Genetically Engineered Foods Update: More Common Than You Think

Sharon Palmer, R.D. & Chris McCullum-Gomez, Ph.D., R.D.

Genetically engineered (GE) foods -- also referred to as biotechnology or genetically modified -- have elicited strong reactions since they were first introduced almost 15 years ago. Depending on whom you listen to, genetic engineering is either "doomsday tech" or "biotechnology for the future." The public opinion on GE foods is split.

According to a Pew Initiative on Food and Biotechnology (one of many initiatives under the umbrella of the Pew Charitable Trusts) survey, 46 percent of respondents don't know what to think about the safety of GE foods; for those with an opinion, about half believe they're basically safe and about half believe they're unsafe.

GE FOODS UNDER THE MICROSCOPE

Most people don't understand the complicated science of biotechnology. GE foods are produced when scientists remove a copy of a gene from one organism and transfer that gene to a different organism. The new gene, which usually produces a new protein in the cell that confers a beneficial trait, then becomes integrated into every cell of the new organism.

Genetically engineered soybeans, corn, canola and cotton contain genes that protect the crop from particular herbicides (weed killers), so that the herbicides can be applied to the crop without harming it. And some varieties of squash and papaya have been engineered with plant virus genes that make them resistant to those particular plant viruses.

How do you know when you're eating GE foods? Under current regulations, the U.S. Food and Drug Administration does not require labeling of GE food products. Only if you buy organic do you know for sure, because organic is the only federally regulated food label that prohibits the use of GE foods. Otherwise, GE food ingredients are ubiquitous: about 95 percent of U.S. soybeans and 60 percent of U.S. corn are GE.

An estimated 70 to 75 percent of all processed foods in U.S. grocery stores probably contain ingredients from GE plants--the majority from corn and soybeans, which are widely used as food ingredients, such as in high fructose corn syrup and soybean oil. In most cases, the GE foods you eat as processed ingredients are in small amounts. For example, by the time GE corn has been processed into high fructose corn syrup, there are virtually no genes left in the food.

HOW SAFE ARE GE FOODS?

Some organizations believe biotechnology is beneficial and safe. The American Dietetic Association released a position paper on food biotechnology in 2006, stating that it can enhance the quality, safety, nutritional value and variety of food available for human consumption, and increase the efficiency of food production, food processing, food distribution, and environmental and waste management.

Other organizations are a bit more cautious. According to the Washington, D.C.-based public advocacy group, Center for Science in the Public Interest (CSPI), GE food companies have found no evidence of harm related to GE crops, but no monitoring of GE food intake is conducted either, and thus adverse affects could go unnoticed.

David Andow, Ph.D., biotechnology expert and Distinguished McKnight University Professor at the University of Minnesota, explains that the U.S. government doesn't require a review of safety on GE foods to humans; thus, it is difficult to determine whether GE foods are safe or not.

The U.S. Food and Drug Administration does not subject GE foods to any specific regulation simply because of their GE status. They have no legal authority to approve GE crops before they are commercialized, thus they regulate GE food and crops through a voluntary notification process by the GE developer, rather than by a mandatory pre-market approval process. CSPI urges that the FDA be mandated to formally approve any GE crop as safe for human and animal consumption before it's turned into food.

"The U.S. public has been eating these foods for quite awhile and we haven't seen any major health problems standing out. We can be assured that something unusual or large increases in health problems are not happening, but if GM foods were to cause only a one percent rise in any disease, we wouldn't be able to detect it, even though that could be a lot of people. In a sense, what we know is reassuring, but what we don't know is not reassuring," adds Andow.

New evidence raises potential safety concerns. New red flags on GE food safety have been raised due to a review published in February 2009 in Critical Reviews in Food Science and Nutrition. Researchers reviewed the scientific literature on human health risks of GE foods and raised the following potential concerns:

--Genes. It might cause the genes to be silenced or changed in their level of expression, or existing genes might be "turned on" that were not previously expressed. This might lead to the disruption of metabolism in unpredictable ways, and to the development of new toxic compounds or an increase in the already existing ones.

--Anti-nutrients. It might cause an increase in existing levels of anti-nutrients (compounds that interfere with absorption of nutrients.)

--Viral DNA. While no proof exists that the use of viral DNA in GE plants can be transferred and cause health concerns, scientists emphasize the need for further studies.

--Antibiotic resistant genes. There is concern that antibiotic resistant genes used as markers in GE crops might be transferred to bacteria in the gastrointestinal tract, thus reducing the effectiveness of antibiotic therapy.

--Absorbing genes. Genes introduced into the plant might be taken up by the gut and incorporated into the genetic make-up of consumers.

--Allergic responses. The introduction of new proteins into foods might produce allergic responses.

The safety of GE feed for animals raised additional concerns for the study reviewers. The animal safety risks observed include:

Effects on body growth

Changes in the blood, pancreas, liver and kidney

Erosion and necrosis of the gastrointestinal tract

Alterations in reproduction, development and mortality

Even when GE food is intended for animals, it is possible for humans to inadvertently eat it, as happened in the much-publicized event when the StarLink GM crop, which was intended for animal feed, was found in taco shells in 2000. The researchers stressed that since GE foods are going to be eaten by every human, whether deliberately or inadvertently, they should be tested even more thoroughly than drugs. They called for longer duration toxicity studies of GE foods using a larger number of animals.

"It has come to light in the past year that there have been several significant effects of some GE foods in short-term animal trials," says Andow. However, he stresses that there's not enough evidence to draw the conclusion that there are definite risks related to GE foods. The science only indicates that there are possible risks that require further investigation.

Biotechnology and environmental risks. From the get-go, scientists have suggested the potential for environmental risks associated with biotechnology. Andow reports that these risks include the development of weeds that can resist herbicides, challenges of maintaining the natural genetic diversity of crops, stimulation of other pest problems, and the reduction of beneficial species like honeybees.

According to the Ecological Society of America, a group of 8,000 ecological scientists, there is concern that the release of GE organisms into the environment could create new or more vigorous pests, harm non-target species like beneficial insects, birds and wildlife; damage beneficial soil organisms, generate new plant viruses, and spread genes to non-crop species to produce virulent weed species.

As new scientific information raises concerns over GE safety in both human health and environmental health, Andow stresses that the presence of "possible" risks doesn't mean that these risks occur. Instead, it's a call for further research to understand these potential risks.

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