FADS1: are you a poor converter of plant omega-3s?
Flax and chia hand you ALA. Your body still has to convert it into the omega-3s that work, and this gene sets how well that goes.
The omega-3s your body actually uses are EPA and DHA. Plants like flax, chia, and walnuts don't give you those. They give you ALA, and you have to convert it, which is where FADS1 comes in. A common variant at rs174546 makes that conversion slower. So if your omega-3 plan is all plants, you may be getting a lot less active EPA and DHA than the label would suggest.
What FADS1 does
If you convert ALA slowly, the simplest fix is to get EPA and DHA ready-made, from oily fish or a fish-oil or algae supplement. That skips the conversion step your genes are bad at.
This matters most if you rarely eat fish, because then you're relying entirely on the conversion your genotype slows down.
Your variants, decoded
The T allele tracks with slower conversion of ALA into EPA and DHA.
| CC | Converts ALA well. |
| CT | Converts less of it. |
| TT | Slowest of the three. Get your EPA and DHA preformed. |
Genotypes are shown order-insensitively and on the forward strand; your own export may print the complementary letters — the meaning is the same.
What the research suggests
Your FADS1 variant means you convert plant ALA into EPA and DHA slowly. Taking EPA and DHA preformed gets you past that step.
Educational only — not medical advice. “General evidence” means the finding is real but the supplement’s benefit isn’t unique to your genotype.
See this matched to your own DNA — free.
Upload your 23andMe or AncestryDNA file and get your actual FADS1 result, plus every other actionable variant — each line cited, your file never stored.
Questions
Does FADS1 mean flax oil won't work for me?
Flax gives you ALA, and FADS1 is what turns that into EPA and DHA. With a slow-conversion variant you pull less active omega-3 out of the same flax, so getting EPA and DHA preformed is the more dependable bet. Flax oil isn't useless, it just isn't your best omega-3 source.