Friday, June 14, 2013

GM Oh No! Part 1 of 3: Human health considerations

A blog of Bridge Environment, updated most Thursdays

This entry is the first in a three-part series about genetically modified organisms (GMOs)

GMOs: Monsters or unsung superheroes?
Genetically modified (GM) food items prompt one of two reactions. Some people panic, not wanting anything to do with them. The panic reaction has dominated European politics and led to a near-ban on growing (but not importing) GMOs. Other people ignore the issue, preferring to remain untroubled by yet another risk of modern life. The denial reaction has dominated US politics so far, where even efforts to label GMOs have fallen flat. These two reactions should not be surprising: they are our natural human responses to uncertainty. To foster a more rational debate regarding GM foods, we present a three-part series. Today we define the term GM, put GM practices into historical context, and consider human health effects. Next week, we will discuss potential ecological consequences. In two weeks, we will wrap up the series with a discussion of intellectual property, market power, and politics. In general, we will conclude that GMOs pose greater risks than proponents would have you believe, but smaller ones than critics suggest. Rather than ban them outright, we encourage smart regulation along with accurate education. With proper oversight and regulation, GMOs are neither terrible monsters nor superheroes capable of saving us from ourselves.

To start, let’s define GMOs by putting them into historical context. Humans have shaped our food supply throughout history and have, through farming practices, caused purposeful genetic modifications in nearly everything we eat. In large part, these modifications are a result of selective breeding1, whereby people produce the next generation of domesticated plants or animals using prize specimens. Over millennia, selective breeding practices shaped the genes of domesticated grains, vegetables, fruits, meats, and even microbial products like cheese and wine, making them more productive and more desirable to consume. In this way, nearly everything we eat could be considered genetically-modified. However, the GMO term is reserved for a specific method of creating new varieties.

The next big technology for shaping our food supply came in the first half of the 20th century when agricultural scientists began causing mutations in plants by exposing them to radiation or harsh chemicals. The resulting individuals are screened for desirable traits and, in some cases, interbred with existing strains to further improve them. The varieties resulting from these processes are even more genetically-modified than those developed via selective breeding alone, but still do not qualify for the term GMOs.

Instead of relying on mutagenic conditions, true GMOs are developed in a calculated and precise way. Specific properties are sought, appropriate genes are identified in other organisms, and then a GMO is engineered by combining the genes of multiple plants or animals, a process referred to as transgenesis. This process is inspired by transduction. Discovered in the early 1950s, transduction is a natural phenomenon by which certain viruses are capable of incorporating a piece of DNA from one host into their own genome, carrying it to another host, and inserting it into the new host’s DNA. As creepy as this phenomenon sounds, it can be beneficial. Transduction is involved in the rapid evolution of antibiotic resistance in bacteria, for example (good for the bacteria even if it is not for us), and has promise for inserting functional gene copies into cells of people who suffer from genetic disorders. When creating a GMO, scientists transfer DNA using plasmids, which have many similarities with the transduction-capable genetic material of viruses. The scientists’ goal is to create a transgenic superorganism.

In some ways, the creation of GMOs is merely a more controlled version of techniques we have used for millennia. From a policy perspective, what separates this technique is the rapidity and scope of changes that can be made. The rate of change offers both promise and peril. For example, consider AquaAdvantage salmon, also known as the Frankenfish. This GM salmon has been engineered by adding genes from Chinook salmon (Oncorhynchus tshawytscha) and ocean pout (Zoarces americanus) to Atlantic salmon (Salmo salar). The introduced genes allow the engineered salmon to grow twice as fast as existing varieties of farmed Atlantic salmon.

The transgenic nature of GMOs tends to fuel our imagination and make us believe we are eating something contaminated. In reality, GMOs are made with precise and controlled technologies compared to the older radiation- and chemical-based methods. Regardless, the genetic changes are the one major lasting effect of the environment that created new varieties using either of these techniques. If there are health risks, they are most likely going to be from the resulting properties of the food, not the details of its creation.

When it comes to health consequences, GM foods are not particularly different from other varieties humans have developed throughout our history. It is possible that any new variant may have unintentional health effects. The obvious solution to this challenge is testing, which does take place on GMOs prior to human consumption. Testing is capable of identifying major toxic issues quickly, but not as capable of identifying rarer problems like an unusual allergy, or long-term risk for diseases like cancer, which may only manifest in some individuals and only after years of exposure.

GMOs have been in our food supply since the mid-1990s and no human health issues have yet been identified. This result does not mean that GMOs are all safe for human consumption. The fact that they can differ so quickly and dramatically from previous varieties means that GMOs should be subject to additional scrutiny and longer-term testing than, for example, a variety derived from selective breeding. However, we should not see GMOs as somehow wholly distinct. In all cases where a new variety is notably novel, we should consider more extensive and longer-term testing.

The same logic applies to labeling. While labeling seems reasonable from a perspective of informed consumers, producers are legitimately worried that a GMO label would be seen by the public as a hazard warning. Such a warning may be warranted if the public does not have faith in the ability of food regulators to accurately gauge the health risks associated with novel food items. However, such a concern could be applied equally well to food items derived via radiation- or chemical-exposure. If we do label, we should do so based on the novelty of a food and accompany that effort with a public education campaign.

This does not necessarily mean that GMOs are safe, but it does mean that health concerns are less of a factor in regulating GMOs than environmental risks and the influences of monopoly power. They will be the subject of our blog entries in the following two weeks.


For more information, read our other blog posts and visit us at Bridge Environment.

1 Selective breeding is so pervasive and effective that it helped inspire Darwin’s development of evolutionary theory.

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