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


OBJECTIVE
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.


METHODS
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.


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


METHODS
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.


CONCLUSIONS
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.
Rodondi
A
A
Division of Bone Diseases, Department of Rehabilitation and Geriatrics, University Hospitals and Faculty of Medicine of Geneva, CH - 1211 Geneva 14, Switzerland.
Ammann
P
P
Ghilardi-Beuret
S
S
Rizzoli
R
R
D000203:Activities of Daily Living; D000369:Aged, 80 and over; D000601:Amino Acids, Essential / Q000494:pharmacology / Q000627:therapeutic use*; D001862:Bone Resorption / Q000178:diet therapy / Q000188:drug therapy*; D003094:Collagen / Q000097:blood*; D003131:Combined Modality Therapy; D004044:Dietary Proteins / Q000494:pharmacology / Q000627:therapeutic use; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D016330:Frail Elderly; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008894:Milk Proteins / Q000494:pharmacology / Q000627:therapeutic use; D010446:Peptide Fragments / Q000097:blood*; D011502:Protein-Energy Malnutrition / Q000178:diet therapy / Q000188:drug therapy*; D000067816:Whey Proteins; D015032:Zinc / Q000494:pharmacology / Q000627:therapeutic use*
D000601:Amino Acids, Essential; D004044:Dietary Proteins; D008894:Milk Proteins; D010446:Peptide Fragments; D000067816:Whey Proteins; C110762:glutamyl-lysyl-alanyl-histidyl-aspartyl-glycyl-glycyl-arginine; D007334:Insulin-Like Growth Factor I; D003094:Collagen; D015032:Zinc