Effects of ingesting protein with various forms of carbohydrate following resistance-exercise on substrate availability and markers of anabolism, catabolism, and immunity

Article (PDF Available)inJournal of the International Society of Sports Nutrition 4(1):18 · November 2007with77 Reads
DOI: 10.1186/1550-2783-4-18 · Source: PubMed
Abstract
Ingestion of carbohydrate (CHO) and protein (PRO) following intense exercise has been reported to increase insulin levels, optimize glycogen resynthesis, enhance PRO synthesis, and lessen the immuno-suppressive effects of intense exercise. Since different forms of CHO have varying glycemic effects, the purpose of this study was to determine whether the type of CHO ingested with PRO following resistance-exercise affects blood glucose availability and insulin levels, markers of anabolism and catabolism, and/or general immune markers. 40 resistance-trained subjects performed a standardized resistance training workout and then ingested in a double blind and randomized manner 40 g of whey PRO with 120 g of sucrose (S), honey powder (H), or maltodextrin (M). A non-supplemented control group (C) was also evaluated. Blood samples were collected prior to and following exercise as well as 30, 60, 90, and 120 min after ingestion of the supplements. Data were analyzed by repeated measures ANOVA or ANCOVA using baseline values as a covariate if necessary. Glucose concentration 30 min following ingestion showed the H group (7.12 +/- 0.2 mmol/L) to be greater than S (5.53 +/- 0.6 mmol/L; p < 0.03); M (6.02 +/- 0.8 mmol/L; p < 0.05), and C (5.44 +/- 0.18 mmol/L; p < 0.0002) groups. No significant differences were observed among groups in glucose area under the curve (AUC) values, although the H group showed a trend versus control (p = 0.06). Insulin response for each treatment was significant by time (p < 0.0001), treatment (p < 0.0001) and AUC (p < 0.0001). 30-min peak post-feeding insulin for S (136.2 +/- 15.6 uIU/mL), H (150.1 +/- 25.39 uIU/mL), and M (154.8 +/- 18.9 uIU/mL) were greater than C (8.7 +/- 2.9 uIU/mL) as was AUC with no significant differences observed among types of CHO. No significant group x time effects were observed among groups in testosterone, cortisol, the ratio of testosterone to cortisol, muscle and liver enzymes, or general markers of immunity. CHO and PRO ingestion following exercise significantly influences glucose and insulin concentrations. Although some trends were observed suggesting that H maintained blood glucose levels to a better degree, no significant differences were observed among types of CHO ingested on insulin levels. These findings suggest that each of these forms of CHO can serve as effective sources of CHO to ingest with PRO in and attempt to promote post-exercise anabolic responses.
BioMed Central
Page 1 of 11
(page number not for citation purposes)
Journal of the International Society
of Sports Nutrition
Open Access
Research article
Effects of ingesting protein with various forms of carbohydrate
following resistance-exercise on substrate availability and markers
of anabolism, catabolism, and immunity
Richard B Kreider*
1
, Conrad P Earnest
†2
, Jennifer Lundberg
†3
,
Christopher Rasmussen
†1
, Michael Greenwood
†1
, Patricia Cowan
†4
and
Anthony L Almada
5
Address:
1
Exercise & Sport Nutrition Lab, Center for Exercise, Nutrition and Preventive Health, Baylor University, Waco, TX, USA,
2
Preventive
Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA,
3
St. Paul Heart Clinic, St. Paul, MN, USA,
4
College
of Nursing, University of Tennessee Medical School, Memphis, TN, USA and
5
ImagiNutrition, Inc., Laguna Niguel, CA, USA
Email: Richard B Kreider* - richard_kreider@baylor.edu; Conrad P Earnest - conrad.earnest@pbrc.edu;
Jennifer Lundberg - jenlundberg@yahoo.com; Christopher Rasmussen - chris_rasmussen@baylor.edu;
Michael Greenwood - mike_greenwood@baylor.edu; Patricia Cowan - pcowan@utmem.edu;
Anthony L Almada - anthony@imaginutrition.com
* Corresponding author †Equal contributors
Abstract
Background: Ingestion of carbohydrate (CHO) and protein (PRO) following intense exercise has
been reported to increase insulin levels, optimize glycogen resynthesis, enhance PRO synthesis, and
lessen the immuno-suppressive effects of intense exercise. Since different forms of CHO have
varying glycemic effects, the purpose of this study was to determine whether the type of CHO
ingested with PRO following resistance-exercise affects blood glucose availability and insulin levels,
markers of anabolism and catabolism, and/or general immune markers.
Methods: 40 resistance-trained subjects performed a standardized resistance training workout
and then ingested in a double blind and randomized manner 40 g of whey PRO with 120 g of
sucrose (S), honey powder (H), or maltodextrin (M). A non-supplemented control group (C) was
also evaluated. Blood samples were collected prior to and following exercise as well as 30, 60, 90,
and 120 min after ingestion of the supplements. Data were analyzed by repeated measures ANOVA
or ANCOVA using baseline values as a covariate if necessary.
Results: Glucose concentration 30 min following ingestion showed the H group (7.12 ± 0.2 mmol/
L) to be greater than S (5.53 ± 0.6 mmol/L; p < 0.03); M (6.02 ± 0.8 mmol/L; p < 0.05), and C (5.44
± 0.18 mmol/L; p < 0.0002) groups. No significant differences were observed among groups in
glucose area under the curve (AUC) values, although the H group showed a trend versus control
(p = 0.06). Insulin response for each treatment was significant by time (p < 0.0001), treatment (p
< 0.0001) and AUC (p < 0.0001). 30-min peak post-feeding insulin for S (136.2 ± 15.6 uIU/mL), H
(150.1 ± 25.39 uIU/mL), and M (154.8 ± 18.9 uIU/mL) were greater than C (8.7 ± 2.9 uIU/mL) as
was AUC with no significant differences observed among types of CHO. No significant group ×
Published: 12 November 2007
Journal of the International Society of Sports Nutrition 2007, 4:18 doi:10.1186/1550-2783-4-
18
Received: 21 October 2007
Accepted: 12 November 2007
This article is available from: http://www.jissn.com/content/4/1/18
© 2007 Kreider et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0
),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 2 of 11
(page number not for citation purposes)
time effects were observed among groups in testosterone, cortisol, the ratio of testosterone to
cortisol, muscle and liver enzymes, or general markers of immunity.
Conclusion: CHO and PRO ingestion following exercise significantly influences glucose and insulin
concentrations. Although some trends were observed suggesting that H maintained blood glucose
levels to a better degree, no significant differences were observed among types of CHO ingested
on insulin levels. These findings suggest that each of these forms of CHO can serve as effective
sources of CHO to ingest with PRO in and attempt to promote post-exercise anabolic responses.
Background
It has been recommended that athletes ingest CHO and
PRO following exercise in order to enhance glycogen
resynthesis, promote an anabolic hormonal environment,
enhance PRO synthesis, and/or lessen the immuno-sup-
pressive effects of intense exercise [1-5]. These recommen-
dations are based on findings that ingestion of CHO
following exercise increases insulin levels promoting gly-
cogen restoration [6-10]. Additionally, increasing insulin
levels following exercise optimizes an anabolic hormonal
environment and can serve as a potent stimulator of PRO
synthesis pathways [8,11-13]. For example, Zawadzki and
associates [10] reported that adding PRO to a post-exer-
cise CHO supplement promoted a greater increase in
insulin levels and glycogen restoration. Chandler and col-
leagues [14] reported that ingesting CHO and CHO/PRO
immediately following exercise promoted a greater
increase in insulin concentrations than those consuming
PRO only or control groups. Additionally, that subjects
ingesting the CHO/PRO-supplement following exercise
had a greater increase in growth hormone than control
subjects and those ingesting PRO alone [14]. The authors
suggest that this increase in insulin and growth hormone
concentration may facilitate a more favorable environ-
ment for recovery than CHO alone [5,14]. Further, Krae-
mer and coworkers [15] found that ingestion of CHO and
PRO two hours before, immediately following, and dur-
ing three consecutive days of resistance-training increased
blood glucose, insulin, growth hormone, and IGF-1 to a
greater degree than a placebo. Others studies have
reported that the provision of PRO or amino acids prior to
and/or following exercise stimulates PRO synthesis
[3,12,16-22]. Consequently, there is considerable evi-
dence to support recommendations that athletes should
ingest CHO and PRO following exercise in order to opti-
mize glycogen resynthesis, promote an anabolic hormo-
nal environment, and increase PRO synthesis [1-5].
While a number of studies have evaluated the effects of
providing different forms of PRO and amino acids on
recovery and/or training adaptations [12,16,23-27], few
studies have evaluated whether the provision of different
forms of CHO with PRO influences recovery indices. The
type of CHO ingested with PRO is an important consider-
ation because the glycemic index of a CHO may enhance
glycogen storage and/or anabolic responses to exercise by
promoting a greater glucose and insulin response [28,29].
Theoretically, ingesting high glycemic index (GI) CHO
would promote the greatest increase in insulin levels, gly-
cogen resynthesis, and PRO synthesis. On the other hand,
since ingestion of CHO with PRO has been reported to
promote greater increases in insulin [9,28,30,31], it is
possible that the insulin response may be maximized
regardless of GI of the CHO ingested. Moreover, ingesting
different forms of CHO may have other physiological
influences that may optimize recovery. For example,
although ingesting a high GI CHO may promote a rapid
increase in insulin levels, it may be more advantageous to
ingest a moderate GI CHO that may allow for a more
gradual increase in glucose and insulin over time much
like findings indicating that different types of PRO and/or
amino acids have varying effects on anabolism and catab-
olism [32] as well as training adaptations [24,25,27]. The
purpose of this study was to examine whether the type of
CHO ingested with PRO following resistance-exercise has
any effects on blood glucose availability, insulin levels,
markers of anabolism and catabolism, and/or general
immune markers during recovery.
Methods
Subjects
Forty subjects (19 males and 21 females) volunteered to
participate in this study. All subjects had participated in at
least one year of resistance training prior to testing and
were informed of the possible risks of the investigation
before giving their written and informed consent previ-
ously approved by the University of Memphis Institu-
tional Review Board for the use of human subjects.
Baseline testing
Prior to the start of this trial, a familiarization session was
conducted to obtain one-repetition maximum (1RM) for
each of nine Nautilus (Nautilus, Inc., Vancouver, WA, USA)
weight-training exercises used during the experimental
treatment. Exercises included the chest press, seated row,
shoulder press, lat pull, leg extension, leg curl, biceps curl,
triceps extension, and leg press. For the exercises in which
1RM was exceeded by the weights available on an individ-
ual machine, the Epley formula was used to predict 1RM
based on the number of repetitions lifted at a given weight
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 3 of 11
(page number not for citation purposes)
[33]. Rest periods between each 1 RM lifting attempt were
not limited so that the subjects had adequate opportunity
to perform to the best of their ability.
Experimental protocol
Subjects reported to the testing laboratory after abstaining
from exercise for 48-hours prior to testing and fasting
overnight (~12 h). The time of day was standardized
within a 2-h starting time for all subjects in order to min-
imize potential diurnal variation in hormonal concentra-
tions. Upon arrival weight (kg) and height (cm) were
recorded. Subjects then donated a pre-exercise baseline
blood samples prior to starting the resistance-training
workout. Each subject performed 3 sets of 10 repetitions
at approximately 70% of 1 RM on nine exercises as
described above. Each set of exercise was interspersed with
a 2-minute rest period and research assistants monitored
all sessions. If a participant could not complete the full 10
repetitions the weight was reduced so 10 repetitions could
be completed during the following set of exercise. During
each set, the weight lifted and the number of repetitions
performed was recorded for each subject in order to calcu-
late total lifting volume. Following the completion of the
workout, subjects returned to the laboratory and donated
a post exercise blood sample.
Supplementation
After the post-exercise blood sample was obtained, sub-
jects received in a double blind and randomized manner
a CHO and PRO supplement containing 40 g of whey
PRO with 120 g of sucrose (S), powdered honey (H), or
maltodextrin (M). The remaining group served as a non-
supplemented control group. These forms of CHO were
selected because prior research in our lab demonstrated
that ingesting 50 g of gel forms of these CHO's resulted in
significantly different glucose and insulin profiles [34].
The H powder (ADM Arkady, Olathe, KS, USA) contained
a 95% mixed CHO source containing fructose (31.5%),
glucose (26%), wheat starch (25.3%), soluble fiber
(12.5%) and maltose (4.7%). The supplements were sim-
ilarly colored, flavored and packaged for double-blind
administration by an independent food-packaging lab
(Paragon Labs, Torrance, CA, USA). Research assistant's
blended pre-measured volumes of the powder into 16
ounces of water to form a milk shake type drink. Subjects
were given as much time as needed to ingest the supple-
ments which typically was less than 5-min. Once the sub-
ject consumed the supplement, a timer was started and
blood samples were taken at 30, 60, 90, and 120-min dur-
ing recovery. A similar time frame for collection of blood
samples was employed for the control group. Subjects
remained seated during the recovery period. As blood
samples were collected, subjects were asked to respond to
a questionnaire assessing the severity of hypoglycemia,
dizziness, fatigue, headache, and stomach upset they
experienced throughout the experiment. Questions were
asked on a scale of 0–10 with 0 having no symptoms and
10 being most severe.
Blood analysis
During the pre-exercise baseline blood collection period,
blood samples were obtained by a qualified nurse/phle-
botomist using standardized venipuncture techniques.
Following exercise, subjects were fitted with a 20G × 1"
Jelco™ intravenous catheter (Johnson & Johnson Medical,
Arlington, TX, USA). Once the catheter was inserted and
stabilized, a locking luer male adapter plug with an inter-
mittent injection site was then connected to the female
end of the catheter. A Vacutainer™ needle (Becton Dickin-
son and company, Franklin Lakes, NJ, USA) was then
attached to a Vacutainer holder in which the needle was
inserted into the injection site of the adapter plug.
Approximately 15 mL of venous blood was collected into
two separate 6 mL labeled Vacutainer brand SST™ tubes
and 5 mL into an EDTA Vacutainer tube (Becton Dickinson
and Co., Franklin Lakes, NJ, USA). Once the blood samples
were obtained, approximately 2–3 mL of Bacteriostatic
0.9% sodium chloride (Abbott Laboratories, North Chicago,
IL, USA) was infused into the catheter line using a syringe.
Once the line was cleared with saline, the catheter was
locked to prevent clotting of blood in the line between
sampling intervals.
Blood samples were then centrifuged for 10 minutes at
3000 rpm in an Adams Physicians Compact Centrifuge
(Clay Adams, Parsippany, NJ, USA). One of the SST tubes
was divided into four labeled 2.0 mL Costar micro centri-
fuge tubes (Corning Inc., Corning, NY, USA) and frozen in
a So-Low Ultra freezer (Environmental Equipment, Cincin-
nati, OH, USA) at -80°C for subsequent hormonal analy-
sis. The second SST tube and an EDTA tube were sent to
Quest Diagnostics (Minneapolis, MN, USA) for analysis of
glucose, muscle and liver enzymes. Serum samples were
assayed using a Technicon DAX model 96-0147 auto-
mated chemistry analyzer (Technicon Inc. Terry Town, NY,
USA) following standard clinical procedures. Whole
blood cell counts with percent differentials were run on
whole blood samples using a Coulter STKS automated
analyzer using standard procedures (Coulter Inc., Hialeah,
FL, USA). These analyzers were calibrated daily to controls
according to manufacturer's recommendations and fed-
eral guidelines for clinical diagnostic laboratories. Test to
test reliability of performing these assays ranged from 2 to
6% for individual assays with an average variation of ±
3%. Samples were run in duplicate to verify results if the
observed values were outside control values and/or clini-
cal norms according to standard procedures. Blood sam-
ples were assayed for each variable at all data points with
the exception that creatine kinase was only measured at
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 4 of 11
(page number not for citation purposes)
baseline, following exercise, and 120 minutes following
supplementation.
Frozen serum samples were assayed at the Exercise Bio-
chemistry Lab at the University of Memphis using stand-
ardized spectrophotometric and enzymatic immunoassay
procedures. Each sample was thawed only once and
decoded only after all the analyses were completed. The
quantitative measurement of insulin was determined
using the DSL-10-1600 ACTIVE™ insulin Enzyme-Linked
Immunosorbent (ELISA) Kit (Diagnostic Systems Laborato-
ries, Webster, TX, USA). All insulin assays were completed
in duplicate and read at 450 and 600 nm with an MRX
Microplate Reader (Dynatech Laboratories, Chantilly, VA,
USA) in ambient conditions averaging 27°C and 23% rel-
ative humidity. Outlying concentrations with coefficients
of variability > 10% were removed to provide the best fit-
ting curve. The intra-assay coefficient of variability for
insulin measurements was 3.4% while the inter-assay
coefficient of variability was 5.2%. The best fitting curve
provided an r
2
value of 0.9916 for insulin. Testosterone
and cortisol were assayed in the same manner as insulin
using ACTIVE™ DSL-10-4000 and DSL-10-2000 Enzyme
Immunoassay (EIA) kits, respectively. The testosterone
and cortisol mean coefficient of variability was 2.6% and
2.3% respectively. Inter-assay coefficient of variability for
testosterone and cortisol were 13.8% and 11%, respec-
tively. The best fitting curve provided an r
2
value of
0.9996 for testosterone and 0.9668 for cortisol.
Data analysis
Data were analyzed using Statview for Windows (SAS
Institute, Cary, NC). A three-way multivariate analysis of
variance (MANOVA) was utilized to examine gender ×
group × time interactions. As noted below, although some
gender effects were observed, no significant group × time
× gender differences were observed. Therefore, two-way
repeated measures analysis of variance (ANOVA) was uti-
lized to evaluate treatment, time, and treatment × time
interactions. Least square significant difference (LSD)
post-hoc analyses were used when significant ANOVA
effects were observed. For values that where significant
between groups at baseline, repeated measures ANCOVA
analyses were employed. Consequent to randomization
procedures, total lifting volume, fasting glucose and insu-
lin concentrations were different between groups. Thus,
covariate adjustments were made to the repeated meas-
ures analysis and AUC measures using these three varia-
bles. Delta concentrations were also calculated on post-
exercise responses by subtracting 30, 60, 90, and 120-
minute concentrations from the immediate un-fed/post-
exercise concentration for glucose, insulin, testosterone
and cortisol so as to determine integrated area under the
curve (AUC) via trapezoidal rules. Data are presented as
means and ± SEM.
Results
Subject demographics
Demographic data for each treatment group are presented
in Table 1. Body mass adjusted 1 RM for the nine exercises
were: chest press (0.83 ± .04 kg·kg
-1
), seated row (1.37 ±
0.06 kg·kg
-1
), shoulder press (0.70 ± 0.05 kg·kg
-1
), lat
pull (0.79 ± 0.03 kg·kg
-1
), leg extension (1.0 ± 0.06
kg·kg
-1
), leg curl (0.51 ± 0.03 kg·kg
-1
), biceps curl (0.62
± 0.03 kg·kg
-1
), triceps extension (0.66 ± 0.04 kg·kg
-1
)
and leg press (2.0 ± 0.1 kg·kg
-1
). After adjustments were
made during the exercise treatment in order to complete 3
sets of 10 repetitions per exercise, the mean percentage of
maximum weight lifted during the weight training stimu-
lus were as follows: chest press (66.6% ± 1.5), seated row
(69.1% ± 1.1), shoulder press (62.1% ± 1.3), lat pull
down (69.5% ± 0.7), leg extension (64.5% ± 2.0), leg curl
(60.8% ± 2.3), biceps curl (64.3% ± 1.1), triceps extension
(67.7% ± 1.0), and leg press (67.9% ± 1.3). The total lift-
ing volume for each treatment group was: control (11,783
± 1,618 kg), sucrose (11,447 ± 1,368 kg), honey (13,049
± 1,320 kg), and maltodextrin (14,410 ± 2,006 kg). No
significant differences were observed among groups in
total lifting volume (p = 0.18).
Gender analysis
Gender analysis revealed that testosterone (p = 0.001) and
the ratio of testosterone to cortisol (p = 0.001) values were
significantly lower in women than men. However, no gen-
der differences were observed in cortisol (p = 0.33). Like-
wise, no group × gender interactions were observed for
cortisol (p = 0.57), testosterone (p = 0.77), or the ratio of
testosterone to cortisol (p = 0.43). Moreover, no signifi-
cant group × time × gender interactions were observed in
cortisol (p = 0.10), testosterone (p = 0.88) or the ratio of
cortisol to testosterone (p = 0.54). Therefore, data were
Table 1: Demographic data
CSHM
Age (y)
x 20.9 24.0 23.3 24.7
± 0.7 1.0 1.1 1.6
Weight (kg)
x 72.4 71.2 70.7 84.5
± 5.9 4.0 4.8 7.1
Height (cm)
x 171.2 171.3 171.2 175.8
± 3.4 5.0 3.7 3.6
Training Volume (days/wk)
x 4.2 4.2 4.1 3.7
± 0.5 0.3 0.4 0.3
Last meal (hrs)
x 10.9 11.0 12.0 11.8
± 0.8 0.7 0.5 0.5
x Represents mean value
± Represents standard error of mean
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 5 of 11
(page number not for citation purposes)
analyzed by a two-way ANOVA and are presented as
means for men and women combined.
Glucose and insulin
Figure 1 presents glucose while Figure 2 shows insulin
concentrations observed during the experiment. Repeated
measures ANCOVA revealed within (p < 0.01) and
between group treatment effects for blood glucose con-
centration (p = 0.056). Within group post-hoc compari-
sons showed the H group glucose concentrations reached
a significant peak 30-min following ingestion compared
to baseline and post-workout concentrations (p < 0.05).
Plasma glucose then declined to a lower concentration
(i.e., versus 30-min) at 60, 90, and 120-min (p < 0.05).
Glucose concentrations in the S group followed a similar
post-feeding response, as 30-minute post ingestion con-
centrations were higher than 60 or 90-minute concentra-
tions (p < 0.05), but not different than the immediate post
workout/un-fed concentration.
Between-group treatment effects were also noted for
plasma glucose concentrations (p < 0.056) as post-hoc
analysis revealed 30 min glucose concentrations for the H
group (7.12 ± 0.2 mmol/L) to be greater than S (5.53 ± 0.6
mmol/L; p < 0.03); M (6.02 ± 0.8 mmol/L; p < 0.05), and
C (5.44 ± 0.18 mmol/L; p < 0.0002). At 60 min following
ingestion, the H group was still greater than the S group (p
< 0.02). The M group was also greater than C 30 min fol-
lowing ingestion (p < 0.03). No between group differ-
ences were observed at 90 and 120 min. Figure 3 shows
AUC data for glucose while Figure 4 presents insulin AUC
data. Blood glucose AUC values showed a significant
treatment effect (p < 0.03) as post-hoc analysis showed
the H treatment glucose concentration tending to be
greater than C group values (p < 0.06).
Significant effects for time (p < 0.0001), treatment (p <
0.00001) and AUC (p < 0.0001) were observed in insulin
values. Insulin concentrations (p < 0.05) and insulin AUC
values (p < 0.05) were significantly higher than C values
at 30, 60 90 120 min (p < 0.05) in the S, H, and M groups.
30-min peak post-feeding insulin for S (136.2 ± 15.6 uIU/
mL), H (150.1 ± 25.3 uIU/mL), and M (154.8 ± 18.9 uIU/
mL) were greater than C (8.7 ± 2.9 uIU/mL) as was the
change in AUC after ingestion of the supplements (C -243
± 162 uIU/mL; S 7,527 ± 883 uIU/mL; H 8,656 ± 1,758
Glucose AUC responsesFigure 3
Glucose AUC responses. Data (mean ± SE) represent the
change in AUC values observed following supplementation for
glucose (top panel) and insulin (bottom panel). * represents (p
< 0.05) difference from control.
-60
-40
-20
0
20
40
60
80
100
120
Control Sucrose Honey Maltodextrin
mmol/L
*
Glucose responsesFigure 1
Glucose responses. Data (mean ± SE) represent individual
treatment time measures for glucose (top panel) and insulin
(bottom panel) for the control (diamond), sucrose (circle),
honey (square), and maltodextrin (triangle) groups. Lower
script values represent statistical significance where: a > post-
exercise condition; b > control, c > honey, d > maltodextrin, e
> sucrose, f < baseline, g < post-exercise, h > baseline. Other
areas of significance are detailed in the "Results" section.
a, b, d, e, h, i, j
b
e
3.00
4.00
5.00
6.00
7.00
8.00
9.00
Baseline Post 30 60 90 120
Time (min)
mmol/L
a,b,d,e,h,i,j
b
h,i
c
Insulin responsesFigure 2
Insulin responses. Data (mean ± SE) represent individual
treatment time measures for glucose (top panel) and insulin
(bottom panel) for the control (diamond), sucrose (circle),
honey (square), and maltodextrin (triangle) groups. Lower
script values represent statistical significance where: a > post-
exercise condition; b > control, c > honey, d > maltodextrin, e
> sucrose, f < baseline, g < post-exercise, h > baseline. Other
areas of significance are detailed in the "Results" section.
0
20
40
60
80
100
120
140
160
180
200
Baseline Post 30 60 90 120
Time (min)
u
IU/mL
a, b, h
a, b, h
a, b, h
a, b, h
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 6 of 11
(page number not for citation purposes)
uIU/mL; M 10,016 ± 974 uIU/mL). However, the type of
CHO ingested with PRO did not significantly affect insu-
lin response.
Anabolic & catabolic hormones
Table 2 presents testosterone, cortisol and the testosterone
to cortisol ratio data observed during the experiment. Sig-
nificant time affects (p < 0.02) were observed for testoster-
one and cortisol concentrations. However, no significant
group × time interactions were observed in testosterone,
cortisol, or the ratio of testosterone to cortisol. Likewise,
no significant differences were observed among groups in
testosterone, cortisol, or the ratio of testosterone to corti-
sol AUC values.
Hepatorenal analysis
Table 3 presents creatinine, blood urea nitrogen (BUN),
and the ratio of BUN to creatine results. Significant time
effects were observed for each of these variables. Nutri-
tional supplementation had no group × time effects on
creatinine and BUN. However, a significant interaction
was observed in the ratio of BUN to creatinine. Post-hoc
analysis revealed that the BUN to creatinine ratio was sig-
nificantly higher toward the end of recovery in the groups
receiving CHO and PRO. However, no differences were
observed among types of supplements investigated.
Muscle and liver enzymes
Table 4 shows muscle and liver enzyme levels observed
during the study. Significant time effects were observed
for creatine kinase (CK) as the postexercise/un-fed and
120-minute post feeding concentrations were higher than
baseline. Mean CK data increased from 136.8 ± 52.8 U/L
at baseline to 264.3 ± 64.3 U/L after exercise and 264.0 ±
63.5 U/L after 120 min following nutritional supplemen-
tation (p < 0.001). No affects were noted for lactate dehy-
drogenase (LDH). Post exercise/un-fed aspartate
aminotransaminase (AST) and alanine aminotransami-
nase (ALT) concentrations were significantly greater than
pre-exercise values. However, AST and ALT levels declined
thereafter. No significant group × time effects were
observed in AST or ALT values among groups.
General immune markers
Table 5 presents general markers of immunity evaluated
in this study. Significant time effects were observed in
WBC, neutrophils, and the ratio of total neutrophils to
total lymphocytes (p < 0.001). However, no significant
group × time interactions were observed.
Side effects
No significant differences were observed among groups in
perceptions of hypoglycemia (p = 0.851), dizziness (p =
0.711), headache (p = 0.422), stomach upset (p = 0.325),
or fatigue (p = 0.837).
Discussion
Ingestion of CHO and PRO following intense exercise has
been reported to increase insulin levels, optimize glyco-
gen resynthesis, enhance PRO synthesis, and lessen the
immuno-suppressive effects of intense exercise
[2,3,8,14,16,35]. Since different forms of CHO have vary-
ing glycemic effects [28,29,34], the purpose of this study
was to determine whether the type of CHO ingested with
PRO following resistance-exercise affects blood glucose
availability, insulin levels, markers of anabolism and
catabolism, and/or general immune markers during the
first two hours of recovery. The major findings of this
study were: 1.) ingesting CHO with PRO following resist-
ance-training promoted significant increases in insulin
levels; 2.) no significant differences were observed among
the forms of CHO ingested on insulin levels suggesting
that each of these types of CHO can be an effective source
of CHO for post-exercise CHO/PRO supplements; 3.) that
glucose levels were maintained to a greater degree in sub-
jects ingesting honey as the source of CHO; and, 4.) post-
exercise nutritional supplementation did not significantly
affect the time course of testosterone, cortisol, the ratio of
testosterone to cortisol, muscle and liver enzyme efflux, or
general markers of immunity during the first two hours of
recovery following resistance-exercise. These findings add
to a growing body of literature indicating that ingestion of
CHO and PRO following exercise can stimulate insulin
levels and thereby anabolic processes [3,5,12,18,20,27].
Moreover, they extend our understanding of how differ-
ent sources of CHO with differing glycemic responses
influence glucose availability, insulin levels, and recovery
indices. The following provides additional insight into the
results observed.
Results from the present study indicate that glucose and
insulin concentrations peaked 30-min following inges-
tion of CHO/PRO and then proceeded to decline for 120-
min. This finding is of interest from a nutrient delivery
and timing standpoint in that it has been suggested that
athletes should ingest CHO and PRO within two hours
following intense exercise in order to optimize the hor-
monal effects of intense exercise and recovery [1,36]. It
has typically been thought that glucose and insulin levels
increase the greatest following ingestion of a high GI form
of CHO and that combining high GI carbohydrates with
PRO would optimize the insulin and glucose response fol-
lowing exercise. For this reason, post-exercise CHO/PRO
supplements often contain dextrose, sucrose, or malto-
dextrin as the source of CHO. However, it is well known
that the GI profile of CHOs may be altered when co-
ingesting CHO with PRO, fat, and/or other nutrients due
to influences on the energy density, osmolality, and/or
gastric emptying rates GI of the meal [30,32,37-40]. Con-
sequently, one can not assume that adding a high GI CHO
to a PRO supplement will yield the most advantageous
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 7 of 11
(page number not for citation purposes)
glucose and insulin response. In support of this conten-
tion, glucose levels were increased to the greatest degree
when ingesting honey as the source of CHO rather than
sucrose or maltodextrin. As noted previously, the honey
powder used in this study contained fructose (31.5%),
glucose (26%), wheat starch (25.3%), and maltose
(4.7%). These findings suggest that it may be more advan-
tageous to ingest a mixture of CHO's with PRO following
exercise in order to promote a more sustained increase in
blood glucose response. However, although ingesting
CHO with PRO significantly increased insulin levels in
comparison to controls, no significant differences were
observe among types of CHO ingested in peak insulin lev-
els (C 8.7 ± 2.9 uIU/mL; S 136.2 ± 15.6 uIU/mL; H 150.1
± 25.3 uIU/mL; M 154.8 ± 18.9 uIU/mL) or AUC values in
insulin observed after ingestion of the supplements (C -
243 ± 162 uIU/mL; S 7,527 ± 883 uIU/mL; H 8,656 ±
1,758 uIU/mL; M 10,016 ± 974 uIU/mL).
It is also interesting to note that glucose values in the H
group stayed above baseline throughout recovery while
values fell below baseline in the S and M groups. Conse-
quently, this form of CHO may help maintain glucose lev-
els and prevent incidents of hypoglycemia that some
individuals may experience when ingesting large amounts
of CHO and PRO. Although we did not measure glycogen
uptake at the muscle, previous research has shown that
ingesting CHO with higher GI following exercise pro-
motes a more rapid resynthesis of muscle glycogen
[28,30,41,42]. Additionally, that ingesting CHO and PRO
following exercise increases muscle glycogen replenish-
ment [6,8,10]. Since co-ingesting CHO with other nutri-
ents influences the energy density, osmolality, gastric
emptying rates, and the GI of the meal [32,37-39], addi-
tional research should evaluate the effects of ingesting dif-
Table 2: Anabolic and Catabolic Hormones
Variable Group Pre Post 30 60 90 120
Testosterone (nmol/L) C x 5.31 5.14 3.65 3.64 3.55 2.60 G p = 0.57
± 1.37 1.38 .88 1.03 1.00 .93 T p = 0.02
S x 3.69 6.11 3.11 3.51 3.53 3.31 G × T p = 0.55
± 1.78 3.29 1.38 2.13 2.08 1.77
H x 3.02 2.73 2.41 2.33 2.35 2.50
± 0.54 0.44 0.36 0.32 0.31 0.25
M x 2.27 2.62 2.09 2.04 1.82 1.51
± 0.67 0.85 0.71 0.60 0.51 0.40
Cortisol C x 517 556 687 441 577 482 G p = 0.23
(nmol/L) ± 89 115 96 85 44 136 T p = 0.00
S x 448 397 526 569 489 294 G × T p = 0.71
± 117 95 97 160 186 36
H x 542 416 477 349 333 257
± 89 568858 5939
M x 508 395 399 406 311 265
± 96 775942 4436
T/C Ratio C x 2.4 2.4 1.9 2.6 2.3 3.3 G p = 0.10
± 0.8 0.9 0.7 1.3 0.9 1.2 T p = 0.09
S x 1.8 2.7 2.0 1.7 2.0 1.9 G × T p = 0.19
± 0.5 1.0 0.7 0.7 0.6 0.5
H x 2.3 2.8 1.9 2.6 2.3 3.3
± 0.8 1.2 0.5 0.9 0.8 1.1
M x 4.3 5.8 3.3 4.5 6.7 5.7
± 1.1 2.4 0.8 1.8 2.4 1.4
x Represents mean value
± Represents standard error of mean
Insulin AUC responsesFigure 4
Insulin AUC responses. Data (mean ± SE) represent the
change in AUC values observed following supplementation for
glucose (top panel) and insulin (bottom panel). * represents (p
< 0.05) difference from control.
-2000
0
2000
4000
6000
8000
10000
12000
Control Sucrose Honey Maltodextrin
u IU/mL
*
*
*
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 8 of 11
(page number not for citation purposes)
ferent forms of CHO with PRO on muscle glycogen
resynthesis following intense exercise.
Post-exercise ingestion of PRO and amino acids have been
reported to stimulate PRO synthesis [3,12,16,19,26].
Additionally, insulin has been reported to be a potent
stimulator of PRO synthesis [3,12,16,18,20]. While there
is some debate whether provision of CHO with PRO and/
or amino acids enhances the effects on PRO synthesis [43]
as well as whether adding PRO or amino acids to CHO
promotes greater glycogen resynthesis [44,45], it is clear
that individuals engaged in intense training need to ingest
these nutrients in order to optimize recovery [1,2,46]. In
the present study, we examined the influence of ingesting
different forms of CHO with PRO on a number of markers
of anabolism and catabolism during recovery in an
attempt to determine whether these nutritional strategies
influenced the acute phase of recovery. Previous research
has indicated that resistance-trained men consuming a
CHO:PRO supplement for one week were found to have
lower cortisol concentrations during supplementation, as
well as higher levels insulin-like growth factor-I following
several days of heavy-resistance exercise [15]. Chandler et
al. [14] also demonstrated that insulin and growth hor-
mone concentrations during recovery from a single heavy-
resistance training session were significantly higher and
testosterone concentrations were lower when subjects
consumed a CHO:PRO supplement immediately before
and 2 h after the workout. The supplements had no effect
on IGF-1 but testosterone concentrations decreased and
were interpreted by the authors to be the result of
increased testosterone clearance [14]. In our trial, testo-
sterone concentrations and the ratio of testosterone to
cortisol significantly increased in response to resistance-
exercise and then declined during the recovery period.
However, the nutritional intervention did not signifi-
cantly influence this response. Interestingly, cortisol levels
increased to the greatest degree in response to exercise in
the non-supplemented control group while decreasing in
the supplemented groups. However, these apparent differ-
ences were not statistically significant. Likewise, signifi-
cant time effects were observed in creatinine, BUN, the
BUN/creatinine ratio, CK, ALT, and AST. However, no sig-
nificant differences were observed among groups with the
exception that the BUN/Creatinine ratio increased signifi-
cantly during recovery following nutritional supplemen-
tation in comparison to the non-supplemented control.
The BUN/Creatinine ratio is a general marker of whole
Table 3: Hepatorenal Variables
Variable Group Pre Post 30 60 90 120
Creatinine (mg/dL) C x 1.0 1.1 1.1 1.0 1.0 1.0 G p = 0.72
± 0.1 0.1 0.1 0.1 0.1 0.1 T p = 0.00
S x 1.11.11.11.11.11.0G × T p = 0.82
± 0 0.1 0.1 0.1 0.1 0.1
H x 1.11.21.11.01.01.0
± 0.1 0.1 0.1 0.1 0.1 0.1
M x 1.21.31.21.11.01.1
± 0.1 0.1 0.1 0.1 0.1 0.1
BUN (mg/dL) C x 13.3 13.7 13 12.9 12.9 12.9 G p = 0.90
± 0.9 0.9 1.1 1.0 1.1 1.0 T p = 0.00
S x 14.3 13.9 13.9 14.6 16 15.8 G × T p = 0.98
± 1.1 0.9 0.9 1 1.1 0.9
H x 14.2 14 13.9 14.1 15.4 15.9
± 1.2 1.2 1.3 1.1 1.3 1.4
M x 14.8 15 14.9 14.1 15.2 16.3
± 1.3 1.2 1.5 0.9 1.0 1.2
BUN/Creatinine
Ratio
C x 12.8 13.1 12.3 12.6 12.5 12.6 G p = 0.70
± 0.5 1.1 0.7 0.5 0.5 0.5 T p = 0.00
S x 13.8 13.4 13.3 14 14.7 16.0* G × T p = 0.04
± 1.3 1.9 1.1 1.1 0.9 1.2
H x 13.6 11.8 12.6 14 15.1* 15.2*
± 1.0 0.9 1.0 1.1 1.2 1.2
M x 12.7 11.6 12.6 13.3 15.1* 14.7
± 0.8 0.7 0.9 0.9 1.2 0.9
x Represents mean value
± Represents standard error of mean
* p < 0.05 versus control
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 9 of 11
(page number not for citation purposes)
body catabolism. Higher levels typically are indicative of
greater PRO degradation. However, the increased BUN/
Creatinine levels observed following supplementation in
the present study were most likely due to the ingestion
and utilization of supplemental PRO.
Finally, research has shown that intense exercise causes an
acute immuno-suppression for several hours after exer-
cise. For this reason, a number of nutritional counter-
measures including CHO and PRO have been proposed to
lessen the immunosuppressive effects of intense exercise
[1,36]. In this study, we examined whether different forms
of CHO influenced general markers of immunity. We
found that WBC, neutrophils, and the total neutrophil to
total lymphocyte ratio were significantly increased in
response to exercise and throughout recovery. These find-
ings support prior findings that intense resistance-training
can promote an immune challenge. However, ingestion of
CHO and PRO had no influence on these responses dur-
ing the acute phase of recovery. Whether, ingestion of
CHO and PRO may influence markers of immunity dur-
ing a more prolonged period of recovery remains to be
determined.
In conclusion, CHO and PRO ingestion following exercise
significantly influences glucose and insulin responses
without significantly altering markers of anabolism,
catabolism or immunity during the first two hours of
recovery. Although ingesting honey as the source of CHO
with PRO tended to maintain blood glucose levels to a
greater degree, no significant differences were observed
among the types of CHO ingested in terms of insulin
response to supplementation. These findings suggest that
each of these types of CHO can serve as effective sources
Table 4: Muscle and Liver Enzymes
Variable Group Pre Post 30 60 90 120
CK (U/L) C x 26 319 - - - 348 G p = 0.48
± 101 112 107 T p = 0.00
S x 187 244 - - - 252 G × T p = 0.67
±3850 61
Hx 138195 - - -184
±2126 25
Mx 196299 - - -272
±5169 61
LDH (U/L) C x 130 187 124 126 133 130 G p = 0.55
± 8 49 7 5 11 9 T p = 0.10
S x 127 189 157 121 124 141 G × T p = 0.95
±637306821
H x 122 142 131 123 121 120
± 566859
M x 132 154 148 125 128 131
± 6910566
AST (U/L) C x 22 28 21 22 22 23 G p = 0.35
± 332232T p = 0.03
S x 22 28 24 21 22 22 G × T p = 0.97
± 232223
H x 19 22 20 19 19 19
± 111111
M x 23 26 24 21 22 22
± 233222
ALT (U/L) C x 14 16 14 14 14 14 G p = 0.25
± 222222T p = 0.00
S x 16 17 15 15 15 15 G × T p = 0.86
± 222222
H x 14 16 14 13 13 14
± 221112
M x 20 21 20 18 17 19
± 233222
x Represents mean value
± Represents standard error of mean
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 10 of 11
(page number not for citation purposes)
of CHO to ingest with PRO following intense resistance-
exercise in an attempt to optimize CHO availability as
well as post-exercise anabolism.
Competing interests
This study was funded by the National Honey Board
(Longmont, CO) under the auspices of the United States
Department of Agriculture (USDA).
Authors' contributions
RBK: Obtained grant, served as PI of study, data analysis,
manuscript preparation
CE: Data analysis and manuscript preparation
JL: Study coordinator and data collection
CR: Lab director, data collection
MG: Data collection and analysis
PC: Medical supervision and data collection
ALA: Research design, assisted in obtaining grant funding,
data analysis
Acknowledgements
We would like to thank the subjects that participated in this study as well
as all the students and laboratory assistants at the University of Memphis
who assisted with data collection and analysis while the Exercise & Sport
Nutrition Lab was located at that university. This study was funded by the
National Honey Board (Longmont, CO) under the auspices of the United
States Department of Agriculture (USDA). All researchers involved inde-
pendently collected, analyzed, and interpreted the results from this study
and have no financial interests concerning the outcome of this investigation.
The results from this study do not constitute endorsement by the authors
and/or their institutions concerning nutrients investigated.
References
1. Campbell B, Kreider RB, Ziegenfuss T, La Bounty P, Roberts M, Burke
D, Landis J, Lopez H, Antonio J: International Society of Sports
Nutrition Position Stand: Protein and Exercise. J Int Soc Sports
Nutr 2007, 4(1):8.
2. Koopman R, Saris WH, Wagenmakers AJ, van Loon LJ: Nutritional
interventions to promote post-exercise muscle protein syn-
thesis. Sports Med 2007, 37(10):895-906.
3. Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK,
Petrini BE, Wolfe RR: Timing of amino acid-carbohydrate
ingestion alters anabolic response of muscle to resistance
exercise. Am J Physiol Endocrinol Metab 2001, 281(2):E197-206.
Table 5: General Immune Markers
Variable Group Pre Post 30 60 90 120
WBC 10
9
/L C x 5.36 6.44 5.85 6.57 7.23 7.67 G p = 0.79
± .41 .84 .64 .62 .70 .68 T p = 0.00
S x 5.46 5.91 5.56 7.13 7.63 7.96 G × T p = 0.82
± .56 .53 .56 .85 .98 .93
H x 5.95 6.20 6.07 7.80 8.33 9.08
± .49 .61 .54 .93 1.03 1.28
M x 5.29 6.20 5.15 6.40 7.48 7.79
± .24 .56 .35 .59 .80 .90
Neutrophils 10
9
/L C x 3.16 4.57 4.38 5.03 5.68 5.91 G p = 0.57
± 0.33 0.85 0.59 0.58 0.68 0.67 T p = 0.00
S x 2.95 3.22 3.91 5.28 5.57 6.64 G × T p = 0.49
± 0.41 0.39 0.50 0.82 0.81 0.81
H x 2.93 3.97 4.31 5.97 6.47 7.00
± 0.37 0.44 0.56 0.92 0.97 1.19
M x 2.85 3.41 3.26 4.35 5.26 5.07
± 0.26 0.46 0.30 0.59 0.80 0.41
Total Neutrophil/
Lymphocyte
Ratio
C x 1.99 3.79 4.07 4.63 5.86 5.08 G p = 0.24
± 0.23 0.98 0.58 0.47 1.06 0.67 T p = 0.00
S x 1.48 1.55 4.58 4.25 3.70 5.12 G × T p = 0.45
± 0.15 0.19 1.40 0.89 0.72 1.35
H x 1.68 2.15 3.56 5.63 6.02 5.95
± 0.22 0.21 0.75 1.57 1.54 1.47
M x 1.64 1.86 2.12 3.38 3.64 3.64
± 0.20 0.36 0.28 0.51 0.49 0.47
x Represents mean value
± Represents standard error of mean
* p < 0.05 versus control
Journal of the International Society of Sports Nutrition 2007, 4:18 http://www.jissn.com/content/4/1/18
Page 11 of 11
(page number not for citation purposes)
4. Tipton KD, Wolfe RR: Exercise, protein metabolism, and mus-
cle growth. Int J Sport Nutr Exerc Metab 2001, 11(1):109-132.
5. Conley MS, Stone MH: Carbohydrate ingestion/supplementa-
tion or resistance exercise and training. Sports Med 1996,
21(1):7-17.
6. Roy BD, Tarnopolsky MA: Influence of differing macronutrient
intakes on muscle glycogen resynthesis after resistance
exercise. J Appl Physiol 1998, 84(3):890-896.
7. Ivy JL: Glycogen resynthesis after exercise: effect of carbohy-
drate intake. Int J Sports Med 1998, 19(Suppl 2):S142-145.
8. Tarnopolsky MA, Bosman M, Macdonald JR, Vandeputte D, Martin J,
Roy BD: Postexercise protein-carbohydrate and carbohy-
drate supplements increase muscle glycogen in men and
women. J Appl Physiol 1997, 83(6):1877-1883.
9. Zachwieja J, Costil DL, Fink WJ: Carbohydrate ingestion during
exercise: effects on muscle glycogen resynthesis after exer-
cise. Int J Sport Nutr 1993, 3:418-430.
10. Zawadzki KM, Yaspelkis BB 3rd, Ivy JL: Carbohydrate-protein
complex increases the rate of muscle glycogen storage after
exercise. J Appl Physiol 1992, 72(5):1854-1859.
11. Hakkinen K, Pakarinen A: Acute hormonal responses to two dif-
ferent fatiguing heavy-resistance protocols in male athletes.
J Appl Physiol 1993, 74(2):882-887.
12. Rasmussen BB, Tipton KD, Miller SL, Wolf SE, Wolfe RR: An oral
essential amino acid-carbohydrate supplement enhances
muscle protein anabolism after resistance exercise. J Appl
Physiol 2000, 88(2):386-392.
13. Tarnopolsky MA, Dyson K, Atkinson SA, MacDougall D, Cupido C:
Mixed carbohydrate supplementation increases carbohy-
drate oxidation and endurance exercise performance and
attenuates potassium accumulation. Int J Sport Nutr 1996,
6(4):323-336.
14. Chandler RM, Byrne HK, Patterson JG, Ivy JL: Dietary supplements
affect the anabolic hormones after weight-training exercise.
J Appl Physiol 1994, 76(2):839-845.
15. Kraemer WJ, Volek JS, Bush JA, Putukian M, Sebastianelli WJ: Hor-
monal responses to consecutive days of heavy-resistance
exercise with or without nutritional supplementation.
J Appl
Physiol 1998, 85(4):1544-1555.
16. Tipton KD, Elliott TA, Cree MG, Aarsland AA, Sanford AP, Wolfe RR:
Stimulation of net muscle protein synthesis by whey protein
ingestion before and after exercise. Am J Physiol Endocrinol Metab
2007, 292(1):E71-76.
17. Biolo G, Fleming RY, Maggi SP, Nguyen TT, Herndon DN, Wolfe RR:
Inverse regulation of protein turnover and amino acid trans-
port in skeletal muscle of hypercatabolic patients. J Clin Endo-
crinol Metab 2002, 87(7):3378-3384.
18. Biolo G, Williams BD, Fleming RY, Wolfe RR: Insulin action on
muscle protein kinetics and amino acid transport during
recovery after resistance exercise. Diabetes 1999,
48(5):949-957.
19. Biolo G, Tipton KD, Klein S, Wolfe RR: An abundant supply of
amino acids enhances the metabolic effect of exercise on
muscle protein. Am J Physiol 1997, 273(1 Pt 1):E122-129.
20. Biolo G, Declan Fleming RY, Wolfe RR: Physiologic hyperinsuline-
mia stimulates protein synthesis and enhances transport of
selected amino acids in human skeletal muscle. J Clin Invest
1995, 95(2):811-819.
21. Biolo G, Maggi SP, Williams BD, Tipton KD, Wolfe RR: Increased
rates of muscle protein turnover and amino acid transport
after resistance exercise in humans. Am J Physiol 1995, 268(3 Pt
1):E514-520.
22. Biolo G, Wolfe RR: Insulin action on protein metabolism. Bail-
lieres Clin Endocrinol Metab 1993, 7(4):989-1005.
23. Dangin M, Boirie Y, Guillet C, Beaufrere B: Influence of the pro-
tein digestion rate on protein turnover in young and elderly
subjects. J Nutr 2002, 132(10):3228S-3233S.
24. Kerksick CM, Rasmussen C, Lancaster S, Starks M, Smith P, Melton
C, Greenwood M, Almada A, Kreider R: Impact of differing pro-
tein sources and a creatine containing nutritional formula
after 12 weeks of resistance training. Nutrition 2007,
23(9):647-656.
25. Kerksick CM, Rasmussen CJ, Lancaster SL, Magu B, Smith P, Melton
C, Greenwood M, Almada AL, Earnest CP, Kreider RB: The effects
of protein and amino acid supplementation on performance
and training adaptations during ten weeks of resistance
training. J Strength Cond Res 2006, 20(3):643-653.
26. Tipton KD, Elliott TA, Cree MG, Wolf SE, Sanford AP, Wolfe RR:
Ingestion of casein and whey proteins result in muscle anab-
olism after resistance exercise. Med Sci Sports Exerc 2004,
36(12):2073-2081.
27. Willoughby DS, Stout JR, Wilborn CD: Effects of resistance train-
ing and protein plus amino acid supplementation on muscle
anabolism, mass, and strength. Amino Acids 2007,
32(4):467-477.
28. Burke L, Hargreaves M: Muscle glycogen storage after pro-
longed exercise: Effect of the glycemic index of carbohydrate
feedings. J Appl Physiol 1993, 75:1019-1023.
29. Burke LM, Collier GR, Hargreaves M: Glycemic index – a new tool
in sport nutrition? Int J Sport Nutr 1998, 8(4):401-415.
30. Burke LM, Collier GR, Hargreaves M: Muscle glycogen storage
after prolonged exercise: effect of the glycemic index of car-
bohydrate feedings. J Appl Physiol 1993, 75(2):1019-1023.
31. van Loon LJ, Saris WH, Kruijshoop M, Wagenmakers AJ: Maximiz-
ing postexercise muscle glycogen synthesis: carbohydrate
supplementation and the application of amino acid or pro-
tein hydrolysate mixtures. Am J Clin Nutr 2000, 72(1):106-111.
32. Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, Beaufrere B:
Slow and fast dietary proteins differently modulate post-
prandial protein accretion. Proc Natl Acad Sci USA 1997,
94(26):14930-14935.
33. Mayhew JL, Prinster JL, Ware JS, Zimmer DL, Arabas JR, Bemben MG:
Muscular endurance repetitions to predict bench press
strength in men of different training levels. J Sports Med Phys
Fitness 1995, 35(2):108-113.
34. Rasmussen C, Kreider R, Lundberg JJ, Cowan P, Greenwood M, Ear-
nest C, Almada A: Analysis of the glycemic index and insulin
response index of ingesting various carbohydrate gels. FASEB
J 2000, 14:A489.
35. Cribb PJ, Hayes A: Effects of supplement timing and resistance
exercise on skeletal muscle hypertrophy.
Med Sci Sports Exerc
2006, 38(11):1918-1925.
36. Nieman DC, Bishop NC: Nutritional strategies to counter
stress to the immune system in athletes, with special refer-
ence to football. J Sports Sci 2006, 24(7):763-772.
37. Maughan RJ, Leiper JB, Vist GE: Gastric emptying and fluid avail-
ability after ingestion of glucose and soy protein hydrolysate
solutions in man. Exp Physiol 2004, 89(1):101-108.
38. Vist GE, Maughan RJ: The effect of osmolality and carbohydrate
content on the rate of gastric emptying of liquids in man. J
Physiol 1995, 486(Pt 2):523-531.
39. Wisen O, Hellstrom PM, Johansson C: Meal energy density as a
determinant of postprandial gastrointestinal adaptation in
man. Scand J Gastroenterol 1993, 28(8):737-743.
40. Burke LM, Collier GR, Beasley SK, Davis PG, Fricker PA, Heeley P,
Walder K, Hargreaves M: Effect of coingestion of fat and protein
with carbohydrate feedings on muscle glycogen storage. J
Appl Physiol 1995, 78(6):2187-2192.
41. Blom P, Hostmark A, Vaage O, Kardel K, Maehlum S: Effects of dif-
ferent post-exercise sugar diets on the rate of muscle glyco-
gen synthesis. Med Sci Sports Exerc 1987, 19:491-496.
42. Burke LM, Collier GR, Davis PG, Fricker PA, Sanigorski AJ, Har-
greaves M: Muscle glycogen storage after prolonged exercise:
effect of the frequency of carbohydrate feedings. Am J Clin Nutr
1996, 64(1):115-119.
43. Koopman R, Beelen M, Stellingwerff T, Pennings B, Saris WH, Kies
AK, Kuipers H, van Loon LJ: Coingestion of carbohydrate with
protein does not further augment postexercise muscle pro-
tein synthesis. Am J Physiol Endocrinol Metab 2007,
293(3):E833-842.
44. Jentjens R, Van Loon LJ, Mann CH, Wagenmakers AJ, Jeukendrup AE:
Addition of protein and amino acids to carbohydrates does
not enhance postexercise muscle glycogen synthesis. J Appl
Physiol 2001, 91:839-846.
45. van Hall G, Shirreffs SM, Calbet JA: Muscle glycogen resynthesis
during recovery from cycle exercise: no effect of additional
protein ingestion.
J Appl Physiol 2000, 88(5):1631-1636.
46. Ivy JL: Dietary strategies to promote glycogen synthesis after
exercise. Can J Appl Physiol 2001, 26(Suppl):S236-245.
    • "These positive effects are in part related to a more powerful insulin secretion [54]. With regard to resistance training, the ingestion of 40 g of whey protein with 120 of sucrose, honey powder or maltodextrine (1:3 protein to carbohydrate ratio) following a typical resistance training workout involving 9 exercises of 3 sets per 10 rep at 70% 1RM, did significantly influence glucose and insulin responses without significantly altering markers of anabolism, catabolism or immunity during the first two hours of recovery [18]. Multinutrients supplements containing whey protein, carbohydrates, amino acids, and other natural compounds such a creatine may optimize recovery time and training induced adaptation192021575859. "
    [Show abstract] [Hide abstract] ABSTRACT: Athletes and recreationally resistance-trained individuals often use protein supplements in an attempt to maximize their training gains and performance. Because of the high bioavailability and solubility and its higher proportion of essential amino acids including Leucine, whey protein extract has been proposed as the best optimal form of protein for strength and power athletes. The objective of this review is to examine the current evidence for the efficacy of whey protein containing supplements to optimize strength training adaptation and outcomes for regular resistance training practitioners. A limited numbers of studies have reported positive effects of whey protein containing supplements (including those with carbohydrate and creatine) for optimizing the anabolic responses and adaptations process in resistance-trained individuals. In order to promote a more anabolic environment and maximize muscle protein synthesis along the day, an eating pattern behavior involving frequents meals (every 3 to 5 h) containing 17 to 20 g of high quality protein (200 to 250 mg/ kg) providing 8 to 10 g of EAA (90 to 110 mg/kg) and about 2 g of Leucine (20 to 25 mg/kg) have been recommended. Special attention should be given to the periworkout hours where the ingestion of whey proteins combined with carbohydrates, creatine monohydrate (0.1 g/kg/d) and other proteins sources such as casein before, during and after workout have been shown to improve training adaptations and enhance the recovery process. However, when considering that the training conditions (workout volume, organization, number of exercises) used in the available studies are substantially different than what athletes actually perform. Optimal whey protein supplementation protocols need to specifically be based on the regular resistance training workout organization and would probably need to consider other doses and timing strategies than what is currently recommended.
    Full-text · Article · Jan 2013 · Applied Physiology Nutrition and Metabolism
    • "A recent study by Kreider and colleagues [431] found that protein and carbohydrate supplementation post workout was capable of positively supporting the post exercise anabolic response. In the last few years many studies have agreed with these findings in that post workout supplementation is vital to recovery and training adaptations [13,104,431432433 . These findings underscore the importance of post-exercise carbohydrate and protein ingestion to support muscle anabolism and strength. "
    [Show abstract] [Hide abstract] ABSTRACT: Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.
    Full-text · Article · Feb 2010
    • "In addition, the different CHO solutions in each of the drinks may have affected postprandial insulin response , which may have influenced protein metabolism. However, a previous study indicated that postprandial insulin response was not significantly different between different CHO solutions co-ingested with protein post resistance exercise (Kreider et al. 2007 ). Therefore, the different CHO solutions would not appear to affect protein metabolism and thus the attenuation of EIMD differently. "
    [Show abstract] [Hide abstract] ABSTRACT: Exercise-induced muscle damage (EIMD) leads to the degradation of protein structures within the muscle. This may subsequently lead to decrements in muscle performance and increases in intramuscular enzymes and delayed-onset muscle soreness (DOMS). Milk, which provides protein and carbohydrate (CHO), may lead to the attenuation of protein degradation and (or) an increase in protein synthesis that would limit the consequential effects of EIMD. This study examined the effects of acute milk and milk-based protein-CHO (CHO-P) supplementation on attenuating EIMD. Four independent groups of 6 healthy males consumed water (CON), CHO sports drink, milk-based CHO-P or milk (M), post EIMD. DOMS, isokinetic muscle performance, creatine kinase (CK), and myoglobin (Mb) were assessed immediately before and 24 and 48 h after EIMD. DOMS was not significantly different (p > 0.05) between groups at any time point. Peak torque (dominant) was significantly higher (p < 0.05) 48 h after CHO-P compared with CHO and CON, and M compared with CHO. Total work of the set (dominant) was significantly higher (p < 0.05) 48 h after CHO-P and M compared with CHO and CON. CK was significantly lower (p < 0.05) 48 h after CHO-P and M compared with CHO. Mb was significantly lower (p < 0.05) 48 h after CHO-P compared with CHO. At 48 h post-EIMD, milk and milk-based protein-CHO supplementation resulted in the attenuation of decreases in isokinetic muscle performance and increases in CK and Mb.
    Full-text · Article · Aug 2008
Show more

Recommended publications

Discover more