Protein-energy malnutrition: the nature and extent of the problem.

The paper begins by describing how the names 'protein malnutrition' and 'protein-energy malnutrition' (PEM) developed from the local name 'Kwashiorkor'. The central feature of severe PEM is oedema; the classical theory suggests that the cause is a deficiency of protein, but other factors are also involved. In the community mild-moderate PEM is defined by deficits in growth. A distinction has to be made between low weight for height (wasting) and low height for age (stunting), Stunting in particular affects some 50% of children worldwide. Its causes and consequences are briefly discussed. In adults, severe PEM has essentially the same features as in children and includes the condition'famine oedema' or 'hunger oedema'; there are again controversies about its cause. In the community, chronic malnutrition is assessed by the body mass index (BMI) (Wt/Ht(2)). Grades of deficiency have been defined and examples are given of functional consequences of a low BMI. Secondary malnutrition differs from primary PEM because of the role played by cytokines and other concomitants of illness or injury. The importance is emphasized of chronicity or duration in determining the clinical picture.