Omega-3 Fatty Acids and Skeletal Muscle Health Jeromson, Stewart; Gallagher, Iain J; Galloway, Stuart D R ...
Marine Drugs,
11/2015, Letnik:
13, Številka:
11
Journal Article, Book Review
Recenzirano
Odprti dostop
Skeletal muscle is a plastic tissue capable of adapting and mal-adapting to physical activity and diet. The response of skeletal muscle to adaptive stimuli, such as exercise, can be modified by the ...prior nutritional status of the muscle. The influence of nutrition on skeletal muscle has the potential to substantially impact physical function and whole body metabolism. Animal and cell based models show that omega-3 fatty acids, in particular those of marine origin, can influence skeletal muscle metabolism. Furthermore, recent human studies demonstrate that omega-3 fatty acids of marine origin can influence the exercise and nutritional response of skeletal muscle. These studies show that the prior omega-3 status influences not only the metabolic response of muscle to nutrition, but also the functional response to a period of exercise training. Omega-3 fatty acids of marine origin therefore have the potential to alter the trajectory of a number of human diseases including the physical decline associated with aging. We explore the potential molecular mechanisms by which omega-3 fatty acids may act in skeletal muscle, considering the n-3/n-6 ratio, inflammation and lipidomic remodelling as possible mechanisms of action. Finally, we suggest some avenues for further research to clarify how omega-3 fatty acids may be exerting their biological action in skeletal muscle.
Background
Older adults are susceptible to dehydration and fluid overload due to a reduced ability to maintain homeostatic control of fluid and electrolyte balance.
Purpose
To assess fluid and ...electrolyte balance responses in young and older men following ingestion of commonly consumed beverages differing in composition.
Methods
12 young and 11 older men were recruited. Euhydrated body mass was recorded. Participants consumed 1L (250 ml every 15 min) of water, fruit juice, a sports drink or low-fat milk in a randomized cross-over design. Urine and blood samples were obtained before and after the drinking period and every hour thereafter for 3-h. Samples were used to determine osmolality, electrolytes (Na
+
and K
+
), water clearance, and glomerular filtration rate.
Results
Free water clearance was significantly higher in Young than Older at 1 and 2 h after the ingestion of W and S (p < 0.05). Net Na
+
and K
+
balance were not different between Young and Older (p = 0.91 and p = 0.65) adults, respectively. At 3 h Na
+
balance was negative after ingesting water and fruit juice, but neutral after sport drink and milk. Net K
+
balance was neutral at 3 h after ingesting milk, but negative after water, fruit juice and sport drink.
Conclusions
Milk was retained longer than other beverages in Young, but not in Older, despite similar net electrolyte balance responses. Older had higher fluid retention in the first 2 h after the ingestion of all beverages, except for milk when compared to Young, indicating an age-related loss of ability to regulate fluid balance under current study conditions.
Omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation has recently been proposed as an ergogenic aid for athletes. This claim is primarily based on mechanistic evidence that n-3PUFA's exert ...anti-inflammatory properties and act to change the functional capacity of the muscle cell by modifying the membrane fluidity of proteins and lipids within the cell membrane. In this review, we critically evaluate the scientific literature that examines the efficacy of n-3PUFA supplementation to improve athlete performance within the context of promoting muscle adaptation, energy metabolism, muscle recovery and injury prevention (e.g. muscle loss during immobilisation, or concussion). These findings have applications to athletes competing in strength/power-, endurance- and team-, based sports. Based on available information, there is some scientific evidence that n-3PUFA supplementation may improve endurance capacity by reducing the oxygen cost of exercise. Moreover, several studies report a benefit of n-3PUFA supplementation in promoting recovery from eccentric-based muscle damaging exercise. In contrast, there is insufficient evidence from studies in athletic populations to support the claim that n-3PUFA supplementation facilitates muscle growth during resistance training or preserves muscle mass during catabolic scenarios such as energy restriction or immobilisation. Moving forward, there remains ample scope to investigate context-specific applications of n-3PUFA supplementation for sport performance.
Our aim was to examine the effects of seven high-intensity aerobic interval training (HIIT) sessions over 2 wk on skeletal muscle fuel content, mitochondrial enzyme activities, fatty acid transport ...proteins, peak O(2) consumption (Vo(2 peak)), and whole body metabolic, hormonal, and cardiovascular responses to exercise. Eight women (22.1 +/- 0.2 yr old, 65.0 +/- 2.2 kg body wt, 2.36 +/- 0.24 l/min Vo(2 peak)) performed a Vo(2 peak) test and a 60-min cycling trial at approximately 60% Vo(2 peak) before and after training. Each session consisted of ten 4-min bouts at approximately 90% Vo(2 peak) with 2 min of rest between intervals. Training increased Vo(2 peak) by 13%. After HIIT, plasma epinephrine and heart rate were lower during the final 30 min of the 60-min cycling trial at approximately 60% pretraining Vo(2 peak). Exercise whole body fat oxidation increased by 36% (from 15.0 +/- 2.4 to 20.4 +/- 2.5 g) after HIIT. Resting muscle glycogen and triacylglycerol contents were unaffected by HIIT, but net glycogen use was reduced during the posttraining 60-min cycling trial. HIIT significantly increased muscle mitochondrial beta-hydroxyacyl-CoA dehydrogenase (15.44 +/- 1.57 and 20.35 +/- 1.40 mmol.min(-1).kg wet mass(-1) before and after training, respectively) and citrate synthase (24.45 +/- 1.89 and 29.31 +/- 1.64 mmol.min(-1).kg wet mass(-1) before and after training, respectively) maximal activities by 32% and 20%, while cytoplasmic hormone-sensitive lipase protein content was not significantly increased. Total muscle plasma membrane fatty acid-binding protein content increased significantly (25%), whereas fatty acid translocase/CD36 content was unaffected after HIIT. In summary, seven sessions of HIIT over 2 wk induced marked increases in whole body and skeletal muscle capacity for fatty acid oxidation during exercise in moderately active women.
This study aimed to examine the effect of altering osmolality or adding sodium alginate and pectin to a concentrated carbohydrate (CHO) beverage on gastric-emptying (GE) rate.
Boluses (500 mL) of ...three drinks were instilled double blind in eight healthy men while seated, GE was measured using the double sampling method for 90 min, and blood samples were collected regularly. Drinks consisted of glucose and fructose (MON; 1392 mOsmol·kg), maltodextrin and fructose (POLY; 727 mOsmol·kg), and maltodextrin, fructose, sodium alginate, and pectin (ENCAP; 732 mOsmol·kg) with each providing 180 g·L CHO (CHO ratio of 1:0.7 maltodextrin or glucose/fructose).
Time to empty half of the ingested bolus was faster for ENCAP (21 ± 9 min) than for POLY (37 ± 8 min); both were faster than MON (51 ± 15 min). There were main effects for time and drink in addition to an interaction effect for the volume of test drink remaining in the stomach over the 90 min period, but there were no differences between MON and POLY at any time point. ENCAP had a smaller volume of the test drink in the stomach than MON at 30 min (193 ± 62 vs 323 ± 54 mL), which remained less up to 60 min (93 ± 37 vs 210 ± 88 mL). There was a smaller volume of the drink remaining in the stomach in ENCAP compared with POLY 20 min (242 ± 73 vs 318 ± 47 mL) and 30 min (193 ± 62 vs 304 ± 40 mL) after ingestion. Although there was a main effect of time, there was no effect of drink or an interaction effect on serum glucose, insulin or nonesterified fatty acid concentrations.
The addition of sodium alginate and pectin to a CHO beverage enhances early GE rate but did not affect serum glucose, insulin, or nonesterified fatty acid concentration at rest.
The use of Distributed Energy Resources (DER) has been proposed as one of the possible solutions to today's energy and environmental challenges. The optimal integration of DER in distribution ...networks is essential to guarantee the best of resource, i.e. maximize their benefits, such as reduction of carbon emissions, reduction of network energy losses and to minimize the negative impacts, which can affect the network quality, cause network sterilization and increase investment and operation costs. Hence, DER planning is a multi-objective problem in which many objectives of interest, sometimes conflicting, need to be optimized simultaneously, and where a compromise for different perspectives (DER developer, Distribution System Operator, regulator) needs to be found. Appropriate multi-objective planning methods that consider technical, environmental and economic impacts of DER integration, and that are able to support a suitable model of stochastic DER and active networks, can provide a deep insight into the case specific and general advantages and drawbacks of DER. Consequently, the interest in multi-objective DER planning has increased in recent years, and a number of novel methods have been proposed in this area. This paper provides a timely review of the state-of-the-art in multi-objective DER planning, and discusses in detail the challenges, trends and latest developments in this field.
In striated muscle, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have differential effects on the metabolism of glucose and differential effects on the metabolism of protein. We have ...shown that, despite similar incorporation, treatment of C
C
myotubes (CM) with EPA but not DHA improves glucose uptake and protein accretion. We hypothesized that these differential effects of EPA and DHA may be due to divergent shifts in lipidomic profiles leading to altered proteomic profiles. We therefore carried out an assessment of the impact of treating CM with EPA and DHA on lipidomic and proteomic profiles. Fatty acid methyl esters (FAME) analysis revealed that both EPA and DHA led to similar but substantials changes in fatty acid profiles with the exception of arachidonic acid, which was decreased only by DHA, and docosapentanoic acid (DPA), which was increased only by EPA treatment. Global lipidomic analysis showed that EPA and DHA induced large alterations in the cellular lipid profiles and in particular, the phospholipid classes. Subsequent targeted analysis confirmed that the most differentially regulated species were phosphatidylcholines and phosphatidylethanolamines containing long-chain fatty acids with five (EPA treatment) or six (DHA treatment) double bonds. As these are typically membrane-associated lipid species we hypothesized that these treatments differentially altered the membrane-associated proteome. Stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics of the membrane fraction revealed significant divergence in the effects of EPA and DHA on the membrane-associated proteome. We conclude that the EPA-specific increase in polyunsaturated long-chain fatty acids in the phospholipid fraction is associated with an altered membrane-associated proteome and these may be critical events in the metabolic remodeling induced by EPA treatment.
Abstract The aim of this study was to examine changes in the lipid profile of red blood cells and muscle tissue along with the expression of anabolic signalling proteins in human skeletal muscle. ...Following a 2-week control period, 10 healthy male participants consumed 5 g d−1 of fish oil (FO) for 4 weeks. Muscle biopsies and venous blood samples were collected in the fasted state 2 weeks prior (W-2) and immediately before (W0) the initiation of FO supplementation for internal control. Muscle biopsies and venous blood samples were again obtained at week 1 (W1), 2 (W2) and 4 (W4) during FO supplementation for assessment of changes in lipid composition and expression of anabolic signalling proteins. There was no change in the composition of any lipid class between W-2 and W0 confirming control. Following FO supplementation n-3 polyunsaturated fatty acid (n-3 PUFA) muscle lipid composition was increased from W0 to W2 and continued to rise at W4. n-3 PUFA blood lipid composition was increased from W0 to W1 and remained elevated for the remaining time points. Total protein content of focal adhesion kinase (FAK) increased from W0 to W4 whereas total mechanistic target of rapamycin (mTOR) was increased from W0 at W1 with no further significant increases at W2 and W4. These data show that FO supplementation results in discordant changes in the n-3 PUFA composition of skeletal muscle compared to blood that is associated with increases in total FAK content.
Abstract Exercise induced muscle damage (EIMD) impairs maximal torque production which can cause a decline in athletic performance and/or mobility. EIMD is commonly assessed by using maximal ...voluntary contraction (MVC), creatine kinase (CK) and muscle soreness. We propose as an additional technique, tensiomyography (TMG), recently introduced to measure mechanical and muscle contractile characteristics. The purpose of this study was to determine the validity of TMG in detecting changes in maximal torque following EIMD. Nineteen participants performed eccentric elbow flexions to achieve EIMD on the non- dominant arm and used the dominant elbow flexor as a control. TMG parameters, MVC and rate of torque development (RTD) were measured prior to EIMD and repeated for another six consecutive days. Creatine kinase, muscle soreness and limb girth were also measured during this period. Twenty four hours after inducing EIMD, MVC torque, RTD and TMG maximal displacement had significantly ( p < 0.01) declined by 37%, 44% and 31%, respectively. By day 6 MVC, RTD and TMG recovered to 12%, 24% and 17% of respective pre-EIMD values. In conclusion, as hypothesised TMG maximal displacement significantly followed other standard EIMD responses. This could therefore be useful in detecting muscle damage from impaired muscle function and its recovery following EIMD.
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