Taking a high dose of fish oil daily for three months may help shift the balance of fats in the body of obese women toward less inflammation, but if they stop taking it, that benefit goes away within a month.

We analyzed the available evidence and found that taking a high dose of fish oil daily for three months may help shift the balance of fats in the body of obese women toward less inflammation, as measured by a lower AA/EPA ratio [1]. The AA/EPA ratio is a marker that reflects the balance between two types of fats in the blood — one linked to inflammation (AA) and one linked to reducing it (EPA). A lower ratio is often associated with a less inflammatory state. What we’ve found so far suggests that this shift happens while the supplement is being taken, but the change does not stay after stopping. When women stopped taking the high-dose omega-3, the AA/EPA ratio returned to its original level within about a month [1]. There were no studies in our review that showed the effect lasting after discontinuation, nor any that contradicted this pattern. This means the benefit appears to depend on continued use. It’s not a permanent change, but rather something that holds only as long as the supplement is taken. We don’t know if longer use would lead to a more lasting effect, or if restarting the supplement after a break would bring back the same benefit. For someone considering this approach, it suggests that if the goal is to maintain a lower AA/EPA ratio, daily intake may need to be ongoing. But we don’t yet know how long someone would need to take it, or whether there are other factors — like diet or movement — that might help sustain the effect after stopping. The evidence we’ve reviewed so far is limited to one set of findings, and more research could change what we understand.