Omega-3s and Skeletal Muscle 💪🏾
Most people don’t take omega-3s as a performance enhancer.
However, a recently published review suggests that omega-3 fatty acids may be beneficial for maintaining or even improving muscle mass and strength.
This paper identified four primary mechanisms through which omega-3s might exert beneficial effects: 1) decreased inflammation; 2) activation of the mTOR pathway in muscle; 3) improved insulin sensitivity; and 4) activation of muscle satellite cells.
Whether omega-3s can enhance anabolic signaling in healthy younger adults who are consuming plenty of protein is still a bit uncertain, with some trials finding benefits and others failing to show improvement. It’s possible that there simply isn’t a whole lot of room for improvement there.
However, they do seem to be promising for older people. It is well established that as we get older, a given dose of protein does not stimulate muscle protein synthesis to the same degree as when we’re younger, due to defects in signaling pathways which regulate muscle growth. Making the body better at turning dietary protein into muscle could be crucial for maintaining health and fighting functional decline with age. Can omega-3 fatty acids do that?
This Week’s Research Highlights
Omega-3 supplementation has been shown to enhance protein anabolism in animal models. To examine whether these fatty acids might have a similar impact in humans, researchers at Washington University School of Medicine in St Louis recruited 16 healthy older adults and randomly assigned them to take either omega-3s (1.86 g of EPA + 1.50 g of DHA) or an equal amount of corn oil (placebo). Before the intervention, the researchers assessed baseline muscle protein synthesis rates in these subjects, and confirmed that they were experiencing anabolic resistance (their rate of muscle protein synthesis was half that of young adults).
After eight weeks, they measured muscle protein synthesis rates in all participants while fasted, and neither group exhibited any relevant changes. Then, they looked at muscle protein synthesis rates during a hyperaminoacidemic-hyperinsulinemic clamp (amino acids and insulin intravenously infused into the blood, intended to simulate a fed state).
The anabolic response to the insulin and amino acids was doubled in the omega-3 group, and this appeared to be driven by increased activation of proteins that make up the mTOR signaling pathway, which regulates muscle growth.
Supplementation with omega-3s over a longer time frame results in increased muscle volume and strength in older adults.
The results of the previous study are promising, but the short duration of the trial meant that it was difficult for the research team to see whether these improvements in muscle protein synthesis would translate to an increase in muscle mass. To test that hypothesis, the researchers recruited 60 healthy older adults (only 44 completed) and randomly assigned them to receive either omega-3 fatty acids (1.86 g EPA + 1.50 g DHA) or corn oil for six months. Before and after treatment, thigh muscle volume was measured via MRI, and various metrics of strength were evaluated.
At the end of the trial, the researchers found that compared to control, supplementation with omega-3s led to increased thigh muscle volume (3.6%) without affecting total body weight. This was accompanied by greater handgrip strength (~5 pounds), and composite 1-rep max muscle strength (4%).
These are relatively small increases, especially compared to what you would see following a resistance training intervention. However, the magnitude of difference between the groups was still clinically relevant, equivalent to the amount of muscle loss that an older adult might typically see over a 3-year period.
In fact, according to the authors, changes in muscle mass and function were “...the same or greater than those achieved with testosterone, growth-hormone, or dehydroepiandrosterone therapy in older adults.”
Random Trivia & Weird News
🦋 The fattest animal on Earth (that we know of) is a moth in the American West.
If asked, I think a lot of people would guess that the fattest creatures would be some sort of marine mammal, since they rely upon blubber for buoyancy and insulation when navigating chilly oceanic waters. And whales certainly do have the largest absolute mass of body fat.
However, in terms of body fat percentage, certain insects are far ahead of them.
Army cutworm moths are found in the prairies of the western US. Over the summer, they gorge themselves on nectar, and by autumn they reach a staggering 72% body fat. Due to their caloric density, they are a key nutrition source for grizzly bears in Yellowstone (the ultimate keto snack, I suppose).
Before judging them, it’s worth noting that they gain this fat mass with good reason, though – to fuel an extraordinary migration.
According to entomologist Todd Gilligan, “Some insects might fly over 100 km in a single day without feeding, thus they need a large energy reserve.”
Podcasts We Loved This Week
- Paul Coen: Aging, exercise and muscle mitochondrial energetics. Via Inside Exercise.
- Sarah Everts: Sweating is our biological superpower. Via Science Friday.
Products We Like
Most omega-3 supplements are derived from fish or other marine wildlife. However, some people are concerned about the sustainability of current fishing practices (or they’re not crazy about the taste of seafood products). If you share these reservations, algal oil might be a smart solution. This oil is derived from microalgae grown in a closed environment, meaning that there is no risk of them absorbing toxic compounds from the ocean, and the process is fully sustainable.
humanOS Catalog Feature of the Week
An ergogenic aid is simply a supplement that enhances physical performance. Dietary intake of these substances can, in theory, affect training adaptations in a couple of different ways. They can achieve this by simply increasing the exercise stimulus from a single training bout - basically just enabling an athlete to train longer or harder, or reducing perceived exertion. But they may also be able to affect gains in endurance by altering cellular responses to exercise-induced stress.
Importantly, these changes in cell signaling may not be universally beneficial from the standpoint of adaptation. For example, it is theoretically possible that a supplement could simultaneously make it easier for an athlete to exercise hard, but also have effects on cellular signaling that actually have a long-term negative impact on the adaptive response to training. What to do then?
In this guide, we review some of the most rigorously researched supplements, discuss how best to use them, and talk about why some supplements that sound like a good idea may actually not be helpful at all. If you are looking for a quick reference sheet of the latest evidence-based guidance on supplements to maximize your performance and adaptations, check it out! 👀