It is a pleasure to introduce this special issue on nutrition and malnutrition in low- and middle-income (LMI) countries. We are very grateful to all the contributors who have helped to cover such a wide spectrum of the subject, and to Andrew Tomkins for writing the editorial.
Elizabeth Poskitt describes the epidemiology and aetiology of obesity and highlights the epidemic in LMI countries, many of which are in nutritional transition. This transition first manifests itself as maternal over-nutrition and at the same time child under-nutrition, especially stunting. There are wide-ranging causes for the increasing incidence of obesity in LMI countries, in particular life-styles growing similar to those in high-income countries, characterised by urbanisation, little exercise, ‘fast foods’ and energy-dense drinks and foods rich in fat and refined carbohydrates. Long-term complications of childhood obesity are now being seen in LMI countries and include hypertension, hyperinsulinaemia and hyperlipidaemia, and there is evidence of racial differences. The importance of controlling childhood obesity is only beginning to be recognised in high-income countries and the same remedies are appropriate for LMI countries and are described in detail in the article.
Andrew Prendergast and Jean Humphrey introduce the concept of the ‘stunting syndrome’ to describe the many sequelae of linear growth failure (stunting), which begins in utero and continues over the first 2 years of life. The pathogenesis of antenatal stunting, at birth to 6 months, between 6 and 24 months and over 24 months is examined in depth. Various interventions to reduce its development at these ages are explored. Stunted children are at greater risk of infections, impaired development and cognition and death, and, as adults, they have a reduced opportunity for economic productivity. Until LMI countries achieve the economic growth and development which improves the lives of most of the population, multi-sectoral nutrition-specific and nutrition-sensitive programmes aimed particularly at pregnant and breastfeeding mothers and the complementary feeding of young children will be required. These programmes are critically examined in this paper.
Ellen Murray and Mark Manary trace the phenomenal success of ready-to-use therapeutic food (RUTF) in managing malnutrition in the community. RUTF is now produced locally in a number of countries. In managing acute malnutrition in the community, supported by WHO, WFP and UNICEF, children with malnutrition are identified by health workers who refer them to the local clinic where they receive RUTF and are followed up every one or two weeks. The programme is particularly important for rural, poor and marginal communities and in places where access is difficult. The value of antibiotics and other additives, modification of RUTF and of plans for future expansion of the programme are outlined.
Maureen Duggan discusses the major challenges of improving child nutrition and of preventing malnutrition. Global and regional trends in child malnutrition are reviewed, including the effect of urbanisation. The differences between nutrition-sensitive programmes, e.g. national policies, agriculture, health and social protection (including cash transfers), water and sanitation, and nutrition-specific programmes, e.g. micronutrient fortification of staples, food supplementation, and early treatment of malnutrition are outlined. The role of commercial complementary foods is examined. The impact of HIV infection on the family and the value of micronutrient supplementation and immunisation in preventing infection are discussed.
Zinc homeostasis and the role of zinc deficiency in infants and children are described in depth by Nancy Krebs, Leland Miller and Michael Hambridge. The various methods and difficulties of identifying zinc deficiency are outlined. Zinc is a negative acute-phase reactant and so levels decline in response to infection, which makes it difficult to analyse zinc levels in children exposed to infection. Infants and children at risk of zinc deficiency include those born to mothers with poor zinc status, low-birthweight infants, older breastfed infants and young children, many of whom are on plant-based complementary diets low in zinc content, of poor bio-availability and limited diversity, viz low cellular animal protein and high phytic acid content. Clinical aspects of zinc metabolism are discussed, including the relationship with growth failure, particularly stunting, and gut disorders, such as environmental enteropathy and coeliac disease. The importance of the sub-clinical effects of zinc deficiency, including oxidant stress, DNA damage and inflammation in the aetiology of these clinical conditions is explored.
Malcolm Blackie’s article on the role of agriculture in child nutrition throws a spotlight on the rural farmer who, by means of the Green Revolution, is able to increase the yield and diversity of food of reliable nutritional quality for home consumption and for sale, and, by thus keeping down the price of food, there should be a beneficial effect on the nutrition of the poor in general. Presently, many farmers in low-income countries maintain a system of low productivity associated with traditional practices over many generations which results in rural households being trapped in poverty, at the mercy of crop failure. New maize seed varieties may double the amount of maize producted from each kilogram of nitrogen compared with traditional maize varieties. Most poor farmers have little access to fertilisers, composts and manures. Rotating maize with a grain legume or growing legumes adjacent to the maize can double the efficiency of nitrogen fertiliser. The development of institutions to convey ideas, practices and knowledge to rural farmers backed by high-quality science is outlined, particularly in relation to southern and eastern Africa. This includes involving farmers in the various experiments on food production and encouraging them to take the initiative in developing the programmes.
The burden of childhood diarrhoea and how it may affect the neurodevelopment of children under 2 years is explored by Jessica MacIntyre and co-authors. Diarrhoea reduces nutrient intake, increases catabolism and decreases absorption, which might reduce energy supply to the developing brain. Impaired cognition has been correlated with the frequency of diarrhoea in early childhood. Also, the gut may be subjected to enterpathogen load without diarrhoea, as happens in environmental enteropathy. However, the association between diarrhoea (and stunting) and cognitive development is not fully understood. Two novel ideas are mentioned. Apolipoprotein E (ApoE) 4 is synthesised mainly in the liver and is involved in cholesterol transport and metabolism. In children with heavy burdens of diarrhoea, early cognitive development may be protected by high levels of ApoE4. Gut microbiota (gut flora) is involved with the digestion of intestinal nutrients and the development of the intestinal epithelium and the immune system, and prevents colonisation of the gut by pathogenic organisms. Studies in germ-free mice (lacking microbiota) have demonstrated increased motor activity and anxiety behaviour compared with specific pathogen-free mice with a normal gut microbiota, which suggests that a healthy microbiota is important for normal development of the brain. The relationship between school, cognitive skills and economic development is discussed. It is pointed out that the number of years of school attendance is not necessarily translated into cognitive skills of the adult work-force; it may be restricted by the effects of a high burden of diarrhoea and other infections in early childhood. The authors believe that investment in the health of young children is important for the economic development of a nation.
Nora Groce and co-authors describe a novel two-way approach to malnutrition and disability whereby under-nutrition or malnutrition can cause or contribute to disability, and, conversely, disability may result in malnutrition, and therefore the prevention and management of both are interlinked. They provide a wide spectrum of examples of these interactions. Maternal under-nutrition can affect the fetus and young infant in a number ways, which may result in disability, e.g. deficiency of folic acid (neural tube defects), vitamin D and calcium, iodine, iron, B12 (vegan diets), and the presence of cephalopelvic disproportion. Malnutrition (often associated with infection) may contribute to physical, sensory, intellectual or mental health disability. Inadequate management of children with disabilities such as cerebral palsy, craniofacial disorders (including cleft lip and palate) and genetic disorders may result in malnutrition. In the case of cerebral palsy, a child might be unable to feed properly and there might be vomiting and a proneness to infection. Mothers stressed by poverty and looking after a number of children may not have the time or skills to feed and tend to a disabled child. There might be difficulty or reluctance to take them to a health facility or to attend school. Amongst a number of recommendations, the authors suggest that disability programmes should have entry points to nutritional services and that nutrition programmes should act as entry points to disability services. It is important that international organisations such as WHO in their guidelines for managing malnutrition should recognise the overlap between malnutrition and the special needs of disabled children.
Judith Kuchenbecker and co-authors undertook in 2011 a cross-sectional nutritional survey in Malawi to assess the nutritional status of infants aged 0–6 months regarding breast-feeding practices. There were 205 mother–infant pairs. The prevalence of stunting [length-for-age Z-score (LAZ) <-2SD] was 39%, wasting (WLZ <-2SD) 2% and underweight (WAZ -2SD) 13%. Forty-three per cent of the infants were exclusively breastfed and their LAZ and WAZ (but not WLZ) were significantly higher than those of infants who were not exclusively breastfed. Exclusive breast-feeding was less common in older infants (81% for infants <1 month compared with 15% for those aged 5 months). The following were associated with exclusive breastfeeding: skin-to-skin contact within 1 hour of birth, seeking advice from health professionals on child feeding, higher educational levels of both mothers and heads of households and fewer episodes of fever or diarrhoea in the 2 weeks before the survey. The study demonstrated the effect on growth and probably on the reduction of infection of exclusive breast-feeding for the first 6 months of life in Malawian infants. Owing to limitations of space, this important contribution will be published in the next issue in February 2015.