Fish oils is rich in essential fatty acids known as DHA and EPA. A study of vegans has found that they have low levels of DHA and EPA – not surprisingly, the levels were similar to those of omnivores not eating much fish. Linseed oil is a good source of other fatty acids however the conversion to EPA and DHA is low. Luckily it is now possible to obtain the essential fatty acids EPA and DHA from non-fish sources. Vegan omega-3 DHA-EPA derived from algae and packaged in vegetarian capsules have become available in recent years. The vegans in the study responded robustly to a relatively low dose of a vegetarian omega-3 supplement.
One vegan source of essential fatty acids is Opti3, which contains 333.5 mg EPA and DHA per capsule.
Sarter B, Kelsey KS, et al, Blood docosahexaenoic acid and eicosapentaenoic acid in vegans: Associations with age and gender and effects of an algal-derived omega-3 fatty acid supplement Clin Nutr, 2014 March 14