Giving fish oil to older mice helps a little with keeping their brain cells flexible, but it doesn't change the levels of certain brain proteins linked to Alzheimer's.

We analyzed the available evidence and found that giving fish oil to older mice appears to help a little with keeping brain cell membranes flexible, but it doesn’t seem to change levels of certain brain proteins tied to Alzheimer’s-like changes [1]. The evidence we’ve reviewed so far leans toward this pattern: fish oil may support membrane fluidity, which is important for how brain cells communicate, but it doesn’t appear to reduce amyloid fragments or alter related proteins in these animals. Membrane fluidity refers to how easily molecules can move through the outer layer of brain cells — something that can become stiffer with age. Fish oil contains omega-3 fats, which are known to be part of cell membranes, and in this case, they may help maintain some flexibility in older mice. However, amyloid fragments are sticky protein pieces that can build up in the brain, and the studies we looked at didn’t show a drop in these fragments after fish oil was given. We didn’t find any studies that contradicted these findings, but we also didn’t see strong evidence that fish oil has a major effect on the brain proteins linked to Alzheimer’s pathology. The number of studies is limited, and all the support comes from a single set of assertions. What this means for now is that fish oil might offer a small benefit to brain cell structure in aging mice, but it doesn’t seem to target the specific protein changes often associated with memory decline. More research would be needed to understand if this effect translates to humans or has any real impact on brain health over time.