It will be a long while before the last word on GM food (and other) crops is written, but it can be useful to check in on the issue periodically to update our knowledge and our thinking. In many respects, the pro and con positions on GM foods have not changed a great deal in the last decade, although opponents and proponents have refined their messages. The limited amount of new research published has sometimes given rise to radically differing interpretations and projections, each side finding fuel for the fire. If there is one indisputable statement on this topic, it’s that the evidence base continues to be woefully inadequate. As we all know, the absence of evidence (showing harm) is not evidence of absence. Similarly, evidence of benefit cannot be properly weighed without looking at the cost required to gain that benefit. In the absence of a substantial evidence base, the major arguments for and against GM foods are often theoretical in nature—what could happen, what might happen, and not so much what has happened.
The case for GM food crops centers primarily on the demand to increase crop production to accommodate the world’s growing population and the desire to benefit poorer countries where feeding the people they already have is an ongoing challenge. The focus thus far in commercially produced GM crops has been to decrease the use of pesticides, herbicides, and fertilizers, thus making the crops less expensive to produce, creating higher yields, and producing less pollution of earth and water. These effects are usually created either by adding pesticides to the crop or by creating a resistance to herbicides used to fight weeds.
A press release concerning a 2010 National Resource Council report titled “The Impact of Genetically Engineered Crops on Farm Sustainability in the United States” noted that “Many U.S. farmers who grow genetically engineered (GE) crops are realizing substantial economic and environmental benefits—such as lower production costs, fewer pest problems, reduced use of pesticides, and better yields—compared with conventional crops.”
These claims are often disputed; see, for example, the report listed under Resources, from The Organic Center (2009), showing that “GE crops are pushing pesticide use upward at a rapidly accelerating pace. In 2008, GE crop acres required over 26% more pounds of pesticides per acre than acres planted to conventional varieties.” It appears that early use of the GE crops may well have lessened pesticide and herbicide use, but their continued and expanded use has seen “an emergence of glyphosate-resistant weeds due to the increased use of glyphosate” on GE soybeans, corn, and cotton” (Union of Concerned Scientists).
Future genetically engineered modifications to food crops that are currently being discussed or attempted include far more controversial changes, such as:
- Decreasing sugar and saturated fat, and increasing fiber
- Increasing the vitamin and mineral content of the crops
- Mass production of pharmaceuticals such as vaccines, thus eliminating all the costs of storing, shipping, and administering them
- Resistance to extremes of climate, leading to longer growing seasons and less vulnerability to unexpected weather changes
The case against GM food crops is harder to summarize quickly, involving both real and potential effects not only in the US but across the globe, and often relying more on theoretical arguments than on actual evidence. Some of those arguments, however, are very powerful, not the least of which is that “manufacturers of genetically altered foods are exposing us to one of the largest uncontrolled experiments in modern history” (Herbert 2000). Clinicians have only to remember the 50-year uncontrolled experiment on women’s lives represented by hormone replacement therapy to understand the possible disaster-in-the-making that might be apparent only with decades of hindsight. (Or we might recall thalidomide or DES or consider today’s issue of statins increasing the risk for diabetes.) The vital question really is this: do we assume that GM food crops are safe until proven otherwise, or do we require thorough, long-term testing to investigate their safety before letting production proceed? The arguments on behalf of requiring more research include the following:
- The addition of new genetic material to existing foods may create new allergens or unwittingly expose allergic individuals to allergens they know about but don’t expect from a seemingly unrelated food.
- Pesticides have known endocrinological effects; how can we justify inserting such chemicals into our food supply in such a fundamental way—that is, in a way that can’t be washed off—when we know they are harmful? (Seralini 2009)
- Religious and philosophical objections arise at the possibility of vegetarians consuming foods into which animal genes have been introduced, or kosher foods containing non-kosher elements.
- Gut bacteria could pick up antibiotic-resistant genes, which are often used as markers by geneticists to trace which foods have adopted the new genetic material.
- If food crops really did contain vaccines, or substantially altered vitamin and mineral levels, what would happen to the animals that eat those crops? Or to people who don’t need the additional nutrients (or who don’t choose to ingest vaccines—a controversial topic already)?
- We don’t know what could happen to human beings over time if we routinely ingest foods with altered biochemical networks that may affect our own digestion and metabolism.
- There is a considerable risk that independent farmers will be unable to produce non-GM and organic crops, as “gene flow” (carried by wind and water) infects their own crops. The more acres under GM production, the greater this risk becomes.
- Farmers whose crops are affected by gene flow risk patent-infringement suits from the big companies, even though they didn’t want the GM crops and may not even have known they were producing them.
- GM crops disrupt sustainable agriculture, altering the diverse sensitivities to climate and geography that have given rise to widely varying farming practices around the world. As sustainable agriculture is weakened, our reliance on monocultures is strengthened, ultimately making the world’s food supply far more vulnerable than it is now. And, not coincidentally, concentrating a great deal of power (and money) in the hands of the companies producing ever fewer varieties of crops.
- History tells us that tolerance to the herbicides and pesticides for which the crops have been modified is going to develop, making us dependent on new genetic modifications to maintain past gains. In fact, a recent study mentioned by the EPA has already documented rootworm resistance in Monsanto Bt corn in Illinois (Bloomberg, Sept 2012). History also tells us that this is always a path of diminishing returns on the investment required.
There are three major obstacles to expanding the evidence base on GM crops. First is that the FDA regards most genetic modifications as so minor that the food is essentially the same with or without it (the “substantially equivalent” argument). That means they don’t require testing for safety. That perspective was supported in a recent systematic review of 12 multigenerational trials, which reported that “GM plants are nutritionally equivalent to their non-GM counterparts and can be safely used in food and feed” (Snell 2012).
A second problem is that although the big companies do engage in research, they regard it as proprietary and therefore they usually don’t publish their data. When they do publish data, their interpretations may differ from more objective analyses (De Vendomois 2010).
A third problem is that in the US no labeling of foods containing GM ingredients is required; therefore, the public doesn’t know the extent to which they are exposed and can’t make choices in the marketplace that would communicate their preferences to producers. That means it is hard to mobilize public opinion in favor of a much greater investment in long-term research, even though 9 in 10 Americans said they wanted genetically engineered foods to be labeled, according to a 2010 national poll (Harmon & Pollack 2012).
While many of us have worried about these and other related issues over the last decade, the expansion of GM food crops has continued virtually unchecked. “For more than a decade, almost all processed foods in the United States—cereals, snack foods, salad dressings—have contained ingredients from plants whose DNA was manipulated in a laboratory…. Almost all the corn and soybeans grown in the United States now contain DNA derived from bacteria. The foreign gene makes the soybeans resistant to an herbicide used in weed control, and causes the corn to produce its own insecticide” (Harmon & Pollack 2012).
With everything else on our plate (so to speak)—wars, economic problems, global warming, an epidemic of chronic disease—will we muster the collective will to address this issue proactively, or will we wait and see? Observing the precautionary principle—better safe than sorry—would normally dictate that we not only engage in significantly expanded research, but that we actually wait for the results of that research before we allow the expansion of GE crops across the world. Unfortunately, that position has not been widely accepted by policymakers in the US government, although that may change as there are many NGO groups actively working on the issue (see Resources list below). For additional information about many aspects of this complex and controversial topic, readers can follow the link under Resources to an archived webinar that IFM hosted featuring Jeffrey Smith, Executive Director of the Institute for Responsible Technology.