Berry compound shows benefits for metabolic health and fat buildup in mouse study
Key takeaways
- Researchers have found that pterostilbene, a natural compound in berries and grapes, reduced abnormal fat accumulation in muscle cells.
- The compound stabilized PPARδ, a protein involved in fatty acid metabolism, potentially supporting muscle cells’ processing of stored lipids for energy instead of building up fat.
- The study authors say that although further testing is needed, the compound may have potential for functional foods and supplements targeting muscle fat metabolism.
Japan-based research has found that pterostilbene — a natural compound found in blueberries, grapes, and other berries — may help muscle cells burn excessive fat rather than storing it. The researchers found that the compound reduced the buildup of abnormal fat in mouse cells, boosted fat breakdown, and stabilized a key protein associated with fatty acid metabolism.
The research team stresses that excess fat stored in skeletal muscle, which can be intensified through high-fat diets, aging, and physical inactivity, is an important health concern. It differs from fat stores under the skin, as lipid droplets that accumulate in muscle cells can hinder normal muscle function, making it more difficult for the body to use glucose and fatty acids.
Reduced metabolic flexibility may, over time, cause insulin resistance. The researchers suggest that finding ways to limit the excess fat in skeletal muscle may support healthy aging while reducing the risk of lifestyle-related diseases such as obesity or type 2 diabetes.
Searching for natural dietary interventions
Published in Food Bioscience, the study highlights that previous research has linked pterostilbene to metabolic effects in the liver and body fat. However, how it affects skeletal muscle is less known, the researchers note.
The study found that pterostilbene can stabilize peroxisome proliferator-activated receptor δ (PPARδ) and influence fat metabolism inside muscle cells. The researchers explain that when PPARδ signaling is active, it promotes oxidation of fatty acids while limiting the accumulation of lipids inside cells.
“We currently lack approved treatments specifically targeting myosteatosis (fat buildup around skeletal muscle tissue),” says study lead Dr. Takakazu Mitani, professor at Shinshu University in Matsumoto, Japan.
“This critical gap led our team to screen food-derived compounds for natural, dietary interventions. During the screening, we identified pterostilbene and focused our investigation on uncovering its precise mechanism of action.”
The results suggest that pterostilbene helps muscle cells break down stored lipids and process them for energy, the researchers highlight.
They found that the strongest reduction in intracellular lipid accumulation was produced by pterostilbene. It did not prevent fatty acids from entering the muscle cells, but increased glycerol outside the cells, which the researchers note is an important sign that fat is being broken down.
These results suggest that the compound helps muscle cells break down stored lipids and process them for energy, the researchers highlight.
Fat metabolism
The researchers say they were surprised by how pterostilbene increased PPARδ signaling. It did this by increasing the amount of PPARδ protein in the cells, rather than directly activating it.
The compound prevented the protein from being broken down through the ubiquitin-proteasome pathway — a system cells use to break down proteins that are damaged or not needed. PPARδ allowed more protein to stay available inside the cells.
“Our findings establish a scientific framework for developing functional foods and nutritional supplements that target muscle fat metabolism. However, beyond the potential of pterostilbene itself, this work provides an experimental framework for identifying other natural compounds that can stabilize the PPARδ protein,” Mitani explains.
The researchers point to metabolic diseases becoming an increasing problem globally, arguing that the findings may be a “starting point” for dietary approaches to combat type 2 diabetes, obesity, and aging-related metabolic decline. Yet, the results are still based on mouse studies, and further testing is therefore needed to confirm that the findings apply to humans.
While stressing that additional studies are required, the research team still highlights the compound as a promising candidate bio ingredient for food and pharmaceutical applications for product innovations targeting muscle fat metabolism.
