Effect of short-term protein deprivation on hemopoietic functions of healthy volunteers.

To ascertain the effects of protein deprivation on hemopoietic parameters in otherwise healthy subjects, three volunteers were placed on diets containing 0.15 g protein/kg body weight for 8 days followed in 2 mo by another 8-day study period during which they ingested their usual diets containing more than 0.9 g protein/kg body weight. Complete blood counts, serum protein determinations, and tests of in vitro and in vivo leukocyte chemotaxis were performed prior to and at the conclusion of each study period. Subjects were phlebotomized of 500 ml on day 7 of each study period. Twenty-four-hour urinary erythropoietin excretion rates were assayed just prior to and again postphlebotomy. Reticulocyte counts were performed at intervals up to 1 wk postphlebotomy. Some of these determinations were replicated during a subsequent study. The hemoglobin and hematocrits decrased slightly but significantly after 8 days on low protein diets. Erythropoietin excretion rates and reticulocyte responses to phlebotomy were also less marked while subjects were on protein depleted diets. Leukocyte chemotaxis, measured both in vitro and in vivo, was also markedly reduced while subjects were on protein-depleted diets. We conclude that 8 days of moderately severe protein deprivation significantly impairs erythropoiesis and leukocyte function in otherwise healthy individuals.