Rapid-turnover transport proteins: an index of subclinical protein-energy malnutrition.

The effect of protein and energy restriction on the plasma proteins, albumin, transferrin, prealbumin, retinol-binding protein, haptoglobulins, and immunoglobulins, was studied in obese subjects. Plasma albumin and transferrins failed to respond to short-term restriction of either protein or energy. Prealbumin and retinol-binding protein, however, were very sensitive to changes in both dietary protein and energy and responded rapidly to refeeding. Prealbumin and retinol-binding protein could be used to detect subclinical malnutrition and monitor the effectiveness of dietary treatment.