The first United Nations Millennium Development Goal (MDG), set in 2000, is to “eradicate extreme hunger and poverty” (1). To achieve this goal, the target is to halve both the number of people suffering from hunger and those whose income is less than $1/d by 2015. This article focuses on why the eradication of child malnutrition is so crucial in the fight against poverty and discusses whether this goal will be achieved within the time frame the United Nations has set.
In some regions of the world, such as Asia, great strides have been made to alleviate hunger, but the difficulties in other regions make the MDGs for nutrition look unachievable (2). Poor nutrition in childhood fuels the poverty cycle, in which underachievement, reduced opportunities, and greater morbidity and mortality ensue for that and subsequent generations.
In recent years overnutrition has resulted in a huge increase in the numbers of children who are overweight or obese. This will become a considerable health burden to many countries because the problem is of epidemic proportions and runs alongside the age-old issue of undernutrition. In some low-to-middle income countries both ends of the nutritional spectrum are found (3,4).
A major challenge that still is unrecognised is the one referred to as hidden hunger, generated by poor dietary quality and involving inadequate micronutrient intake. Implementing appropriate intervention strategies for specific populations is the only way in which the MDGs have any chance of being achieved.
Undernutrition remains a huge cause of mortality for children throughout the world, with approximately 10 million children dying before the age of 5 years. Although global childhood mortality declined from 147 deaths per 1000 live births in 1970 to 80 deaths in 2002, improvements are not universal. In some regions, especially in sub-Saharan Africa, childhood mortality has not decreased, and 14 African countries have child mortality rates that are higher now than in 1990 (5). HIV/AIDS has also had a significant impact in this region.
Low Birth Weight
An estimated 1 in 6 infants is born with a low birth weight; that is, less than 2500 g (6). Worldwide, >20 million babies are born with low birth weight, around 95% of them in developing countries. Even this is an underestimate because many babies born at home or with traditional birth attendants are not weighed at all. The problem arises because they either have been born too early, have experienced growth restriction, or both. The health and nutrition of the mother significantly influence these factors. A low birth weight predisposes an infant to a wide range of other risk factors including developing and dying from diarrhoea or infectious diseases. Continued malnutrition and underweight can also lead to decreased cognitive development (7) with a significant impact on productivity in adulthood, and an increased risk of wasting or stunted growth (8).
In affluent societies, low birth weight is known to be a significant risk factor for other health outcomes in later life. These outcomes include coronary heart disease, stroke, type 2 diabetes mellitus, and the metabolic syndrome. Their impact cannot be discounted in developing countries, where early deprivation may “programme” a child so that subsequent “overnutrition” may have a significant effect on morbidity and mortality rates (9). Actions, including better maternal nutrition, breast-feeding and improved complementary feeding, to ensure optimal fetal development to reduce the immediate health impact and the future increased chronic disease risk are therefore warranted.
The first MDG target, halving the number of people suffering from hunger, uses the prevalence of underweight in children under 5 years old as a key indicator. Underweight measures chronic malnutrition (low height for age or stunting) as well as acute malnutrition (low weight for age or wasting), but the contribution of stunting to underweight is greater than that of wasting.
Stunting is generally declining worldwide. The World Health Organization (10) reported that between 1990 and 2000, the global prevalence of stunting in children fell from 34% to 29%. However, in eastern Africa, the number of children with stunting increased in this period from 40 million to 45 million. Stunting is defined by the World Health Organization as 2 standard deviations below the z scores for height and for age. Children who are underweight or stunted in growth may not show catch-up growth in later childhood and thus carry the risk of continuing poor health into adult life (11). In some countries, for example, South Africa, children who are growth stunted coexist with those who are overweight or obese (12). This of course has complex implications for policymakers.
Children who have low weight for age (wasted) are at increased risk of dying from pneumonia, measles, malaria or diarrhoea (13). Throughout the world the numbers of underweight children are decreasing and it is thought this global decline will continue until 2015, the date by which the MDGs should have been achieved. However, it is unlikely that the goals will universally be met. The great improvements are mainly due to the formidable economic and social changes in Southeast Asia, whereas in other parts of the world, such as sub-Saharan Africa, the prevalence of underweight in children under age 5 years is forecast to increase from 24% to 26.8%. In this region, HIV/AIDS has had a huge impact on the population, and continues to affect the health and development of infants and children (2).
For an increasing number of children, overweight and obesity have become the health issue of their generation. Even in countries that have traditionally been associated with good dietary health, such as the Mediterranean countries of southern Europe, obesity is commonplace in children (14). Italy, for example, has an estimated 35% of primary-school children (7–11 y) with a body mass index >25. Overnutrition is also found in populations that may also have malnutrition, and it is often the poor and disadvantaged sectors of the population who suffer (15).
Global estimates of overweight suggest that some 20 million children and 1 billion adults are overweight. Chronic noncommunicable diseases such as heart disease, cancer, stroke and diabetes account for 60% of global deaths and 47% of the burden of disease. The incidence of noncommunicable diseases is expected to grow as many low to middle income countries start to exhibit the diseases formerly associated with more affluent countries.
The International Obesity Task Force has shown an increasing incidence of childhood obesity in the last decade, and it is expected to continue to rise dramatically over the next several decades unless serious action is undertaken to reduce the environmental pressure to avoid energy overconsumption and sedentary lifestyles (16).
As with malnutrition, the obesity epidemic is multidimensional. The high availability of low-cost, high–energy content foods and drinks, with ever-expanding portion sizes available in fast food outlets promoted by heavy marketing is 1 of the main determinants (17). The increased amount of leisure time spent in sedentary activities such as television viewing and playing electronic games (18), with a corresponding reduction of physical activity in schools and transportation policies encouraging sedentary behaviour is another determinant (19). A link between the decline in breast-feeding and a concomitant rise in childhood overweight has also been demonstrated (20).
Malnutrition is not just about insufficient energy intake. In many parts of the world, inadequate dietary iron, zinc, iodine and vitamin A cause significant ill health that affects generation after generation. Malnutrition of the child feeds into an insidious vicious cycle of poor health and poor outcomes throughout life. Poor childhood nutrition does not equip women for pregnancy and birth; a malnourished mother with low stores of micronutrients gives birth to children who continue in the same cycle. Elderly people are more susceptible to infections and less able to take care of young children. The cycle of malnutrition therefore continues from 1 generation to the next. Interventions are needed not only for children but also for the mothers. There is no doubt that improving maternal nutrition can improve the birth outcomes and the subsequent growth of the offspring (26).
Iron deficiency is a less obvious form of malnutrition than protein energy malnutrition but it permeates all aspects of child health in developing countries. Iron-deficiency anaemia affects the growth, cognition, motor development and social development of children, resulting in reduced school performance and lowered productivity. In conjunction with serious infection, it also can bring about irreversible and lifelong consequences, diminishing the potential of the child. Iron-deficiency anaemia is an extremely common condition, especially in Africa where the incidence is as high as 80% of children under 5 years (21), closely followed by India and other countries in southern and Southeast Asia.
Iodine deficiency remains a significant problem in those parts of the globe with low water levels of iodine. The consequences of this deficiency particularly affect pregnant women and their offspring with increased risk of perinatal mortality and the mental retardation of the child (22). In areas where iodine deficiency is endemic it is estimated that up to 15% of the population can suffer from cretinism (23). South central Asia has a high prevalence of iodine deficiency, with 104 million schoolchildren having insufficient iodine. Iodine deficiency is often combined with iron deficiency, thus creating a long-term threat to neurodevelopment, as in the case of Tajikistan (24).
Vitamin A deficiency is one of the most common deficiency syndromes in children in developing countries (25). Deficiency leads to reduced immunity, with the resultant increased severity and complications of infections. There can be growth faltering and poor development, and the breakdown of epithelial cells in the respiratory and digestive tract. Because vitamin A is also essential for good vision, deficiency leads to poor night vision, xerophthalmia and ultimately to blindness.
Cost of Micronutrient Malnutrition
Interventions to reduce micronutrient deficiency can have a significant effect on subsequent generations and improve the economic performance of segments of the population. Studies in China have clearly shown the economic impact of interventions to reduce iron and iodine deficiency and decrease stunting (27). It has been estimated that the increase in productivity due to a 30% reduction in iron-deficiency anaemia over 10 years would be worth 107 billion yen. If childhood anemia was also reduced by 30% during the same time period, the economic gain would be as much as 348 billion yen, considerably less than the cost of any intervention.
Despite major economic development in recent decades, childhood nutrition remains a great challenge for the human species. A combination of undernutrition, overnutrition and poor dietary quality affect to a variable extent all of the world's populations, often combined in the same areas and even in the same families. Malnutrition often accompanies the life of individuals from conception and is transmitted by 1 generation to the next. Countries with lower income per capita and poor socioeconomic strata are mainly affected and, in turn, malnutrition hampers their development.
As shown by some success stories, general interventions to reduce poverty and improve livelihoods are necessary, but often not sufficient to improve nutritional status. Specific nutrition actions are therefore also needed. These must start from conception and early infancy.
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