Protein malnutrition is more common in countries where there is a lack of adequate food supplies within a country or as the result of social, economic and cultural factors that limit the consumption of protein by vulnerable groups of the population, even when the total supplies are adequate for the population as a whole. This is why the average figures for protein intake expressed on a per capita basis do not reflect the frequently encountered gross inadequacy of protein in the diet of the vulnerable groups in the population. Moreover, a low intake of calories and frequent episodes of infection often lead to considerable wastage of even the small quantity of protein consumed and are major factors in the widespread protein-energy deficiency. During famine and other emergency situations, this problem becomes particularly serious.
Protein malnutrition is an important cause of infant and young child mortality, stunted physical growth, low work output, premature ageing and reduced life span in the developing world. Recent research has also revealed a link between malnutrition in infancy and early childhood, and impaired learning and behaviour in later life. The widespread occurrence of protein malnutrition especially among infants, pre-school children, and expectant and nursing mothers in many developing nations spells grave danger to the full expression of the genetic potential of the population of large sections of the world community.
Protein malnutrition, which is a problem of crisis proportions for developing countries, must be recognized by the entire world community as a threat to world peace and stability which it can ignore only at its own peril. It is imperative that each developing country understand now the magnitude and appalling implications of the problem. Adequate nutrition is a prerequisite of the development of a nation's human resources. It is a fundamental goal as well as a basis for all economic and social progress.
In laboratory experiments, it has been shown that animals raised on a diet consisting of all the necessary vitamins and other nutrients, but only 60 to 65% of the calories of their normal diet, will live significantly longer.