Notes

Fish is the largest source of omega-3 (EPA and DHA). Fish consumption does not change dramatically over the seasons. Therefore, Omega-3 should also be supplemented in summer. In summer, more vitamin D is produced in the skin, but still supplementing is also very desirable in summer.

What’s the difference between fish oil and cod liver oil?
-Fish oil and cod liver oil are two different oils even though they both come from fish and have a similar fatty acid profile.

Fish oil is extracted from the flesh of tuna, herring, cod and other deep-sea oily fish species. It’s rich in omega-3 fatty acids such as EPA and DHA but doesn’t have much vitamin A or D.

Cod liver oil comes from the liver of the cod fish. It has less omega-3s but is very rich in vitamins A and D. It was routinely spooned out to children in the 1960s as a source of vitamin D in northern Europe where sunlight is limited during their long winters. And it may return to fashion again given the increasing reports of borderline deficiency of vitamin D now appearing.

Some people take cod liver oil in winter when they spend less time outdoors so don’t make their own vitamin D from sunshine, then switch to fish oil in summer so as to not take in more vitamin D than they need.

If you like numbers, cod liver oil contains less EPA and DHA (around 8% EPA and 10% DHA) than fish oil (at 18%EPA and 12%DHA).