Protein and energy intake during weaning. III. Effects on plasma amino acids.
Preprandial plasma amino acid concentrations were measured at 5 and 6 months of age in 30 healthy term infants who were either breast-fed ad libitum or fed one of two different formulas (1.9 g of protein per 100 ml with a whey:casein ratio of 50:50; 2.9 g of protein per 100 ml with a whey:casein ratio of 20:80) ad libitum, plus the same supplementary food regimen. The mean plasma concentrations of total amino acids and especially total essential amino acids were higher in the formula-fed infants. Those fed formula also had plasma concentrations of methionine, isoleucine, phenylalanine, leucine, valine, threonine, aspartate, proline, lysine, tyrosine, histidine that exceeded plasma concentrations of breast-fed infants by 2 or more standard deviations. Concentrations of arginine, glutamic acid, glutamine, ornithine, serine, cystine did not differ and taurine was higher in the breast-fed infants. The data indicate that formulas in common use today during weaning (4-6 months) provide excessive protein intakes when compared to the breast-fed control infants. A lowering of protein concentration and a further manipulation of the whey:casein ratio is necessary if plasma amino acid patterns similar to those found in breast-fed infants is to be achieved with artificial feeding.
Axelsson
I
I
Department of Paediatrics, University of Lund, Malmö, Sweden.
Borulf
S
S
Abildskov
K
K
Heird
W
W
Räihä
N
N
D000596:Amino Acids / Q000097:blood*; D001942:Breast Feeding; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D006801:Humans; D007223:Infant; D007225:Infant Food; D007227:Infant Nutritional Physiological Phenomena; D014886:Weaning
D000596:Amino Acids; D004044:Dietary Proteins