Birds do it. Snakes do it. Even educated shoppers do it. Let's do it, let's buy eggs enriched with omega-3s.

Only, let's not be deceived by the allure of the "omega-3" halo. That's because whenever you hear about the benefits of omega-3s, what that's really about are the long-chain omega-3 fatty acids EPA and DHA. The shorter-chain ALA typically is derived from flax. While flax has some good things going for it, it is a mere shadow of EPA and DHA. To be specific, that shadow is between about 2 and 15 percent of EPA and DHA. Studies show the conversion rate of ALA to EPA and DHA to range from about 5-15 per cent for EPA and 2-5 per cent or even less for DHA. That's because ALA is mostly used for energy, and thus quickly removed from the blood, whereas EPA and DHA are not.

Indeed, the reason the FDA granted a qualified health claim for EPA and DHA from fish sources and explicitly not for flax is because of the fairly large evidence base for EPA and DHA compared to ALA.

So when you see on a box of eggs that it's fortified with "225 mg omega-3s!" chances are good that you're actually getting only about 20 mg of the really good omega-3s you really want.

Unless, that is, you get the eggs that specifically state they are enriched with DHA. One company pretty much owns the market here, and that company and brand is Martek's life'sDHA. You'll see the green and white logo on the box delineating as much.

Disclosure: I have no ties whatsoever to Martek, which also pretty much owns the infant formula market, so when you see formula fortified with DHA, chances are excellent that it's also life'sDHA.

That said, even run-of-the-mill omega-3 enriched eggs provide about 12 times more omega-3 fatty acids than regular eggs, based on an average omega-3 content of 0.5 grams in omega-3 enriched eggs versus 0.04 grams in regular eggs. This statistic courtesy of the Flax Council of Canada—where most flax is grown.

That flax is an omega-3 but will not get consumers appreciable quantities of EPA and DHA has created some confusion among food manufacturers, some of which have used flax in their products to boast the content of omega-3s. Consumers who are more familiar with the omega-3 term may believe by buying omega-3 foods they are getting the benefits of EPA and DHA. Different sources of omega-3s have different benefits, so source wisely.

The great thing about DHA eggs is there is published research to vouch for it. In one study, pregnant women who consumed DHA had babies with longer gestational length and greater cerebral maturation.

Another study feeding pregnant women DHA eggs (135mg/DHA per egg) showed they had higher blood DHA levels than women consuming ordinary eggs (18mg DHA per egg in this study). DHA intake and birth weight also aligned.

Another study gave pregnant women DHA-enriched eggs (133mg DHA per egg) during their last trimester. Of the 291 women in the study, those who ate the DHA eggs demonstrated a trend for higher birth weight, length and head circumference. There was another group of women in the study who ate ordinary eggs, containing 33mg DHA per egg. "These data suggest that increasing DHA intake among pregnant women may have great potential in optimizing pregnancy outcomes and the developmental outcomes of their infants as well," said lead researcher Susan Carlson, Ph.D., a professor in the department of dietetics and nutrition at the University of Kansas Medical Center.

Take-away here—for manufacturers as well as consumers—is to source and serve eggs with pre-formed DHA instead of flax. No offense, Canada. You can keep your gold medals.