Something's Fishy Here

Pink salmon in Washington's Elwha River. Source: NOAA

Almost a year ago, HealthTwisty published this blog post about genetically modified (GM) salmon. At the time, the FDA ruling on the safety of the fish was expected at any time. Since then, the application to approve GM fish has been under review, but now things seem to be bubbling up again with a ruling expected any time.

I have to admit, these fish confound me. For the record, I'm not opposed to genetic engineering. After all, I appreciate that humans have figured out, for example, how to hijack the genome of bacteria to create medicines, such as insulin, in vast quantities and to very high standards. Here's a simple interactive infographic of that type of genetic engineering, which is the basis for introducing most new traits into different organisms.

The salmon situation is a bit different. For one thing, they are the first GM animal to reach this level of scrutiny. Because they are live beings, they could potentially interact with conventional salmon and cause unknown outcomes. And because we eat them, we will eat the results of whatever genetic modification has taken place. Such a precedent-setting situation calls for hypervigilance on the part of the federal government to review the science and safety data, as well as extra caution before opening what is sure to be a floodgate of GM animals (already other GM fish are in the regulatory pipeline, and there have been studies on the safety profile of meat from cloned mammals). The biggest questions surrounding these salmon focus on two main issues:

1. environmental issues (what would happen if these GM salmon escaped into natural habitats?)
2. health issues (what effects will the genetically engineered fish flesh have on humans once ingested?)

Environmental Issues

Tidal channel, Angoon, Alaska. Source: NOAA

AquaBounty, the company that created the GM salmon, assures us that all of the GM fish will be females and that they will be sterile due to the addition of an extra chromosome. These safeguards are designed to keep the altered DNA out of the wild salmon population. But, as two scientists who were on the FDA review panel reminded us recently on NPR, nothing is ever 100%. There will be GM salmon who are not sterile, and there will probably be GM salmon that can escape from their cages and find their way to natural habitats. The outcome is uncertain if those two, admittedly remote but still possible, situations occur together.

As the NPR transcript shows, these scientists were not satisfied with the quality of the risk assessment that was submitted as part of the FDA application for these fish. Specifically, two key aspects of formal risk assessment were not completed: a failure mode analysis (which is a quantitative analysis of what could go wrong that would allow the fish to escape as well as what could happen if some fish did escape) and a formal uncertainty analysis (which pulls together all the aspects of the process that are unknown).

In fact, one of the scientists being interviewed, Anne Kapuscinski, PhD, a professor of sustainability science and chair of the Environmental Studies Program at Dartmouth College, said that the data presented to the FDA

"...had gaps, and the quality of the analysis of the data, especially the statistical analysis, was really quite a low bar."

Now remember, the scientists interviewed by NPR were on the FDA review panel, which reviews the FDA's recommendations prior to the recommendations going forward. The panel is intended to be part of a check and balance situation to ensure that the FDA's ruling is impartial and that the organization has all the information required to make the best decision. So for scientists on this panel to question the quality of the data submitted to the FDA was not comforting to me, at all. It was the opposite of comforting. The data given to the FDA in support of this very, very important decision should meet the highest, most stringent standards accepted by our scientific community.

So there's that.

Let's look at the health issues.

Health Issues

Source: NOAA

The second point, about the possible health effects these salmon could have on humans, has not been addressed clearly, either. In fact, almost all of the supporting FDA documents are focused on the environmental impact of the GM salmon, not on the health effects. Perhaps that's because the FDA has classified the GM salmon as an "veterinary drug" rather than a "food additive." (Here are a couple of links, one scientific and one legal, that explain the difference and why it is sort of strange that the review of the GM salmon is overseen by the FDA's Center for Veterinary Medicine.) Apparently, there is no formal classification for GM fish/mammals for the FDA to create a protocol for reviewing.

Unfortunately for consumers, the regulations governing a new animal drug are far less stringent than those applied to a food additive. That makes a certain intuitive sense; after all what animals are given may not require the same level of purity or burden of proof of safety as what is given to humans (this is debatable, considering we often eat those animals and therefore ingest the byproducts of what they were given. But whatever. That's the way it is.).

Currently, there is speculative information on the health benefits of these salmon. For example, the increased availability and decreased price of salmon that could result from GM salmon could encourage consumers to eat more salmon. One group of researchers estimated that an increase in salmon consumption could prevent an estimated 1,400 deaths annually from cardiac disease in the US.

Conversely, others, like the Ocean Conservancy, note that a GM fish is not nutritionally equal to a conventional fish. For example, the ratio of omega 3 fatty acids to omega 6 fatty acids differ between the normal and GM fish, other nutrients differ between the two types of fish, and allergens may be elevated in the GM fish (there is some discussion that elevated levels of fish antigens could cause more people to become allergic to fish). But what concerns me the most, and is always buried at the end of statements, is the long-term effect that the extra insulin-like growth factor 1 (IGF-1) from these fish will have on our health.

A brief primer on IGF-1. Our livers make IGF-1 in response to human growth hormone. IGF-1 is what makes our cells grow. It is what allows the GM salmon to grow more quickly than they would naturally. It is associated with breast, colon, and prostate cancers. It's powerful stuff and all the details about how it affects our bodies have not been worked out.

We have been confronted with this issue before, but it has been in our milk supply, not in our fish. Bovine growth hormone, given to cows to increase their milk production, increases IGF-1 in cows and can be passed along into their milk. The benefits to consumers that we heard for BGH were the same that we are hearing for the GM fish: the lower prices that can be gained by increasing the volume of milk produced will allow more people to purchase milk and reap the health benefits of it, as well as allow dairy farmers to stay in business.

But, here's the rub.

European countries will not buy our milk from cows that have received BGH due to the higher levels of IGF-1 it contains. In the mid 1990s, when I was considering what type of milk to feed my infant, I asked a couple of pediatric endocrinologists what they fed their kids. They said organic milk, and would continue to do so until more was known about what, if any, effects the extra IGF-1 would have on people. So I did the same (as much as possible considering not all cheeses and yogurts are labeled with the source of their milk). BGH has been a great experiment that may, over the long run, prove to be safe, but may prove to  increase obesity and cancers. I have been willing to wait that one out until the results are in, probably in another generation or two.

And, that is what I have decided to do if GM salmon receives FDA approval: wait it out until enough evidence is in that I'm satisfied that the fish is safe. But the problem is, I won't really know the provenance of my salmon because there is no requirement to label it as GM. Therefore, I am lobbying my congressional representatives and signing petitions on behalf of non-profit organizations, not to ban GM salmon, but to ensure that it will be labeled so that I can make up my own mind about whether or not I want to eat it.

I encourage everyone to learn about this fish and the technology involved. It is clear that feeding the ever-growing world with healthy food will become more and more challenging in the coming decades, and our depleted fishing stocks cannot be counted on to supply much without significant help. GM salmon do offer a way to increase our food supply. But there will be risks. Only we can decide if those risks are worth it.

Here are the FDA web pages devoted to salmon and GM salmon.

Here's a list where you can find your Congressional representatives.

Here's a petition to sign about labeling.

This HealthTwisty post has some good references to learn more about this salmon.

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