Health Concerns

There is no evidence that genetically engineered foods are any less safe to eat than conventional foods. Nutritionally they are equivalent to their non-GE counterparts. Several issues frequently come up in discussions about GE products. This page gives an overview of the most common concerns and provides information about how these issues are addressed to maintain food safety.


Antibiotic resistance

Safety of eating foreign DNA


People with food allergies have an unusual immune reaction when they are exposed to specific proteins called allergens. About 2 percent of people across all age groups have a food allergy of some sort. The majority of foods do not cause any allergy in the majority of people. Food-allergic people usually react only to one or a few allergens in one or two specific foods. A major safety concern raised with regard to genetic modification technology is the risk of introducing allergens and toxins into otherwise safe foods. The Food and Drug Administration (FDA) recommends that allergy testing be completed on transgenic foods before they are marketed and all currently used GE crops have undergone testing.

soybeansThe first step in assessment of the allergenicity of a GE crop is looking at the origin of the gene being used. If the gene comes from an organism known for creating allergic reactions, the protein is evaluated using the blood serum of individuals with known sensitivity. If there is no reaction with the blood serum, further testing is completed using human subjects. These methods were used to determine that a Brazil nut gene that had been transferred to soybeans might cause a reaction in some individuals (Nordlee, 1996). Pioneer, the company developing the GE soybean, stopped development of the variety and never marketed the product.

If a new protein is produced, it may be difficult to evaluate its allergenicity. In these cases, the amino acid sequence of the protein is compared to the amino acid sequences of known allergens. Further evaluation methods include looking at the length of the proteins and how quickly they are broken down by the chemicals and heat found in the human digestive tract. If these tests show higher risk for allergenicity, additional testing is be completed before the product is approved for human consumption.

On the positive side, genetic engineering has the potential to reduce allergy risks in our current foods. Non-allergenic varieties can be developed so individuals can consume foods safely. Transgenic technology is being used to remove the allergens from peanuts, one of most serious causes of food allergy.

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Antibiotic resistance

There are concerns that the practice of using antibiotic markers to identify and trace plants that have undergone gene transfer may speed up the development of antibiotic resistant bacteria. The rise of diseases that are resistant to treatment with common antibiotics is a serious medical problem.

Not all attempts at gene transfer are successful and the presence of the desired trait may not be evident early in the development process. Because of this, scientists connect a easily detected gene to the desired gene. If the marker gene is present, the desired gene is also present. One marker gene that has been used gives antibiotic resistance to the plants. After gene transfer has been attempted, the plants are placed into petri dishes that have the antibiotic. The plants that have the antibiotic resistant gene survive and the plants that do not have the gene die. The surviving plants have the desired gene and can be taken to the next stage of development. The crop that is developed will have both genes.(Link to geo-pie information)

The concern is that bacteria will acquire the resistant gene directly from the plants or from undigested DNA within the animal or human digestive tract. The potential risk of transfer from plants to bacteria is substantially less than the risk of normal transfer between bacteria, or between humans and bacteria. Research indicates that gene transfer from plants to bacteria is rare, if it does occur. Nevertheless, to be on the safe side, FDA has advised food developers to avoid using antibiotic genes that are not commonly found in nature and to use other types of markers.

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Safety of eating GE DNA

DNA diagramDNA is found in nearly all of the foods we eat; plants and animals contain DNA in each cell. Our digestive system breaks down DNA before it is absorbed; ingested DNA does not interact with our own DNA.

Bt and the protein it makes have been used as a natural pesticide by organic and conventional farmers for many decades. The Bt protein is specific to certain insects who have receptor cells in their digestive tract. Humans and other mammals do not have those receptors.

While human studies are not practical due to the difficulty of controling for other factors, animal studies have compared growth using GE feed to non-GE feed. Animals fed GE crops do not show any significant differences in growth or health (Preston, 2005; Hyun et al., 2004; Erickson et al., 2003).

Genetically engineered papaya have a gene for the protein coat of the papaya ringspot virus. People eat this gene in its natural form whenever they consume non-GE virus infected papaya.

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