Dietary Protein Deficiency

Abstract

The need for an orderly arrangement of amino acid sequences in polypeptide chains emphasizes the importance of eight or more "essential" amino acids which are not synthesized by the human body and must therefore be supplied regularly in the diet. A brief account is given of the history of protein in nutritional studies, of mehlnahrschaden as an early problem of pediatrics, of kwashiorkor and of the international recognition (1949-1953) of "protein malnutrition" as "the most serious and most widespread disorder of malnutrition still existent in the world. Clinical and laboratory medical scientists have seen in the problems an opportunity both for productive applied research and for basic research into the mutual interaction of energy-producing and other nutrients. Typical of the latter emphasis is the substitution of the term protein-calorie malnutrition for protein malnutrition. A short account is given of experimental evidence supporting the primary and dominant role of deficiency of a group of essential amino acids in the etiology and pathogenesis of kwashiorkor. The effects of protein-calorie malnutrition on the integrity and function of many systems of the human body are yielding to clinical research. Animal models are now being studied by several groups. They will certainly elucidate many aspects of nutritional physiology which are still obscure. Some very simple clinical and public health parameters can now be relied upon to detect the prevalence of unhealthy starch-dependence in child populations. These parameters reveal themselves in simple statistics of growth and of disease arising from failure of resistance to widely prevalent microorganisms.