Journal of the International Society of Sports Nutrition. 3(2): 12-18, 2006. (www.sportsnutritionsociety.org)
18
in addition to the high protein content contributed to
the elevated resting IGF-1 response. It is likely that
the relatively low energy intakes observed in the
subjects of this study may have contributed to the
lack of change seen in IGF-I.
No changes were observed in resting testosterone
concentrations or in the T/C ratio. A limited number
of studies have shown that high protein diets tend to
reduce resting testosterone concentrations
10
and that
both protein content and the protein-to-carbohydrate
ratio are inversely related to resting testosterone
concentrations
9,10
. However, this may be a factor of
high relative dietary protein consumption. The
protein content of RL (21.2%) and AL (28.6%) were
lower than that reported by Anderson and colleagues
(44% of total energy from protein)
10
, and may not
influence resting testosterone concentrations to the
same degree.
CONCLUSION
The results of this study do not provide any support
for protein intakes greater than recommended levels
in collegiate strength/power athletes for body
composition improvements, or alterations in resting
hormonal concentrations. Inadequate energy intakes
likely contributed to these results. Although elevated
protein content did not produce significantly greater
strength improvements, results suggest that further
study is warranted on the effect of high (> 2.0 g
kg
-
1
day
-1
) protein intake on strength and lean tissue
accruement. However, future research needs to
insure appropriate caloric consumption in the
examination of strength/power athletes.
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