This Compound In Berries May Support Healthier Muscle Metabolism
We tend to talk about muscle health in terms of how much muscle we have. Are we building enough? Are we losing it as we age? Are we eating enough protein to maintain it?
But there's another side of muscle health that gets much less attention: how well those muscles actually handle and use energy.
Skeletal muscle is one of the body's biggest consumers of fuel, constantly switching between carbohydrates and fat depending on what you're doing and what energy is available. When that flexibility starts to decline, fat can accumulate where we don't necessarily want it, including inside muscle cells.
Researchers are now looking at whether certain compounds in food could influence that process. And a new study1 points to one found naturally in blueberries, grapes, and other berries.
How food compounds affect fat inside muscle cells
For the study, researchers grew mouse muscle cells in the lab and exposed them to several compounds naturally found in foods. They wanted to see whether any of those compounds changed how much fat built up inside the muscle cells and how the cells processed that fat.
And to be clear, we're not talking about the body fat you can see or pinch. Small amounts of fat are stored within muscle cells and can be used for energy. But when too much builds up in and around muscle, it can interfere with how those cells function. This excess fat accumulation, known as myosteatosis, is associated with aging, physical inactivity, insulin resistance, and other forms of metabolic dysfunction.
One compound in particular caught the researchers' attention: pterostilbene, a polyphenol naturally found in blueberries, grapes, and other berries that's closely related to the better-known resveratrol.
Researchers treated the muscle cells with pterostilbene and then looked at two things: whether less fat accumulated inside the cells and whether the compound changed the way those cells broke down and used fat for energy.
Pterostilbene helped muscle cells use fat for energy
Pterostilbene reduced the amount of fat that built up inside the muscle cells, but the way it did that was particularly interesting.
The compound didn't appear to stop fat from entering the cells. Instead, it seemed to help the muscle cells break down more of that fat and use it for energy.
Researchers traced much of this effect back to a protein called PPARδ, which helps control how muscle cells process fat. When PPARδ is active, it essentially tells the cell to turn on genes involved in breaking down fatty acids for fuel.
Pterostilbene appeared to help that protein stick around longer. Normally, cells are constantly breaking down and replacing proteins, including PPARδ. The compound slowed that breakdown, leaving more PPARδ available to keep those fat-processing pathways switched on.
And when researchers reduced PPARδ in the cells, much of pterostilbene's effect went away. That gave them another clue that this protein was a key part of what was happening. The simplest way to think about it is that pterostilbene didn't keep fat out of muscle cells. It appeared to help the cells become better at using the fat that was already there for energy.
Why this could matter for muscle & metabolic health
We usually think about healthy muscle in terms of strength and muscle mass, but muscle also plays a huge role in metabolism. It's one of the major places your body uses glucose and fatty acids for energy, and healthy muscle should be able to move between those fuel sources depending on what your body needs.
Problems can arise when excess fat starts accumulating inside muscle instead of being efficiently used. That buildup is associated with insulin resistance, inactivity, aging, and other metabolic problems.
So, if researchers can find ways to help muscle cells process fat more efficiently, that could eventually have implications for metabolic health as we age.
Keep in mind that this study was done in mouse muscle cells grown in a lab, not in humans. We don't yet know whether eating foods that contain pterostilbene would produce the same effects in human muscle, or how much someone would need to consume to make a meaningful difference.
RELATED READ: This Is The Best Creatine To Gain Muscle & Lose Fat
The takeaway
What this study does give us is a closer look at one of the ways compounds in food may influence how our muscles process fuel.
There's still a long way to go before we know whether pterostilbene can meaningfully affect muscle health in humans. In the meantime, the things we already know support healthy muscle metabolism still matter most: resistance training, regular movement, and a nutrient-dense diet. And maybe add another handful of blueberries to your breakfast bowl tomorrow morning.
