Download International SportMed Journal, 8

Separating fact from hype
Protein Supplements for
Increased Performance?
 Performance-enhancing
supplements abound.




Branched-chain
amino acids
Whey
Creatine
Many others
 Muscle fibers mostly
comprised of branchedchain amino acids.


“Anabolic response”
regulated by
essential amino acid
(EAA) intake –
particularly leucine,
a branched-chain
amino acid
Skeletal muscle
protein turnover
regulated by quality
of dietary protein
intake.
 No benefit seen with
leucine or other branchedchain amino acid
supplementation with
adequate dietary EAA
intake.
 Healthy adults
engaged in noncompetitive sports or
physical activity saw
no benefits from
supplemental protein
or branched-chain
amino acid
supplementation
(Nemet & Eliakim,
2007; Pasiakos &
McClung, 2011).
 Only endurance
athletes, persons with
cachexia or calorically
deprived, and the
elderly see benefits.
 Power-lifters or resistance
trained athletes experience
benefits of supplemental
protein intake when whey
or rice supplementation
given post-exercise (Joy et
al., 2013).
 Key features of diet used:
 Carbohydrate intake
was 50% of total
kcalories
 Fat intake was 25% of
total kcalories
 Protein intake from all
sources including
supplements was 25%
of total kcals
 This was not a high
protein, low
carbohydrate diet
 Creatine supplementation
 Benefits athletes
engaged in sport
activities featuring
short bursts (<30
seconds) of high
intensity energy
output that rely on
anaerobic glucolysis –
sprinting & power
lifting. Other groups
experiencing benefits
include
vegetarians/vegans
and the elderly.
 Enhances muscle
recovery time for
athletic activities
relying on anaerobic
glycolysis with longterm training. (Rawson
& Persky, 2007).
References
Joy, J. M., Lowery, R. P., Wilson, J. M., Purpura, M., De Souza, E. O., Wilson, S. M. C…
Jager, R. (2013). The effects of 8 weeks of whey or rice protein supplementation
on body composition and exercise performance. Nutrition Journal, 12(1), 1-7.
Nemet, D., & Eliakim, A. (2007). Protein and amino acid supplementation in sport.
International SportMed Journal, 8(1), 11-23.
Pasiakos, S. M., & McClung, J.P. (2011). Supplemental dietary leucine and the skeletal
muscle anabolic response to essential amino acids. Nutrition Reviews, 69(9),
550-557.
Rawson, E. S., & Persky, A. M. (2007). Mechanisms of muscular adaptations to creatine
supplementation. International SportMed Journal, 8(2), 43-53.