By Bill Chameides
Is the U. S. Food and Drug Administration asking the right questions?
Genetically modified (or GM) foods have been a source of fierce controversy ever since they first hit the market place some 14 years ago. See here and here. These organisms are much like the flora and fauna one finds naturally with a notable exception. The genetic make-up of the GM food has been, as the name implied, modified in the laboratory to bring out certain, presumably, desirable traits. For example, Bt corn gains resistance to corn borers from a protein taken from the soil bactertium, Bacillus thuringiensis, thus avoiding, at least in theory, the need for pesticides.
Opponents of GM foods argue that propagating these synthetic organisms will open a Pandora's box of risks that include poisoning the natural gene pool and poisoning our bodies with synthetic foods. Proponents of GM foods argue that genetic modification is not fundamentally different from the processes that horticulturalists and animal breeders have been using for millennia to develop desirable strains and breeds - albeit with a greater reach often combining disparate species (e.g., instead of crossbreeding broccoli with cauliflower, genetic modification allows the `crossbreeding' of bacteria and corn). They also argue that concerns about propagation can be adequately addressed through appropriate safeguards (for example, sterile crops).
Despite the opposition, GMOs have made huge market inroads in agriculture (although the EU has largely resisted their use). But genetically engineered animals have not yet entered the marketplace... until now.
AquaBounty Technologies, based in Waltham, Massachusetts, has developed a fast-growing GM salmon that it hopes to bring to market within three years. The product, AquAdvantage salmon is an Atlantic salmon that contains a growth hormone gene from the Chinook salmon as well as a genetic on-switch from the ocean pout, an eel-like fish. The on-switch from the pout keeps the salmon growing throughout the year, which enables it to grow to market size in about half the time as farmed Atlantic salmon. (See graph here.)
However, for AquaBounty to sell AquAdvantage salmon as a commercial alternative to conventional farmed Atlantic salmon it must get approval from the U.S. Food and Drug Administration (FDA) by submitting a New Animal Drug Application (NADA). This is new territory - no genetically engineered animal has ever been approved for human consumption in the United States,...but AquaBounty hopes that is about to change and the FDA has already said it is safe.
In making that assessment [pdf], the primary question the FDA considered was the product's direct effect on health. Simply put, they asked: is eating AquAdvantage salmon safe as compared to eating conventional farmed Atlantic salmon?
Seems reasonable, right? No, say Martin Smith, a colleague of mine at Duke's Nicholas School and co-authors in a Policy Forum piece published in Science last week. Smith et al argue that there are larger issues related to the aggregate market for food protein and how changes in that market impact public health. For example, the authors note that salmon is generally regarded as a healthier source of protein than beef because of its higher concentration of omega-3 fatty acids. (There are some concerns about high levels of toxins such as PCBs and mercury in salmon, but the authors argue that "For adults, overall health benefits exceed health risks from consuming fish.") If the consumption of GM salmon leads to lower prices for salmon, then that should lead to more salmon consumption and presumably improved public health. The authors argue that this is a potentially important overall health effect from consuming GM fish that the FDA should not ignore in their assessment.
What About the Environment?
On the flip side, there are also important adverse environmental impacts from the commercialization of AquAdvantage salmon that the FDA should consider. For the most part the discussion of environmental impact has been dominated by concerns that AquaBounty's super salmon might escape into the wild creating havoc with wild salmon as well as other cascading effects. No self-respecting environmentalist and/or fishing enthusiast could stomach that eventuality. But neither could AquaBounty, because that would mean that their prized patented organism would be available for anyone with a rod and line. And so, the company has developed what they believe is an escape-proof plan [pdf]: the eggs would be produced at a site on Prince Edward Island, Canada; shipped, grown to market size and processed in Panama (presumably where the waters are too warm to allow salmon to survive); and then sent to the United States for sale.
So from an environmental point-of-view all is well with AquaBounty's proposal, right? Not quite, say Smith and his co-authors. Salmon raised on a farm, including AquAdvantage salmon, require a steady diet of protein and that protein usually comes from the ocean; an ocean that is suffering already from overfishing. And, somewhat counterintuitively, producing fish on a farm often drains more protein from the ocean than just catching the equivalent fish from the ocean. For example, 1 kg of commercially farmed salmon typically requires about 3 kg or more of fish caught from the ocean. A major expansion of the production of farm-raised salmon as a result of the marketing of AquaBounty's new technology could place undo pressure on already stressed wild fish stocks used to feed farmed salmon. Ultimately that pressure could lower rather than raise the availability of affordable fish with potentially negative health impacts.
So What's the FDA to Do? It's Complicated
Growing up in New York City in the `50s, choosing what to eat was a simple exercise. Open the fridge door, find something my Mom left there that looked good and eat. I now understand, like most Americans, that it's a lot more complicated. There are a whole host of implications for personal and environmental health with every bite we take. Weighing those factors makes our food choices more complicated, but then that's the nature of the beast.
Smith et al. have a similar message for the FDA: as you consider the efficacy of AquAdvantage salmon don't forget -it's complicated too.