Protein quantity, not protein quality, accelerates whole-body leucine kinetics and the acute-phase response during acute infection in marasmic Malawian children.
The present study compared leucine kinetics and acute-phase-protein concentrations in three groups of marasmic, acutely infected Malawian children fed one of three isoenergetic diets. These were: an enhanced-protein-quality diet (egg-white+tryptophan, providing 1.2 g protein/kg per d; n 14); an increased-protein-content diet (egg-white+tryptophan, providing 1.8 g protein/kg per d; n 14); a standard-protein diet (1.2 g milk protein/kg per d; n 25). The hypotheses tested were that children receiving a diet with more protein would have greater rates of non-oxidative leucine disposal and that children receiving an isonitrogenous diet with a higher protein quality would have lower rates of leucine oxidation. The children were studied after 24 h of therapy using standard [(13)C]leucine stable-isotope tracer techniques. The children receiving the higher-protein-content diet had greater leucine kinetic rates than those receiving the standard-protein-content diet; non-oxidative leucine disposal was 170 (sd 52) v. 122 (sd 30) mumol leucine/kg per h (P<0.01). Leucine oxidation was less in the children receiving the enhanced-protein-quality diet than in those receiving the standard-protein-quality diet; 34 (sd 12) v. 45 (sd 13) mumol leucine/kg per h (P<0.05). The children receiving the high-protein-content diet increased their serum concentration for five of six acute-phase proteins 24 h after starting therapy, while those receiving the standard-protein-content diet did not. These data suggest that there was greater whole-body protein synthesis, and a more vigorous acute-phase response associated with the higher-protein-content diet. The clinical benefits associated with a higher protein intake in marasmic, acutely infected children need further study.
Manary
M J
MJ
College of Medicine, University of Malawi, Blantyre. manary@kids.wustl.edu
Yarasheski
K E
KE
Smith
S
S
Abrams
E T
ET
Hart
C A
CA
D000208:Acute Disease; D000209:Acute-Phase Proteins / Q000378:metabolism*; D000210:Acute-Phase Reaction; D000596:Amino Acids / Q000032:analysis; D000886:Anthropometry; D002675:Child, Preschool; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000494:pharmacology / Q000592:standards; D005260:Female; D006801:Humans; D007223:Infant; D007239:Infections / Q000097:blood / Q000150:complications*; D007930:Leucine / Q000097:blood*; D008297:Male; D010084:Oxidation-Reduction; D011502:Protein-Energy Malnutrition / Q000097:blood* / Q000150:complications
D000209:Acute-Phase Proteins; D000596:Amino Acids; D004044:Dietary Proteins; D007930:Leucine