Omega-3 fatty acids enhance the beneficial effect of BCAA supplementation on muscle function following eccentric contractions.

Background: This study investigated the combined effect of branched-chain amino acids (BCAA) and fish oil (FO) on muscle damage caused by eccentric contractions (ECCs) of the elbow flexors, with a special focus on muscular function. Methods: Twenty-nine untrained male participants were enrolled in this double-blind, placebo-controlled, parallel study. The participants were randomly assigned to the placebo (PL) group (n = 9), BCAA supplement group (n = 10), and BCAA+FO supplement group (n = 10). The BCAA+FO group consumed eicosapentaenoic acid (EPA) 600 mg and docosahexaenoic acid (DHA) 260 mg per day for 8 weeks, while the BCAA and BCAA+FO groups consumed 9.6 g per day for 3 days prior to and until 5 days after ECCs. Participants performed six sets of 10 ECCs at 100% maximal voluntary contraction (MVC) using dumbbells. Changes in MVC torque, range of motion (ROM), muscle soreness using visual analog scales, upper circumference, muscle thickness, echo intensity, and serum creatine kinase (CK) were assessed before, immediately after, and 1, 2, 3, and 5 days after ECCs. Results: The MVC torque was significantly higher in the BCAA+FO group than in the PL group immediately after ECCs (p < 0.05) but not in the BCAA group. Both BCAA and BCAA+FO groups showed greater ROM and lower muscle soreness than the PL group (p < 0.05). CK was significantly lower in the BCAA group than in the PL group at 5 days after ECCs (p < 0.05). Conclusions: This study reveals that supplementation with BCAA and FO may favorably impact immediate recovery of peak torque production. Alternatively, in comparison to PL group, BCAA supplementation favorably reduces creatine kinase.

Prior beetroot juice ingestion offsets endothelial dysfunction following prolonged sitting.

Nutritional strategies to prevent endothelial dysfunction following prolonged sitting remain largely unknown. Given that beetroot juice (BRJ) ingestion enhances nitric oxide (NO) bioavailability, we aimed to evaluate whether prior BRJ ingestion would prevent sitting-induced endothelial dysfunction in the leg. Eleven healthy young males (n = 7) and females (n = 4) underwent two experimental trials of prolonged sitting with prior: 1) placebo (PL) ingestion (PL trial) and 2) BRJ ingestion (BRJ trial). All subjects ingested 140 mL of PL or BRJ (∼0.0055 or ∼12.8 mmol of nitrate, respectively) immediately before 3 h of sitting. Pre- and post-sitting measurements of popliteal artery flow-mediated dilation (FMD) and blood pressure, and blood collection were undertaken. During the sitting period, an hourly assessment of popliteal artery diameter and blood velocity, blood pressure, and blood collection were performed. Popliteal artery blood flow and shear rate were significantly and similarly reduced during the sitting period in both trials (P < 0.001). Plasma nitrate and NOx (total nitrite and nitrate) concentrations were significantly increased relative to baseline in the only BRJ trial, and the overall concentrations were significantly higher in the BRJ trial (P < 0.001). Popliteal artery FMD was significantly reduced after the sitting period in the PL trial (P < 0.05), whereas no reduction was observed in the BRJ trial. Therefore, prior BRJ ingestion would prevent sitting-induced leg endothelial dysfunction via enhancing NO bioavailability.NEW & NOTEWORTHY The present study elucidates that beetroot juice ingestion before prolonged sitting offsets sitting-induced leg endothelial dysfunction. Data from the present study provides novel physiological information that enhancing NO bioavailability by dietary nitrate supplementation is an effective tool for prevention of the detrimental vascular effects of prolonged sitting.

Polyunsaturated Fatty Acids, Exercise, and Cancer-Related Fatigue in Breast Cancer Survivors.

Cancer-related fatigue (CRF) is one of the most frequently reported and disabling symptoms in cancer survivors. With its negative impact on the activities of daily living, work, social activities, and mood, CRF causes severe impairment of quality of life. A previous study showed that omega-6 polyunsaturated fatty acid (PUFA) supplementation unexpectedly reduced CRF compared with omega-3 PUFA supplementation and that omega-6 PUFA supplementation reduced pro-inflammatory serum markers in fatigued American breast cancer survivors. Meanwhile, a recent meta-analysis of individual patient data revealed significant benefits of exercise interventions on CRF. Recently, we completed our randomized controlled trial among early-stage Japanese breast cancer survivors, in which we examined the effect of baseline blood PUFA characteristics on change in CRF during the 12-week trial by exercise group and confirmed that increased Cancer Fatigue Scale (CFS) was associated with both docosahexaenoic acid (DHA) (p = 0.06) and omega-3 index (p = 0.08) at baseline in all participants (n = 46, omega-6/omega-3 ratio = 6.79, SD = 1.90). On the contrary, DHA at baseline was positively correlated with change in CRF (r = 0.40, p = 0.06) in the control group (n = 24, omega-6/omega-3 ratio = 7.0). Moreover, eicosapentaenoic acid (EPA) at baseline was positively correlated with leg strength (r = 0.39, p = 0.10) in the exercise group. In conclusion, blood PUFA balance might be associated with the effect of exercise on CRF. In addition, higher EPA in individuals who conducted exercise likely has a beneficial effect on muscle strength. Further investigation is needed to clarify the interaction between PUFAs and exercise for alleviating CRF.

4-week eicosapentaenoic acid-rich fish oil supplementation partially protects muscular damage following eccentric contractions.

BACKGROUND: We previously showed 8-week of fish oil supplementation attenuated muscle damage. However, the effect of a shorter period of fish oil supplementation is unclear. The present study investigated the effect of fish oil, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for 4 weeks on muscular damage caused by eccentric contractions (ECCs) of the elbow flexors. METHODS: Twenty-two untrained men were recruited in this double-blind, placebo-controlled, parallel design study and the subjects were randomly assigned to the EPA and DHA group (EPA and DHA, n = 11) and placebo group (PL, n = 11). They consumed either EPA 600 mg and DHA 260 mg per day or placebo supplement for 4 weeks prior to exercise. Subjects performed 60 ECCs at 100 % maximal voluntary contraction (MVC) using a dumbbell. Changes in MVC torque, range of motion (ROM), upper arm circumference, muscle soreness, echo intensity, muscle thickness, serum creatine kinase (CK), and interleukin-6 (IL-6) were assessed before exercise; immediately after exercise; and 1, 2, 3, and 5 days after exercise. RESULTS: ROM was significantly higher in the EPA and DHA group than in the PL group immediately after performing ECCs (p < 0.05). No differences between groups were observed in terms of MVC torque, upper arm circumference, muscle soreness, echo intensity, and thickness. A significant difference was observed in serum CK 3 days after ECCs (p < 0.05). CONCLUSIONS: We concluded that shorter period EPA and DHA supplementation benefits joint flexibility and protection of muscle fiber following ECCs.

Plasma Eicosapentaenoic Acid Is Associated with Muscle Strength and Muscle Damage after Strenuous Exercise.

BACKGROUND: Although the ingestion of total omega-3 fatty acids (omega-3) is positively related with muscular strength in older persons, little is known about the effect of omega-3 plasma levels on muscular function before and after exercise in young men. Moreover, omega-3 supplementation has a positive role in exercise-induced acute muscle damage. This study investigated the relationship between plasma omega-3 in the blood and promotion and preservation of muscle strength after eccentric contractions (ECCs) in young men. METHODS: Thirty-two healthy young men participated in this study. We assessed plasma omega-3 level and the maximal voluntary contraction (MVC). Twenty-six out of them exercised 60 ECCs at 100% MVC. We measured the MVC torque, flexibility before and immediately after exercise, 1-5 days post exercise. RESULTS: The levels of eicosapentaenoic acid (EPA) and EPA/arachidonic acid were positively associated with muscle strength (p < 0.05). Higher levels of omega-3 EPA and docosahexaenoic acid prevented the reduction in the MVC and limited joint flexibility after ECCs. CONCLUSIONS: The present study reveals that higher levels of EPA are important to promote muscle strength and preserve the strength loss after exercise.

Muscular endurance and muscle metabolic responses to 8 weeks of omega-3 polyunsaturated fatty acids supplementation.

BACKGROUND: It has been well known that exercise training improves muscular endurance; however, whether nutritional strategies can be used to enhance muscular endurance remains unclear. Herein, we tested the hypothesis that 8 weeks of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation, known to promote oxygen availability and lipid metabolism, would attenuate muscular fatigue caused by numerous muscle contractions. METHODS: Nineteen healthy men were randomly assigned to a placebo group (n = 9) and fish oil group (n = 10) in a double-blind fashion. The fish oil group consumed EPA-rich fish oil that contains 600-mg EPA and 260-mg DHA per day for 8 weeks. The placebo group received matching capsules for the same duration of time. After the 8-week intervention, subjects performed muscular endurance test that was repeated knee extensions with weights equal to 40% of the subject's body weight. RESULTS: Maximal repetitions to exhaustion were recorded. In addition, maximum isometric voluntary muscle contraction (MVC), muscle metabolism using near-infrared spectroscopy, and blood lactate were measured during the test. Subjects in both groups reached exhaustion after the muscular endurance test, while the maximal repetitions did not differ between the groups. Similarly, there is no significant difference in oxygen saturation in muscle tissue (StO2), an index of muscle oxygen availability, between the groups. Also, MVC and blood lactate did not change between groups. CONCLUSION: In conclusion, the present study provided evidence that muscle fatigue caused by knee extensions cannot be attenuated by EPA and DHA supplementation in healthy subjects.

Eight weeks of fish oil supplementation does not prevent sitting-induced leg endothelial dysfunction.

Prolonged sitting impairs leg endothelial function and this impairment is thought to be mediated by a sustained reduction in blood flow-induced shear stress. However, whether nutritional strategies can be used to prevent sitting-induced leg endothelial dysfunction remains unknown. Herein, we tested the hypothesis that 8 weeks of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation would prevent endothelial dysfunction associated with sitting. Nineteen healthy men were randomly assigned to a placebo group or EPA+DHA group in a double-blind fashion. The EPA+DHA group was administered EPA-rich fish oil, containing 600 mg EPA and 260 mg DHA per day for 8 weeks. The placebo group received matching capsules for the same duration of time. Popliteal artery flow-mediated dilation (FMD) was measured at baseline and before and after a 3-h sitting period. During sitting, blood pressure, popliteal artery diameter, and blood velocity were measured every hour. Throughout the sitting period, popliteal artery blood flow and shear rate were markedly and similarly reduced in both groups (P < 0.05). However, counter to the hypothesis, 3 h of sitting impaired popliteal artery FMD to the same extent in both groups (P < 0.05). In conclusion, daily EPA and DHA supplementation is not effective at preventing the detrimental effects of prolonged sitting on leg endothelial function. Novelty We provide evidence that sitting-induced leg endothelial dysfunction in young healthy subjects cannot be remediated by a nutritional strategy known to produce cardiovascular benefits. This could be partially due to the low total dose of EPA and DHA administered.

Supplementation of eicosapentaenoic acid-rich fish oil attenuates muscle stiffness after eccentric contractions of human elbow flexors.

BACKGROUND: This study aimed to investigate the effect of supplementation of fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the damage of the biceps brachii after eccentric contractions (ECCs) of the elbow flexors, particularly focusing on muscle stiffness. METHODS: Sixteen men were included in this double-blind, placebo-controlled, parallel design study and the participants were randomly assigned to the EPA and DHA supplement group (EPA, n = 8) and placebo group (PL, n = 8). They consumed either EPA 600 mg and DHA 260 mg per day or placebo supplement for 8 weeks prior to exercise. Moreover, they performed six sets of 10 ECCs at 100% maximal voluntary contraction (MVC) using a dumbbell. Changes in MVC torque, range of motion (ROM), upper arm circumference, muscle soreness, muscle echo intensity, and muscle stiffness were assessed before exercise; immediately after exercise; and 1, 2, and 5 days after exercise. RESULTS: MVC torque and ROM were significantly higher in the EPA group than in the PL group after ECCs (p < 0.05). Muscle soreness, upper arm circumference, and muscle echo intensity were significantly higher in the PL group than in the EPA group after ECCs (p < 0.05). In addition, muscle stiffness at 150° was significantly higher in the PL group than in the EPA group immediately after ECCs (p < 0.05). CONCLUSION: The present study showed that EPA and DHA supplementation has a positive role in inhibiting muscle stiffness after ECCs. TRIAL REGISTRATION: This trial (UMIN000028165) was registered on 10th/July/2017.

Eicosapentaenoic Acid-Rich Fish Oil Supplementation Inhibits the Decrease in Concentric Work Output and Muscle Swelling of the Elbow Flexors.

OBJECTIVE: The aim of this study was to test the hypothesis that 8-week eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation improves peripheral muscle performance by concentric contractions (CONs) of elbow flexors in humans. METHODS: Sixteen healthy men were randomly administered with EPA and DHA supplement (EPA, n = 8) or placebo (PL, n = 8) by a double-blind method. The EPA group was administered EPA-rich fish oil, containing 600 mg EPA and 260 mg DHA per day for 8 weeks. The subjects performed 5 sets of 6 maximal CONs of elbow flexors. The work output and peak torque were assessed during exercise. Changes in the maximal voluntary isometric contraction torque, range of motion (ROM), upper arm circumference, muscle fatigue by rating of perceived exertion, transverse relaxation time, cross-sectional area (CSA), and lactate in blood were also assessed before, immediately after, and 1 day after exercise. RESULTS: The work output during CONs in the EPA group was greater than that in the placebo group at the fifth set (EPA group; 94.0 ± 11.7%, placebo group; 82.5 ± 11.7%, p < 0.05). In addition, ROM in the EPA group was significantly greater than that in the placebo group immediately after exercise (p < 0.05). The increase of CSA in the EPA group was significantly smaller than that in the placebo group immediately after exercise (p < 0.05). CONCLUSIONS: The present study suggests that the reduction of muscle work output caused by 30 CONs can be attenuated by an 8-week EPA and DHA supplementation. In addition, EPA and DHA supplementation can cause inhibition for reduction of ROM and increase of CSA after CONs.

Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) in Muscle Damage and Function.

Nutritional supplementation not only helps in improving and maintaining performance in sports and exercise, but also contributes in reducing exercise fatigue and in recovery from exhaustion. Fish oil contains large amounts of omega-3 fatty acids, eicosapentaenoic acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3). It is widely known that omega-3 fatty acids are effective for improving cardiac function, depression, cognitive function, and blood as well as lowering blood pressure. In the relationship between omega-3 fatty acids and exercise performance, previous studies have been predicted improved endurance performance, antioxidant and anti-inflammatory responses, and effectivity against delayed-onset muscle soreness. However, the optimal dose, duration, and timing remain unclear. This review focuses on the effects of omega-3 fatty acid on muscle damage and function as evaluated by human and animal studies and summarizes its effects on muscle and nerve damage, and muscle mass and strength.

Effect of eicosapentaenoic acids-rich fish oil supplementation on motor nerve function after eccentric contractions.

BACKGROUND: This study investigated the effect of supplementation with fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the M-wave latency of biceps brachii and muscle damage after a single session of maximal elbow flexor eccentric contractions (ECC). METHODS: Twenty-one men were completed the randomized, double-blind, placebo-controlled, and parallel-design study. The subjects were randomly assigned to the fish oil group (n = 10) or control group (n = 11). The fish oil group consumed eight 300-mg EPA-rich fish oil softgel capsules (containing, in total, 600 mg EPA and 260 mg DHA) per day for 8 weeks before the exercise, and continued this for a further 5 days. The control group consumed an equivalent number of placebo capsules. The subjects performed six sets of ten eccentric contractions of the elbow flexors using a dumbbell set at 40% of their one repetition maximum. M-wave latency was assessed as the time taken from electrical stimulation applied to Erb's point to the onset of M-wave of the biceps brachii. This was measured before and immediately after exercise, and then after 1, 2, 3, and 5 days. Changes in maximal voluntary isometric contraction (MVC) torque, range of motion (ROM), upper arm circumference, and delayed onset muscle soreness (DOMS) were assessed at the same time points. RESULTS: Compared with the control group, M-wave latency was significantly shorter in the fish oil group immediately after exercise (p = 0.040), MVC torque was significantly higher at 1 day after exercise (p = 0.049), ROM was significantly greater at post and 2 days after exercise (post; p = 0.006, day 2; p = 0.014), and there was significantly less delayed onset muscle soreness at 1 and 2 days after exercise (day 1; p = 0.049, day 2; p = 0.023). CONCLUSION: Eight weeks of EPA and DHA supplementation may play a protective role against motor nerve function and may attenuate muscle damage after eccentric contractions. TRIAL REGISTRATION: This trial was registered on July 14th 2015 (https://upload.umin.ac.jp/cgi-open-bin/ctr/index.cgi).

Eicosapentaenoic and docosahexaenoic acids-rich fish oil supplementation attenuates strength loss and limited joint range of motion after eccentric contractions: a randomized, double-blind, placebo-controlled, parallel-group trial.

PURPOSE: This study investigated the effect of eicosapentaenoic and docosahexaenoic acids-rich fish oil (EPA + DHA) supplementation on eccentric contraction-induced muscle damage. METHODS: Twenty-four healthy men were randomly assigned to consume the EPA + DHA supplement (EPA, n = 12) or placebo (PL, n = 12) by the double-blind method. Participants consumed EPA + DHA or placebo supplement for 8 weeks prior to exercise and continued it until 5 days after exercise. The EPA group consumed EPA + DHA-rich fish oil containing 600 mg EPA and 260 mg DHA per day. Subjects performed five sets of six maximal eccentric elbow flexion exercises. Changes in the maximal voluntary contraction (MVC) torque, range of motion (ROM), upper arm circumference, muscle soreness as well as serum creatine kinase, myoglobin, IL-6, and TNF-α levels in blood were assessed before, immediately after, and 1, 2, 3, and 5 days after exercise. RESULTS: MVC was significantly higher in the EPA group than in the PL group at 2-5 days after exercise (p < 0.05). ROM was also significantly greater in the EPA group than in the PL group at 1-5 days after exercise (p < 0.05). At only 3 days after exercise, muscle soreness of the brachialis was significantly greater in the PL group than in the EPA group (p < 0.05), with a concomitant increase in serum IL-6 levels in the PL group. CONCLUSION: Eight-week EPA + DHA supplementation attenuates strength loss and limited ROM after exercise. The supplementation also attenuates muscle soreness and elevates cytokine level, but the effect is limited.

Effects of combined ß-hydroxy-ß-methylbutyrate (HMB) and whey protein ingestion on symptoms of eccentric exercise-induced muscle damage.

BACKGROUND: The purpose of this study was to examine the effects of combined ß-hydroxy-ß-methylbutyrate (HMB) and whey protein ingestion on muscle strength and damage following a single bout of eccentric exercise. METHODS: Eighteen untrained male subjects were assigned to HMB and Whey protein (HMB + Whey; 3 g/day HMB and 36.6 g/day whey protein, n = 6), HMB (3 g/day, n = 6), or whey protein (36.6 g/day, n = 6) groups. Ingestion commenced 7 days before non-dominant elbow flexor eccentric exercise (30 deg/sec, 6 reps × 7 sets) and continued until 4 days post-exercise. The maximal isometric strength, muscle soreness, plasma creatine kinase (CK), lactate dehydrogenase (LDH) were assessed pre-exercise, and at 1, 2, 3, and 5 days after exercise. RESULTS: The change scores of maximal isometric strength significantly decreased at day 1, 2, and 5 in the whey protein group compared to pre value and that in HMB + Whey protein and HMB groups decreased at day 1 and 5. The muscle soreness significantly increased in the whey and HMB + Whey protein groups at day 3 compared to pre value (p < 0.05). CK and LDH significantly increased (time effect: p < 0.05) after exercise. However, all data were not significant difference among the groups. CONCLUSIONS: These results suggest that ingestion of combined HMB and whey protein does not have a role to inhibit muscle strength loss and soreness, and decrease in muscle damage markers after eccentric exercise in comparison with HMB and whey protein alone.

Dietary apple polyphenols have preventive effects against lengthening contraction-induced muscle injuries.

We examined whether polyphenols from dietary apple have protective effects against exercise-induced muscle strain injury. Sixteen male Wistar rats were randomly assigned into the apple polyphenol (APP; N=8) and control (CON; N=8) groups. The APP and the CON groups were fed diets with and without 5% APP, respectively. After a 3-wk feeding period, the gastrocnemii of the animals were subject to lengthening contractions with electrical stimulation and forced ankle dorsiflexion. Isometric torques were measured before and after the lengthening contractions and on days 1, 2, 3, 5, and 7 after the contractions. On day 7, the animals were sacrificed and the gastrocnemii harvested. Thiobarbituric-acid-reactive substances, protein carbonyl, and mRNA of antioxidative proteins in the muscles were quantified. The APP group had significantly lower torque deficits than the CON group on days 3, 5, and 7 after the eccentric contractions. The thiobarbituric-acid-reactive substances and protein carbonyl levels in the case of the APP group were significantly lower than those in the case of the CON group. The APP group had significantly higher glutathione-S-transferase alpha1 mRNA levels than the CON group. Therefore, we conclude that dietary APPs have protective effects against lengthening contraction-induced muscle injury.