrated that the inclusion of dairy products in the management of severe acute malnutrition is most effective. For children suffering from moderate acute malnutrition the evidence for the superiority of milk-based diets is less clear. There is an unmet need for evaluating locally produced milk-free alternatives at lower cost, especially in countries that rely on imported dairy products. New strategies for the dietary management of childhood undernutrition need to be developed on the basis of research findings, current child feeding practices, socio-cultural conditions and local resources. Exclusive and continued breast-feeding supported by community-based nutrition programmes using optimal combinations of locally available complementary foods should be compared with milk product-based interventions.

Maternal profiles and social determinants of malnutrition and the MDGs: What have we learnt?

Background

Maternal socio-demographic and health profiles are important determinants of malnutrition in children. In the 1990s, malnutrition was associated with low-birth-weight, young mothers and low maternal socio-economic status at Princess Marie Louise Children’s Hospital (PML). It is not known how this has changed by efforts to achieve the Millennium Development Goals. We examined socio-demographic and health profiles of mothers of children with acute malnutrition and those without the condition to identify risk factors for malnutrition and focus on preventive efforts.

Methods

An unmatched case–control study was conducted in 2013 at PML, the largest facility for treating malnourished children in Ghana in 2013. Mothers of children with moderate and severe acute malnutrition were compared with mothers of well-nourished children. Weight-for-height was used to classify malnutrition. Record forms and a semi-structured questionnaire were used for data collection. An analysis was done with Stata 11.0 software.

Results

Altogether, 371 mothers were studied consisting of 182 mothers of malnourished children and 189 mothers of well-nourished children. Mothers of malnourished children were more likely to be unmarried or cohabiting, have lower family incomes, HIV infection and chronic disease. They were less likely to stay with or provide alternative care for their child. Awareness and use of social services, health insurance and a cash transfer programme were low. A remarkable reduction in the number of malnourished children occurred when families earned more than $250 USD a month. Over-nutrition was present in both groups of mothers.

Conclusion

Low family income, unmarried status and type of child care were the main social determinants of malnutrition. There appears to be a reduction in the number of other poor socio-demographic characteristics in both the study and control groups compared to results from a previous study at the same centre, probably because of efforts toward attaining the MDGs. These findings suggest that prevention and optimum management need to involve multidisciplinary teams consisting of health professionals, social workers and/or key workers to enable families at risk to access social care and social protection interventions (MDG 1). This will make the management of malnutrition more effective, prevent relapse, protect the next child and address maternal over-nutrition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-2853-z) contains supplementary material, which is available to authorized users.

Management of severe acute malnutrition in low-income and middle-income countries

Kwashiorkor and marasmus, collectively termed severe acute malnutrition (SAM), account for at least 10% of all deaths among children under 5 years of age worldwide, virtually all of them in low-income and middle-income countries. A number of risk factors, including seasonal food insecurity, environmental enteropathy, poor complementary feeding practices, and chronic and acute infections, contribute to the development of SAM. Careful anthropometry is key to making an accurate diagnosis of SAM and can be performed by village health workers or even laypeople in rural areas. The majority of children can be treated at home with ready-to-use therapeutic food under the community-based management of acute malnutrition model with recovery rates of approximately 90% under optimal conditions. A small percentage of children, often those with HIV, tuberculosis or other comorbidities, will still require inpatient therapy using fortified milk-based foods.