The scope and consequences of nutritional problems
As we approach the twenty-first century, hunger and malnutrition remain the most devastating problems facing the world's poor. Although the proportion and absolute number of chronically undernourished people 2 has declined worldwide, progress has been uneven among developing countries (Figure 1). For developing regions as a whole, the estimated number of people suffering from chronic malnutrition has declined from 941 million to 786 million people over the past two decades. The challenge facing the international community is to build upon the progress that has occurred and accelerate the processes that improve nutrition.
2 Defined as those people whose estimated daily energy intake over a year falls below that required to maintain body weight and support light activity.
In Asia and the Pacific striking improvements have occurred in the last 20 years, the proportion of the population affected by undernutrition declined from 40 percent to 19 percent. Nevertheless, the highest number of chronically undernourished people, 528 million, live in this region The region with the largest proportion of the population affected by undernutrition, 33 percent, is Africa. The actual number of Africans affected by undernutrition has increased dramatically, rising from 101 million people in 1969-71 to 128 million in 1979-81 and reaching 168 million in 1988-90.
The consequences of malnutrition are varied and far-reaching undernutrition can retard growth and development, reduce physical activity, impair resistance to infection, increase morbidity and lead to disabilities and death. Approximately 192 million children under five years of age suffer from acute or chronic protein-energy malnutrition During seasonal food shortages and in times of famine and social unrest, this average number increases. The percentage of underweight children under five years of age has declined in the last 15 years, but the absolute numbers have remained fairly stable because of population increases (Table 1).
Lack of specific nutrients within the diet causes serious health problems in many countries (Table 2). Over 1000 million people are at risk of iodine deficiency, often because little iodine is present in local soils. Severe or moderate iodine deficiency during pregnancy or early childhood can lead to neurological or hyperthyroid cretinism, resulting in deaf-mutism, impaired motor coordination, growth failure, severe mental defects and increased rates of abortion and stillbirths.
An estimated 40 million people are affected by insufficient intake of vitamin A. Vitamin A deficiency occurs when fruit and vegetable consumption and, in some cases, fat intake are low. This deficiency is the most common cause of preventable childhood blindness. It may also lead to night blindness, decreased resistance to infections and increased morbidity and mortality rates from various infections, especially diarrhoeal and respiratory infections and measles.
Poor nutritional status in general is associated with increased prevalence of anemia, pregnancy and delivery problems, and increased rates of intrauterine growth retardation, low birth weight and perinatal mortality In adults, undernourishment and anemia, can lead to poor health, can impair productivity because of reduced physical and intellectual performance and can constrain community and national development. Over 2000 million people, primarily women of child-bearing age and young children, are affected by the lack of iron.
Deficiencies of zinc, selenium and other trace elements affect large numbers of people in certain areas. Outbreaks of beriberi, pellagra and scurvy occur in refugee camps and among other deprived populations. Finally, rickets affects significant numbers of children.
Prevalence and number of underweight children under five years of age, by region.
Prévalence de l'insuffisance pondérale chez les enfants de moins de cinq ans par régions.
Prevalencia y número de niños menores de cinco años con falta de peso, por regiones.
a Underweight is defined as weight-for-age less than minus 2 SD of the WHO reference.
Diet and non-communicable diseases
The emergence of obesity and various non-communicable diseases, including heart disease, hypertension, non-insulin-dependent diabetes and some cancers may be linked to changing dietary patterns and lifestyles. Dietary imbalances for instance inadequate intakes of dietary fibre or excessive energy intakes have been associated with these diseases. There is concern that the prevalence of diet related non communicable diseases will increase among younger segments of the population as well as the elderly. This would place additional burdens on health services and development.
Population at risk of and affected by micronutrient malnutrition (millions).
Populations menacées et affectées par des carences en oligo-éléments (en millions).
Población a riesgo y afectada por malnutrición debida a carencia de micronutrientes (millones).
a WHO regions.
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