Is Genetically Modified Food Safe? by David A. Weseloh, Ph.D.
Scientists warn that long term tests are needed on a large scale to determine the safety of genetically modified (GM) foods. These tests have not been done to date. Without these tests, how do we know if GM foods are as safe as those produced through traditional breeding?
Here are some of the potential risks that researchers have identified:
- Producing "super weeds"
The biologists' fear that genes designed to give crops an advantage may be passed on to weeds and other wild plants has already proved to be well-founded. Herbicide-tolerant canola has cross-pollinated with a related weed species which produced a herbicide-tolerant descendant. This newly-created resistance gives the weed an edge over competing plants.
- Losing a safe natural pesticide
The soil bacterium Bacillus thuringiensis (Bt) produces a protein that is toxic to insects that are considered to be pests. A gene that is derived from this bacterium is one of the most popular genes added to genetically modified products. It is true that Bt crops have helped farmers to cut back on synthetic insecticides, but biologists warn that overexposure to Bt by bugs can help the insects to evolve resistance. Adding Bt to plants may render it useless as one of the few safe and effective pesticides available to organic farmers, who generally use it in small and judiciously applied quantities.
- Harm to butterflies and other helpful insects
In May 1999 researchers from Cornell University reported that, in laboratory studies, monarch butterfly caterpillars that ate milkweed dusted with pollen from Bt corn developed abnormally or died. This gives rise to the worry that other helpful insects could be harmed by exposure to food-plants contaminated through cross-pollination with genetically modified plants.
If a gene from a peanut or shellfish were added to corn it could have fatal consequences for people with allergies. Researchers showed a few years ago that a Brazil nut gene spliced into soybeans gave rise to allergies in people sensitive to nuts. Even though the FDA requires US companies to report any altered foods that contain known problem proteins, some scientists fear that unknown allergens could slip by.
- Resistance to Antibiotics
When scientists splice a foreign gene into a plant or a microbe, they often link it to another gene called a marker. The marker helps determine if the first gene was successfully taken up. Most markers code for resistance to antibiotics. Some researchers warn that these genes might be passed on to disease-causing microbes in the intestines of people who eat altered food. This would contribute to the growing public health problem of antibiotic resistance.
There is no scientifically valid study that shows that altered foods are toxic. On the other hand, some researchers believe that it is possible that genetic manipulation could enhance natural plant toxins in unexpected ways. If a gene is switched on it could cause a plant to pump out poisons. Paul Billings, a medical geneticist at the Department of Veterans' Affairs in Grand Prairie, Texas, has said "We'd never know until people started dropping."
- Bad Nutrition
A study to be published in the Journal of Medicinal Food found that concentrations of phytoestrogens (compounds thought to protect against heart disease and perhaps cancer) were lower in GM soybeans than in traditional strains. Scientists also say that foreign genes might alter the nutritional value of food in other unpredictable ways.
A simple solution to the problem of knowing whether the food that we eat is GM or not is for the government to require that any food containing any GM ingredient be labeled as such. That way the consumer would have the choice. I would only suggest that approach as an interim solution. This interim solution does not solve several of the possible problems mentioned above but at least it helps and it could be implemented fast.
The ultimate solution is to require that extensive studies be made before GM food is introduced. Europe has rejected GM food in huge numbers. The United States has not. Maybe we should take a lesson from our European neighbors.
© 1999 by David A. Weseloh, Ph.D.
Insert date: 2009-05-16
Last update: 2009-05-16