If you have a certain version of a gene called FADS1, it might make it harder for your body to turn plant fats into important brain and heart-healthy fats like EPA and DHA—because of how that gene is switched on or off.

What we've found so far is that the evidence leans toward the idea that the FADS1 rs174537 gene variant may influence how the body produces EPA and DHA by affecting gene activity [1]. Our analysis of the available research shows this link is supported by 20.0 studies or assertions, with no studies found that refute it [1]. We looked at the evidence around whether this specific gene variant—FADS1 rs174537—plays a role in how well the body converts plant-based fats into long-chain omega-3 fatty acids like EPA and DHA. These fats are important for brain and heart health. The data we’ve reviewed suggests that people with certain versions of this gene may have differences in how the gene is “switched on or off,” which could affect the body’s ability to make these fats efficiently [1]. This doesn’t mean everyone with this gene variant will have lower levels of EPA and DHA—it means the evidence we’ve reviewed points to a possible biological mechanism that might make the conversion process less effective in some people [1]. Since gene activity can vary based on genetics, the evidence suggests this variant may be one factor among many. Based on what we’ve reviewed so far, we can’t say for sure how strong this effect is, or how it plays out in different people. But the current analysis does show a consistent direction in the data: this gene variant appears to be linked to changes in how the body handles fat metabolism through gene regulation [1]. Practical takeaway: If you’re relying on plant-based omega-3s (like flaxseed or walnuts), your genes might influence how well your body uses them. Some people may benefit from including direct sources of EPA and DHA, like fatty fish or algae-based supplements, especially if their genetics affect conversion.