Maryland Nurse, February 1, 2005


[Rachel's introduction: Two nurses examine the issues surrounding genetically modified foods and conclude that, until more is known, a precautionary approach is called for.]

By Katie Huffling, RN, BSN and Barbara Sattler, PhD, RN, FAAN

Over the past few years there has been growing controversy over genetically modified foods. Unfortunately, it can be difficult to find independent, scientifically rigorous information about this hotly debated topic. As nurses, our patients, families, and friends look to us for information regarding a variety of health matters, including nutrition; yet many of us have not been formally educated about nutrition. By educating ourselves about this important subject, we can become advocates for our communities and ourselves in regards to genetically modified foods.

Genetically modified foods are described in the literature under a variety of other names. These all refer to the same process. They refer to the selection of desired traits from one organism and its genetic placement into another organism. Theoretically, genetically modified foods have the potential to be very beneficial. For example, traits that make plants resistant to harmful insects can be inserted, nutrients that were not previously in that particular plant may be added, or modifications can be made to improve the ability of a plant to grow in regions of the world where the conditions are inhospitable to the growth of traditional, non-modified plant varieties. Genetically modified foods have been increasingly used by farmers and were grown on over 109 million acres in 2001 and over half of the soy grown worldwide has been genetically engineered. So why is there so much controversy surrounding genetically modified foods? In order to understand the differing views one should first know how genetically modified foods are made.

The method of genetically modifying foods is a highly technical process. In order to produce the desired trait, many different genes, from a variety of organisms, need to be inserted. Many genetically modified foods have over 30 added genes. First the gene that produces the desired trait is isolated. This gene is then spliced into bacteria that are known to attach to seeds and transmit genes into them. The bacteria is mixed with the seeds that the scientist would like modified and if all goes as planned the bacteria transmits the gene to the seed. It is not enough that the gene is transmitted but the gene must be inserted in the right place on the seed DNA for the trait to be produced.

Scientists have developed a system to easily determine if the gene is in the correct position. They add a gene that causes resistance to a particular antibiotic. After the genes have been transmitted, they expose the seeds to this antibiotic. If the inserted genes are in the correct place, the antibiotic will not kill the seeds. These resistant seeds are then selected and grown. The plants grown from these seeds will then be tested for the desired trait.


The many names of genetically modified foods:

** Transgenic

** Genetically engineered

** Bioengineered

** Genetically modified organisms


The use of antibiotic resistant traits in genetic modification has been one of the sources of controversy and raises a red flag for nurses. There is concern that these traits could be transferred to the humans and animals that eat these foods, exacerbating an already widespread problem of antibiotic resistance. This could negatively impact the ability of nurses to provide quality care for our patients. Nurses are painfully aware of the limited armament we have to combat infections and recognize the threat that antibiotic resistant organisms could present.

In a study that addresses safety concerns such as changes in nutrients, toxins, and allergens, the National Academy of Sciences (NAS) has recently released guidelines for implementing safety assessments of genetically modified foods (Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects, 2004). Current mandates require companies to assess for "intended and predictable" effects of genetic modification. The NAS is recommending these mandates be changed to a more thorough safety assessment that includes unexpected changes. They also recommend that genetically modified organisms be evaluated after market introduction in order to monitor the real life experience and validate the initial safety assessment. This tracking system would be especially useful in identifying allergens within genetically modified foods and determining the prevalence of allergic reactions to these foods within the general population.

One of the marketing ploys most frequently sited by the companies that create genetically engineered seeds is that these seeds may have the ability to reduce the impact of important global diseases. For example, Vitamin A deficiency is common in developing countries worldwide. This deficiency is the most common cause of childhood blindness and is implicated in the deaths of many malnourished children and adults. Even though supplementation is inexpensive and easy to provide, many developing countries do not have the resources to distribute it. Scientists have developed a type of rice that produces beta-carotene (which the body converts to Vitamin A). The ability to produce beta-carotene was taken from a daffodil gene. This gene makes the rice turn a yellow color and the rice has thus been called "Golden Rice."

On the surface "Golden Rice" sounds like an amazing advancement, but as you delve deeper, some yellow flags emerge. First, beta-carotene must be converted into Vitamin A. It is estimated that only 10% of beta-carotene is actually made into Vitamin A. When using this estimate, a child would have to eat approximately six pounds of cooked Golden Rice each day in order to get the recommended daily allowance of Vitamin A. Also, some fat in the diet is required to adequately absorb beta-carotene. Many malnourished people do not have sufficient fat in their diet, thereby impeding their ability to absorb beta- carotene. Golden Rice is still not available for use by the public so its ability to reduce Vitamin A deficiency remains to be seen.

Another marketing strategy of the genetically modified seed industry is its claim that genetically modified crops will increase worldwide production of food, thereby reducing world hunger. They extend this argument to claim that if larger quantities of food are produced on existing farmland, the world's growing population will be able to be fed without further destruction of rainforests and other environmentally sensitive areas. This supposition does not address the true causes of hunger in most of the world. As stated by the American Dietetic Association, "There is sufficient food to feed everyone...Poverty, gender inequity, ethnocentrism, racism, and lack of political will are all key constraints to solving the problem of world hunger and malnutrition" (Struble & Aomari, 2003). Hunger is not caused by a lack of food being produced, but rather an inability to pay for food and social and political unrest that make it difficult to obtain, distribute and/or grow food. Also, most of the genetically engineered crops being developed are not varieties that can be grown in climates where malnutrition is most prevalent. The varieties being developed are those that will have the ability to make the most profit, such as corn and soybeans, which are key elements in the processed foods that are likely to be consumed in developed countries, like the United States.

Another argument of the industry is that genetically modified plants may reduce the amount of agricultural pesticides used. Pesticides can have a significant, negative health effect on the farmers who use them, the consumers who ingest pesticide residues on the foods they consume, and the whole ecosystem. As genetically modified crops have become more prevalent, a reduction in pesticide use is not always found. In fact, in some areas of the United States, pesticide use has actually increased. This may be due to the difficulty in growing these crops in certain areas of the country. Also, some crops have been engineered to be resistant to herbicides (a type of pesticide). With this resistance, farmers can now spray more herbicides, such as weed killers, without having to worry about the chemicals affecting their crop, thus increasing the amount of pesticides used.

One way that decreased pesticide use may be achieved is by the addition of a gene from the bacteria Bacillus thurengiensis (Bt). This causes plants to produce a substance that is toxic to insects. Organic farmers have used Bt for years as a natural insecticide. Unfortunately, insect pests are very good at becoming resistant to insecticides. The widespread use of genetically modified Bt crops has made many in the organic farming community concerned that one of the few resources they have available to combat insect pests may soon be ineffective. Bt is also used in many communities to control the mosquito population. With the increasing number of mosquito-born illnesses, such as the West Nile virus, it is vital that the effectiveness of this important form of mosquito control be maintained. Finally, there is evidence that Bt enhanced crops may negatively affect monarch butterfly populations (Losey et al, 1999). While there are conflicting studies regarding this outcome, it seems likely that monarch butterflies have the potential to be seriously harmed by Bt containing plants. Are there other vulnerable populations - animal, insect, human -- that could also be affected? The science is not yet developed to answer this question.

Nurses consistently support full disclosure labeling policies on the basis that people have the right to know and make informed decisions about what they eat, drink, and breathe. However, corporations have, to date, successfully lobbied against labeling genetically modified foods. They state that these foods have been deemed safe by the federal government so no additional labeling is required. Still, consumers have consistently asked for labeling of genetically modified foods. As the acclaimed food and nutrition author and professor at New York University Marion Nestle states, "If we are what we eat and we don't know what we are eating, do we know who we are?" There is the potential for allergic reactions and labeling would allow people with known allergies to make informed food choices. Individuals who do not eat meat may object to eating products that have animal genes added. Without labeling they are unable to know if what they are eating goes against their religious or moral beliefs.

The issues regarding genetically modified foods are complex It may be that a cautious approach is the best one. In 2003, the American Nurses Association adopted the Precautionary Principle as its guiding tenet for environmental health. This principle advocates a cautious approach to technologies that have the potential to cause negative environmental or health effects. Though there are many potential benefits from genetically modified foods, the possibility of far- reaching negative outcomes should direct us towards a more thorough study of these foods before their widespread use. Such an approach would place us on a safer, more precautionary path.


Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health, National Research Council. (2004). Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects. The National Academies Press: Washington, D.C.

Losey, J.E., Rayor, L.S., &Carter, M.E. (1999). Transgenic pollen harms monarch larvae. Nature, 399, 214.

Struble, M.B. & Aomari, L.L. (2003). Addressing world hunger, malnutrition and food insecurity. Retrieved September 15, 2004 from American Dietetic Association web site