Because June is corn and cucumber month and because, according to the USDA, 86% of all corn planted in the United States has been genetically engineered in some way, it seems appropriate to review the controversies surrounding the genetically modified varieties of this grain. (Reference 1)
Currently, the world population stands at almost 7 billion people and is expected to reach 9 billion before beginning to decline. Genetically engineered foods grew out of an attempt to eliminate food insecurity and provide reliable sources of food for the earth’s expanding population. There is some concern, however that this new technology carries some risks that have not yet been properly investigated.
How is the corn being modified?
There are two common modifications in corn. The first is designed to make corn plants more resistant to a kind of weed killer that is known by the trade name Roundup. The second is a gene that causes the corn to produce Bacillus thuringiensis (Bt) toxins, which kill pests when they eat the corn.
Benefits of Genetically Modified Corn
Virginia Gewin, (Ref 2) argued that genetically modified corn that produces its own Bt reduces the need for external applications of pesticides. This helps beneficial insects that would otherwise die due to the spraying of poisons to combat, for example, the corn borer.
The use of the herbicide Roundup has been the subject of criticism because the company creating the genetically modified corn, Monsanto, has in effect created a monopoly for Roundup. However, even critics of genetically modified foods acknowledge that the use of this weed killer has led to reduced tilling of the soil, an agricultural practice that has reduced soil erosion.
Another possible advantage is that genetically modified crops may have lower levels of fungal infections. When corn crops contain Bt, insect pests eat the crops and die, leaving fewer holes in the plants in which the fungi can grow. Since many fungi produce toxins that are thought to be carcinogenic, this technology may reduce cancer.
Biologists have discovered that genes can be transferred between organisms in ways that don’t involve reproduction. Theoretically, this means that DNA from genetically modified plants could somehow become part of naturally occurring bacteria and create a life form to which the earth, and we, are not adapted.
Another risk is that insects eating the genetically modified corn could become resistant over time. In fact, this happened in Puerto Rico, where farmers once planted genetically modified corn almost exclusively. Insects called fall armyworms used to eat Bt corn and die, but now they don’t because they have become tolerant to it.
Because genetically modified foods are often pesticide-resistant, they often contain high levels of these substances. An October 2010 study published in the “Journal of Occupational Medicine and Toxicology” (Ref 3) found that human liver cell lines in test tubes died rapidly when exposed to 4 herbicides often sprayed on these crops and that even low levels of these substances caused profound alterations in the activities of liver enzymes.
Additionally, research done on genetically modified rice has turned up some disturbing results. A study published in the January 2011 issue of the “Journal of Food Science” found that rats fed genetically modified rice for 90 days had lower levels of the “good” bacteria like those in the Lactobacillus family, and higher levels of E. coli, which can cause serious illness and even death. Because colon health depends on the bacteria it harbors, this result implies that genetically modified foods can indeed damage the health of the animal eating them.(Ref 4)
Scientific Integrity of Genetically Modified Food Studies
An October 2010 article in the International Journal of Biological Science extended the controversy created by an earlier article claiming that GMO corn produced signs of liver and kidney toxicity in rats. The authors of the study make the following points:
- It is impossible to conduct epidemiological studies of the effects of genetically modified foods because GMO food does not have to be labeled as such in either the U.S. or Latin America, where most of this food is eaten. It is therefore impossible to determine with any accuracy who ate this food and how much.
- When they obtained the records of the scientific studies conducted by the companies producing the genetically modified foods—they had to get a court order—they found significant differences between rats fed GMO food and those fed traditional diets. Most of these differences involved the livers and kidneys of the experimental animals.
- The scientific studies were inadequate in the following ways:
- Too few experimental animals were used to yield reliable results. In one study, only 10 animals were used.
- In another study, only 40 rats were fed GMO food while 320 rats were fed a “normal” diet. This huge imbalance between control animals and test subjects could have altered the results of statistical tests used to assess risks.
- Only rats were used for the tests.
- The longest feeding studies lasted for 90 days, a design that made it impossible to assess the long-term effects of these foods.
- There are no data on reproductive or multi-generational effects of such a diet.
- The statistical analyses used by the various biotechnology companies was open to debate, to put it mildly. If better statistical methods had been used, the results of the feeding studies might have been different.
Clearly, the use of genetically modified corn has both great potential benefits, especially for undernourished people in the third world. Yet, just as clearly, unanswered questions remain about its effects, especially in the long term and especially on children. If you are inclined to be cautious about genetically modified foods, your best choice is to buy organic corn and soybeans. Since canola oil is often made from genetically modified seeds, you may also want to avoid using it. However, you need to be aware of the fact that corn is a “promiscuous pollinator” and that even organic corn is likely to contain some modified genes.
2. “PLoS Biology”; Genetically Modified Corn— Environmental Benefits and Risks; Virginia Gewin; October 13, 2003; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC212689/?tool=pubmed
5. “International Journal of Biological Science”; Debate on GMOs Health Risks after Statistical Findings in Regulatory Tests; Joel Spiroux de Vendomois, et al.;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC212689/?tool=pubmed