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Table 5 Plasma amino acid concentrations and indexes at baseline and at 3 and 6 months in elderly patients exclusively receiving a protein-enriched enteral diet

From: A specific protein-enriched enteral formula decreases cortisolemia and improves plasma albumin and amino acid concentrations in elderly patients

Amino Acids (μmol/L) 0 mo 3 mo 6 mo P*
Aliphatic amino acids     
   Alanine 317 ± 33 315 ± 39 342 ± 32 .607
   Glycine 143 ± 18 183 ± 20 208 ± 18 .168
Branched-chain amino acids     
   Isoleucine 38 ± 4 41 ± 6 52 ± 3 .062
   Leucine 68 ± 8a 57 ± 6a 96 ± 6b .002
   Valine 146 ± 22ab 130 ± 12a 178 ± 12b .007
Hydroxyl amino acids     
   Threonine 87 ± 10a 132 ± 20b 150 ± 17b .001
   Serine 75 ± 7 77 ± 10 83 ± 7 .449
Sulfur amino acids     
   Taurine 7 ± 1a 11 ± 3b 102 ± 11c <.001
   Cysteine 20 ± 5a 25 ± 8a 68 ± 6b <.001
   Methionine 24 ± 7a 59 ± 8b 24 ± 1a .002
Acidic amino acids and amides     
   Glutamic Acid 47 ± 7 46 ± 8 46 ± 8 .766
   Glutamine 454 ± 64a 500 ± 102a 968 ± 123b .001
   Aspartic Acid 7 ± 1 7 ± 1 6 ± 1 .189
   Asparagine 43 ± 8a 21 ± 6a 71 ± 6b .001
Aromatic amino acids     
   Phenylalanine 36 ± 5a 37 ± 4a 51 ± 3b .015
   Tyrosine 40 ± 4a 38 ± 4a 56 ± 5b .017
Basic amino acids     
   Arginine 30 ± 4a 44 ± 6ab 54 ± 5b .005
   Citrulline 31 ± 7a 25 ± 5a 46 ± 4b .006
   Histidine 81 ± 14a 130 ± 13b 85 ± 5a .022
   Lysine 86 ± 12 114 ± 16 91 ± 5 .189
   Ornithine 77 ± 14 99 ± 21 83 ± 7 .549
   Imino acids     
   Hydroxyproline 12 ± 2 14 ± 2 8 ± 1 .257
   Proline 190 ± 25a 128 ± 13b 194 ± 21a .046
Amino Acid Indexes     
   NEAA/EAA 2.54 ± 0.14a 2.34 ± 0.52b 2.93 ± 0.20a .008
   BCAA (μmol/L) 256 ± 32a 228 ± 16a 326 ± 21b .007
   Alanine/Threonine 3.85 ± 0.40a 3.93 ± 0.41ab 2.56 ± 0.31b .017
   Glycine/Valine 1.09 ± 0.15 2.12 ± 0.62 1.23 ± 0.12 .420
   Alanine/Leucine 4.85 ± 0.40a 5.78 ± 0.66a 3.59 ± 0.27b .004
   Alanine/BCAA 1.36 ± 0.15ab 1.35 ± 0.13a 1.05 ± 0.07b .017
   Phenylalanine/Tyrosine 0.92 ± 0.07 1.00 ± 0.06 0.96 ± 0.05 .449
   Cysteine/Methionine 1.46 ± 0.41a 0.88 ± 0.40a 2.80 ± 0.20b .001
   H Index 2.25 ± 0.22 2.52 ± 0.21 1.98 ± 0.13 .071
   Whitehead Index 2.66 ± 0.25a 2.50 ± 0.35a 4.15 ± 0.43b <.001
  1. NEAA, nonessential amino acids; EAA, essential amino acids; BCAA, branched-chain amino acids; H Index, relationship between the sum of serine, glycine, and alanine concentrations and the BCAA concentration; Whitehead Index, relationship between the sum of serine, glycine, glutamine, and taurine concentrations and the sum of methionine and BCAA concentrations. Tryptophan concentrations are not reported, because much of this amino acid is bound to plasma proteins, which are eliminated during the deproteinization step in the analytical procedure
  2. * Differences among sample times were tested using Friedman test for three repeated measures, considering P < 0.05 to be significant.
  3. x ± SEM (for all values)
  4. ‡ Differences between times were analyzed using the Wilcoxon test, considering P < 0.05 to be significant. In each group, mean values within the same row with unlike superscript letters were significantly different.