Genetically engineered foods, introduced in the 1990s, are now prevalent in our food supply. The Institute for Responsible Technology estimates that 80 to 90 percent of the processed food products in grocery stores today contain genetically modified foods or ingredients derived from them. 

What are GMOs?

Genetically modified organisms (GMOs) are foods that are produced using various modern genetic engineering techniques that are distinguished from traditional cross-breeding (wherein plants or animals are selected for breeding based on desirable characteristics). Genetic engineering allows the selection of specific traits by moving a gene or a set of genes from one organism to another. Unlike in traditional cross-breeding, genetic engineering allows foreign genes to be moved from one species to another. Transgenic salmon, for example, was genetically altered with a growth hormone from another, larger ocean fish so that it reaches full size in half the usual time, cutting costs and growing profits of salmon farmers. 

Why are GMOs used?

In agriculture, GMOs are most commonly used to genetically modify seeds for two basic reasons. The first is to develop a crop’s resistance to an herbicide, such as glyphosate (trade name Roundup), so that farmers can spray for weeds, plant food crops, and then spray for weeds again without harming the crops. The other reason is to engineer a pesticide protein, such as Bacillus thurogiensis (commonly called Bt), into the seed so that the pesticide is present in every cell of the plant to kill common crop pests, such as the European corn borer. 

This technology benefits farmers, as they no longer have to use a variety of pesticides for different weed and pest types, and they have more flexibility with regard to the timing of pesticide application. Weeds no longer need to be pulled by hand. In addition, the technology allows several large seed manufacturers, such as Monsanto, Bayer, and Dupont, to sell patented proprietary seeds at a premium. This is particularly advantageous for Monsanto, as farmers will buy not only the company’s proprietary seeds but also its Roundup herbicide. 

Due to widespread farmer acceptance, GMO technology has been used in most of our major food crops. Here's a list of some U.S. crops and the percentage of GMOs they contain:

• Soy (93 percent)
• Cotton (93 percent)
• Canola (90 percent)
• Corn (87 percent)
• Sugar beets (95 percent)
• Hawaiian papaya (more than 50 percent)

Should we be concerned?

When approval of genetically modified foods was first considered, the foods were deemed to be “substantially equivalent” to their non-engineered counterparts by the industry and the U.S. Food and Drug Administration and therefore were subjected to limited animal feeding studies (lasting 90 days or less) before being approved for market. These tests have been conducted primarily by the companies who market the seeds; the foods have not been subjected to rigorous independent testing. In addition, assumptions were made about the technology. The pesticide protein from Bt crops was thought not to survive digestion, for example, but a 2011 article in the journal Reproductive Toxicology detected the protein in 93 percent of maternal and 80 percent of fetal blood samples. Though the actual significance of this research is unclear, it raises troubling questions about some of our basic assumptions about these foods. 

Furthermore, this technology promised reduced use of pesticides, and strategies were applied to prevent weed resistance. However, a 2009 study by the Organic Center showed that the use of pesticides has actually increased, and some weeds have developed a resistance to Roundup, prompting a return to more toxic pesticides. In addition, consumer benefits such as increased nutrition and reduced allergens have been promised for several crops, but so far, the use of GMOs primarily benefits seed and pesticide suppliers and farmers. 

Proponents of the technology say the benefits outweigh the risks; others believe that the U.S. should take a more precautionary approach, as have officials in Europe, Japan and elsewhere, where fewer seed crops are approved and/or labeling of foods containing GMOs is required.

How to avoid GMOs?

Most polls show that consumers, whether they support the use of GMOs or not, overwhelming support the labeling of genetically modified foods. However, due to the policy of substantial equivalence, the FDA does not require such labeling. If products are similar to their non-engineered counterparts, there is no need to label them. 

To avoid consuming GMOs, look for certified organic products with the U.S. Department of Agriculture (USDA) seal. GMOs are not allowed in organic foods. You can also look for products that carry the Non-GMO Project seal, which indicates that the nonprofit group, the Non-GMO Project, has verified them as non-GMO.

For foods without a seal, avoid products derived from the primary GMO-containing crops: soy, cotton, canola, and corn. A comprehensive list of ingredients made from GMOs is available by clicking here.