Effect of cysteine-rich whey protein (immunocal®) supplementation in combination with resistance training on muscle strength and lean body mass in non-frail elderly subjects: a randomized, double-blind controlled study.
OBJECTIVE
The purpose of the present study was to examine the effect of a cysteine-rich whey protein (Immunocal®) supplementation in combination with resistance training on muscle strength and lean body mass (LBM) in elderly individuals. We hypothesized that the cysteine-rich whey protein (Immunocal®) group would experience a greater increase in muscle strength and lean body mass versus the control group (casein).


METHODS
Randomized double-blind controlled intervention study.


METHODS
Institut de Recherches Cliniques de Montréal in Montreal, Canada.


METHODS
Ninety-nine non-frail elderly subjects were recruited.


METHODS
Participants were randomly assigned into two groups. The experimental group received a cysteine-rich whey protein isolate (Immunocal®) (20 g/day) and the control group received casein (20 g/day) during a 135-day period. In addition, both groups performed the same resistance training program (3 times per week).


METHODS
Body composition (DXA) and muscle strength (leg press) were measured.


RESULTS
Of the 99 recruited participants, 84 completed the 135-day study period. Of these, 67 subjects (33 in the casein group and 34 in the Immunocal® group) complied and used at least 80 % of the study product and completed at least 80 % of their training sessions. Results in this selected group show an increase in all three muscle strength variables (absolute, normalized by BW and by LBM) by 31.0 %, 30.9 % and 30.0 %, respectively in the casein group as well as 39.3 %, 39.9 % and 43.3 %, respectively in the Immunocal® group after the intervention (p < 0.05). The increases in muscle strength favored Immunocal® versus casein by approximately 10 % when expressed in kg per kg BW and in kg per kg LBM (p < 0.05). No significant changes were found between pre-and-post intervention in both groups for total LBM.


CONCLUSIONS
Our findings showed increases in muscle strength in both groups after resistance training, however, significant additional increases were observed in muscle strength with the addition of a cysteine-rich whey protein (Immunocal®) versus casein.
Antony Karelis, PhD, Department of Kinanthropology, Université du Québec à Montréal, 8888, succ centre-ville, Montreal, Quebec, Canada, H3C 3P8, Tel: 001-514-987-3000 ext. 5082, Fax: 001-514-987-6616, Email: karelis.antony@uqam.ca.
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D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002364:Caseins / Q000008:administration & dosage; D003545:Cysteine / Q000032:analysis*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology*; D011792:Quebec; D055070:Resistance Training; D000067816:Whey Proteins / Q000008:administration & dosage* / Q000737:chemistry* / Q000494:pharmacology
D002364:Caseins; D000067816:Whey Proteins; D003545:Cysteine