Questions and thoughts about fish oil supplements.

[g_na]

A recent conversation about fish brought up the topic of fish oil supplements. Since I am, shall we say, opposed to the fishing industry in general, I started thinking about why fish oil is supposed to be healthy, and whether or not there were any alternatives.

Here's a little background info about why fish oil is considered healthy: It is a

Comments

[eto_theipi]

It does sound like it would be evolutionarily unsound to rely on fish for EPA, which suggests that the ALA -> EPA conversion isn't prohibitively difficult.

This paper's abstract makes it sound like your body will convert more ALA into EPA if your diet doesn't include as much:
Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the precursor-product ratio of α-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort.
CONCLUSIONS: Substantial differences in intakes and in sources of n-3 PUFAs existed between the dietary-habit groups, but the differences in status were smaller than expected, possibly because the precursor-product ratio was greater in non-fish-eaters than in fish-eaters, potentially indicating increased estimated conversion of ALA. If intervention studies were to confirm these findings, it could have implications for fish requirements.

Here's one that directly addresses your question, for cardiovascular consequences of EPA:
Do vegetarians have to eat fish for optimal cardiovascular protection?
Unfortunately, the conclusion makes it sound like there hasn't been enough research.

This one suggests that supplementing with ALA raises EPA (but not DHA) levels in vegetarian diets:
DHA status of vegetarians.

More specifically, flax seed oil (which contains ALA, but not EPA) supplementation *does* increase EPA levels:
Bioavailability of alpha-linolenic acid from flaxseed diets as a function of the age of the subject.
RESULTS: All subjects who received flaxseed oil showed a significant increase in plasma ALA and eicosapentaenoic acid (EPA) concentrations over the course of this study.