Higher levels of IGF-1 in GM salmon
The Guardian, 7 September 2010
*Genetically modified salmon is deemed safe for human consumption - despite higher levels of a suspected carcinogen
[image caption: 'If salmon and milk and a whole range of edible food-like substances yet to come contain elevated levels of IGF-1, when, exactly, are we supposed to start worrying?']
With fish stocks around the world depleted by overfishing and disrupted by climate change, farm-raised salmon stands as a viable if not entirely appetising alternative.
Last Friday, though, the US Food and Drug Administration (FDA) took a potentially dangerous step. The agency ruled that salmon whose genes have been altered so that they grow more rapidly than their wild counterparts are safe for human consumption. In so doing, the FDA opened the door for salmon to become just another unhealthful cog in the industrial-food machine. And it may have foisted upon the public yet another cancer risk.
According to a report in the New York Times, FDA scientists found that the altered fish, developed by AquaBounty Technologies, based in the Boston area, were unlikely to escape into the environment and cross-breed with native schools of Atlantic salmon. The agency also found that even though the genetically altered salmon carry elevated levels of insulin-like growth factor-1 (IGF-1), a suspected carcinogen, those levels are so minute that they pose no health risk.
Precautions aside, it requires considerably more than the customary level of naivety to believe wild salmon wouldn't be contaminated by their laboratory-designed cousins. If AquaBounty's progeny ever come to market, it would only be a matter of time before some unforeseen accident undid everyone's best intentions.
But it is the IGF-1 about which we truly ought to be concerned, because the FDA's finding is evidence of an unacceptably narrow focus. The substance occurs naturally in salmon and other animal products, and the agency tells us that the genetically altered fish contains only a tiny amount more. Yet, by considering such matters one at a time, the FDA may well be introducing us to many tiny risks that start adding up to a very real risk.
This isn't the first time we've had to worry about IGF-1. In the 1990s, the FDA approved the use of genetically engineered recombinant bovine-growth hormone (rBGH, also known as rBST) to induce cows to produce more milk. It was, and is, a controversial practice, and I wrote about it for an iconoclastic (and defunct) environmental journal called Garbage magazine.
My reporting convinced me that rBGH posed a greater risk to cows than to humans, as the unnaturally high rate of milk production stressed the animals, sometimes resulting in an infection known as mastitis. (Which is treated with antibiotics. Which enter the food supply. Which - well, you get the picture.)
But cows given rBGH, like genetically altered salmon, also have higher levels of IGF-1, some of which makes its way into the milk. Not enough to worry about? Perhaps. But if salmon and milk and a whole range of edible food-like substances (to use Michael Pollan's phrase) yet to come contain elevated levels of IGF-1, when, exactly, are we supposed to start worrying?
In addition to being linked to colon, prostate and breast cancer, IGF-1 is a trigger for puberty, which has led to speculation that too much could cause puberty to come about prematurely. IGF-1 also has its uses, both legitimate and dubious. When human-growth hormone is administered as a corrective to children with certain rare types of hormonally based dwarfism, it stimulates the production of IGF-1, which in turn boosts growth. A quick search of the internet also reveals that IGF-1 is touted as an anti-aging formula and as a body-building substance.
As it happens, I recently finished Jared Diamond's celebrated book Guns, Germs and Steel, which, among other things, explains the civilising effects of domesticating that is, genetically altering certain plants and animals. But genetic engineering as practiced in the Fertile Crescent thousands of years ago contained within it certain limits that ensured some degree of safety. Even the green revolution of the 1960s was based on tried-and-true methods of selective breeding.
By contrast, modern scientific tools allow genetic engineers to try just about anything in order to see what will happen. AquaBounty's Atlantic salmon, for instance, contain a growth-hormone gene from Chinook salmon and another gene from an entirely different fish, the ocean pout, which has the effect of keeping that growth-hormone gene switched on. The result is an alien creature, unknown in the natural world.
Consumer and governmental wariness has so far prevented genetically modified foods from taking over our grocery shelves. Milk from cows given rBGH is banned by the European Union, Japan, Australia, New Zealand and Canada. Some American companies - even Wal-Mart - have done a nice business selling milk guaranteed to be from rBGH-free cows.
Likewise, a host of consumer organisations is fighting against genetically modified salmon. Typical is this statement from Wenonah Hauter, executive director of Food & Water Watch, which is full of warnings about the environmental, toxic and even allergenic hazards posed by "mutant salmon".
The FDA won't make a final decision until later this fall, after a round of public hearings. So perhaps this is not yet a done deal. Maybe Michelle Obama is importuning her husband even now. Trouble is, there are few politicians willing to incur the wrath (and eschew the campaign contributions) of the American industrial food system.
In the end, the battle over genetically modified salmon is emblematic of a larger problem: an ongoing shift away from real food in favour of substances concocted in a lab.