Taking fish oil supplements with EPA and DHA over time makes the membranes of your red blood cells more filled with these types of fats, making them more flexible but also more prone to damage from...

Taking 6.26 grams of n−3 fatty acids from menhaden oil daily for six weeks raises the levels of EPA and DHA in the fatty components of blood cell membranes in healthy adult men.

When healthy young men take a specific form of omega-3 fatty acids bound to medium-chain triglycerides for eight weeks, their blood shows a higher ratio of EPA to arachidonic acid than when they take the same fatty acids in a simple mixed form.

Eating a lot of soybean oil for a month lowered levels of DHA — a healthy omega-3 fat — in red blood cells, possibly because the two types of fats compete to get into cell membranes.

If men eating low-carb food swap out butter and fatty meats for oils like olive or fish oil, their blood gets more of the good fats that fight inflammation, the bad-to-good fat ratio drops a lot, and their cholesterol and triglycerides still improve.

If you're a healthy young adult, taking a high-purity fish oil supplement might help your body absorb more of the good omega-3s (like EPA and DHA) into your red blood cells compared to a lower-purity version—even if the difference in dose is pretty small.