| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Human Biology, Maastricht University, 6200 MD Maastricht; and Department of Internal Medicine, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
ACKNOWLEDGEMENTS
FOOTNOTES
REFERENCES
ABSTRACT 
Oostenbrug, G. S., R. P. Mensink, M. R. Hardeman, T. De
Vries, F. Brouns, and G. Hornstra. Exercise performance, red blood
cell deformability, and lipid peroxidation: effects of fish oil and
vitamin E. J. Appl. Physiol. 83(3):
746-752, 1997.
Previous studies have indicated that fish oil
supplementation increases red blood cell (RBC) deformability, which may
improve exercise performance. Exercise alone, or in combination with an
increase in fatty acid unsaturation, however, may enhance lipid
peroxidation. Effects of a bicycle time trial of ~1 h on RBC
characteristics and lipid peroxidation were, therefore, studied in 24 trained cyclists. After 3 wk of fish oil supplementation (6 g/day),
without or with vitamin E (300 IU/day), trial performance,
RBC characteristics, and lipid peroxidation were measured
again. RBC deformability appeared to decrease during
endurance exercise. After correction for hemoconcentration, plasma
total tocopherol concentrations decreased by 0.77 µmol/l
(P = 0.012) or 2.9% and carotenoid
concentrations by 0.08 µmol/l (P = 0.0008) or 4.5%. Endurance exercise did not affect the lag time and
rate of in vitro oxidation of low-density lipoproteins (LDLs), but the
maximum amount of conjugated dienes formed decreased by 2.1 ± 1.0 µmol/mmol LDL cholesterol (P = 0.042) or 1.2%. Fish oil supplementation with and
without vitamin E did not affect RBC characteristics or exercise
performance. Both supplements decreased the rate of LDL oxidation, and
fish oil supplementation with vitamin E delayed oxidation. The amount
of dienes, however, was not affected. The supplements also did not
change effects of exercise. We conclude that the changes observed
during endurance exercise may indicate increased oxidative stress, but
further research is necessary to confirm this. Fish oil supplementation does not improve endurance performance, but it also does not cause or
augment changes in antioxidant levels or LDL oxidation during exercise.
oxidative stress; diet; unsaturated fatty acids; antioxidants
INTRODUCTION THE DEFORMABILITY OF RED BLOOD CELLS (RBCs) decreases
during exercise (8, 29), which may impede blood flow through various regions of the microcirculation (23). The reduced
deformability may, at least partly, be due to increased production of
free radicals during exercise, which induces peroxidation of
unsaturated fatty acids in membrane phospholipids and polymerization of
membrane proteins (26). Several studies have also indicated that
dietary fish oils increase the deformability of RBC as a result of the incorporation of (n-3) fatty acids in the membrane (4, 28) and
facilitate the transport of RBC through the microcirculation (3).
Therefore, fish oil supplementation may enhance oxygen supply to
muscles and improve exercise performance.
However, incorporation of the highly unsaturated fatty acids in
membranes may increase the membranes' susceptibility to lipid peroxidation, especially in combination with exercise. Previously, we
(21) have reported that the susceptibility to oxidation of low-density
lipoproteins (LDLs) was increased by 20% after fish oil
supplementation and that this potentially unbeneficial effect could be counteracted by the antioxidant vitamin E.
Therefore, we have investigated the effects of exercise and fish oil
supplementation, with or without vitamin E, on the deformability of
RBCs and lipid peroxidation and the effects of the supplements on
exercise performance.
METHODS Subjects and Study Design
max) of each participant was
determined. Four to 7 days later, the subjects performed
an endurance exercise test on a cycle ergometer. For the next 3 wk,
eight subjects received a placebo supplement (P group), eight subjects
received a fish oil supplement (F group; 6 g of fish oil daily), and
eight subjects received the fish oil supplement together with vitamin E
(FE group; Ephynal 300, 300 IU DL-
-tocopherol acetate
daily). Data from previous studies (11, 12, 14, 21, 29) indicated that eight subjects in each group were sufficient to detect, with a power of
80%, a difference in change between the experimental groups for RBC
deformability of <2%, for endurance performance of 7%, and for LDL
oxidation in vitro of 10%. The three groups were stratified for
max, and, as far as possible, one subject from each
group was tested on the same day. At the end of the study, exercise
testing procedures were repeated.
Placebo capsules, containing microcrystalline cellulose, were supplied
by the pharmacy of the Academic Hospital Maastricht (Maastricht, The
Netherlands). The fish oil capsules (Fish-EPA) were a generous gift
from Orthica (Weesp, The Netherlands), and Ephynal 300 capsules were
from Hoffmann-La Roche (Basel, Switzerland). The fish oil capsules
contained (wt/wt) 17.6% eicosapentaenoic acid [(EPA) C20:5
(n-3)] and 12.5% docosahexaenoic acid [(DHA) C22:6
(n-3)], and only 0.12% vitamin E (0.01% 
-tocopherol, 0.03% 
+
-tocopherol, 0.08% -tocopherol), as analyzed by gas
chromatography and high-performance liquid chromatography (HPLC),
respectively.
Exercise Performance Protocols
max test.
max was determined during an incremental cycle
ergometer test with 3-min intervals (16). Oxygen uptake was measured
continuously (Oxycon Delta, Mijnhard, The Netherlands).
max of each subject, as measured the week before
supplementation started, was used for both endurance exercise tests.
The second max test, performed after 15-17
days of supplementation, was used to detect changes in
max and plasma lactate concentrations due
to the supplements.
Endurance exercise test.
Before and after the 3-wk period of supplementation, subjects were
asked to perform a prefixed absolute workload on a linearly functioning
cycle ergometer (Lode Excalibur Sport, Lode, Groningen, The
Netherlands), in as little time as possible. The workload was based on
70% of the max of each subject, and the workload output depended directly on the pedaling frequency. During the test,
subjects were only informed about the cumulative achieved amount of
work, as displayed by a 0-100% indicator of the total workload.
Time as well as pedaling frequency were blinded to the subjects.
Subjects were allowed to drink tap water ad libitum. The time needed to
complete the test was used as a measure of physical performance. This
new validated endurance exercise test, resembling a time trial of ~1
h, has been described in detail by Jeukendrup et al. (14).
Blood Sampling
max test.
At the end of each workload step, antecubital blood was
collected via an intravenous Teflon catheter (Baxter, Utrecht, The Netherlands) in
Na2EDTA · 2H2O
(final concentration 2 g/l). Samples were centrifuged for
10 min at 1,600 g and 4°C, and
plasma was stored at 
40°C for lactate analysis later.
Endurance exercise test.
Before and immediately after each test, fasting free-flowing
antecubital venous blood was collected in decapped
K3EDTA-containing Monoject tubes
(final concentration 1.5 g/l; Sherwood Medical, Ballymoney, Northern
Ireland) and in heparin (final concentration 143 US Pharmacopea units/5
ml; Monoject tubes). Tubes were immediately closed, and
blood and anticoagulant were carefully mixed. One tube with
EDTA-anticoagulated blood was sent to Amsterdam (at ambient
temperature) and was analyzed the next day for RBC deformability and
plasma viscosity. Extensive pilot experiments demonstrated that such
transport did not significantly affect RBC deformability (results not
reported). EDTA-containing plasma was prepared by centrifugation (10 min, 1,300 g, 4°C).
Part of the plasma was stored at 80°C for antioxidant
analysis. RBCs were washed twice with EDTA-containing saline (28.64 g
Na2EDTA · 2H2O/l,
7.00 g NaCl/l) and stored under nitrogen at 40°C for a
maximum of 4 days.
Blood Analyses
Lactate. EDTA-containing plasma, collected duringmax tests,
was analyzed for lactate (enzymatic lactate dehydrogenase method; LDH no. 106984, Boehringer Mannheim, Mannheim, Germany) on a COBAS-BIO centrifugal analyzer (Hoffmann-La Roche).
Hematologic variables, RBC deformability, and plasma viscosity.
Hematologic variables in EDTA-anticoagulated blood were
analyzed on a Coulter counter (model MD 18, Miami, FL), and changes in
blood and plasma volume during endurance exercise were calculated by
using hematocrit (Hct) and hemoglobin (Hb) values (5).
RBC deformability was measured based on the ektacytometric principle
using a laser-assisted optical rotational cell analyzer [(LORCA)
R&R Mechatronics, Hoorn, The Netherlands] (11).
Briefly, 25 µl of EDTA-anticoagulated blood were suspended in 5 ml of
a 5% solution of polyvinylpyrrolidone (300 mosmol/l, Sigma Chemical, St. Louis, MO). This sample was then subjected to several rotational speeds at 21°C, giving final shear stresses ranging from 0.30 to
53.35 Pa. Laser diffraction was used to follow the change of the RBC
population from biconcave toward an ellipsoid morphology under
increased shear stress, and the deformability [elongation index
(EI)] of the RBCs was calculated from the major and minor axis of
the ellipsoid diffraction pattern (Fig. 1).
Apart from the near-maximum values at a shear stress of 30 Pa as
previously reported (29), we also evaluated the EI at 0.95, 3, and 9.5 Pa, because, for example, rigidification of RBC with glutaraldehyde decreases the EI only at lower shear stresses (12). The rest of the
EDTA-containing blood was centrifuged for 10 min at 3,000 g and room temperature, and the
viscosity of the plasma was measured in duplicate at a shear rate of
70/s by using a Contraves LS 30 viscometer (Contraves, Zürich,
Switzerland).
Phospholipid fatty acids. Phospholipids were extracted from the RBCs, and their fatty acids were methylated and analyzed by gas chromatography as described by Foreman-van Drongelen et al. (7), with the modification that fatty acids were separated on BPX70 polar and BP1 nonpolar capillary columns (Scientific Glass Engineering, Austin, TX). Fish oil from the capsules was directly methylated with triheptadecanoin as internal standard. The polyunsaturated fatty acid (PUFA) unsaturation index was calculated as the sum of the molar percentage of each PUFA (mol/mol total fatty acids · 100%) multiplied by its number of double bonds. Plasma antioxidants. EDTA-containing plasma was analyzed for retinol, tocopherols, and carotenoids by HPLC with simultaneous absorbance and fluorescence detection as described by Hess et al. (13), with the modification that an internal standard (retinol acetate) was used, and extraction of lipids was performed twice to improve recovery. Fish oil capsules were dissolved (20 mg oil/ml) in ethanol-dioxane-acetonitrile (1:1:3, EDA) and were analyzed by HPLC. Chromatogram peak areas were calibrated against standards dissolved in EDA. Because pure phytofluene was not available, quantitative determination of this compound was not possible.
-Tocopherol coeluted with -tocopherol. The
canthaxanthin standard eluted separately from the lutein standard, but
in plasma samples canthaxanthin appeared as a shoulder on the lutein
peak. Therefore, concentrations of lutein reported here may also
include canthaxanthin.
-Tocopherol (all racemic), -tocopherol, -cryptoxanthin,
lycopene, and -carotene standards were a generous gift from
Hoffmann-La Roche. Lutein, retinol (all
trans), -tocopherol, and
-carotene were obtained from Sigma Chemical, and canthaxanthin was
obtained from Fluka Chemie (Bornem, Belgium). Retinyl
acetate and all other chemicals were purchased from Merck (Darmstadt,
Germany).
LDL isolation and oxidation.
LDLs were isolated from fresh EDTA-containing plasma immediately after
collection by short-run, single-spin, density-gradient ultracentrifugation. In a 4.9-ml OptiSeal polyallomer centrifuge tube
(Beckman Instruments, Palo Alto, CA), 0.85 ml of a 0.49 g/ml potassium
bromide solution and 1.52 ml of plasma were gently mixed with a
spatula. This mixture was carefully overlayered with distilled water,
containing 1 g/l
Na2EDTA · 2H2O. The tube was then
centrifuged for 1 h at 561,000 g by using a near-vertical
tube rotor (NVT-90, Beckman Instruments) in an XL-80 ultracentrifuge
(Beckman Instruments). The top 0.6 ml was removed, and
the next 1.6 ml, containing LDLs, were collected. EDTA was removed from
LDL samples by gel filtration, by using two PD-10 Sephadex G25-M gel
filtration columns (Pharmacia, Roosendaal, The Netherlands) placed on
top of each other and a nitrogen-purged mobile phase
[phosphate-buffered saline (PBS); composition (in mmol/l): 9.61 Na2HPO4,
1.56 NaH2PO4,
and 154 NaCl, pH 7.4]. The EDTA-free LDLs were kept
under a nitrogen atmosphere to prevent oxidation and were analyzed for
cholesterol content (Monotest cholesterol, Boehringer Mannheim).
Within 15 min after gel filtration, an aliquot of each sample was
diluted in a quartz cuvette with PBS (not purged with nitrogen) to a
final concentration of 0.26 mmol cholesterol/l, and oxidation was
initiated with CuCl2 (final
concentration 2 µmol/l). Oxidation of PUFAs at 37°C was measured
spectrophotometrically by monitoring the formation of conjugated fatty
acid dienes at 234 nm. The lag time before rapid formation of
conjugated dienes was calculated from the intercept of linear lines
through the point of maximum rate of diene formation and the absorbance
immediately after addition of copper (6). In addition, the time at
which the maximum rate of oxidation was reached
(TRmax) was also determined.
TRmax represents a combined effect
of the lag time and the rate of oxidation.
Statistics
Effects of endurance exercise were examined before supplementation for all 24 subjects together by Student's paired two-tailed t-test. To evaluate the effects of the supplements, responses were calculated for each subject as the changes in exercise parameters and preendurance exercise biochemical values over the period of supplementation. Differences in responses between the three experimental groups were then compared by analysis of variance (ANOVA). The P group allowed us to correct for possible drifts with time. Differences between the experimental groups in changes during exercise after supplementation compared with changes during exercise before supplementation were also compared by ANOVA. The overall level of significance was set at P < 0.05. Because between-group ANOVA involved three simultaneous comparisons, between-group levels of significance were set to P < 0.017, according to the Bonferroni method. All statistical analyses were performed by using the Statistical Analysis System (SAS Institute, 1989). Values are reported as means ± SE.RESULTS
Effects of Endurance Exercise Before Supplementation
Body weights were similar in all groups (P: 74.8 ± 8.0; F: 74.5 ± 6.3; FE: 71.6 ± 6.1 kg) throughout the study. During the presupplementation endurance exercise test, subjects lost on average 0.56 ± 0.07 kg (P
0.0001) of
body weight and consumed on average 0.65 ± 0.06 liter of water.
Effect of endurance exercise on hematologic variables, RBC
deformability, and plasma viscosity.
During the presupplementation endurance exercise test, the average RBC
concentration, total Hb, and Hct increased by 5.3-5.7%. White
blood cell concentrations increased from 5.38 ± 0.16 × 109/l before exercise to
7.48 ± 0.29 × 109/l after exercise
(P 0.0001). Platelet concentrations
increased from 202 ± 7 × 109/l to 259 ± 10 × 109/l
(P 0.0001). Blood volume decreased
by 5.0 ± 0.6% during exercise and plasma volume by 9.0 ± 1.0%. RBC deformability decreased during exercise, but only the
decrease in EI of 0.005 ± 0.002 (P = 0.035) or 1.6% at a shear rate of 3 Pa reached statistical
significance. Plasma viscosity increased from 1.46 ± 0.02 mPa · s before exercise to 1.52 ± 0.02 mPa · s after exercise
(P = 0.005).
Effect of endurance exercise on plasma antioxidants.
Unadjusted plasma antioxidant concentrations increased during endurance
exercise. After correction for the decrease in plasma volume in each
subject, however, plasma antioxidant concentrations decreased
significantly, except for retinol (Table
1). Total tocopherol
concentrations decreased by 0.77 ± 0.28 µmol/l
(P = 0.012) or 2.9 ± 1.1%, and
total carotenoid concentrations decreased by 0.08 ± 0.02 µmol/l
(P = 0.0008) or 4.5 ± 1.2%.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Effects of Fish Oil and Vitamin E Supplementation
Effect of supplements on RBC phospholipid fatty acids. Compliance with the fish oil supplements was confirmed by an increase in the concentration of (n-3) PUFA in RBCs from 5.2 to 7.0 g/100 g of fatty acid in the F group (P 0.0001 vs. P) and from 5.2 to 7.6 g/100 g in the FE group
(P 0.0001 vs. P) during the study
(Table 3). The increase in
EPA was larger in the FE group (P = 0.001 vs. F), but other indicators of compliance, such as changes in
DHA and intake of capsules, were similar. Although increases in (n-3)
PUFAs were accompanied by decreases in (n-6) PUFAs, the degree of PUFA
unsaturation was significantly increased after supplementation with
fish oil (Table 3).
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
max.
Prestratification by max at the start of
the study resulted in similar values of 5.0 ± 0.2, 4.9 ± 0.2, and 5.0 ± 0.2 W/kg in the P, F, and FE groups, respectively. During
the study, max slightly improved in all
groups (0.12 W/kg or 2.5%), but no significant differences between the
groups were noticed.
At the start of the study, mean maximal oxygen consumption
(
O2 max) during the
test was 4.4 ± 0.1 l/min, and it did not differ significantly
between the groups. After supplementation, O2 max increased by
0.01 ± 0.09 l/min in the P group, by 0.13 ± 0.13 l/min in the F
group, and by 0.15 ± 0.09 l/min in the FE group. However, these
changes were not significantly different between the groups
(P > 0.3). Lactate concentrations at
various workloads during the max test, before and
after supplementation, were also similar.
Effect of supplements on endurance exercise performance.
The average time to complete the endurance exercise test at the start
of the study was 55.9 ± 0.6 min (n = 24). After supplementation, performances were similar in all groups
and changed by only 0.11 ± 0.49, 0.23 ± 1.35, and
0.07 ± 1.16 min in the P, F, and FE groups, respectively
(P > 0.8 between groups).
Effect of supplements on hematologic variables, RBC
deformability, and plasma viscosity.
After supplementations, RBC concentrations, Hb, Hct, RBC deformability,
and plasma viscosity, as well as their changes during exercise, were
similar in the three experimental groups.
Effect of supplements on plasma antioxidants.
Before supplementation, plasma antioxidant concentrations were similar
in the three experimental groups and were similar to values previously
observed in sedentary subjects (not shown). Fish oil supplementation
alone did not significantly affect plasma antioxidant concentrations.
Intake of the vitamin E capsules in the FE group was verified by an
increase in the plasma -tocopherol concentration
from 20.0 ± 1.0 to 35.5 ± 2.5 µmol/l (P 0.0001 vs. other groups). This was accompanied by a significant decrease in
+-tocopherol from 1.93 ± 0.25 to 0.75 ± 0.09 µmol/l (P < 0.004 vs. other groups).
Decreases in plasma antioxidant concentrations during endurance
exercise were smaller after fish oil and fish oil and vitamin E
supplementation than were exercise-induced decreases after P supplementation (Table 1). However, differences between the groups did
not reach statistical significance.
Effect of supplements on LDL oxidation in vitro.
Before supplementation, LDL oxidation parameters were similar in all
three groups. At the end of the supplementation period, the lag time
tended to increase in the FE group compared with the other groups
(P = 0.052 vs. F;
P = 0.113 vs. P; Fig.
2). The rate of oxidation in vitro
decreased by 0.52 ± 0.16 µmol dienes · mmol LDL
cholesterol
1 · min1
in the F group (P = 0.010 vs. P) and
by 0.82 ± 0.18 µmol dienes · mmol LDL
cholesterol1 · min1
in the FE group (P = 0.0003 vs. P;
P = 0.159 vs. F), whereas the P group
showed a slight increase (0.07 ± 0.08 µmol
dienes · mmol LDL
cholesterol1 · min1;
Fig. 2). TRmax
remained unchanged in the P and F groups but increased significantly in
the FE group (change: 15.0 ± 5.7 min; P = 0.007 vs. P;
P = 0.040 vs. F; Fig.
2). The maximum amount of dienes formed in vitro did not
change significantly during the study, and no differences were,
therefore, noticed between the groups (Fig. 2).
1 · min1,
and maximum amount of conjugated dienes in µmol/mmol LDL cholesterol. Significant differences from change in placebo group (by analysis of
variance): * P 0.01;
** P < 0.001.
After supplementation, changes in parameters of LDL oxidation during exercise, if any, did not differ significantly between the groups (Table 2).
DISCUSSION
The present study examined the effects of fish oil and vitamin E supplementation on exercise performance, RBC deformability, plasma antioxidant status, and in vitro LDL oxidation.
Effects of Endurance Exercise Before Supplementation
Effect of endurance exercise on hematologic variables, RBC deformability, and plasma viscosity. During endurance exercise, hemoconcentration of ~5% was observed, which was caused by a 9% reduction of the plasma compartment. At the same time, RBC deformability decreased at 3 Pa but not at 30 Pa, as reported by Van der Brug et al. (29) after their subjects performed a combination of cycling and running for 140 min. After a marathon, whole blood filterability was also impaired (8). Others, however, did not find a decrease in RBC filterability after a marathon (20). Guezennec et al. (9) observed a decrease in RBC filterability during a 1-h cycling exercise at a simulated altitude of 3,000 m in a hypobaric chamber but not at sea level. Although a decrease in RBC deformability is usually reported after longer exercises, the sensitive and reproducible LORCA technique (12) used in this study also detected a decrease after a 1-h time trial. In the present study, the change in RBC deformability was small (<2%), but together with the 4.2% increase in plasma viscosity it may have a significant effect on whole blood viscosity, as previously demonstrated (29). Effect of endurance exercise on plasma antioxidants. Plasma tocopherol and carotenoid concentrations, adjusted for hemoconcentration, decreased during exercise. Indirectly, this may indicate increased lipid peroxidation. After 45 min of running (18) or 90 min of submaximal cycling (30), no changes in plasma vitamin E were reported. Data from the latter study, however, were not adjusted for hemoconcentration, and a decrease in plasma vitamin E is, therefore, conceivable. Measurements of blood reduced and oxidized glutathione after submaximal cycling also indicated increased oxidative stress, but this was insufficient to cause damage to RNA (30). On the other hand, another explanation for the decreased antioxidant concentrations is possible. Exercise-activated lipoprotein lipase (27) may have caused a transfer of tocopherols (15), and maybe also of carotenoids, from the circulation to tissues. This might also explain why plasma concentrations of retinol, which is mainly transported via a specific retinol binding protein, and much less via lipoproteins, did not decrease during exercise. However, others showed that, in muscle tissue, vitamin E concentrations also decrease after exercise (18). Effect of endurance exercise on LDL oxidation in vitro. LDL oxidation in vitro was little affected by endurance exercise. The amount of conjugated dienes formed in vitro decreased slightly after exercise, and theoretically this indicates that the relative amounts of PUFAs in the native LDLs had decreased (22). This agrees with results of Sumikawa et al. (24), who showed that exercise decreased the proportion of PUFAs in RBC phospholipids of untrained subjects.Effects of Fish Oil and Vitamin E Supplementation
Effect of supplements on exercise performance. Exercise performance, as measured by validated exercise tests, was not significantly altered by fish oil or fish oil and vitamin E supplementation in the present study. Themax
slightly increased during the study in all groups. This small increase,
however, was insufficient to improve endurance performance during the
time trial. Nor were effects of fish oil supplementation on
max or O2 max found in
sedentary subjects (1). In well-trained subjects, Leaf and Rauch (17)
found an increase in
O2 max (predicted O2 max, based on
treadmill performance) after daily supplementation with 6 g of fish
oil, but no increase in
O2 max was noticed after supplementation with 12 g/day, and neither supplement improved treadmill performance.
Effect of supplements on RBC deformability.
The ~2 g/100 g increase in (n-3) PUFAs in membrane
phospholipids of RBC after fish oil supplementation did not affect RBC deformability. Results from other studies are conflicting. Earlier studies showed that supplementation with ~3.5 g/day of EPA (4) or
fish oil (28) for 4-6 wk increases RBC (4) and whole blood (28)
filterability, but no control groups were used. Guezennec et al. (9)
reported that in trained subjects compared with nonsupplemented trained
controls, daily supplementation with 2 g of fish oil for 6 wk improved
filterability of washed RBCs after hypoxic exercise. Preexercise RBC
filterability, however, was not improved by the supplement (9). A
dose-response study also showed no effect of supplementation with up to
6 g/day of (n-3) fatty acid ethyl ester for 12 wk on filterability of
10% RBC solutions (2). The latter studies, together with the present
one, show that supplementation with fish oil in moderate quantities
does not significantly affect RBC deformability. Although
supplementation with large quantities might affect RBC deformability,
this is probably not feasible in humans.
Effect of supplements on plasma antioxidants.
Fish oil supplementation did not affect plasma antioxidant
concentrations. A decrease in plasma antioxidant concentrations after
fish oil supplementation has been reported (19), but this was not
confirmed in the present study or by others (10). Additional vitamin E
supplementation, however, increased plasma -tocopherol and decreased
plasma +-tocopherol concentrations, as has been found by others
(18).
Effect of supplements on LDL oxidation in vitro.
The lag time during oxidation of LDL in vitro was not affected by fish
oil supplementation and was only nonsignificantly increased by
additional vitamin E supplementation. A previous study in sedentary male subjects (21) showed a larger increase in lag time after fish oil
and vitamin E supplementation compared with a decrease in lag time in
subjects who received fish oil supplementation without vitamin E. Recently, Suzukawa et al. (25) also found a decrease in lag time after
fish oil compared with corn oil supplementation in drug-treated
hypertensive subjects.
In the present study, both fish oil and fish oil and vitamin E
supplementation reduced the rate of LDL oxidation in vitro. This not
only was found in a previous study (21) but also was reported by
Suzukawa et al. (25). The mechanism responsible for this decrease is
unknown, however. The decrease in rate of oxidation in the F group
hardly affected the TRmax.
Additional vitamin E supplementation delayed oxidation of LDL, although
the apparent difference with the F group was only of borderline
significance.
Fish oil supplementation did not affect the amount of conjugated dienes
formed during LDL oxidation in vitro, whereas a previous study (21)
showed a 20% increase after supplementation with a similar amount of
fish oil. In addition, the in vitro formation of thiobarbituric
acid-reactive substances in LDL samples is also increased after fish
oil supplementation (10, 25). Although the fast method of LDL
preparation used in the present study was different from the
time-consuming method in the previous one (21), comparison of the two
methods in sedentary volunteers showed no significant difference in the
amount of conjugated dienes formed in vitro (results not reported).
In conclusion, this study shows that a 1-h intense exercise decreases
RBC deformability, causes consumption or a shift of plasma tocopherols
and carotenoids, and decreases the formation of conjugated dienes
during oxidation of LDL in vitro. Although these changes may suggest
increased oxidative stress during exercise, the physiological meaning
of these small changes need further investigation. Contrary to previous
findings, no adverse effects of fish oil supplementation on parameters
of lipid peroxidation were found. However, this study also shows that
moderate fish oil supplementation does not significantly improve RBC
deformability or physical performance.
ACKNOWLEDGEMENTS
This study was supported by a grant from the Isostar Sport Nutrition Foundation.
FOOTNOTES
Address for reprint requests: R. P. Mensink, Maastricht Univ., Dept. of Human Biology, PO Box 616, 6200 MD Maastricht, The Netherlands.
Received 13 May 1996; accepted in final form 23 April 1997.
REFERENCES
| 1. | Ågren, J. J., H. Pekkarinen, H. Litmanen, and O. Hanninen. Fish diet and physical fitness in relation to membrane and serum lipids, prostanoid metabolism and platelet aggregation in female students. Eur. J. Appl. Physiol. 63: 393-398, 1991. |
| 2. |
Blonk, M. C.,
H. J. Bilo,
J. J. Nauta,
C. Popp-Snijders,
C. Mulder,
and
A. J. Donker.
Dose-response effects of fish-oil supplementation in healthy volunteers.
Am. J. Clin. Nutr.
52:
120-127,
1990 |
| 3. | Bruckner, G., P. Webb, L. Greenwell, C. Chow, and D. Richardson. Fish oil increases peripheral capillary blood cell velocity in humans. Atherosclerosis 66: 237-245, 1987[Medline]. |
| 4. |
Cartwright, I. J.,
A. G. Pockley,
J. H. Galloway,
M. Greaves,
and
F. E. Preston.
The effects of dietary  -3 polyunsaturated fatty acids on erythrocyte membrane phospholipids, erythrocyte deformability and blood viscosity in healthy volunteers.
Atherosclerosis
55:
267-281,
1985[Medline].
|
| 5. |
Dill, D. B.,
and
D. L. Costill.
Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration.
J. Appl. Physiol.
37:
247-248,
1974 |
| 6. | Esterbauer, H., G. Striegl, H. Puhl, and M. Rotheneder. Continuous monitoring of in vitro oxidation of human low density lipoprotein. Free Radic. Res. Commun. 6: 67-75, 1989[Medline]. |
| 7. | Foreman-van Drongelen, M. M. H. P., A. C. van Houwelingen, A. D. M. Kester, C. E. Blanco, T. H. M. Hasaart, and G. Hornstra. Influence of feeding artificial-formula milks containing docosahexaenoic and arachidonic acids on the postnatal long- chain polyunsaturated fatty acid status of healthy preterm infants. Br. J. Nutr. 76: 649-667, 1996[Medline]. |
| 8. | Galea, G., and R. J. L. Davidson. Hemorrheology of marathon running. Int. J. Sports Med. 6: 136-138, 1985[Medline]. |
| 9. | Guezennec, C. Y., J. F. Nadaud, P. Satabin, and P. Lafargue. Influence of polyunsaturated fatty acid diet on the hemorrheological response to physical exercise in hypoxia. Int. J. Sports Med. 10: 286-291, 1989[Medline]. |
| 10. | Harats, D., Y. Dabach, G. Hollander, M. Ben-Naim, R. Schwartz, E. M. Berry, O. Stein, and Y. Stein. Fish oil ingestion in smokers and nonsmokers enhances peroxidation of plasma lipoproteins. Atherosclerosis 90: 127-139, 1991[Medline]. |
| 11. | Hardeman, M. R., P. T. Goedhart, J. G. G. Dobbe, and K. P. Lettinga. Laser-assisted optical rotational cell analyser (L.O.R.C.A.); I. A new instrument for measurement of various structural hemorheological parameters. Clin. Hemorheol. 14: 605-618, 1994. |
| 12. | Hardeman, M. R., P. T. Goedhart, and N. H. Schut. Laser-assisted optical rotational cell analyser (L.O.R.C.A.); II. Red blood cell deformability: elongation index versus cell transit time. Clin. Hemorheol. 14: 619-630, 1994. |
| 13. | Hess, D., H. E. Keller, B. Oberlin, R. Bonfanti, and W. Schüep. Simultaneous determination of retinol, tocopherols, carotenes and lycopene in plasma by means of high-performance liquid chromatography on reversed phase. Int. J. Vitam. Nutr. Res. 61: 232-238, 1991[Medline]. |
| 14. | Jeukendrup, A., W. H. M. Saris, F. Brouns, and A. D. M. Kester. A new validated endurance performance test. Med. Sci. Sports Exerc. 28: 266-270, 1996[Medline]. |
| 15. | Kayden, H. J., and M. G. Traber. Absorption, lipoprotein transport, and regulation of plasma concentrations of vitamin E in humans. J. Lipid Res. 34: 343-358, 1993[Medline]. |
| 16. | Keizer, H. A., H. Kuipers, G. van Kranenburg, and P. Geurten. Influence of liquid and solid meals on muscle glycogen resynthesis, plasma fuel hormone response, and maximal physical working capacity. Int. J. Sports Med. 8: 99-104, 1986. |
| 17. |
Leaf, D. A.,
and
C. R. Rauch.
Omega-3 supplementation and estimated O2 max: a double blind randomized controlled trial in athletes.
Ann. Sport Med.
4:
37-40,
1988.
|
| 18. |
Meydani, M.,
W. J. Evans,
G. Handelman,
L. Biddle,
R. A. Fielding,
S. N. Meydani,
J. Burrill,
M. A. Fiatarone,
J. B. Blumberg,
and
J. G. Cannon.
Protective effect of vitamin E on exercise-induced oxidative damage in young and older adults.
Am. J. Physiol.
264 (Regulatory Integrative Comp. Physiol. 33):
R992-R998,
1993 |
| 19. |
Nair, P. P.,
J. T. Judd,
E. Berlin,
P. R. Taylor,
S. Shami,
E. Sainz,
and
H. N. Bhagavan.
Dietary fish oil-induced changes in the distribution of -tocopherol, retinol, and -carotene in plasma, red blood cells, and platelets: modulation by vitamin E.
Am. J. Clin. Nutr.
58:
98-102,
1993 |
| 20. | Neuhaus, D., C. Behn, and P. Gaehtgens. Haemorheology and exercise: intrinsic flow properties of blood in marathon running. Int. J. Sports Med. 13: 506-511, 1992[Medline]. |
| 21. | Oostenbrug, G. S., R. P. Mensink, and G. Hornstra. Effects of fish oil and vitamin E supplementation on copper-catalysed oxidation of human low density lipoprotein in vitro. Eur. J. Clin. Nutr. 48: 895-898, 1994[Medline]. |
| 22. |
Reaven, P.,
S. Parthasarathy,
B. J. Grasse,
E. Miller,
F. Almazan,
F. H. Mattson,
J. C. Khoo,
D. Steinberg,
and
J. L. Witztum.
Feasibility of using an oleate-rich diet to reduce the susceptibility of low-density lipoprotein to oxidative modification in humans.
Am. J. Clin. Nutr.
54:
701-706,
1991 |
| 23. |
Simchon, S.,
K.-M. Jan,
and
S. Chien.
Influence of reduced red cell deformability on regional blood flow.
Am. J. Physiol.
253 (Heart Circ. Physiol. 22):
H898-H903,
1987 |
| 24. | Sumikawa, K., Z. Mu, T. Inoue, T. Okochi, T. Yoshida, and K. Adachi. Changes in erythrocyte membrane phospholipid composition induced by physical training and physical exercise. Eur. J. Appl. Physiol. 67: 132-137, 1993. |
| 25. | Suzukawa, M., M. Abbey, P. R. Howe, and P. J. Nestel. Effects of fish oil fatty acids on low density lipoprotein size, oxidizability, and uptake by macrophages. J. Lipid Res. 36: 473-484, 1995[Abstract]. |
| 26. | Szygula, Z. Erythrocytic system under the influence of physical exercise and training. Sports Med. 10: 181-197, 1990[Medline]. |
| 27. | Taskinen, M.-R., E. A. Nikkila, S. Rehunen, and A. Gordin. Effect of acute vigorous exercise on lipoprotein lipase activity of adipose tissue and skeletal muscle in physically active men. Artery 6: 471-483, 1980[Medline]. |
| 28. | Terano, T., A. Hirai, T. Hamazaki, S. Kobayashi, T. Fujita, Y. Tamura, and A. Kumagai. Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects. Atherosclerosis 46: 321-331, 1983[Medline]. |
| 29. | Van der Brug, G. E., H. P. F. Peters, M. R. Hardeman, G. Schep, and W. L. Mosterd. Hemorheological response to prolonged exercise; no effects of different kinds of feedings. Int. J. Sports Med. 16: 231-237, 1995[Medline]. |
| 30. |
Viguie, C. A.,
B. Frei,
M. K. Shigenaga,
B. N. Ames,
L. Packer,
and
G. A. Brooks.
Antioxidant status and indexes of oxidative stress during consecutive days of exercise.
J. Appl. Physiol.
75:
566-572,
1993 |
This article has been cited by other articles:
|
|
 |
|
  E. Theuwissen and R. P. Mensink Simultaneous Intake of {beta}-Glucan and Plant Stanol Esters Affects Lipid Metabolism in Slightly Hypercholesterolemic Subjects J. Nutr., March 1, 2007; 137(3): 583 - 588. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Cesari, S. B. Kritchevsky, B. J. Nicklas, B. W. H. J. Penninx, P. Holvoet, P. Koh-Banerjee, S. R. Cummings, T. B. Harris, A. B. Newman, and M. Pahor Lipoprotein Peroxidation and Mobility Limitation: Results From the Health, Aging, and Body Composition Study Arch Intern Med, October 10, 2005; 165(18): 2148 - 2154. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. P. Bogers, P. van Assema, A. D. M. Kester, K. R. Westerterp, and P. C. Dagnelie Reproducibility, Validity, and Responsiveness to Change of a Short Questionnaire for Measuring Fruit and Vegetable Intake Am. J. Epidemiol., May 1, 2004; 159(9): 900 - 909. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Cesari, M. Pahor, B. Bartali, A. Cherubini, B. W. Penninx, G R. Williams, H. Atkinson, A. Martin, J. M Guralnik, and L. Ferrucci Antioxidants and physical performance in elderly persons: the Invecchiare in Chianti (InCHIANTI) study Am. J. Clinical Nutrition, February 1, 2004; 79(2): 289 - 294. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Medved, M. J. Brown, A. R. Bjorksten, J. A. Leppik, S. Sostaric, and M. J. McKenna N-acetylcysteine infusion alters blood redox status but not time to fatigue during intense exercise in humans J Appl Physiol, April 1, 2003; 94(4): 1572 - 1582. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. P. Bogers, P. C. Dagnelie, K. R. Westerterp, A. D. M. Kester, J. D. van Klaveren, A. Bast, and P. A. van den Brandt Using a Correction Factor to Correct for Overreporting in a Food-Frequency Questionnaire Does Not Improve Biomarker-Assessed Validity of Estimates for Fruit and Vegetable Consumption J. Nutr., April 1, 2003; 133(4): 1213 - 1219. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Park and S. B. Choi Effects of {alpha}-tocopherol supplementation and continuous subcutaneous insulin infusion on oxidative stress in Korean patients with type 2 diabetes Am. J. Clinical Nutrition, April 1, 2002; 75(4): 728 - 733. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. D. Toft, M. Thorn, K. Ostrowski, S. Asp, K. Moller, S. Iversen, C. Hermann, S. R. Sondergaard, and B. K. Pedersen N-3 polyunsaturated fatty acids do not affect cytokine response to strenuous exercise J Appl Physiol, December 1, 2000; 89(6): 2401 - 2406. [Abstract] [Full Text] [PDF] |
