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Omega-3 fatty acids supplementation improves endothelial function and maximal oxygen uptake in endurance-trained athletes

Authors:
  • Akademia Wychowania Fizycznego im. Jerzgo Kukuczki w Katowicach

Abstract

Abstract The study aimed to evaluate the effects of a 3-week n-3 polyunsaturated fatty acids (n-3 PUFA) supplementation on serum nitric oxide (NO), asymmetric dimethyloarginine (ADMA), ultrasound indices of endothelial function and maximal oxygen uptake ([Formula: see text]) of elite cyclists. The effects of dietary supplementation (n-3 PUFA at a dose of 1.3 g twice daily for 3 weeks) and placebo administration on flow-mediated dilatation (FMD), pulse wave velocity, serum markers (NO, ADMA), lipid profile, and [Formula: see text] were analysed in 13 cyclists both before and after dietary protocols. Significant differences between pre- and post-intervention baseline NO levels were observed after n-3 PUFA dietary protocol (13.9 ± 4.2 vs. 23.5 ± 3.6 µmol·l(-1); P < 0.001). Higher post-intervention baseline NO level was observed after n-3 PUFA diet compared with placebo (23.5 ± 3.6 vs. 15.3 ± 3.0 µmol·l (-1); P < 0.01, respectively). The n-3 PUFA increased baseline NO concentration (ΔNO) by 6.7 ± 3.8 µmol·l(-1) and placebo by 1.6 ± 4.4 µmol·l(-1). The positive correlation was observed between baseline post-intervention NO concentration and maximal oxygen uptake (r = 0.72; P < 0.01) and also between ΔNO and [Formula: see text] (r = 0.54; P < 0.05) in response to omega-3 fatty acids supplementation. There was an association between a 5.25% higher FMD (P < 0.05) and higher [Formula: see text] (P < 0.001) after n-3 PUFA diet compared with lower values of placebo (r = 0.68; P < 0.05). These findings suggest that an increase in NO release in response to n-3 PUFA supplementation may play a central role in cardiovascular adaptive mechanisms and enhanced exercise performance in cyclists.
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... 399 mg of DHA increased exercise economy during a steady-state submaximal cycloergometer test. In one crossover study with trained cyclists, researchers observed an increase inVO 2max after 3 wk of supplementation with a daily dose of 660 mg of EPA and 440 mg of DHA (25). ...
... Given the large cross-sectional study indicating that inverse relationship betweeṅ VO 2max and C-reactive protein is modified by omega-3 fatty acid levels (29), this may be the case. Moreover, an increase in insulin sensitivity due to unsaturation of skeletal muscle membranes (30), improved calcium handling by skeletal muscle sarcoplasmic reticulum (23), and improved endothelial function via increase in NO release (25) should be taken into account in searching for potential mechanisms of action. Of note, in the present study, 13 out of 14 participants in the OMEGA group showed an improveḋ VO 2peak compared with a variable response in the MCT group, in which only 9 out of 12 runners improved their results. ...
... Compared with previous studies in which performance indicators were assessed, our supplementation protocol (2234 mg of EPA and 916 mg of DHA daily for 12 wk) was a higher dose over a longer supplementation period (9,(23)(24)(25). However, what values of O3I are sufficient for amateur and competitive athletes to optimize athletic performance remains a question to be answered in future studies. ...
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Purpose To investigate the effects of 12 weeks of omega-3 fatty acid supplementation during endurance training on Omega-3 index (O3I) and indicators of running performance in amateur long-distance runners. Methods 26 amateur male long-distance runners aged ≥29 years supplemented omega-3 fatty acid capsules (OMEGA group, n = 14; 2234 mg of EPA and 916 mg of DHA daily) or medium chain triglycerides capsules as placebo (MCT group, n = 12; 4000 mg of MCT daily) during 12-week of endurance training. Before and after intervention, blood samples were collected for O3I assessment and an incremental test to exhaustion and 1500-m run trial were performed. Results O3I was significantly increased in the OMEGA group (from 5.8% to 11.6%, P < 0.0001). A significant increase in VO2peak was observed in the OMEGA group (from 53.6 ± 4.4 ml*kg-1*min-1 to 56.0 ± 3.7 ml*kg-1*min-1, P = 0.0219) without such change in MCT group (from 54.7 ± 6.8 ml*kg-1*min-1 to 56.4 ± 5.9 ml*kg-1*min-1, P = 0.1308). A positive correlation between the change in O3I and change in running economy was observed when data of participants from both groups were combined (-0.1808 ± 1.917, P = 0.0020), without such an effect in OMEGA group alone (P = 0.1741). No effect of omega-3 supplementation on 1500-m run results was observed. Conclusions 12 weeks of omega-3 fatty acid supplementation at a dose of 2234 mg of EPA and 916 mg of DHA daily during endurance training resulted in improvement of O3I and running economy and increased VO2peak without improvement in the 1500-m run trial time in amateur runners.
... Although some studies show no improvements in cardiopulmonary-muscle oxidative function following supplementation with fish oil containing omega-3 fatty acids [5,6], several studies do indicate a positive effect. For example, long-term EPA and DHA supplementation may contribute to the improvement in VO 2max [7] or to the reduction in the cost of aerobic exercise in trained cyclists [8,9]. Moreover, our recent study showed that 12-week supplementation with omega-3 fatty acids improved running economy (RE) in amateur runners [10]. ...
... These effects are related to the incorporation of EPA and DHA into the erythrocyte cell membrane [31], skeletal muscles [32] and heart [33]. Furthermore, the systemic response to supplementation with omega-3 fatty acids as exemplified by maximum oxygen uptake [7], exercise economy [9,10] or anaerobic endurance capacity [34] is well-known. Nevertheless, in our study, for the first time, an attempt was made to link the effect of supplemental EPA + DHA to changes in OUEP and OUE@VAT. ...
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Peak oxygen uptake (VO2peak) is one of the most reliable parameters of exercise capacity; however, maximum effort is required to achieve this. Therefore, alternative, and repeatable submaximal parameters, such as running economy (RE), are needed. Thus, we evaluated the suitability of oxygen uptake efficiency (OUE), oxygen uptake efficiency plateau (OUEP) and oxygen uptake efficiency at the ventilatory anaerobic threshold (OUE@VAT) as alternatives for VO2peak and RE. Moreover, we evaluated how these parameters are affected by endurance training and supplementation with omega-3 fatty acids. A total of 26 amateur male runners completed a 12-week endurance program combined with omega-3 fatty acid supplementation or medium-chain triglycerides as a placebo. Before and after the intervention, the participants were subjected to a treadmill test to determine VO2peak, RE, OUE, OUEP and OUE@VAT. Blood was collected at the same timepoints to determine eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes. OUE correlated moderately or weakly with VO2peak (R2 = 0.338, p = 0.002) and (R2 = 0.226, p = 0.014) before and after the intervention, respectively. There was a weak or no correlation between OUEP, OUE@VAT, VO2peak and RE despite steeper OUE, increased OUEP and OUE@VAT values in all participants. OUE parameters cannot be treated as alternative parameters for VO2peak or RE and did not show changes following supplementation with omega-3 fatty acids in male amateur endurance runners. <br/
... Supplementation of omega-3 polyunsaturated fatty acids (ω-3 PUFA) is frequent in elite athletes [132]. Overall, ω-3 PUFA are welltolerated and can improve exercise performance and minimize strenuous training-induced muscle dysfunction in athletes via their antioxidant and anti-inflammatory properties [133][134][135][136]. In this context, docosahexaenoic-(DHA)-rich fish oil supplementation (3 g daily for 60 days) in marathon runners beneficially affected lymphocyte function changes induced by the marathon race [137]. ...
... A study with patients with obesity supplemented with EPA and DHA for 8 weeks showed decreased plasma ADMA levels [29]. On the other hand, a study involving trained cyclists showed no changes in plasma ADMA level after three weeks of omega-3 fatty acid supplementation [30]. Other studies have shown that the ADMA level in response to other supplementation interventions is difficult to assess [31,32] due to disturbances resulting from amino acid metabolism/gluconeogenesis and various levels of skeletal muscle damage [33]. ...
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It is not fully understood how supplementation with omega-3 fatty acids affects themetabolism of amino acids required for the bioavailability/synthesis of NO, i.e., L-arginine (L-arg), asymmetric dimethylarginine (ADMA), their metabolites, and the L-arg/ADMA ratio and their impact on running economy (RE) in runners. Thus, 26 male amateur endurance runners completed atwelve-week study in which they were divided into two supplemented groups: the OMEGA group (n = 14; 2234 mg and 916 mg of eicosapentaenoic and docosahexaenoic acid daily) or the MCT group (n = 12; 4000 mg of medium-chain triglycerides daily). At the same time, all participants followed an endurance training program. Before and after the 12-week intervention, blood was collected from participants at two time points (at rest and immediately post-exercise) to determine EPA and DHA inred blood cells (RBCs) and plasma levels of L-arg, ADMA, and their metabolites. RBC EPA and DHA significantly increased in the OMEGA group (p < 0.001), which was related to the resting increase in L-arg (p = 0.001) and in the L-arg/ADMA ratio (p = 0.005) with no changes in the MCT group. No differences were found in post-exercise amino acid levels. A total of 12 weeks of omega-3 fatty acid supplementation at a dose of 2234 mg of EPA and 916 mg of DHA daily increased levels of L-arg and the L-arg/ADMA ratio, which indirectly indicates increased bioavailability/NO synthesis. However, these changes were not associated with improved RE in male amateur endurance runners.
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