Zinc increases the effects of essential amino acids-whey protein supplements in frail elderly

J Nutr Health Aging. 2009 Jun;13(6):491-7. doi: 10.1007/s12603-009-0099-5.


Protein undernutrition is frequent in the elderly. It contributes to the development of osteoporosis, possibly via lower IGF-I. Dietary zinc can influence IGF-I production.

Objectives: To determine the influence of dietary zinc addition on IGF-I and bone turnover responses to essential amino acids-whey (EAA-W) protein supplements in frail elderly.

Design and setting: A daily oral protein supplement was given to hospitalized patients for 4 weeks. On a randomized, double-blind basis, patients received either an additional 30 mg/day of zinc or control.

Participants: Sixty-one hospitalized elderly aged 66.7 to 105.8, with a mini-nutritional assessment score between 17 and 24 were enrolled.

Measurements: Activities of daily living; dietary intakes; serum IGF-I, IGF-BP3, CrossLapsTM, osteocalcin and zinc were measured before and after 1, 2 and 4 weeks of protein supplementation.

Results: Serum IGF-I rapidly increased in both groups. Zinc accelerated this increase with changes of +48.2 +/- 14.3 and +22.4 +/- 4.7% (p < .05) by 1 week, in the zinc-supplemented and control groups, respectively. Zinc significantly decreased the serum bone resorption marker CrossLapsTM by already 1 week. Activities of daily living improved by +27.0 +/- 3.1 and +18.3 +/- 4.5% in zinc-supplemented and control groups, respectively.

Conclusion: In the elderly, zinc supplementation accelerated the serum IGF-I response to EAA-W protein by 1 week and decreased a biochemical marker of bone resorption.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living*
  • Aged, 80 and over
  • Amino Acids, Essential / pharmacology
  • Amino Acids, Essential / therapeutic use*
  • Bone Resorption / diet therapy
  • Bone Resorption / drug therapy*
  • Collagen / blood*
  • Combined Modality Therapy
  • Dietary Proteins / pharmacology
  • Dietary Proteins / therapeutic use
  • Dietary Supplements
  • Double-Blind Method
  • Female
  • Frail Elderly
  • Humans
  • Insulin-Like Growth Factor I / metabolism*
  • Male
  • Milk Proteins / pharmacology
  • Milk Proteins / therapeutic use
  • Peptide Fragments / blood*
  • Protein-Energy Malnutrition / diet therapy
  • Protein-Energy Malnutrition / drug therapy*
  • Whey Proteins
  • Zinc / pharmacology
  • Zinc / therapeutic use*


  • Amino Acids, Essential
  • Dietary Proteins
  • Milk Proteins
  • Peptide Fragments
  • Whey Proteins
  • glutamyl-lysyl-alanyl-histidyl-aspartyl-glycyl-glycyl-arginine
  • Insulin-Like Growth Factor I
  • Collagen
  • Zinc