(and Why It Matters to You)
When creatures live in the wild--whether they be fish, animal or fowl--they eat a very different diet than when they are raised in captivity. "You are what you eat" applies equally to humans, animals and even plants--so if you're eating something that was once alive, it's good to know what that creature dines on.
We know, for example, that the omega-3 fat content of grass-fed beef is very different from that of their factory-farmed brethren. And we know that plants grown in mineral-rich soil are richer in those minerals than plants that barely survive in barren soil. But when we're looking at a foods commonly viewed as health food, like salmon, it's easy to forget that the same cautions apply.
Wild salmon dine on a crustacean called krill. Krill are little creatures resembling shrimp that are now being looked at for their astonishingly potent health benefits. They are a great source of omega-3 fats, for example, and krill oil as a supplement has been used successfully in research as a treatment for PMS symptoms (3mg a day is the dosage that seems to work, if you're interested.) And krill are also loaded with an antioxidant called astaxanthin.
Astaxanthin is a member of the carotenoid family (which also includes beta-carotene), and it has great potential in human health and nutrition. It's a powerful biological antioxidant. A recent scientific review in the March 2006 Journal of Natural Products examined the scientific literature from 2002 to 2005 on the most significant activities of astaxanthin, including its antioxidative and anti-inflammatory properties and its effects on cancer, diabetes, the immune system and ocular (eye) health. A paper in the Biological and Pharmaceutical Bulletin in January 2005 suggested that astaxanthin had both antihypertensive and neuroprotective effects--that means it may lower blood pressure and protect the brain! Astaxanthin occurs naturally in a variety of living organisms (including krill). And it's what gives wild salmon their red color.
But here's the problem: In the wild, salmon forage the oceans feeding on colorful crustaceans (like krill), plankton and algae, which naturally impart a beautiful shade of pink to the flesh of their predators. But when salmon are farmed and unable to forage, their flesh is an insipid, unappealing color--one few people would find appealing. Hence, canthaxanthin or astaxanthin or both are added to the feed of farmed salmon. Apparently, although astaxanthin is normally found in wild salmon, canthaxanthin is more efficiently bioabsorbed. Almost 100 percent of all farmed salmon is artificially colored with either canthaxanthin or astaxanthin, a process sometimes euphemistically called "color finishing."
Responding to an ever-increasing demand for salmon--which must, however, be pink--several major chemical companies produce canthaxanthin and astaxanthin for color finishing. One chemical firm synthetically produces canthaxanthin and an astaxanthin called Carophyll Pink from petrochemicals and provides customers with its SalmoFan--much like an artist's color wheel, but in various shades of pink--to help salmon farmers and buyers select a color that sells well.
Warning: According to reports in the journal Science, farmed salmon may contain high levels of dioxins. PCB levels may be up to eight times higher in farmed salmon compared to wild salmon. And in July 2003, the Environmental Working Group (EWG) released a report stating that farmed salmon purchased in the United States contain the highest level of PCBs in the food supply system. Omega-3 content may also be lower in farm-raised salmon than in the wild variety.
Salmon is still one of the healthiest foods you can eat, and for many good reasons, not the least of which is its positive effect on heart health. But it's probably a good idea to seek out wild salmon whenever possible. It comes by its color naturally--by eating its natural diet--and it's likely to be higher in omega-3s and lower in some of the man-made additives and contaminants that you don't want in your diet.
Tip: Try canned salmon--almost all of them are wild!