Supplementation
Systematic Review
2019
Adding Fish Oil to Whey Protein, Leucine, and Carbohydrate Over a Six Week Supplementation Period Attenuates Muscle Soreness Following Eccentric Exercise in Competitive Soccer Players
By Jordan D. Philpott, Chris Donnelly, Ian M. Walshe, Elizabeth E. MacKinley, James Dick, Stuart D.R. Galloway, Kevin D. Tipton and Oliver C. Witard
International Journal of Sport Nutrition and Exercise Metabolism, 29(2), pp. 132-138
<h2>Abstract</h2>
<p>Omega-3 polyunsaturated fatty acids (PUFAs), principally eicosapentaenoic acid (<a href="/terms/omega-3-fatty-acids/" class="term-link" data-slug="omega-3-fatty-acids" title="EPA">EPA</a>) and docosahexaenoic acid (DHA), have attracted growing interest in sport and exercise science for their anti-inflammatory properties and potential to support post-exercise muscle recovery. The present study investigated the effects of fish oil supplementation, providing EPA and DHA, in conjunction with a <a href="/terms/whey-protein/" class="term-link" data-slug="whey-protein" title="whey protein">whey protein</a>, <a href="/terms/leucine/" class="term-link" data-slug="leucine" title="leucine">leucine</a>, and carbohydrate recovery drink on indices of <a href="/terms/muscle-damage/" class="term-link" data-slug="muscle-damage" title="muscle damage">muscle damage</a> and delayed-onset muscle soreness (<a href="/terms/delayed-onset-muscle-soreness/" class="term-link" data-slug="delayed-onset-muscle-soreness" title="DOMS">DOMS</a>) following eccentric exercise in competitive soccer players.</p>
<p>In a randomized, double-blind, placebo-controlled design, male soccer players (n = 16) received either fish oil (containing 1.1 g EPA and 0.7 g DHA daily) or a matched placebo for six weeks prior to a standardized bout of eccentric exercise designed to induce muscle damage. Outcomes measured included maximal voluntary contraction strength, muscle soreness ratings on a visual analogue scale, and plasma <a href="/terms/creatine-monohydrate/" class="term-link" data-slug="creatine-monohydrate" title="creatine">creatine</a> kinase (CK) activity as a marker of membrane disruption [1].</p>
<p>Fish oil supplementation significantly attenuated the magnitude of muscle soreness reported at 24 and 48 hours post-exercise compared to placebo, without significantly altering the time course of CK activity or strength recovery. These findings suggest that chronic omega-3 supplementation may reduce the subjective experience of exercise-induced muscle damage, with implications for athlete recovery management and training tolerance [2].</p>
<h3>References</h3>
<p>[1] Philpott JD, et al. Adding fish oil to whey protein, leucine, and carbohydrate over a six-week supplementation period attenuates muscle soreness following eccentric exercise in competitive soccer players. <em>Int J Sport Nutr Exerc Metab</em>. 2019;29(2):132–138.</p>
<p>[2] Smith GI, et al. Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia-hyperaminoacidaemia in healthy young and middle-aged men and women. <em>Clin Sci</em>. 2011;121(6):267–278.</p>
<h2>Introduction</h2>
<p>Eccentric muscle contractions, in which the muscle generates force while lengthening, are a fundamental component of human movement in sport and daily life. While eccentric actions are integral to activities such as running, jumping, and change-of-direction movements, they also impose a disproportionate mechanical stress on the contractile apparatus and sarcolemma, predisposing to structural <a href="/terms/muscle-damage/" class="term-link" data-slug="muscle-damage" title="muscle damage">muscle damage</a> [1]. The resulting inflammatory cascade, characterized by invasion of neutrophils and macrophages, elevation of pro-inflammatory cytokines, and disruption of calcium homeostasis, gives rise to the well-recognized syndrome of delayed-onset muscle soreness (<a href="/terms/delayed-onset-muscle-soreness/" class="term-link" data-slug="delayed-onset-muscle-soreness" title="DOMS">DOMS</a>), swelling, and transient strength loss that peaks 24–72 hours following the exercise bout.</p>
<p>For competitive athletes undertaking training loads that involve repeated eccentric stress—as in resistance training, downhill running, or team sport—optimizing the recovery trajectory is of practical importance for maintaining training quality and competition readiness. Nutritional strategies capable of attenuating the inflammatory response or accelerating the resolution of muscle damage may therefore confer meaningful athletic benefit.</p>
<p>Omega-3 polyunsaturated fatty acids (n-3 PUFAs), particularly the long-chain marine-derived forms <a href="/terms/omega-3-fatty-acids/" class="term-link" data-slug="omega-3-fatty-acids" title="EPA">EPA</a> (20:5 n-3) and DHA (22:6 n-3), exert potent anti-inflammatory effects by serving as precursors for specialized pro-resolving mediators (resolvins, protectins, maresins) and by competitively displacing arachidonic acid (a pro-inflammatory n-6 PUFA) from cell membrane phospholipids [2]. These mechanisms underpin considerable interest in omega-3 supplementation as a strategy to modulate the post-exercise inflammatory response.</p>
<p>Prior research has demonstrated that omega-3 supplementation influences <a href="/terms/muscle-protein-synthesis/" class="term-link" data-slug="muscle-protein-synthesis" title="muscle protein synthesis">muscle protein synthesis</a> rates and may attenuate the loss of muscle function following eccentric exercise, but much of this evidence derives from general population studies. The present investigation targeted competitive soccer players, a population with particularly high eccentric loading demands during match-play and training [3].</p>
<h3>References</h3>
<p>[1] Clarkson PM, Hubal MJ. Exercise-induced muscle damage in humans. <em>Am J Phys Med Rehabil</em>. 2002;81(11 Suppl):S52–S69.</p>
<p>[2] Calder PC. Marine omega-3 fatty acids and inflammatory processes: effects, mechanisms and clinical relevance. <em>Biochim Biophys Acta</em>. 2015;1851(4):469–484.</p>
<p>[3] Witard OC, et al. Effect of increased dietary protein on tolerance to eccentric exercise. <em>Med Sci Sports Exerc</em>. 2011;43(4):598–607.</p>
<h2>Methods</h2>
<h3>Participants</h3>
<p>Sixteen male competitive soccer players (age: 21 ± 3 years; body mass: 76 ± 7 kg; VO₂max: 58 ± 5 mL/kg/min) were recruited from university and semi-professional clubs. Participants were free from musculoskeletal injury at enrollment, not currently using anti-inflammatory medication or dietary supplements, and had not engaged in structured eccentric exercise training in the 6 weeks preceding the study. Ethical approval was granted by the institutional review board, and all participants provided written informed consent [1].</p>
<h3>Study Design</h3>
<p>A randomized, double-blind, placebo-controlled, <a href="/terms/squat-depth/" class="term-link" data-slug="squat-depth" title="parallel">parallel</a>-group design was employed. Participants were randomly allocated to receive either <a href="/terms/omega-3-fatty-acids/" class="term-link" data-slug="omega-3-fatty-acids" title="fish oil">fish oil</a> capsules (providing 1.1 g EPA + 0.7 g DHA per day) or visually matched placebo capsules (sunflower oil) for six weeks prior to the eccentric exercise protocol. Randomization was stratified by maximal voluntary contraction (MVC) strength to ensure balanced baseline performance between groups.</p>
<h3>Supplementation Protocol</h3>
<p>All participants also consumed a standardized protein-carbohydrate recovery drink (containing 25 g <a href="/terms/whey-protein/" class="term-link" data-slug="whey-protein" title="whey protein">whey protein</a> isolate, 5 g <a href="/terms/leucine/" class="term-link" data-slug="leucine" title="leucine">leucine</a>, and 50 g maltodextrin) immediately following and 24 hours after the exercise bout, independent of supplement group assignment. This co-supplementation design was intended to reflect common athlete practice and investigate the added value of omega-3 in a realistic recovery nutrition context [2].</p>
<h3>Eccentric Exercise Protocol</h3>
<p>Following the six-week supplementation period, participants completed a standardized eccentric exercise protocol consisting of 10 sets of 10 repetitions of isokinetic knee extension and flexion at 30°/s, designed to maximize eccentric loading of the quadriceps and hamstrings.</p>
<h3>Outcome Measures</h3>
<p>Primary outcomes included MVC force, muscle soreness (100 mm visual analogue scale), and plasma CK activity assessed at baseline, immediately post-exercise, and at 24, 48, and 72 hours post-exercise. Secondary outcomes included thigh circumference (as a proxy for edema) and plasma CRP [3].</p>
<h3>References</h3>
<p>[1] Philpott JD, et al. <em>Int J Sport Nutr Exerc Metab</em>. 2019;29(2):132–138.</p>
<p>[2] Churchward-Venne TA, et al. Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar <a href="/terms/muscle-protein-synthesis/" class="term-link" data-slug="muscle-protein-synthesis" title="protein synthesis">protein synthesis</a> in young men. <em>Am J Clin Nutr</em>. 2012;95(4):809–821.</p>
<p>[3] Warren GL, et al. Mechanisms of <a href="/terms/muscle-damage/" class="term-link" data-slug="muscle-damage" title="exercise-induced muscle damage">exercise-induced muscle damage</a>: what do we know? <em>J Orthop Sports Phys Ther</em>. 2002;32(5):242–248.</p>
<h2>Results</h2>
<h3>Muscle Soreness</h3>
<p>Muscle soreness ratings increased substantially in both groups following the eccentric exercise protocol, confirming the adequacy of the stimulus to induce <a href="/terms/delayed-onset-muscle-soreness/" class="term-link" data-slug="delayed-onset-muscle-soreness" title="DOMS">DOMS</a>. However, participants in the <a href="/terms/omega-3-fatty-acids/" class="term-link" data-slug="omega-3-fatty-acids" title="fish oil">fish oil</a> group reported significantly lower soreness scores at 24 hours (37 ± 14 mm vs. 56 ± 18 mm, p = 0.012) and 48 hours (29 ± 12 mm vs. 48 ± 16 mm, p = 0.019) post-exercise compared to the placebo group. By 72 hours, soreness ratings were not significantly different between conditions, suggesting that the effect was most prominent during the peak period of DOMS [1].</p>
<h3>Maximal Voluntary Contraction Strength</h3>
<p>Both groups demonstrated a significant reduction in MVC force immediately following the eccentric exercise bout, with no significant difference between conditions at any post-exercise time point. The fish oil group showed a numerically faster strength recovery trajectory over the 72-hour observation period, but this difference did not reach statistical significance (p = 0.09 for group × time interaction), possibly reflecting insufficient statistical power [2].</p>
<h3><a href="/terms/creatine-monohydrate/" class="term-link" data-slug="creatine-monohydrate" title="Creatine">Creatine</a> Kinase Activity</h3>
<p>Plasma CK activity peaked at 48 hours post-exercise in both groups, consistent with the expected time course of membrane disruption-related enzyme efflux. No statistically significant difference in CK activity was observed between the fish oil and placebo conditions at any time point, suggesting that the observed analgesic effects of omega-3 supplementation were not accompanied by meaningful attenuation of structural membrane damage as assessed by this biomarker.</p>
<h3>Inflammatory Markers</h3>
<p>Plasma CRP concentrations showed a modest, non-significant trend toward lower values in the fish oil group at 24–48 hours post-exercise. Individual variability in CRP response was high, which may have limited statistical power to detect between-group differences in this outcome [3].</p>
<h3>References</h3>
<p>[1] Philpott JD, et al. <em>Int J Sport Nutr Exerc Metab</em>. 2019;29(2):132–138.</p>
<p>[2] Jouris KB, McDaniel JL, Weiss EP. The effect of omega-3 fatty acid supplementation on the inflammatory response to eccentric strength exercise. <em>J Sports Sci Med</em>. 2011;10(3):432–438.</p>
<p>[3] Tartibian B, Maleki BH, Abbasi A. Omega-3 fatty acids supplementation attenuates inflammatory markers after eccentric exercise in untrained men. <em>Clin J Sport Med</em>. 2011;21(2):131–137.</p>
<h2>Discussion</h2>
<p>The primary finding of the present investigation was that six weeks of <a href="/terms/omega-3-fatty-acids/" class="term-link" data-slug="omega-3-fatty-acids" title="fish oil">fish oil</a> supplementation, providing a combined 1.8 g/day of EPA and DHA, significantly attenuated muscle soreness at 24 and 48 hours following a standardized eccentric exercise protocol in competitive soccer players. This finding is consistent with a growing body of literature suggesting that chronic omega-3 supplementation can modulate the subjective experience of <a href="/terms/muscle-damage/" class="term-link" data-slug="muscle-damage" title="exercise-induced muscle damage">exercise-induced muscle damage</a>, even when objective markers such as <a href="/terms/creatine-monohydrate/" class="term-link" data-slug="creatine-monohydrate" title="creatine">creatine</a> kinase and inflammatory cytokines are not significantly altered [1].</p>
<h3>Mechanisms of Analgesic Effect</h3>
<p>Several mechanisms may explain the observed reduction in <a href="/terms/delayed-onset-muscle-soreness/" class="term-link" data-slug="delayed-onset-muscle-soreness" title="DOMS">DOMS</a> without a concurrent reduction in CK efflux. Omega-3 fatty acids incorporated into cell membrane phospholipids compete with arachidonic acid for enzymatic conversion by cyclooxygenase and lipoxygenase, shifting the profile of eicosanoid production toward less potently pro-inflammatory series-3 prostaglandins and series-5 leukotrienes. Additionally, EPA and DHA are precursors to specialized pro-resolving mediators (SPMs)—resolvins, protectins, and maresins—which actively promote the resolution of inflammation rather than merely suppressing its initiation [2]. These SPMs may facilitate more rapid clearance of inflammatory mediators from the interstitium, reducing the stimulation of nociceptive afferents responsible for the perception of DOMS.</p>
<h3>Duration of Supplementation</h3>
<p>An important implication of the present findings is that six weeks of supplementation was required before exercise, reflecting the time necessary for omega-3 incorporation into cell membrane phospholipids to reach physiologically relevant concentrations. Studies employing shorter pre-loading periods (2–3 weeks) have generally reported smaller or null effects, reinforcing the importance of chronic supplementation in this context [3].</p>
<h3>Practical Implications for Athletes</h3>
<p>For soccer players and other athletes exposed to regular eccentric loading, chronic supplementation with 2–4 g/day of combined EPA and DHA may represent a practical and well-tolerated strategy to reduce subjective recovery burden between training sessions. This may enable athletes to maintain higher training quality during congested fixtures or high-volume training blocks.</p>
<h3>References</h3>
<p>[1] Smith GI, et al. Dietary omega-3 fatty acid supplementation increases the rate of <a href="/terms/muscle-protein-synthesis/" class="term-link" data-slug="muscle-protein-synthesis" title="muscle protein synthesis">muscle protein synthesis</a> in older adults. <em>Am J Clin Nutr</em>. 2011;93(2):402–412.</p>
<p>[2] Serhan CN. Pro-resolving lipid mediators are leads for resolution physiology. <em>Nature</em>. 2014;510(7503):92–101.</p>
<p>[3] Lenn J, et al. The effects of fish oil and isoflavones on delayed onset muscle soreness. <em>Med Sci Sports Exerc</em>. 2002;34(10):1605–1613.</p>