Chia Seeds as a Replacement for Fish Oil?

I would note that Chia seeds contain short-chain omega-3s, which are not the same as EPA/DHA (i.e., the long-chain omega-3s that we're looking for). The short chains (alpha linoleic acid, or ALA) have to be converted to EPA and DHA in the body, which reportedly isn't extremely efficient.

Generally, plant sources provide ALA and studies have shown that increased ALA consumption does not result in increased DHA in the body (Williams, C. M.; Burdge, G. Long-Chain n-3 PUFA: Plant v. Marine Sources Proceedings of the Nutrition Society 2006, 65, 42-50.)

According to a recent lecture I was watching (by Mat Lalonde), the highest estimated conversion of ALA to DHA is 4% (Emken et al., 1994), while most other studies have reported less than 0.05% (Burdge et al., 2002; Burdge & Wooton, 2002; Burdge et al., 2003).

The best estimates put the efficiency of ALA conversion to EPA at 0.2%, EPA to DHA at 0.13%, and DPA to DHA at 0.05% (Pawlosky et al., 2001).

I would say that you would get more benefit from consuming fish oil, for instance, rather than chia seeds or flaxseed. For me, I try not to use supplements, but rather use this type of stuff as clues of a healthy diet. You can get fish oil and omega-3s from eating fish, which also have the great stats you were referring to.

Also, if you're consuming these 'vitals' from the diet, it leaves less on the plate to get you into trouble. I find that many people use supplements as insurance or to basically enrich or fortify the diet. I have always found it somewhat ludicrous that nutritionists, the USDA, the AHA, the ADA, etc. would say, for example, that breakfast cereals are good sources of vitamins, minerals, and fiber that were added via fortification. Do you think this would fly with the cattle industry if they sprinkled a multivitamin on their meats? We make brownies "vitalicious," which I think is wildly missing the point in the context of good nutrition.

If you predominately eat naturally occurring and naturally raised (i.e. grass-fed meat) or wild caught meat, fish, fowl and vegetables everything seems to fall into place. It certainly doesn't exonerate us from looking critically at these foods, and it doesn't mean that foods that originated or were eaten later than pre-agricultural periods are inherently evil, but you would be hard-pressed to find a better framework for humans.