Protein-Calorie Malnutrition Viewed as a Challenge for Homeostasis

Abstract

Protein-calorie malnutrition is a serious danger for the composition and size of the protein matrix in the human body, evoking physiological counter-reactions, which in turn tend to preserve this matrix, not in substance but with regard to its function. Such reactions are called “homeostatic reactions”, leading to a functional adaptation under conditions of external stress. From the point of view of a physiologist, it is worthwhile to go back more than 40 years and to reconsider 6 postulates which were outlined by Walter Bradford Cannon in 1926, in a paper which unfortunately was buried in a Jubilee Volume in honour of Charles Richet (Cannon, 1926). I would like to quote these postulates in Cannon’s own words:

• “1. In an open system, such as our bodies represent, composed of unstable structure and subjected continually to disturbance, constancy is in itself evidence that agencies are acting or are ready to act to maintain this constancy.

• 2. If a homeostatic condition continues, it does so because any tendency towards a change is automatically met by increased effectiveness of a factor or factors which lessen the change.

• 3. A homeostatic agent does not act in opposite directions at the same point.

• 4. Homeostatic agents, antagonistic in one region of the body, may be cooperative in another region.

• 5. The regulating system which determines a homeostatic state may comprise a number of cooperating factors brought into action at the same time or successively.

• 6. When a factor is known which can shift a homeostatic state in one direction, it is reasonable to look for automatic control of that factor or for a factor or factors having an opposing effect.”