Effects of eight weeks of eicosapentaenoic acid and medium-chain triacylglycerol structured lipid intake on EPA/AA ratio and muscle performance in young men.

Objective Structured lipids containing medium-chain fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) from fish oil (EPA/MCT) and it improve overall endurance. However, their effects on local muscle endurance remain unclear. This study aimed to investigate the effects of EPA/MCT intake on muscle endurance during leg extension exercises and subsequent muscle fatigue. Methods This 8-week, placebo-controlled, randomized, double-blind parallel-group trial involved 20 healthy young men. Subjects were randomly assigned to an EPA/MCT group (10 subjects) and a placebo group (PL group, 10 subjects). They consumed 4560 mg of the test food daily for 8 wk before an exercise intervention. The EPA/MCT supplement contained 600 mg of EPA, 260 mg of DHA, and 1890 mg of MCT (1110 mg of octanoic acid and 780 mg of decanoic acid). After the 8-week intervention, the subjects performed four sets of leg extension exercises at 40% of their body weight until exhaustion. The number of repetitions per set and the total repetitions across the four sets served as indicators of muscle endurance. Isometric maximum voluntary contraction (MVC), range of motion, circumference, muscle thickness, echo intensity, and muscle stiffness were measured before and after exercise to assess muscle fatigue. Results There was no difference between the groups in the number of repetitions for sets 1–4 or in the total number of repetitions during the leg extension exercise. In the EPA/MCT group, a significant negative correlation was observed between the increase in the blood EPA/AA ratio and the rate of decrease in the number of repetitions. Additionally, the decrease in MVC after exercise was significantly smaller in the EPA/MCT group than in the PL group. Conclusion Our study results suggest that an 8-week intake of EPA/MCT can increase the blood EPA/AA ratio and improve muscle endurance performance. Additionally, EPA/MCT intake reduces muscle fatigue after exercise.

BackgroundWe 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.MethodsTwenty-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.ResultsROM 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).ConclusionsWe concluded that shorter period EPA and DHA supplementation benefits joint flexibility and protection of muscle fiber following ECCs.

Conflicting results have been reported regarding the effects of resistance exercise training with eccentric (lengthening muscle) versus concentric (shortening muscle) contractions on changes in maximal voluntary contraction (MVC) strength assessed by different contraction modes. The main objective of this systematic review with meta-analyses was to compare the effectiveness of maximal isokinetic eccentric-only and concentric-only strength training for changes in maximal voluntary eccentric (MVCECC), concentric (MVCCON), and isometric contraction (MVCISO) strength in healthy adults. We conducted a systematic search in PubMed, SPORTDiscus, and Google Scholar from February to March 2024 for studies that met the following criteria: (1) randomized controlled trials; (2) inclusion of eccentric-only and concentric-only strength training groups; (3) use of an isokinetic dynamometer for training and testing; (4) reporting changes over time in MVCCON and MVCECC; and (5) using healthy adult participants. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. A multilevel random-effects model meta‑analyses with robust variance estimation were performed in Rstudio software using metafor and clubSandwich packages. Moreover, sensitivity analysis was performed, excluding the highly influential studies. The potential moderating role of sex, training status and age of the participants, muscles, velocity in training and testing, initial MVCECC, MVCCON, and MVCECC/MVCCON ratio, and training-related variables such as number of repetitions per set, number of sets, rest period between sets, number of sessions per week, and duration of the training protocol were also assessed. Twenty-seven studies matched with the criteria, and overall 162 study results were identified and included in the meta-analyses. Greater effects on MVCECC were found after eccentric-only than concentric-only training (Hedges' g: 1.51; 27 vs. 10%; p < 0.001). However, no differences were evident between the training modalities for changes in MVCCON (Hedges' g: -0.10; 13% vs. 14%, p = 0.726) and MVCISO (Hedges' g: -0.04; 18 vs. 17%; p = 0.923). The subgroup analyses showed smaller effect of eccentric-only than concentric-only training on MVCCON when eccentric-only training was performed at higher velocities than the velocities of MVCCON testing (Hedges' g: -0.99; p = 0.010). Meta-regressions showed that the longer the training period, the greater the superior effect of eccentric-only over concentric-only training on MVCECC. Eccentric-only strength training is more effective for improving MVCECC, but both concentric-only and eccentric-only training provide similar effects on improving MVCCON and MVCISO. Further studies are necessary to investigate the mechanisms underpinning the superior effect of eccentric-only training.

The New Dietary Fats in Health and Disease

Randomized Structured Triglycerides Increase Lymphatic Absorption of Tocopherol and Retinol Compared with the Equivalent Physical Mixture in a Rat Model of Fat Malabsorption

Plasma and tissue fatty acid profiles of growing pigs fed structured or non-structured triacylglycerides containing medium-chain and marine oil fatty acids

Nitrogen sparing effect of structured triglycerides containing both medium-and long-chain fatty acids in critically ill patients; a double blind randomized controlled trial

Comparison was made between the intestinal absorption and lymphatic transport of a randomly interesterified fish oil and medium-chain triglyceride (MCT) structured triglycerides (STG) vs. the physical mix in rat small intestine following ischemia and reperfusion (I/R) injury. Under halothane anesthesia, the superior mesenteric artery (SMA) was occluded for 20 min and then reperfused in I/R rats. The SMA was isolated but not occluded in control rats. In both treatment groups, the mesenteric lymph duct was cannulated and a gastric tube was inserted. Each treatment group received 1 ml of the fish oil-MCT STG or physical mix (7 rats/group) through the gastric tube followed by an infusion of PBS at 3 ml/h for 8 h. Lymph was collected hourly for 8 h. Lymph triglyceride, cholesterol, and decanoic and eicosapentaenoic acids increased rapidly and maintained a significantly higher output (P < 0.01) with STG compared with physical mix in control rats over 8 h. After I/R, lymphatic triglyceride output decreased 50% compared with control. Gastric infusion of STG significantly improved lipid transport by having a twofold higher triglyceride, cholesterol, and decanoic and eicosapentaenoic acids output to lymph compared with its physical mix (P < 0.01). We conclude that STG is absorbed into lymph significantly better than physical mix by both the normal intestine and the intestine injured by I/R.

Structured triglycerides (STs) containing both medium-chain fatty acids (MCFA) and polyunsaturated fatty acids (PUFA) in the same molecule offer nutritional and therapeutic benefits. The aim of this work was to establish the incorporation of MCFA into fish oil triglycerides (TAGs), while maintaining substantial levels of docosahexaenoic and eicosapentaenoic acids. The effects of different acyl donors (capric acid methyl ester/MeC10 or medium chain triglyceride/TCM) and of the catalyst (chemical or enzymatic) on the fatty acid composition of the reaction product were studied. The fatty acid composition of the fish oil TAG was modified after interesterification to contain MCFA, and it depended on the catalyst and on the substrates. Thermograms obtained by Differential Scanning Calorimetry (DSC) showed that interesterification promoted noteworthy changes in the melting profile of the samples. STs of clinical nutrition interest containing both EPA and DHA obtained from fish oil along with MCFA were successfully produced.

We studied the long-chain conversion of [U-13C]alpha-linolenic acid (ALA) and linoleic acid (LA) and responses of erythrocyte phospholipid composition to variation in the dietary ratios of 18:3n-3 (ALA) and 18:2n-6 (LA) for 12 weeks in 38 moderately hyperlipidemic men. Diets were enriched with either flaxseed oil (FXO; 17 g/day ALA, n=21) or sunflower oil (SO; 17 g/day LA, n=17). The FXO diet induced increases in phospholipid ALA (>3-fold), 20:5n-3 [eicosapentaenoic acid (EPA), >2-fold], and 22:5n-3 [docosapentaenoic acid (DPA), 50%] but no change in 22:6n-3 [docosahexanoic acid (DHA)], LA, or 20:4n-6 [arachidonic acid (AA)]. The increases in EPA and DPA but not DHA were similar to those in subjects given the SO diet enriched with 3 g of EPA plus DHA from fish oil (n=19). The SO diet induced a small increase in LA but no change in AA. Long-chain conversion of [U-13C]ALA and [U-13C]LA, calculated from peak plasma 13C concentrations after simple modeling for tracer dilution in subsets from the FXO (n=6) and SO (n=5) diets, was similar but low for the two tracers (i.e., AA, 0.2%; EPA, 0.3%; and DPA, 0.02%) and varied directly with precursor concentrations and inversely with concentrations of fatty acids of the alternative series. [13C]DHA formation was very low (<0.01%) with no dietary influences.

Rationale for different formulations of omega-3 fatty acids leading to differences in residual cardiovascular risk reduction

Cytochromes P450 (CYPs) metabolize polyunsaturated long-chain fatty acids (PUFA-LC) to several classes of oxygenated metabolites. Through use of human recombinant CYPs, we recently showed that CYP1A1, -2C19, -2D6, -2E1, and -3A4 are mainly hydroxylases, whereas CYP1A2, -2C8, -2C9, and -2J2 are mainly epoxygenases of arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), respectively. It is worth noting that the last double bond of these PUFAs, i.e., omega6 in AA or omega3 in EPA and DHA, respectively, was preferentially epoxidized. In this study, we have characterized the stereoselectivity of this epoxidation reaction by comparison with the PUFA-LC epoxide stereoisomers obtained from the enantioselective bacterial CYP102A1 F87V. The stereoselectivity of the epoxidation of the last olefin of AA (omega6), EPA (omega3), or DHA (omega3) differed between the CYP isoforms but was similar for EPA and DHA. These data give additional insight into the PUFA-LC epoxide enantiomers generated by the hepatic CYPs.

Beneficial physiological effects of long-chain n-3 polyunsaturated fatty acids are widely accepted but the mechanism(s) by which these fatty acids act remains unclear. Herein, we report the presence, distribution, and regulation of the levels of n-3 epoxy-fatty acids by soluble epoxide hydrolase (sEH) and a direct antinociceptive role of n-3 epoxy-fatty acids, specifically those originating from docosahexaenoic acid (DHA). The monoepoxides of the C18:1 to C22:6 fatty acids in both the n-6 and n-3 series were prepared and the individual regioisomers purified. The kinetic constants of the hydrolysis of the pure regioisomers by sEH were measured. Surprisingly, the best substrates are the mid-chain DHA epoxides. We also demonstrate that the DHA epoxides are present in considerable amounts in the rat central nervous system. Furthermore, using an animal model of pain associated with inflammation, we show that DHA epoxides, but neither the parent fatty acid nor the corresponding diols, selectively modulate nociceptive pathophysiology. Our findings support an important function of epoxy-fatty acids in the n-3 series in modulating nociceptive signaling. Consequently, the DHA and eicosapentaenoic acid epoxides may be responsible for some of the beneficial effects associated with dietary n-3 fatty acid intake.

The infants who cannot be breastfeed need to obtain energy and nutrition from other sources, such as formula. In this study, a human milk fat substitute (HMFS) rich in structured triglycerides (STG) and with a variety of fatty acids was prepared by one-step transesterification reaction. The optimum conditions for the lipase-catalyzed transesterification between basa catfish oil solid fraction, Cinnamomum camphora seed kernel oil, linseed oil, microbial oil and algae oil were studied and the in vitro digestibility of the constructed HMFS was investigated. Under the optimal conditions, the obtained HMFS contained 58.86% STG and 39.73% sn-2 palmitic acid (PA). Fatty acid composition analysis showed that HMFS was composed of capric acid (Ca), lauric acid (La), oleic acid (O), linoleic acid (L), linolenic acid (Ln), arachidonic acid (ARA) and docosahexaenoic acid (DHA). LC-MS/MS analysis found that 142 new triglycerides were generated, such as Ca-P-ARA, Ca-P-Ln, La-P-ARA, La-P-L and P-O-ARA. Moreover, compared with physical mixture (PM), HMFS had better melting and crystallization temperature and the fatty acid release rate of HMFS was significantly improved. These results suggested that HMFS may have a great application in infant food as a nutritional ingredient.

Meta-analysis of the efficacy and safety of structured triglyceride lipid emulsions in parenteral nutrition therapy in China