Our Genetically Modified Diets

January 10th, 2010

How much do we want to know about our food?

There is growing public awareness of the routine hazards of food: insecticide and herbicide residues, and meat and dairy products loaded with hormones and medications —and whatever. But the abundance of junk food at the supermarkets does not suggest serious public resistance yet, and fast food restaurants still seem to be busy.

Americans are also apparently fairly complacent about genetically modified foods GM food (GM, GMF, or GMO for genetically modified organisms), certainly more relaxed than Europeans and many Asians. But our cultural shrug may be due to relative ignorance, not just passive indifference. And because GM products are not just like everything else we're used to, it really is a good idea to know more about them.

It's quite possible that food labels will not be a good source of information. The United States and Canada do not require GM labeling on foods. The claim usually invoked is that GM products are "substantially equal" to non-GM products, and for that reason do not require regulation or labeling. The courts so far have sided with the very powerful GM companies, and the influence of the GM giants into the government and legal system is impressive enough that change in the near future is unlikely.

GM food causes consternation in many other nations because there really are issues. But trying to grapple with the pros and cons of GM products —from modification techniques to seeds to farming and to end products—can require a good bit of technical reading. There is plenty of information on the subject, but it can be hard to locate readable, reliable, objective information.

Some basics

Farmers have bred plants selectively for centuries to develop qualities such as higher yield, better flavor, and resistance to disease or pests. Scientific advancements in the past couple of decades have enhanced this straightforward type of breeding by transferring specific genes between related species: from, for example, a potato species that is relatively immune to a devastating disease to a species that is highly vulnerable. Such techniques have been very successful in improving a number of staple crops, including potatoes and wheat. This type of genetic modification involving related species is uncontroversial.

The type of genetic engineering that is controversial involves transgenic techniques (recombinant DNA, rDNA), in which selected genetic material from one organism is transferred into the genome of an unrelated one. Examples include the transfer of bacterial, plant or animal genes to unrelated plant species. A common "pesticide gene" is Bacillus thuringiensis (Bt) toxin, a common soil bacterium that, inserted into the genome of a soy or corn species, deters certain insects and is supposed to reduce the need for pesticide spraying. Likewise, genetic alterations that increase the tolerance of a crop to one or more herbicides (e.g., Monsanto's Roundup Ready) should, in principle, reduce the need for multiple herbicides. However, there is so far no clear indication that GM crops have reduced the need for sprayed herbicides or pesticides over the long term.

Transgenic mutations would not occur naturally, and because there are numerous unknowns about long-range ecological and health effects, the resulting GM seeds are controversial in many nations. Despite concerns, most large-scale corn, soybean, and cotton crops are now genetically modified to contain herbicides, pesticides, or both. Other major GM crops include sugar cane, sugar beets and alfalfa. Resistance to importing GM products and even to growing GM crops is slowing diminishing in other parts of the world, such as the European Union, Japan and South Korea.

Some issues

Transgenic modification has the potential to improve crops in ways that traditional breeding cannot. There are potential benefits in yield, climate adaptation, disease-resistance, pest-resistance, and nutritional value. If GM crops are successful they can help alleviate the food shortages associated with the combined global population increase and reduction in cultivable land over the next few decades. However, if GM crops introduce too many health, ecological and environmental hazards, we will have to trust that the alternative "green" revolution will be sufficient and will be able to meet the huge coming climate and environmental challenges.

Here is a brief list of the biggest issues:

Crop yield issues. In principle, GM crops are supposed to save farmers money by increasing yield while simultaneously reducing the need for herbicides and pesticides. This may be easier to achieve in the short term, and perhaps eventually even in the long term. However, sustained yield increases have not yet been demonstrated.

Economic issues: Theoretically, with greater yields and reduced pesticides and herbicides, farmers using GM seeds should see greater profits. For large scale, industrial-type farming this may be true, but for smaller farmers the economic benefit may be limited. Many nations impose restrictions and in some cases prohibit GM products. So, if farmers in developing nations grow GM products, they may find it hard to sell them in the EU and other international markets.

Legal issues: Patents are typically awarded for non-biological objects and processes; but with the GM revolution large corporations such as Monsanto hold patents for biological innovations, including GM seeds. These biological patents are likely to have serious implications.

As an example, the courts have supported the right of Monsanto to sue a farmer if the company finds even trace evidence that Monsanto seed has been used without purchase. So, pollen or seed that inevitably strays from a legitimate (contracted) field via wind, insects or birds can get a farmer into a great deal of legal trouble. The recent trend among American farmers to avoid planting "refuge" crops may reflect farmers" anxieties about such lawsuits. Refuge crops lack the GM mutations such as the insecticide Bt. They are planted near GM fields so that pests will not be limited to the Bt plants, and will not build up immunity to the toxin. But stray pollen or seeds from the GM fields can easily contaminate the refuge fields, and the rights of the GM companies are favored over those of the farmers.

GM companies can also force farmers to purchase specific herbicides produced by the company. Further, farmers are not permitted to hold back seeds that could be used in the next planting season. Instead, they must purchase new seeds in the spring. The extensive control of the GM companies over farmers is likely to create substantial legal battles.

Health issues: One great prospect of GM crops is that many nutritional elements can be engineered into their genomes. Rice, for instance, has been developed to include beta carotene and other key nutrients that are scarce in many parts of the world.

But addition of genetic material to one plant from another unrelated plant can cause unexpected problems, such as allergic reactions. In this important sense, GM plants are not "substantially equal" to natural plants, as the seed companies claim. If corn and soybean plants contain proteins from completely different plants such as Brazil nuts, some consumers are at risk and need to know about such genetic material.

Researcher Alan McHughen, author of Pandora's Picnic Basket, explains that the degree to which alien proteins in the DNA of GM plants can cause risks varies with both the type of imported DNA and with the level or nature of the processing. The soy plant does contain foreign genetic material (e.g., Bt toxin). Derivatives of soy plants found in processed foods such as tofu contain "non-functional" DNA. And extracts, such as oil or lecithin from soy beans, contain no DNA. So a potential allergen in a GM crop may be rendered harmless in plant products. This is the kind of information that needs to be made broadly available to the public, and the public needs to know how to verify such information.

Because of the potential health risks of unknown elements in GM foods, the European Union and many non-European nations require GM labeling. These nations are perhaps less impressed with the GM corporations" claim that their products are "substantially equal" to natural products, and therefore do not require labeling.

Ecological and environmental issues: GM plants can be developed that can thrive in quite extreme conditions, including dryness, cold, or poor soil. This engineered adaptability could be a boon to many nations where present crop production is even now completely inadequate to meet the needs of the population, and where the situation will become critical as the climate changes.

The technical benefit of genetic engineering may be offset by ecological costs, some of which have already been documented. When industrial farming was first introduced —well before the GM revolution—the huge productivity obscured the severe environmental damage and the ecological devastation that accompanied this agriculture. We know from that experience that GM crops are not autonomous entities; they are part of their respective ecological systems, and they can damage those systems at multiple levels: soil, water, biodiversity.


The situation regarding GM foods is somewhat reminiscent of the uncertainties of more traditional attempts to eliminate crop pests by importing alien animals, insects or plants that would save the crops. One example is the giant cane toad, introduced to Australia and other Pacific nations as a form of natural pest control in the cane fields. The toad quickly reduced the pests, but with its voracious and non-discriminating appetite it also created a severe imbalance in the biosystem. Many other experiments of this sort have also accidentally created new and sometimes intractable problems.

Because GM plants are also bound to present unanticipated problems, it is important for companies developing the seeds to provide well designed field and medical studies. Clear information should be made available to the public. At this time a lot of the literature on GM crops is quite technical, and it is a challenge to sort out objective information from distortions of both proponents and opponents of GM food. In addition, GM food should be labeled. And finally, the legal implications of biological patents deserve much more scrutiny.

GM crops are probably a permanent part of the global landscape, simply because the problem of feeding the world is going to get very tricky in the next few decades. The United Nations Population Project predicts an uncomfortably crowded planet with about 13 billion people by the year 2050. It is not at all clear that Earth has the capacity to support a population of that size, and certainly not when changes in the climate will probably be rather dramatic. Arable land is limited now, but the limitations will be felt much more as population explosion coincides with expected shrinkage in land that can be cultivated.

GM seeds that are disease and pest resistant, and seeds that contain supplemental nutrients can be made safe for animals, people, and the environment, and economically beneficial to farmers, may become a necessary part of the solution. But equally important are better overall strategies for food production, including reduction of agricultural waste, more efficient use of available land, more local farms and community gardens, improvements in saving water and distributing it, and better ways to distribute food around the globe.

Yvonne Stapp January 10, 2010

Some resources

Alan McHughen. 2000. Pandora's Picnic Basket. The author is a Canadian biotech professional who gives a balanced view of the issues. New York: Oxford University Press.

Bill Lambrecht. 2001. Dinner at the New Gene Café. New York: St. Martin's Press

Peter Pringle. Food, Inc: Mendel to Monsanto—the promises and perils of the biotech harvest. New York: Simon & Schuster, c2003.

Information online:

Organization for Food Safety http://truefoodnow.org/

Union of Concerned Scientists http://www.ucsusa.org/food_and_agriculture/

Organization for Food Safety http://truefoodnow.org/

US Dept Agriculture


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