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Omega-3 fatty acids supplementation improves endothelial function and maximal oxygen uptake in endurance-trained athletes
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.
... N-3 supplementation demonstrated several positive effects on cardiovascular function in some studies [21,24]. One study found that a 6000 mg dose of supplemental n-3 (3000 mg + 2000 mg) increased stroke volume (SV) and cardiac output (CO) during moderate workloads while tending to attenuate decreases in systemic vascular resistance (SVR) [21]. ...
... The same supplementation also reduced resting mean arterial pressure (MAP) [21]. Another study reported n-3 supplementation of 1300 mg (660 mg EPA + 440 mg DHA) increased baseline nitric oxide (NO) levels, highlighting a potential mechanism for improved vascular function [24]. ...
... Some studies have highlighted the potential of n-3 to enhance aerobic capacity and exercise efficiency [24,28,29]. One reported an increase in VO2max following n-3 supplementation, while another study observed a significant rise in VO2peak among participants receiving 2234 mg EPA + 916 mg DHA [24,28]. ...
Background/Objectives: Omega-3 fatty acids (n-3), recognized for their anti-inflammatory and brain health benefits, are being studied to enhance cognitive function, aid physical recovery, and reduce injury rates among military service members (SMs). Given the unique demands faced by this tactical population, this systematic review aims to evaluate the evidence of n-3 to support physical and mental resilience and overall performance. Methods: This review was conducted in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and includes articles that assessed n-3 status or implemented n-3 interventions in relation to physical and cognitive performance, recovery, and injury outcomes (2006 to 2024). Of the 1606 articles yielded in screening through Covidence, 755 were irrelevant, leaving 226 studies for full-text eligibility. Of those 226 studies, 165 studies were excluded, and 61 studies were included in this review. Results: The results highlighted evidence-based findings in five key areas where omega-3 fatty acids are being evaluated to benefit military service members. These key areas include cardiopulmonary function, exercise recovery, cognitive function, injury recovery, and strength and power. While existing research suggests promising benefits, the most significant evidence was seen with cardiopulmonary function, exercise recovery, and cognitive function. Conclusions: Current research is promising and shows potential benefits, but the results are inconclusive and inconsistent. Future research is needed to determine optimal n-3 status, dose, and possibly type of n-3 across the various performance outcomes. Understanding these gaps in research will be essential to creating evidence-based n-3 guidelines for optimal performance of SMs.
... Improved endothelial function potentially allows athletes to maintain better cardiovascular function and sustain higher levels of athletic performance [34,35]. By increasing NO production, omega-3 fatty acids, particularly EPA and DHA (converted from ALA), promote vasodilation and enhance blood flow, therefore increasing oxygen uptake and delivery to muscles and supporting aerobic metabolism [34]. ...
... Improved endothelial function potentially allows athletes to maintain better cardiovascular function and sustain higher levels of athletic performance [34,35]. By increasing NO production, omega-3 fatty acids, particularly EPA and DHA (converted from ALA), promote vasodilation and enhance blood flow, therefore increasing oxygen uptake and delivery to muscles and supporting aerobic metabolism [34]. The presence of antioxidants alongside unsaturated fatty acids found in walnuts might help attenuate oxidative stress in athletes, thus improving muscular performance and immune function [35]. ...
... The presence of antioxidants alongside unsaturated fatty acids found in walnuts might help attenuate oxidative stress in athletes, thus improving muscular performance and immune function [35]. The antiinflammatory properties of omega-3s help reduce exercise-induced muscle soreness and damage (by reducing the production of pro-inflammatory cytokines and ROS as well as increasing anti-inflammatory mediators), allowing athletes to recover more efficiently after intense workouts [34]. Indeed, previous studies showed that high PUFA content in walnuts, particularly omega-3 fatty acids, supports membrane fluidity, reduces inflammation, and enhances recovery after exercise [36]. ...
Cardiovascular diseases (CVDs) are the leading causes of death worldwide. A healthy diet has an important role in delaying the development of many modifiable risk factors of CVD, including abdominal obesity, high blood pressure, high plasma levels of cholesterol, and glucose. The consumption of various nuts, especially walnuts, may benefit both primary and secondary prevention due to their bioactive components. This review focuses on (1) the protective role of walnut consumption on CVD at large (2) and the potential cellular and molecular mechanisms by which they have beneficial effects on vascular endothelial function. Walnuts contain many essential ingredients (such as polyunsaturated fatty acids, phenolic compounds, and vitamin E) necessary for the healthy functioning of membranes. Since membranes are involved in nearly all processes associated with life-related function, the main underlying mechanism of walnut-improved cardiovascular function is likely based on improving membrane composition and function by providing all of the substrates necessary for membranes, such as cell, mitochondria, Golgi, nucleus, and so on. In addition to endothelial cell function, all other cells and membranes are likely to benefit from walnut consumption, suggesting that incorporating walnuts into the human diet is essential, for example, during higher physical and mental demand, such as exercise, and may mitigate the risk for the development of cardiovascular diseases and compensate for the sedentary lifestyle, especially in those of an older age.
... A special role in the functional state of the vascular endothelium is played by n-3 polyunsaturated fatty acids (n-3 PUFAs). Their positive effect on the functional state of blood vessels in healthy people has been proven [2,3], as has their ability to optimize physical performance [4]. Specifically, n-3 PUFAs are known to improve vascular endothelial function by increasing the formation and bioavailability of the endothelial-dependent relaxation factor nitric oxide (NO) through the activation of endothelial NO-synthase [5]. ...
... Several possible effects of n-3 PUFAs on NO synthesis have been discussed; however, the exact mechanisms of action of fatty acids have not been described. Thus, n-3 PUFAs are thought to contribute to increased NO availability [3,4,7,8]. Another pathway of NO synthesis has been associated with increased endothelial NO synthesis and even increased endothelial NO synthase activity [9,10]. Overall, these beneficial effects of n-3 PUFAs on NO levels may help to reduce systemic vascular resistance and blood pressure [11]. ...
... Cross-country skiers have a very high maximal oxygen uptake, and they are able to perform submaximal exercise at a rather high metabolic rate [4], which may lead to an intensification of the processes of production of reactive oxygen species. Thus, this group of athletes is a successful model for studying metabolic effects in humans during exercise, especially since trained cross-country skiers can actually perform difference-intensive work, revealing subtle regulatory mechanisms. ...
Background: The aim of this study was to investigate the relationships between levels of n-3 essential polyunsaturated fatty acids (n-3 PUFAs) and stable nitric oxide (NO) metabolites in the plasma of athletes. Methods: Highly trained crosscountry skiers (males, n = 39) were examined. The fatty acid profile of the total plasma lipids was determined by gas chromatography. The plasma NO level was studied by a colorimetric method via reaction with Griess reagent. Results: A widespread deficiency of essential n-3 PUFAs in the plasma of athletes (more than 80% of the subjects) was demonstrated in association with an imbalance in the levels of nitrates (NO 3) and nitrites (NO 2). A lower value of n-3 linolenic acid in the plasma (0.21 mol/%) was associated with a NO 3 level below the normal range (n-3 C18:3 and NO 3 Rs = 0.461; p = 0.003). Higher levels of n-3 eicosapentaenoic acid (0.8 mol/%) were associated with a concentration of NO 2 above the normal value (n-3 C20:5 and NO 2 Rs = 0.449; p = 0.004). Conclusion: For the first time, the participation of essential n-3 PUFAs in the nitrite-nitrate pathway of NO synthesis in highly trained skiers was demonstrated.
... The total score for each article was calculated as a percentage and categorized as high (80-100%), fair (50-79%), or low (50%). Two reviewers independently evaluated all studies, and any discrepancies between them were resolved through consensus ( Table 2, Ref. [10,[13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]). ...
... The studies included were published between 1997 and 2022 (Table 3, Ref. [10,[13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]). The number of participants ranged from 10 to 36 athletes. ...
... Various sports modalities were observed in included studies. Five studies solely assessed soccer players [14,[17][18][19][20], four studies were exclusively conducted with runners [21][22][23][24], two studies evaluated cyclists [10,25]. Each of the following modalities was represented by one study: Swimmers [13], judo athletes [26], CrossFit athletes [27], paddlers [28], endurance athletes [29], athletes in rowing, sailing, triathlon, and running [30], soccer, volleyball, and swimming athletes [31], basketball, volleyball, and swimming athletes [32], and athletes in strength and endurance modalities [33]. ...
Background: This study aims to summarize the evidence regarding the effects of polyunsaturated fatty acids (PUFAs) supple-mentation on both amateur and professional athletes. Objective: The aim is to elucidate the impacts of PUFAs supplementation on physical performance, inflammatory response, biochemical profile, anthropometric/body composition, and performance outcomes in athletes. Methods: Articles published up to December 2023 were retrieved from databases including Cochrane Library, PubMed/Medline, Scopus, and Embase. Selected articles met eligibility criteria and quality methodology. Data on inflammatory response, biochemical markers, anthropometric/body composition, and neuromuscular indicators were extracted. Results: Twenty-one studies were included in this systematic review. PUFAs supplementation resulted in decreased levels of certain inflammatory markers (interferon-gamma, interleukin 1, prostaglandin E2, and tumor necrosis factor alpha). However, no significant differences were observed in interleukin 4, 6, 8, 10, and matrix metalloproteinase 9. Additionally, there were no differences in glycemic (glucose and insulin) and lipid metabolism (high density lipoprotein (HDL)) cholesterol, low density lipoprotein (LDL), triglycerides). A reduction in reactive oxygen species levels was noted. No significant differences were found in muscle fatigue markers and anthropometry. Some performance parameters (neuromuscular and aerobic) improved following supplementation, including performance on the Yo-Yo distance test, resting energy expenditure, exercise time to exhaustion, and maximum oxygen consumption/maximum heart rate. Conclusion: Supplementation with PUFAs (600-3150 mg) in athletes led to reductions in inflammation and oxidative stress markers, as well as improvements in specific aerobic performance parameters. However, no significant effects were observed on glycemic and lipid profiles, anthropometric profiles, or body composition.
... 14,15 Additionally, new research has been examining how n-3 PUFAs could improve athletic performance in athletes across a variety of sports. [16][17][18][19] Levels of n-3 PUFA consumed by collegiate athletes have been shown to be extremely low, with the majority of athletes showing some level of deficiency. 15,20,21 In a study examining a similarly active population (e.g., army cadets), Heileson et al. demonstrated that cadets with lower Army Combat Fitness Scores tend to have lower levels of n-3 PUFAs. ...
... Multiple authors have investigated the impact of n-3 PUFA on cardiovascular performance, with mixed findings ranging from significant improvements in running economy (i.e., oxygen cost) 18 , to no improvement in VO2max in high-level cyclists. 17 Additionally, Heileson et al. found improvements in strength assessments (e.g., 1RM bench press) following ten weeks of fish oil supplementation and resistance training in a similar aged active population. 31 The length of supplementation in these studies varies widely, ranging from three to twelve weeks, indicating a continued need to examine the ideal supplementation protocol for performance improvement. ...
Introduction: NCAA track and field (T&F) athletes hold one of the longest competitive seasons, making adequate nutrition and supplementation critical. Studies suggest that omega-3 polyunsaturated fatty acids (n-3 PUFA) supplementation may benefit athletic performance, strength, and body composition. This study examined the effects of n-3 PUFA supplementation on sport performance, hand grip strength, and body composition in NCAA Division I T&F athletes. Methods: Twenty-five NCAA Division I T&F athletes (14 females, 11 males) were recruited. In a single-blind randomized controlled trial, participants consumed either: 4.0 grams of fish oil (FO) or 4.0 grams of placebo (i.e., coconut oil) daily for eight weeks, starting at the beginning of their outdoor season competitions. Body composition, hand grip strength, sport performance, and omega-3 indexes were sampled prior to in-season competition and following the 8-week supplementation. Data were analyzed using a two-way repeated measures ANOVA (p < 0.05). Results: FO group saw a significant increase in omega-3 index (p = 0.004, but no significant differences in body composition, hand grip strength, or performance. Despite improvement in omega-3 index, all participants still possessed levels below current recommendations. Conclusions: No changes in body composition, hand grip strength, or sport performance were found, despite improvements in omega-3 status with supplementation.
... On the other hand, ω-3 fatty acid supplementation increased NO bioavailability in patients with cardiovascular problems, but not in healthy subjects [29]. In another study, omega-3 supplementation for 3 weeks resulted in increased basal serum NO as compared with pretreatment levels in athletes [30]. Omega-3 supplementation for 3 months also increased plasma NO levels in both sedentary and athletes in university students [31]. ...
The toxic effect of ethanol on the cerebral cortex and protective effects of omega-3 fatty acids against
this neurotoxicity were investigated. Twenty eight male Wistar-albino rats were divided into 4 groups.
Rats of the ethanol and ethanol withdrawal groups were treated with ethanol (6 g/kg/day) for 15 days. Animals
of the ethanol+omega-3 group received omega-3 fatty acids (400 mg/kg daily) and ethanol. In rats of the ethanol group
SOD activity was lower than in animals of the control group. In rats treated with omega-3 fatty acids along
with ethanol, SOD activity increased. GSH-Px activity and MDA levels in animals of all groups were similar.
In ethanol treated rats NO levels significantly decreased as compared to the animals of the control group
(6.45±0.24 nmol/g vs 11.05±0.53 nmol/g, p<0.001). In rats receiving ethanol+omega-3, there was a significant increase
in the NO level as compared to animals of the ethanol group (13.12±0.37 nmol/g vs 6.45±0.24 nmol/g, p<0.001).
Thus, ethanol administration leads to oxidative damage and a decrease in the NO level. Omega-3 fatty acids have
a protective role against ethanol induced oxidative damage and normalize the NO level.
... Oostenbrug et al. [46] supplemented 24 well-trained male cyclists with 6 g·day −1 for 3 weeks, with or without vitamin E (300 IU·day −1 ), and did not find any effect on VO 2 max or time-to-exhaustion testing. On the other hand, in a study by Zebrowska et al. [13], a small dose of 1.3 g·day −1 ω-3 PUFAs for three weeks led to an increased VO 2 max in well-trained cyclists, which was attributed to an improved endothelial function. In the present study, despite a greater daily dosage of ω-3 PUFAs compared to other studies, both groups similarly improved VO 2 max. ...
The aim of this study was to investigate the effects of a supplement rich in ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) and antioxidant vitamins on physical performance and body composition following a period of high-intensity functional training (HIFT). Nineteen healthy young adults (nine males, ten females) underwent an 8-week HIFT program (3 days·week⁻¹) where they were randomized 1:1 into either the supplement group (SG)—n = 10, receiving a 20 mL daily dose of a dietary cocktail formula (Neuroaspis™ PLP10) containing a mixture of ω-3 and ω-6 PUFAs (12,150 mg), vitamin A (0.6 mg), vitamin E (22 mg), and γ-tocopherol (760 mg)—or the placebo group (PG)—n = 9, receiving a 20 mL daily dose of virgin olive oil. Body composition, cardiorespiratory fitness, muscle strength, and muscle endurance were assessed before and after the training period. Body mass did not change, but muscle mass increased by 1.7 ± 1.9% or 0.40 ± 0.53 kg in the SG (p = 0.021) and decreased by 1.2 ± 1.6% or 0.28 ± 0.43 kg (p = 0.097) in the PG, compared with baseline. VO2max, vertical jump, squat 1RM, bench press 1RM, and muscle endurance increased similarly in both groups. The effects of HIFT on physical performance parameters, muscle damage, and inflammation indices were not affected by the supplementation. In conclusion, HIFT combined with high doses of ω-3 and ω-6 PUFAs and antioxidant vitamins resulted in a small but significant increase in muscle mass and fat reduction compared with HIFT alone.
Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of the literature surrounding the effects of long-chain omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplementation on exercise performance, recovery, and brain health. This position stand is intended to provide a scientific foundation for athletes, dietitians, trainers, and other practitioners regarding the effects of supplemental ω-3 PUFA in healthy and athletic populations. The following conclusions represent the official position of the ISSN: Athletes may be at a higher risk for ω-3 PUFA insufficiency.
Diets rich in ω-3 PUFA, including supplements, are effective strategies for increasing ω-3 PUFA levels.
ω-3 PUFA supplementation, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been shown to enhance endurance capacity and cardiovascular function during aerobic-type exercise.
ω-3 PUFA supplementation may not confer a muscle hypertrophic benefit in young adults.
ω-3 PUFA supplementation in combination with resistance training may improve strength in a dose- and duration-dependent manner.
ω-3 PUFA supplementation may decrease subjective measures of muscle soreness following intense exercise.
ω-3 PUFA supplementation can positively affect various immune cell responses in athletic populations.
Prophylactic ω-3 PUFA supplementation may offer neuroprotective benefits in athletes exposed to repeated head impacts.
ω-3 PUFA supplementation is associated with improved sleep quality.
ω-3 PUFA are classified as prebiotics; however, studies on the gut microbiome and gut health in athletes are currently lacking.
Vascular aging, marked by alterations in the structure and function of blood vessels, including heightened arterial stiffness and impaired endothelial function, is linked to a higher likelihood of developing cardiovascular and age-associated pathological conditions. Oxidative stress and inflammation are key stimulation factors in vascular aging. Engaging in healthy dietary habits could enhance the functioning of blood vessels. The aim of this study was to conduct a literature review of the evidence regarding the relationship between food regimens, nutraceuticals, and dietary supplements and vascular health. A search of electronic databases, including PubMed, Scopus, and Web of Science Core Collection, was performed. Experimental and observational studies evaluating the association between food groups, nutraceuticals, supplements, and endothelial function and/or arterial stiffness were deemed eligible for this narrative review. Based on the current body of the included studies, food groups, nutraceuticals, and dietary supplements may not demonstrate superiority over placebos in enhancing markers of vascular health. To obtain more reliable evidence on the effectiveness of interventions in vascular health, additional RCTs with larger sample sizes, extended follow-up periods, and multi-center participation are necessary. Enhancing the credibility of these RCTs requires better control of dietary variables and more precise measurement of vascular health markers.
Increased muscle oxidative stress and inflammatory responses among athletes and has been reported consistently. In addition, it is well known that exhaustive and/or unaccustomed exercise can lead to muscle fatigue, delayed onset muscle soreness, and a decrement in performance. Omega-3 polyunsaturated fatty acids (PUFAs) have been shown to decrease the production of inflammatory eicosanoids, cytokines and reactive oxygen species, possess immunomodulatory effects, and to attenuate inflammatory diseases. While a number of studies have assessed the efficacy of omega-3 PUFA supplementation on red blood cell deformability, muscle damage, inflammation, and metabolism during exercise, only a few studies have evaluated the impact of omega-3 PUFA supplementation on exercise performance. It has been suggested that the ingestion of EPA and DHA of approximately 1-2 g per day, at a ratio of EPA to DHA of 2:1, may be beneficial in counteracting exercise-induced inflammation and for the overall health of an athlete. However, the human data is inconclusive as to whether omega-3 PUFA supplementation, at this dosage, is effective in attenuating the inflammatory and immunomodulatory response to exercise, and improve exercise performance. Thus, attempts should be made to establish an optimal omega-3 fatty acid dosage to maximise the risk/reward ratio of supplementation. It should be noted that high omega-3 PUFA consumption may lead to immunosuppression and prolong bleeding time. Future studies investigating the efficacy of omega-3 PUFA supplementation in exercise-trained individuals should consider using an exercise protocol of sufficient duration and intensity in order to produce a more robust oxidative and inflammatory response.
The aim of the present study was to test the hypothesis that the cardiovascular-protective effects of eicosapentaenoic acid (EPA) may be due, in part, to its ability to stimulate the AMP-activated protein kinase (AMPK)-induced endothelial nitric oxide synthase (eNOS) activation. The role of AMPK in EPA-induced eNOS phosphorylation was investigated in bovine aortic endothelial cells (BAEC), in mice deficient of either AMPKα1 or AMPKα2, in eNOS knockout (KO) mice, or in Apo-E/AMPKα1 dual KO mice. EPA-treatment of BAEC increased both AMPK-Thr172 phosphorylation and AMPK activity, which was accompanied by increased eNOS phosphorylation, NO release, and upregulation of mitochondrial uncoupling protein-2 (UCP-2). Pharmacologic or genetic inhibition of AMPK abolished EPA-enhanced NO release and eNOS phosphorylation in HUVEC. This effect of EPA was absent in the aortas isolated from either eNOS KO mice or AMPKα1 KO mice fed a high-fat, high-cholesterol (HFHC) diet. EPA via upregulation of UCP-2 activates AMPKα1 resulting in increased eNOS phosphorylation and consequent improvement of endothelial function in vivo.
Nitric oxide (NO) is a potent signalling molecule that influences an array of physiological responses. It was traditionally assumed that NO was derived exclusively via the nitric oxide synthase (NOS) family of enzymes. This complex reaction requires a five electron oxidation of L-arginine and is contingent on the presence of numerous essential substrates (including O2) and co-factors. Recently an additional, O2-independent, NO generating pathway has been identified, where nitrite (NO2 ) can undergo a simple one electron reduction to yield NO. NO2 is produced endogenously from the oxidation of NO and also from the reduction of dietary nitrate (NO3 ) by facultative bacteria residing on the tongue. Recent data show that dietary NO3 supplementation, which increases the circulating plasma [NO2 ], reduces the O2 cost of submaximal exercise in healthy humans. This finding is striking given that efficiency during moderate-intensity exercise has been considered to be immutable. There is evidence that the muscle ATP turnover at a fixed work rate is reduced and the mitochondrial P/O ratio is increased following NO3 supplementation, which offers important insights into the physiological bases for the reduced [Vdot] during exercise. NO3 supplementation has also been shown to improve exercise performance in both healthy and patient populations. Therefore, dietary NO3 supplementation may represent a practical and cost-effective method to improve exercise efficiency and exercise tolerance in humans. Given that a NO3 -rich diet may have numerous cardiovascular and other health benefits, dietary NO3 intake may have important implications for human lifelong health and performance.
Human beings evolved consuming a diet that contained about equal amounts of ω-6 and ω-3 essential fatty acids. Today, in Western diets, the ratio of ω-6 to ω-3 fatty acids ranges from approximately 10:1 to 20:1 instead of the traditional range of 1:1 to 2:1. Studies indicate that a high intake of ω-6 fatty acids shifts the physiologic state to one that is prothrombotic and proaggregatory, characterized by increases in blood viscosity, vasospasm, and vasoconstriction, and decreases in bleeding time. ω-3 fatty acids, however, have anti-inflammatory, antithrombotic, antiarrhythmic, hypolipidemic, and vasodilatory properties. Excessive radical formation and trauma during high-intensity exercise leads to an inflammatory state that is made worse by the increased amount of ω-6 fatty acids in Western diets, although this can be counteracted by eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). For the majority of athletes, especially those at the leisure level, general guidelines should include EPA and DHA of about 1 to 2 g/d at a ratio of EPA:DHA of 2:1.
Purpose of review:
Vascular function is recognized as an early and integrative marker of cardiovascular disease. While there is consistent evidence that the quantity of dietary fat has significant effects on vascular function, the differential effects of individual fatty acids is less clear. This review summarizes recent evidence from randomly controlled dietary studies on the impact of dietary fatty acids on vascular function, as determined by flow-mediated dilatation (FMD).
Recent findings:
Critical appraisal is given to five intervention studies (one acute, four chronic) which examined the impact of long-chain n-3 polyunsaturated fatty acid [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] on FMD. In the acute setting, a high dose of long-chain n-3 polyunsaturated fatty acid (4.9 g per 70 kg man) improved postprandial FMD significantly, compared with a saturated fatty acid-rich meal in healthy individuals. In longer-term studies, there was limited evidence for a significant effect of EPA/DHA on FMD in diseased groups.
Summary:
The strongest evidence for the benefits of EPA/DHA on vascular function is in the postprandial state. More evidence from randomly controlled intervention trials with foods will be required to substantiate the long-term effects of EPA/DHA, to inform public health and clinical recommendations.
Flow-mediated dilation (FMD) is a noninvasive indicator of endothelial function and is routinely expressed as the percentage change in arterial diameter (FMD%) from a resting baseline (Dbase) to a postischemic peak (Dpeak). This expression is equivalent to the ratio of Dpeak/Dbase and is, therefore, dependent on important statistical assumptions, which have never been analysed in the context of FMD%. We aimed to investigate these assumptions, via a comparison of FMD between samples of children and adults, as well as to explore other approaches to scaling diameter change for Dbase. We found that FMD% did not scale accurately for interindividual differences in Dbase but, as expected, overestimated endothelial function for low Dbase and vice versa. We argue that this imprecise scaling of FMD% is predictable, not explained by physiology and is probably common. This problem is resolved by applying scaling principles, whereby the difference in diameter is the outcome and Dbase is a covariate in a logarithmic-linked generalized linear model. A specific allometric expression of FMD can be derived and we found this to be Dpeak/Dbase rather than a simple ratio in our particular dataset. We found that sample differences in endothelial function were inaccurate with FMD% versus our new allometric approach, and that FMD% misclassified participants into 'high' and 'low'cohorts, which has implications for prognostic-type studies. We conclude that the general use of FMD% could have led to biased comparisons of different conditions and/or populations in past studies. Our new approach to scaling FMD is flexible for different datasets and is not based on the current assumption that a percentage change is appropriate in all circumstances.
2004;7(1):48-56. Recent evidence suggests that omega-3 fatty acids from fish oil (FO) stimulate fat oxidation in liver and perhaps skeletal muscle. Our purpose was to examine the effect of an acute high-dose and a chronic low-dose of FO on fat oxidation during exercise. Seven recreationally active males (age 21-27 yr) jogged for 60 min at 60 % VO 2 max in three trials administered in random order: 1) no meal (NM), 2) 4 h following a high-fat meal (HFM), and 3) 4 h following an isocaloric HFM partly substituted with FO (HFM+FO). The FO supplement contained 60 % eicosapentaenoic acid, and 40 % docosahexaenoic acid. Subjects then supplemented 4 g/day of FO for 3 wk and while remaining on the supplementation regimen, repeated the same three trials in random order. Indirect calorimetry was used for the determination of oxygen consumption, respiratory exchange ratio, and energy expenditure from fat and carbohydrate. Heart rate, and rating of perceived exertion were also monitored for each test. The acute high-dose FO had no significant affect on fat use during exercise. In contrast, chronic supplementation significantly augmented total fat energy expenditure as compared to trials before supplementation in each of the three treatments versus trials prior to chronic supplementation (NM, 269.1 ± 49.8 v. 245.7 ± 36.2 Kcal, P = 0.009; HFM, 295.2 ± 40.2 v. 260.8 ± 36.4, P = 0.001; HFM+FO, 299.0 ± 38.7 v. 280.4 ± 35.9 Kcal, P = 0.002). These data suggest that chronic, but not acute FO supplementation enhanced the contribution of lipid during exercise in young active males.