Effects of oral amino acid supplementation on long-term-care-acquired infections in elderly patients

Arch Gerontol Geriatr. 2011 May-Jun;52(3):e123-8. doi: 10.1016/j.archger.2010.09.005.


The very high general infection rate (IRI) observed in our Geriatric Intensive Rehabilitation Center (GIRC) led us to investigate whether patient supplementation with essential amino acids (EAAs), modulators of immuno-competence, could reduce IRI. Eighty elderly patients admitted to our GIRC (n=40; age 79.5 ± 7.71; male/female 14/26) or placebo (n=40; age 82.13 ± 6.15; male/female 13/27) were allocated to an 8 g/day oral EAAs group and were surveyed for infections (>48 h from admission) over the first month of their hospital stay. The IRI was 67% for the entire population of patients, 82.5% (33/40 patients) in the placebo group and 52% (21/40 patients) in the EAA group (p<0.02). When patients were divided into infection group (IG) and without-infection group (WIG), independently of post randomization allocation, the WIG had higher levels of serum albumin (p<0.001), blood hemoglobin (Hb) concentration (p=0.01), dietary protein (p=0.008) calorie intakes (p=0.05) but lower serum C-reactive protein (CRP) (p<0.001). The factor of CRP>0.8 mg/dl and Hb ≤ 12 in females, ≤13 in males was associated 4 times and 3.6 times risk of infection, respectively, by sex. EAAs supplementation may lower the risk of infection by 30% in the rehabilitative elderly population. CRP and blood hemoglobin levels can be considered risk markers of future infection.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Aged, 80 and over
  • Amino Acids, Essential / administration & dosage*
  • C-Reactive Protein / metabolism
  • Cross Infection / prevention & control*
  • Dietary Proteins / metabolism
  • Dietary Supplements*
  • Energy Intake
  • Female
  • Hemoglobins / metabolism
  • Humans
  • Incidence
  • Long-Term Care
  • Male
  • Serum Albumin / drug effects


  • Amino Acids, Essential
  • Dietary Proteins
  • Hemoglobins
  • Serum Albumin
  • C-Reactive Protein