What is the 'catabolic crisis model' in older adults?

The catabolic crisis model describes a destructive cycle in older adults where repeated periods of inactivity or immobilization lead to muscle loss that may not fully recover. Each 'insult' accelerates a downward trajectory, eventually leading to a disability threshold where daily activities become impossible without assistance, and increases mortality risk.

How quickly does muscle atrophy occur with inactivity?

With complete inactivity or muscle disuse, muscle mass declines very rapidly, with losses of 7-10% in size or mass within the first seven days. Even reduced physical activity, like a low daily step count, can downregulate protein synthesis and negatively impact metabolic health.

What is anabolic resistance, and can omega-3s help older adults overcome it?

Anabolic resistance refers to the reduced ability of older adults' muscles to respond effectively to dietary protein and amino acids for muscle protein synthesis. Emerging evidence suggests omega-3s may enhance muscle's sensitivity to amino acids, potentially aiding older adults who struggle with protein intake or anabolic resistance, though robust evidence is still needed.

How long does it take for omega-3s to integrate into muscle tissue for their anabolic effects?

Omega-3s don't have acute anabolic effects; their benefits come from modifying the lipid composition of muscle tissue. It takes approximately four weeks of high-dose supplementation (e.g., 5 grams/day) to see a substantial change in the muscle's omega-3 profile, which then typically plateaus between six and eight weeks.

Do omega-3s affect muscle strength gains, especially in older women?

Some studies suggest omega-3s can enhance strength responses, particularly in older women undergoing resistance training. The mechanism might involve DHA incorporation into myelin sheaths or neural networks, improving strength adaptation, though more research is needed to fully understand this effect.

How does inflammation in muscle tissue impact protein synthesis?

High or low-grade inflammation inside muscle cells can put 'the brakes' on protein synthesis by negatively impacting initiation factors, such as eIF2 alpha. Resolving this intracellular inflammation is a potential mechanism through which omega-3 fatty acids may enhance protein synthesis, especially in older populations.

Are omega-3 fatty acids currently being studied for cancer cachexia?

Yes, there is evidence that EPA treatments may protect against cancer-related muscle wasting (cachexia). Research is ongoing, including collaborations exploring how omega-3s might protect against chemotherapy's negative impact on muscle in a mitochondrial-dependent manner.

What are Dr. Chris McGlory's current omega-3 research trials focusing on?

Dr. McGlory's lab has several ongoing trials, including studies on sex differences in muscle with omega-3 feeding, a large bed rest study combining high-dose omega-3s with essential amino acids, and a surgery study with ACL patients to assess omega-3 efficacy in hyperinflammatory settings, all aiming for mechanistic insights and clinical outcomes.

Does aerobic exercise interfere with muscle growth from resistance training?

While some early cellular and rodent studies suggested an 'interference effect' (aerobic exercise inhibiting mTOR), human research largely does not support this. In fact, aerobic conditioning might even promote muscle growth by enhancing capillarization and nutrient delivery, and activating satellite cells, which aid in muscle remodeling and hypertrophy.

Chris McGlory, PhD, on the Anabolic Potential of Omega-3 Fatty Acids

FoundMyFitness

Science & Technology4 min read99 min video

Jul 3, 2023|97,068 views|1,271|137

Omega-3 Omega-3 Fatty Acids Chris McGlory PhD Rhonda Patrick PhD muscle protein synthesis disuse atrophy catabolic crisis model weightlifting bodybuilding resistance exercise omega-3 fish oil benefits resistance exercise training

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Key Moments

TL;DR

Omega-3s show anabolic potential for muscle health, combating disuse atrophy and potentially aiding sarcopenia, especially in older adults.

Key Insights

Omega-3 fatty acids, particularly EPA and DHA, demonstrate anabolic properties, enhancing muscle protein synthesis and mitigating muscle loss.

Supplementation with omega-3s can significantly reduce muscle atrophy during periods of disuse or immobilization, potentially by half.

While protein intake is crucial, it may not fully prevent disuse atrophy; omega-3s can enhance the muscle's sensitivity to amino acids.

Omega-3s may offer benefits for older adults, helping to combat anabolic resistance and sarcopenia by improving muscle protein synthesis response.

The incorporation of omega-3s into muscle cell membranes takes time (around four weeks) and is crucial for their functional effects.

Emerging research suggests omega-3s might improve mitochondrial function and play a role in resolving low-grade inflammation within muscle tissue.

INTRODUCTION TO OMEGA-3 AND MUSCLE PHYSIOLOGY

This discussion explores the surprising role of omega-3 fatty acids beyond their well-known benefits for brain and cardiovascular health, focusing instead on their significant impact on muscle mass, strength, and overall muscle health. Dr. Chris McGlory, an expert in muscle physiology, highlights how omega-3s are emerging as potent agents in combating muscle loss, particularly in scenarios of disuse atrophy and age-related sarcopenia. The focus is on their anabolic potential, which is more profound than often assumed.

UNDERSTANDING MUSCLE DISUSE ATROPHY

Muscle disuse atrophy, the loss of muscle mass and strength due to inactivity, can occur rapidly. Even two weeks of immobilization can lead to a substantial decrease in muscle size. This is particularly concerning for older adults, as it can trigger a downward spiral into a 'catabolic crisis,' where muscle loss impedes daily activities and increases disability. While nutrition, especially adequate protein and essential amino acids, can offer partial protection, it cannot entirely prevent this decline.

OMEGA-3 AS A COUNTERMEASURE TO ATROPHY

Research, including studies with immobilized young women, indicates that high-dose omega-3 supplementation can significantly protect against muscle mass loss during disuse. The omega-3s are incorporated into muscle cell membranes, potentially enhancing the muscle's sensitivity to amino acids and improving the muscle protein synthesis response. This suggests omega-3s are not just anti-catabolic but may also be actively anabolic in specific contexts of reduced protein intake or disuse.

ROLE IN OLDER ADULTS AND ANABOLIC RESISTANCE

Omega-3s show particular promise for older adults, who often face both reduced protein intake and anabolic resistance—a diminished ability of muscles to respond to protein and exercise stimuli. By enhancing muscle protein synthesis, omega-3s could help counteract sarcopenia, the age-related loss of muscle mass and strength. Emerging evidence suggests omega-3s might improve muscle strength and walking performance when combined with resistance training, offering a novel therapeutic avenue.

MECHANISMS AND DOSING CONSIDERATIONS

The anabolic effects of omega-3s are thought to involve modifications to muscle cell and mitochondrial membranes, influencing cellular processes. This incorporation takes time, typically around four weeks for significant changes in muscle phospholipid composition. While doses used in studies have been relatively high (e.g., 5 grams per day), the optimal dosage and duration are still under investigation. The benefits may be more pronounced in individuals with lower baseline omega-3 status or suboptimal protein intake.

IMPACT ON MITOCHONDRIAL FUNCTION AND INFLAMMATION

Beyond protein synthesis, omega-3s may modulate mitochondrial function, the powerhouses of cells. Mitochondria are critical for energy production, which fuels energy-intensive processes like muscle protein synthesis. Omega-3s might improve mitochondrial respiration and energy efficiency. Furthermore, omega-3s have anti-inflammatory properties that can resolve low-grade inflammation within muscle tissue, a condition that can negatively impact protein synthesis pathways, thereby playing a dual role in muscle health.

OMEGA-3 AND MUSCLE STRENGTH VS. MASS

While omega-3s appear protective of muscle mass during disuse, their specific impact on strength gains in conjunction with resistance training is an active area of research. Some studies suggest a sex-specific benefit, particularly in women, where omega-3 supplementation during resistance training may enhance strength adaptations. The precise mechanisms, potentially involving neural pathways or enhanced nutrient delivery, are still being elucidated, highlighting the complexity of muscle adaptation.

FUTURE RESEARCH AND CLINICAL IMPLICATIONS

Ongoing research aims to confirm these findings in larger, diverse populations, including men and older individuals undergoing surgery or experiencing immobilization. The translation of this research into clinical practice requires robust, well-designed randomized controlled trials. While food sources like fatty fish are beneficial, achieving the doses used in studies often necessitates supplementation. The ultimate goal is to establish clear clinical guidelines for omega-3 use in preventing muscle loss and optimizing muscle health.

Mentioned in This Episode

●Supplements

●Organizations

●Studies Cited

●Concepts

●People Referenced

Common Questions

Omega-3s enhance the sensitivity of muscle tissue to amino acids, thereby increasing the rate of muscle protein synthesis, which is typically diminished during periods of disuse. This can mitigate muscle loss and even accelerate recovery, as shown in studies where high-dose omega-3s during immobilization led to better muscle preservation and faster recovery.

Topics

Muscle Disuse Atrophy

Mentioned in this video

personStuart Galloway

Collaborator with Chris McGlory at Stirling, passionate about the topic of omega-3s and their effect on skeletal muscle.

personAvira Mazarak

A researcher in Alberta, Canada, doing excellent work on how omega-3s can protect against the negative impact of chemotherapy on muscle.

personPaula Miata

A student in Graham Holloway's lab who conducted mitochondrial analysis for McGlory's omega-3 and immobilization study.

conceptLAT1

An amino acid transporter, specifically for branched-chain amino acid leucine, whose gene expression was probed in McGlory's study but didn't show definitive changes.

personBetina Mittendorfer

A researcher whose group published landmark papers showing enhanced protein synthetic response to amino acid infusion with Omega-3s in younger and older people, replicated by Stuart Gray.

personStuart Gray

A researcher who replicated Mittendorfer's findings with krill oil, showing similar increases in strength and size with omega-3 supplementation.

studyFafard et al. paper

Chris McGlory's paper, presumably the 2019 study, on high-dose omega-3 fatty acids supplementation on muscle disuse atrophy in young women, which showed protective effects.

organizationLuke Van Loon's group

A research group that published a paper suggesting that impairment in protein synthesis with disuse is intracellular, not due to transport across the membrane.

concepteIF2 Alpha (eIF2α)

An initiation factor for protein synthesis that can be phosphorylated and impinged upon by an inflammatory state, thus putting the brakes on protein synthesis.

organizationQueen's University

Where Dr. Chris McGlory is currently an assistant professor and has set up his lab to continue researching omega-3s and human skeletal muscle.

personJames Morton

Supervisor of Chris McGlory's early research at Liverpool John Moore's University, focusing on applied sports science and nutritional interventions.

personKevin Tipton

An expert in metabolism who trained Chris McGlory to use stable isotopes in human skeletal muscle context while at Stirling, Scotland.

personBen Wall

Lead author from Luke Van Loon's group on a paper about protein synthesis impairment with disuse.

conceptmTOR pathway

A key anabolic signaling pathway for muscle protein synthesis, which appears to be affected by omega-3s, potentially indirectly through enhanced amino acid response.

personGraham Close

Supervisor of Chris McGlory's early research at Liverpool John Moore's University, focusing on applied sports science and nutritional interventions.

supplementEssential Amino Acids

Important for stimulating muscle protein synthesis. Optimal intake is crucial for mitigating disuse atrophy, but not a complete blockade.

personChris McGlory

Assistant professor at Queen's University, whose research focuses on omega-3 fatty acids' influence on muscle mass, protein synthesis, and mitochondrial function.

supplementKrill Oil

A source of omega-3 fatty acids, similar to fish oil, used in studies to replicate findings on increasing strength and size.

conceptp70S6K1

A target of the mTOR pathway, whose phosphorylation at the 389 residue is involved in muscle protein synthesis regulation.

personGordon Smith

Lead author on one of Betina Mittendorfer's landmark papers on omega-3 and muscle protein synthesis, also referenced for sarcopenia research.

organizationLiverpool John Moore's University

Where Chris McGlory started his research career, focusing on applied sports science and nutritional interventions.

personGraham Holloway

An expert in mitochondrial biology at Guelph who collaborated on studies involving omega-3s and mitochondrial analysis during immobilization in young women.