When we stopped eating fish, I realised I had been relying on it more than I thought — not just as a meal, but as a nutritional shortcut for omega-3 fatty acids.
The conversion problem
Plant foods contain ALA, a precursor to the long-chain omega-3s EPA and DHA that the body actually uses. The conversion rate from ALA to EPA and DHA is low and varies between individuals. Flaxseeds and walnuts are good ALA sources, but they are not direct equivalents to fish oil or oily fish.
What we tested over six months
- Daily ground flaxseed added to porridge and smoothies
- Walnuts as a regular snack for adults
- An algae-based DHA supplement for both adults from month three onward
We did not test the children for omega-3 status — the testing is not straightforward and our GP did not consider it necessary given their diet was otherwise varied. That remains an open question for us.
What changed
The adults noticed nothing dramatic. What the experiment clarified was that flaxseed and walnuts felt like reasonable ALA coverage, but the algae supplement gave us more confidence about DHA specifically. Algae is where fish get their DHA in the first place, so the logic of going directly to the source made sense to us and to the dietitian we consulted at month four.