Protein-energy malnutrition--its epidemiology and control.

The four most important deficiency diseases in developing countries today are protein-energy malnutrition (PEM), xerophthalmia, nutritional anemias, and iodine deficiency disorders. Of these, PEM is the most important and the most difficult to control. The immediate cause is usually insufficient intake or proper utilization of energy and protein. However, the interaction of nutrition and infections plays an important role in PEM. Underlying causes include poverty, inequity, poor food production and distribution, and lack of knowledge. We now recognize that protein deficiency is less important than energy and food deficiency. The actual cause of the edema in kwashiorkor is still not proven. Better ways of defining PEM have been accepted. Mild or moderate PEM are best judged by anthropometry; regular weighing, for monitoring growth, may be a useful control strategy. Because infections play such an important role in PEM, three practical approaches-immunization, deworming of children, and oral rehydration therapy for diarrhea--are discussed. Modernization and Westernization have sometimes aggravated the problem of malnutrition in nonindustrialized countries. The decline in breast-feeding and greater use of infant formula provide a good example of this problem. Finally, economic improvement in the Third World is essential if PEM is to be greatly reduced.