Effects of Protein Deficiency in Humans

One way to avoid a deficiency of an essential amino acid is to include a variety of different proteins in the diet, since it is unlikely that they all will be deficient in the same amino acids. Unfortunately, this is not possible in many regions of the world where food is limited. A large proportion of the world’s population suffers from some form of protein-energy-malnutrition, or PEM. Sometimes the malnutrition is due to insufficient caloric intake, but more often it occurs because the diet is inadequate with respect to protein and/or vitamins. Within the United States many children living in the slums of our larger cities and in poverty-stricken rural areas suffer from PEM. A particular severe form of PEM is kwashiorkor (see Figure below), a protein-deficiency disease characterized by degeneration of the liver, sever anemia, and inflammation of the skin.

Kwashiorkor is particularly common among children in countries where the diet consists primarily of a single plant material, as in Indonesia, where rice is the main food, and in parts of Africa and Latin America, where corn (maize) is the principal staple. Worldwide, corn is the second or third largest crop and it is a staple for nearly half the world’s malnourished people. For this reason intense efforts have been directed at breeding strains of corn with a higher quality protein. The results have been spectacular; quality protein maize (QPM) has a protein quality twice that of normal corn and almost equal to milk. QPM is now being field tested in different regions for adaptability to different climates, rainfall, temperature, soils, pests, etc. If the field trials are successful, it will be good news for the impoverished populations in Mexico and Central America where maize constitutes 85 percent of the grain consumed.

A child suffering from kwashiorkor. Kwashiorkor is a severe protein-deficiency disease caused by eating protein from a single source, such as rice or corn. The most obvious external symptom is inflammation of the skin, evident here on the child’s arms and legs.