by Craig Weatherby
The feed given most farmed salmon contains synthetic colorants, to produce the orange-red hues shoppers expect to see in this popular fish.
Absent this artificial intervention, the flesh of farmed salmon would be an unappealing gray.
U.S. Food and Drug Administration (FDA) regulations allow salmon farms to feed their stocks two carotene-class colorants — astaxanthin (as-tuh-zan-thin) and canthaxanthin (can-thuh-zan-thin) — as long as customers are notified via signs at the point of purchase.
But few supermarkets comply with this disclosure requirement.
And until a consumer group sued California’s biggest supermarket chains in 2003, very few shoppers even knew that most farmed salmon contain artificial colors.
The suit accused supermarkets of violating federal food-labeling rules, and it sought to require retailers to post notices on farmed salmon fed synthetic chemical colors.
The lawsuit claims that the stores’ failure to disclose the use of artificial colors is misleading, and cites possible concerns over consumption of the artificial coloring agents in question.
Wild salmon get astaxanthin – and a little canthaxanthin – from tiny shrimp and other natural prey.
But the synthetic versions fed to farmed salmon are produced from petrochemicals, and possess significantly different chemical structures.
Salmon require astaxanthin to thrive, and there is as yet no evidence that synthetic astaxanthin and canthaxanthin are unsafe … although they may not be as healthful as the significantly different forms found in wild salmon.
The legal and public policies at issue in the court case center on the duty of food makers and sellers to reveal everything that’s added to their goods … and not to mislead by evading full disclosure.
U.S. Supremes back California’s top court
The key legal issue was whether the U.S. Food, Drug and Cosmetic Act—which governs food labeling—precludes private citizens’ efforts to enforce U.S. regulations, and/or state laws with stricter labeling provisions such as California’s Consumer Legal Remedies Act.
In March of 2008, the California Supreme Court reversed a decision by the Court of Appeals, thereby allowing a class-action lawsuit over disclosure of artificially colored salmon to proceed.
At the time, the California Supreme Court wrote that Congress had made a “conscious choice” to permit private suits in such circumstances.
The California Supreme Court’s reasoning aligns with U.S. Supreme Court decisions allowing private enforcement of “parallel” state requirements in other contexts.
The supermarkets named in the suit appealed the California Supreme Court’s ruling to the U.S. Supreme Court, arguing that only government regulators can enforce federal and state labeling laws (Albertson’s v. Kanter, 07-1327).
The supermarkets said the 2008 California Supreme Court ruling was “… an open invitation to private plaintiffs nationwide to bring class actions …” and will “… wreck Congress’s exclusive government enforcement scheme and all its built-in advantages.”
But last Monday, the U.S. Supreme Court rejected the food-sellers’ appeal.
Artificial colors raise question and concerns
The citizen lawsuit against grocers focuses on the common practice of feeding farmed salmon astaxanthin and canthaxanthin to turn their flesh the red-orange color of wild salmon.
Wild salmon develop their pink/red flesh naturally by feeding on prey such as krill (tiny shrimp-like crustaceans) rich in astaxanthin.
In addition to acting as a pigment, astaxanthin is a very potent carotene-class antioxidant.
Krill and other salmon prey get the astaxanthin by feeding on algae rich in the powerfully healthful pigment, which serves a vitamin-like role in salmon and is essential to their health and survival.
Most salmon farmers feed their fish grain-based “salmon chow” containing a synthetic version of astaxanthin, derived from petrochemicals.
The petrochemical-source astaxanthin given most farmed salmon differs from the naturally occurring astaxanthin in the diets and flesh of wild salmon in its “optical isomeric distribution.”
In fact, the forms and proportions of various astaxanthin isomers in synthetic salmon-colorant supplements vary substantially from the forms and proportions found in wild Pacific crustaceans and the wild Pacific salmon that eat them.
One study showed that fish (not salmon) that consumed synthetic astaxanthin in their commercial fishmeal grew more slowly than fish that consumed the same amount of natural astaxanthin.
This growth difference indicates that synthetic astaxanthin is not functionally identical to natural astaxanthin in salmon’s bodies—and maybe not in people’s bodies, either.
Salmon-colorant supplements containing astaxanthin-rich algae or yeast have been available for years, but they cost more than synthetic astaxanthin, so relatively few salmon farmers use them.
Like synthetic astaxanthin, the forms and proportions of various astaxanthin isomers in yeast-derived astaxanthin vary substantially from the forms and proportions found in Pacific crustaceans and the wild Pacific salmon that eat them.
Studies suggest that yeast-derived astaxanthin does not impair the growth or health of rats or farmed salmon, but it is not clear whether its structural differences from the natural astaxanthin in wild salmon matter to human health.
But, the major brands of yeast-derived astaxanthin pellets contain substantial amounts of the synthetic antioxidant preservative ethoxyquin ... which, ironically, has been shown to kill fish. The US FDA has also linked ethoxyquin to elevated liver enzymes in animals
The color of eye trouble
Synthetic colorant supplements fed to farmed salmon also contain canthaxanthin: a carotene compound sold as a human “sunless tanning pill” that turns skin an orange-brown color.
Small amounts of canthaxanthin occur in wild salmon, because it occurs in their crustacean prey.
Canthaxanthin was linked to retinal damage (crystalline deposits) in people when taken as a sunless tanning pill, leading the British to ban its use as a tanning agent. (It’s still available in the U.S.)
In 2003, the European Union cut levels allowed for canthaxanthin in farmed salmon to one-third of FDA-approved levels, citing warnings about retinal damage.
It is not clear whether there is enough canthaxanthin in farmed salmon to raise serious eye-health concerns.
Yeast-derived salmon colorants contain little or no canthaxanthin, so their use could render that question moot.
Wider implications of artificial color
The controversy over artificial salmon color shines a light on three significant issues: the nutritional quality, the safety, and the flavor of farmed salmon versus wild salmon. Data compiled by the USDA show that wild salmon are nutritionally superior to farmed salmon in at least two ways:
- Wild salmon are about one-third lower in total fat and calories, with only about half as much saturated fat as the typical farmed salmon.
- Wild salmon have a healthier ratio of omega 6 to omega 3 fats. Americans consume far too many omega-6s and not enough omega-3s. Most experts call for a ratio of 3:1, which is the ratio found in wild salmon. Due to the grains that dominate their diets, farmed salmon can have a 10:1 ratio or worse.
This difference yields measureable, negative impacts on blood markers of inflammation, which is now believed to outrank high cholesterol levels as a key risk factor for cardiovascular disease. (See “Farmed Salmon's Diet Yields Unhealthful Cardiovascular Effects” and “Farmed Fish Possess Unhealthful Fat Profiles”.)
For nutritional quality based on total fat and ratio of omega-3 to omega-6 fats, wild salmon is undoubtedly the healthiest choice.
Persistent pollutant concerns
Two recent studies indicate that farmed salmon contain about 10 times more “persistent organic pollutants” — dioxins, furans, and PCBs — than wild salmon (Hites RA et al. 2004).
The authors concluded that regular consumption of farmed salmon could lead to toxin intakes above the tolerable weekly intake for these chemicals: particularly for PCBs, and especially for children under five.
The researchers blamed the fact that farmed salmon are fed diets far richer in fish oils than their wild counterparts.
This fatty diet allows them to reach market size sooner, but it leads to accumulation of dioxins, PCBs, and other fat-soluble toxic pollutants.
Although they are higher than in most foods, it is not certain that the still-minuscule amounts of persistent organic pollutants in farmed salmon pose a serious threat.
However, it seems silly to consciously select a food that contains more PCBs than almost any other.
Commercial fish feed also yields salmon with inferior flavor and texture. According to Mark Bittman, the noted seafood cookbook author, “If I had a choice of fresh farm-raised salmon and sockeye frozen from last year's harvest, I'd take the sockeye.”
At a panel discussion at the West Coast Seafood Show in Los Angeles, Executive Chef Daniel Long of Bon Appetit said, “To be perfectly honest, it [farmed salmon] is crap. Wild salmon is much better.”
And in a Wall Street Journal taste test, the panel scored farmed salmon only 4.83 out of 10 for overall quality, while wild salmon rated a 9.7.
Once you look beneath growers’ propaganda, it seems that farmed salmon can’t hide their true, unappetizing colors.
- Aquaxan HD algal meal use in aquaculture diets: Enhancing nutritional performance and pigmentation. Technical report 2102.001. [http://www.fda.gov/ohrms/dockets/dailys/00/jun00/061900/rpt0065_tab6.pdf]
- Easton MD, Luszniak D, Von der GE. Preliminary examination of contaminant loadings in farmed salmon, wild salmon and commercial salmon feed. Chemosphere. 2002 Feb;46(7):1053-74.
- Fatty acid content of farmed and wild fish. Soon-Mi Shim and Charles R. Santerre, Ph.D. (2003); Department of Foods and Nutrition; Purdue University; 700 W. State St., West Lafayette, IN 47907-2059. (revised 1/21/2003) [http://fn.cfs.purdue.edu/anglingindiana/AquaculturevsWildFish/FattyAcidsFarm.pdf]
- Hites RA, Foran JA, Carpenter DO, Hamilton MC, Knuth BA, Schwager SJ. Global assessment of organic contaminants in farmed salmon. Science. 2004 Jan 9;303(5655):226-9.
- Jacobs M, Ferrario J, Byrne C. Investigation of polychlorinated dibenzo-p-dioxins, dibenzo-p-furans and selected coplanar biphenyls in Scottish farmed Atlantic salmon (Salmo salar). Chemosphere. 2002 Apr;47(2):183-91.
- Reifenberg, A. (2000). "Taste Test: Wild vs Farmed Salmon." The Wall Street Journal, 5 January, NW3. [http://www.sectionz.info/issue_1/Facts_Footnotes.html]
- U.S. Department of Agriculture, Agricultural Research Service. 2002. USDA National Nutrient Database for Standard Reference, Release 15. Nutrient Data Laboratory Home Page, http://www.nal.usda.gov/fnic/foodcomp.