Giving fish oil to older mice for three weeks helps fix their brain cells' energy production, which normally gets weaker as they age.

We analyzed the available evidence on whether fish oil restores mitochondrial function in aged mouse brain cells, and what we’ve found so far leans toward a positive effect. Nine studies or assertions support the idea that giving fish oil to older mice for three weeks helps improve energy production in their brain cells, which tends to decline with age [1]. No studies or assertions in our review contradicted this finding. Mitochondria are the tiny structures inside cells that produce energy. As mice age, these structures often become less efficient, which may affect how well brain cells work. In the studies we reviewed, fish oil appeared to help reverse some of this decline, suggesting it may support better energy output in aging brain cells. The improvement was observed after just three weeks of supplementation, which hints that the effect may happen relatively quickly. However, we only reviewed one type of evidence — all findings came from studies on mice, and all focused on a single time frame and dosage. We don’t yet know if this effect holds under different conditions, or whether it translates to humans. The evidence doesn’t tell us how fish oil works at the molecular level, or whether the improvement in energy production leads to better memory or behavior in the mice. What we’ve found so far is limited but consistent. The pattern across the studies we reviewed suggests fish oil may help restore mitochondrial function in aged mouse brain cells, but we can’t say how strong, lasting, or generalizable this effect is. More research would be needed to understand the full picture. If you’re considering fish oil for brain health, this early evidence in mice offers a reason to explore it further — but it’s not proof it will work the same way in people.