Is Omega 3 missing from vegan diets?

Question

Is Omega 3 missing from vegan diets? Are there any food supplements that provide Omega 3 not derived from animals?

Answer 1

A distinction needs to be made between the different omega 3 fatty acids, namely ALA, EPA and DHA. All three of them are needed in a healthy human. Humans can metabolise ALA into EPA, and EPA into DHA, but the process is inefficient, can be inhibited by high Omega 6 fat intake, and requires a huge supply of ALA (or EPA, to produce DHA). (Other omega 3 acids exist, but are not as important for the human diet.)

• ALA occurs mainly in linseed, rapeseed, soy, walnuts and some other nuts, grains and pulses. It is easy to maintain a sufficient level of ALA in a vegan diet, as soon as the awareness is raised.
• EPA is rarely found in plants. The only food that supplies it naturally seems to be seaweed and other algae.
• DHA is even rarer in plants. Only some special type of algae supply it. It is very important for the brain and the nervous system (see e.g. this article).

In summary, in order to have a healthy supply of all Omega 3 fatty acids as a vegan, you need to do at least one of the following:

• Eat significant quantities of linseed, rapeseed, soy, walnuts and other ALA-rich foods. (Hopefully, you will metabolise sufficient EPA and DHA.)
• Eat EPA-rich seaweed, being cautious not to overdose with iodine and heavy metals. (Hopefully, you will metabolise sufficient DHA.)
• Supplement your diet with algae-based EPA and DHA.

Answer 2

Some scientific research suggests that possible deficiency of omega-3 is not a major concern for vegetarians or vegans.

There are several kinds of Omega 3: ALA, EPA and DHA. The first can be found in plant products, such as linseed and chia seed, while the second and third belong primarily to animal products like fish, but can be sourced from algae. Hence omega 3 intakes are obviously different according to diet:

While intakes of the omega-3 fatty acid 𝛼-linolenic acid (ALA) are similar in vegetarians and non-vegetarians, intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are low in vegetarians and virtually absent in vegans.

(Saunders 2012)

However our body can convert ALA into EPA and DHA. When vegans' blood was tested, the same paper states:

Plasma, blood and tissue levels of EPA and DHA are lower in vegetarians than in non-vegetarians. Vegetarians do not exhibit clinical signs of DHA deficiency.

(Saunders 2012)

Similar results were found in another study:

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.

(Welch 2010)

In less technical language, the researchers found that vegetarians and vegans were eating less EPA and DHA. However ALA, EPA and DHA blood levels were similar for the three diet groups (omnivorous, vegetarians, vegans). This is somewhat surprising since common scientific literature -quoted in the same article- says that conversion rate from ALA into EPA and DHA are quite low. The same researchers suggested that vegetarians and vegans are more capable of converting ALA into other omega-3 fatty acids.

As for the stability of blood omega-3 levels, another study worth citing states:

The proportions of plasma long-chain n−3 fatty acids were not significantly affected by the duration of adherence to a vegetarian or vegan diet. This finding suggests that when animal foods are wholly excluded from the diet, the endogenous production of EPA and DHA results in low but stable plasma concentrations of these fatty acids.

(Rosell 2005)

One last point to consider might be the need for Omega-3 supplement for narrow sectors of population with special needs. The same paper by Saunders says:

Vegetarians with increased needs or reduced conversion ability may receive some advantage from DHA and EPA supplements derived from microalgae. A supplement of 200–300 mg/day of DHA and EPA is suggested for those with increased needs, such as pregnant and lactating women, and those with reduced conversion ability, such as older people or those who have chronic disease (eg, diabetes).

Answer 3

Grains, nuts, algae, and flax are all potential sources of Omega 3 (source)

Answer 4

Omega3 is contained in vegetarian/vegan food, and in good quantities, in particular some of the top rich foods in Omega3 are good for a vegan diet.

• Edamame/Soy (but be careful, soy based foods increase chance of getting fat, and according to some experts increase breast cancer)
• Nuts, are surprisingly rich in Omega3 (9000 mg over 100g of nuts)
• Beans, maybe not Omega3 rich like flax, but still a good source

(Source)