Of the processed foods lining grocery shelves, 60% to 70% include at least one genetically modified (GM) ingredient. What does this mean? Should we be concerned about these products?

In the genetic engineering process, scientists use recombinant DNA technology to create new artificial characteristics in organisms. Sometimes this process is used to make crops resistant to pests or herbicides (DOE 2012; FDA 2011). The resulting organism—which can be a medicine, vaccine, food, food ingredient, feed, or fiber—is considered GM, genetically engineered, or transgenic (DOE 2012).

The United States produces more GM crops than any other country (DOE 2012; ISAAA 2012; WebMD 2003). Corn (maize), soybean, cotton, and canola are the most common (Byrne 2012). In 2009, 88% of the maize, soybeans, and cottonseeds U.S. farmers planted were GM (GMO Compass 2009). In 2011, 16.7 million farmers grew GM crops (ISAAA 2012).

Because most processed foods contain soybean or corn ingredients, grocery stores sell many GM foods (Byrne 2012). What are the implications?

GM advocates maintain these types of crops are beneficial because of their improved taste and quality; reduced maturation time; increased nutrients, yields, and stress tolerance; resistance to disease, pests, and herbicides; and new products and growing techniques (DOE 2012; WebMD 2003). They argue GM foods increase food security for future generations and benefit the environment because they conserve soil, water, and energy and provide environmentally friendly bioherbicides and bioinsecticides (DOE 2012; Tait and Barker 2011; Johnson, Strom, and Grillo 2008).

Opponents of GM foods and crops worry about the health, ethical, and environmental impacts of the process. Two of the main health concerns of GM foods are the possible introduction of allergens and antibiotic resistance (DOE 2012; Johnson, Strom, and Grillo 2008; IOM and NRC 2004; WebMD 2003).

GM foods can introduce new proteins to the human diet, which could theoretically create an allergic response. However, the World Health Organization (WHO 2012) reports no known allergic effects to GM foods currently on the market. Genetic engineering also could reduce a food’s allergenicity or toxin levels (IOM and NRC 2004).

Antibiotic resistance is possible because scientists use resistant marker genes to identify transformed cells during development. Some worry these genes could transfer to a body’s cells after consumption. WHO (2012) encourages the use of technology without antibiotic resistant genes.

Controversies surround the United States’ food labeling policy, which doesn’t require GM foods to be identified; a potential monopoly of the world’s food production; and the ethical dilemma of tampering with nature (DOE 2012). Outcrossing, a process in which GM plants are blended with conventional crops, can be problematic (WHO 2012).

WHO (2012) recommends assessing individual foods and their safety on a case-by-case basis. However, the organization maintains currently available GM foods are unlikely to negatively impact human health. With a plethora of opinions about the safety, benefits, and consequences of GM foods, we must make our own evidence-based decisions about what to eat. Perhaps the best we can do is to stay informed and think carefully about the health impacts of all foods.

Do you have a question for the Health Wise column to answer? Send an e-mail to streker@nsta.org.

Acknowledgment

Thanks to Lawrence J. Cheskin, associate professor of health, behavior, and society and director of the Johns Hopkins Weight Management Center at Johns Hopkins University in Baltimore, Maryland, for reviewing this column.

References

Byrne, P. 2012. Labeling of genetically engineered foods. Colorado State University Extension.

GMO Compass. 2009. Maize, soybean, cotton: 88% genetically modified.

Institute of Medicine (IOM) and National Research Council (NRC). 2004. Safety of genetically engineered foods. Washington, DC: National Academies Press.

International Service for the Acquisition of Agri -Biotech Applications (ISAAA). 2012. Global status of commercialized biotech/GM crops: 2011.

Johnson, S. R., S. Strom, and K. Grillo. 2008. Quantification of the impacts on U.S. agriculture of biotechnology-derived crops planted in 2006. Washington, DC: National Center for Food and Agricultural Policy.

Tait, J., and G. Barker. 2011. Global food security and the governance of modern biotechnologies. EMBO Reports 12: 763–768.

U.S. Department of Energy (DOE). 2012. Genetically modified foods and organisms. Human Genome Project Information.

U.S. Food and Drug Administration (FDA). 2011. Consumer Q&A. Animal & Veterinary.

WebMD. 2003. Are biotech foods safe to eat?

World Health Organization (WHO). 2012. 20 questions on genetically modified foods.