Issues with the New GM Foods — What Are They?

Peggy G. Lemaux

American Baker’s Association Technical Liasion Committee Meeting

March 20, 2001

Why Did Unrest Start in Europe?

Despite biotechnology’s potential for providing options to the farmer in the near- and long-term and to consumers in the long-term, the products and who is developing them are making a portion of the public nervous. Biotechnology is certainly not the first technology over which intense public discussion has arisen. There was intense discussion over pasteurization, the introduction of margerine and more recently over food irradiation. Such debate can be constructive and can help shape responsible deployment and use of the technology. But, it can also divert critical thinking away from the development of useful pathways for utilizing the technology.

The issues surrounding the use of biotechnology to modify foods have become increasingly contentious in the past two years in the U.S., following some rather strong outcries by consumers in Europe. Why the concerns in Europe? The reasons for these outcries were in some ways understandable. Food safety scares occurred in the E.U. over mad cow disease and dioxin-contaminated foods. These incidents eroded consumer confidence in the ability of their regulatory agencies to insure food safety. The decisions made by government officials during these controversies were perceived by many to be based on political expediency rather than on public safety concerns. This undermined consumer confidence in the government’s ability to assure food safety with foods derived from biotechnology.

Other factors fueling the controversy, some of which also pertain to the situation in the U.S., included the following.

How do U.S. Consumers Feel About the New GM Foods?

Over the years many polls have been conducted relating to the acceptance of the new GM foods. In general, the results of these polls consistently show that if the consumer sees a benefit in the product, they will buy it. Results from an International Food Information Council poll conducted frequently over the last five years show that, if individuals were asked if they would buy a food product made with biotechnology that was disease-resistant and resulted in less pesticides being used, consistently 65-70% of people said yes.

That the consumer seeing a benefit is important to people’s answers was shown dramatically in a Roper Starch poll taken in August of 1999. At that time only 37% of consumers were aware of potential benefits of the new GM foods. However, their enthusiasm for a particular new GM food increased as they learned how these foods might benefit them or the environment. Acceptance ranged from 57% for foods that taste better as a result of biotechnological improvements to 73% if the new GM foods were produced with fewer pesticides.

Consumers’ lack of trust in regulatory agencies in Europe has been crucial; it affects the acceptance of any technology and has certainly played a role in the acceptance of GM foods in Europe. In contrast to that situation, results of many polls in the U.S. indicate that respondents have confidence in the U.S. Food and Drug Administration, the federal regulatory arms responsible for food safety and one of the agencies that monitors the new GM foods. In a Gallup poll conducted in the summer of 1999, 75% of Americans had either a great deal or a fair amount of confidence in the federal government to ensure food safety; only 5% had no confidence at all. Although I haven’t seen a similar poll in the E.U., I would venture to guess the results would be very different.

What Food Safety Issues Have Arisen Related to the New Technologies?

Many issues have been raised regarding GM foods. What is important to one person or group of people may be of no concern to others. That is because the perception of "risk" or acceptable risk depends on the individual and their value systems. Risk per se can be determined quantitatively, while safety is acceptable risk, something decided upon by an individual, based on his/her own interpretation of the scientific measurement. For example, air travel does involve some quantifiable risk, but some individuals consider it safe. In other words, the benefits of air travel outweigh its potential risks for those people, especially if they have to get from San Francisco to New York City in one day!

Brazil Nut Protein in Soybean

So, what are some of the issues related to GMO’s and food safety? One concern is the possibility for creating new allergens. An often-raised example of the potential for this risk is the work initiated in the early 1990’s by Pioneer Hi-Bred to improve the protein quality of soybean. That approach involved using a naturally occurring protein from Brazil nut, which compensated for the amino acid imbalance in the soy nut. During the course of the development of this product, however, the scientists at Pioneer and the University of Wisconsin conducted immunological studies on human sera and discovered that some individuals had allergies to this protein. Work on the project was quickly terminated.

So this example shows that it is possible to introduce an allergen into a food, but it also shows that the procedures used by companies in the development process are likely to lead to the discovery of problems before a food is marketed. But is this a situation that would only occur with the new GM foods? No. For example, the kiwi fruit, although not a significant source of food allergies when it was introduced into the U.S. in 1962, today causes food allergies in about 2% of the population. For some of these individuals, it can be life-threatening because of cross-reactivity to latex.

Taco Bell Tacos

A more recent example relating to possible allergens in GM foods is the Taco Bell situation. At the end of September 2000, it was discovered that Taco Bell tacos contained a variety of GM corn that had not been approved for human consumption, only animal consumption. This happened because this particular variety of corn contained a Bt gene modified to slow its digestion in the insect gut, making it a more effective pesticide. The change also made the protein less digestible in the human gut.

This triggered the EPA’s decision not to approve it for human consumption, since slow digestibility is one of the criteria agencies use to identify potential allergens. Although the protein failed some of the other tests that earmark potential allergens, further testing was required because of the slower digestion and greater heat stability. What are the implications of this? Most allergens are slowly digested in the human body, so the allergens can be presented to the immune system in the small intestine. Although there are exceptions and there are many proteins that are slowly digested that are not allergens, finding this characteristics was enough for the EPA to decide not to approve the variety for human consumption; more testing was needed to show that it either was or was not an allergen. The agency approved it for animal use since allergenicity is not an issue in livestock.

When the corn was found in human food, the regulatory agencies issued a recall on the foods, an act that they needed to do. Where the system went wrong was in the company’s marketing the seed for a large acreage crop with that type of restriction. Crops like corn, soy, and wheat are moved about the country in bulk and it is problematic to assure complete segregation. But this incident did point out some shortcomings of the system and it provides an opportunity for changes to be made in a situation where human health was not compromised. This incident pointed out a shortcoming of the system and provided an opportunity to make changes before it occurs in a situation where human health is compromised.

Even if the B.t. protein in this corn variety were determined to be an allergen, human exposure to the protein is so low as to make sensitization to the allergen unlikely. Most allergenic proteins must be present at levels of 1-40% in a food; the B.t. protein in this case was present only at 0.3% in the kernels and at a much lower percentage in taco shells since this variety represented only 0.3% of U.S. corn.

It should be pointed out, however, that it is possible to use the new tools of biotechnology to remove allergens. This has already been done in rice, which is a major allergen in Southeast Asia, and work is currently underway in my and Bob Buchanan’s lab to create a hypoallergenic wheat.

Changes in Nutritive Content

Another potential issue is the reduction of the nutritive content in the new GM foods. The example that has raised the most concern relates to the soybean in which comparisons of levels of certain secondary compounds in the GM varieties were at odds with the determination of the same compounds in non-GM varieties. The difficulty with such comparisons is that if one were to take a particular lot of non-GM soybean from Georgia and compare it for the same compounds with another lot of non-GM soybean from Iowa, or two soybean lots grown under different environmental conditions.

Biological systems are not like computers in which the outcome of a particular maneuver is the same regardless of what day you do the procedure. Companies marketing the new GM crops conduct extensive testing to show that the nutritive content of the GM variety is comparable to that of the conventional parental variety. These tests include comparisons of gross protein, CHO and fat content as well as more detailed studies of specific amino acid and vitamin and mineral content. In the case of the GM soybean they also looked at comparisons of antinutrients, like lectins and trypsin inhibitors; they were found to be the same. The studies on food safety also include animal studies to look at levels of toxins and allergenicity, in certain cases.

Genetic engineering is being used to improve the nutritive value of foods. In a recent example, a protein from Amaranthus was used to improve the protein quality and quantity in potato, a very poor source of protein.


There are other issues that have been raised that I don’t have time to discuss, like antibiotic resistance and horizontal gene transfer. But let me discuss for a moment issues relating to labeling. In essence the labeling issue is for most consumers a "right to know" issue, not a food safety issue. They just want to know what they are eating, just as members of the Jewish population want assurances that their food is kosher. That it is not a food safety issue is born out by the fact that many wanting labeling want labeling of meat, if the animal is fed GM grain. In no way can I imagine that this is a food safety issue.

While mandatory labeling is required in Europe, it is not likely that it will be federally mandated in the U.S. Regarding labeling, the question for me is not so much whether people should have this choice, but who will pay to have that information on the label? Should all citizens, regardless of their need or desire to know whether the food is GM be required to pay for this information?

This is a societal issue, not a scientific one, and only time will tell what will happen. But, if testing is done, it will be a costly issue especially for those foods labeled GM-free. This is because it will require tracking of foods, not so much a problem with individual fruits or vegetables but it will be for processed foods, and molecular testing for the presence and perhaps the quantity of the introduced genes and their protein products.

Why do farmers use the crops?

But why do farmers want to use crops such as B.t. corn or cotton? According to data collected from 1996 and 1997, farmers received the biggest share of financial gain from planting B.t. cotton. The total increase in world supplies of cotton in 1997 was worth $190.1 million; U.S. farmers’ share of this total surplus was 42%. The company that developed the variety, Monsanto, received 35%, and Delta and Pine Land, which provided seeds to farmers, received 9%. The US consumer received the smallest part of this surplus, 7%. Besides the economic benefit, there is also an environmental benefit to B.t. cotton. Due to its adoption, there was a reduction of 2.2 million pounds of insecticides used on cotton in 1997, when compared to 1992 pesticide-use figures.

The benefits to farmers of B.t. corn are not as clear. B.t. corn is resistant to the European corn borer (ECB), a pest which burrows into the stem of the corn interfering with nutrient and water transport. Because it is difficult to anticipate the degree of insect pressure in a given year, many farmers must accept yield losses in years of heavy infestation. This can lead to losses of up to 7% of the total U.S. harvest, resulting in >$1 billion in damage and control costs per year.

The advantage of a plant producing its own insecticide has led, in high infestation years, to reduced damage by insects and higher yields. For example, in 1997, a high infestation year, the yield premium of B.t. corn was ~ 12 bushels/acre. A secondary benefit is that B.t. ears were less infected with fungus and the levels of fungal toxins, like mycotoxin, were lower.

But, B.t. seeds are more expensive than conventional ones, so in years when insect pressure is low, yield losses to insect damage are low and the cost of seed is not recovered. Estimates are that in 3 out of 13 years insect pressure will not be sufficient for farmers to make profits with GM seeds; 1998 and 1999 are examples of such years; 1997 was not and farmers made significant money.