This article explains some differences between plant and animal sources of Omega 3 fatty acids that are important to your overall health.
Dr Mercola has a great article that goes into the differences between plant and animal derived omega 3 fatty acids. The are NOT equal, they are NOT interchangeable and eating only plant based sources does not satisfy a crucial need the body has for building blocks. Here is some data from the whole article. If the link still works when you come to read this I recommend reading the whole article.
The difference between triglyceride-bound, marine animal (fish and krill oil) derived omega-3 (docosahexaenoic acid DHA) and eicosapentaenoic acid (EPA) versus phospholipid-bound, plant derived alpha-linolenic acid ALA.
Omega-3s EPA/DHA are considered “essential” fats as your body cannot make them and, hence, you must get them from your diet. Your body needs these polyunsaturated fats for a variety of functions, including digestion, muscle activity, blood clotting, visual acuity, memory and learning, and basic cell division and function of cell receptors.
Plant sourced Omega-3 ALA on the other hand is quite ubiquitous in the diet and therefore there is no real need to supplement. Although your body can convert some of the ALA found in plants to the DHA found in marine oils, it is very rare for it to be more than 5 percent and typically found to be 1 to 3 percent, or even as low as .1%. This is an insufficient amount to have any significant benefit.
The Key Difference between the two is that plant derived ALA Is a source of energy whereas EPA and DHA are structural elements.
According to Nils Hoem, Ph.D., a leading scientist in omega-3 phospholipids, when you look at the uptake and distribution of EPA and DHA you see something rather strange.
After eating a meal of salmon or taking a krill or fish oil, the fatty acid level in your plasma (blood) will remain elevated for more than three days afterward. “Your body works on its distribution, redistribution and re-redistribution for three days. That’s hardly consistent with being “just food,” he says.
On the other hand, the short-chain omega-3s (ALA) are rapidly absorbed, peaking a couple of hours after ingestion. Within 10 hours, they’re gone. This suggests your body is using them very differently.
http://articles.mercola.com/sites/articles/archive/2016/07/11/health-benefits-omega-3-fats.aspx