Toxic Reactions

Unlike allergic reactions, all humans are susceptible to toxic, poisonous substances. If a GM food contains toxic components greater than the natural range of its traditional twin, the GM food is unacceptable. To date, GM foods have proved to be no different from their conventional counterparts with respect to toxicity. In fact, in some instances there is more confidence in the safety of GM foods because naturally occurring toxins that are overlooked or brushed aside in conventional foods are measured in GM food premarket safety assessments.

Tomatine, a naturally occurring toxin in tomatoes, was largely ignored until a GM tomato was developed. The FDA considered it important to measure the potential changes in tomatine. Analyzing both the traditional and the GM tomato, they found no differences in the levels of tomatine. GM tomatoes have yet to be approved for human use.

Court Heiarchy
Figure 4.6. Regimen of tests used for safety assessments of GM foods. [Figure adapted from GAO-02-566, Genetically Modified Foods (GAO analysis of FDA documents).]

Antinutrients

Antinutrients are naturally occurring compounds that interfere with absorption of essential nutrients. A GM canola oil was submitted to the FDA for approval. The genetic modification had altered its fatty acid composition. To determine whether the modification had produced an unintended antinutrient effect, rendering the oil unsafe, its antinutrient composition was compared to that of traditional canola oil. Here again, the levels were similarly low.

To ensure that GM foods do not have decreased nutritional levels, nutrient composition or the nutrition profile of GM foods is determined. Tests measure amino acid level, oils, fatty acids, and vitamin content. Figure 4.6, displays the battery of tests that a GM food must traverse before obtaining FDA approval. The tests provide evidence at key decision points as to what additional tests must be performed. Tests on the source of the newly expressed protein, amino acid sequence similarity, and digestibility are typical for both allergenicity and toxicity assessments, while serum screening is used only for allergenicity assessment.

Figure 4.6 represents typical tests undertaken by a company in the safety assessment of a GM food. The figure is not meant to be a comprehensive illustration that is used in every safety assessment. Antinutrients are tested as a subset of toxicity. In addition, they are often measured with a simple nutrition/composition profile. If a company transfers genetic material from an allergenic source and undertakes serum screening tests, it does not have to go though serum screening again if in vitro digestibility tests uncover a similarity to an allergen. At such a point, it would be assessed by amino acid sequence similarity and in vitro digestibility tests for potential toxicity.

If a food company reaches the "stop (or consult)" decision point, there are clearly allergenicity or toxicity issues. This means that further tests will be discontinued and the food item removed from development. If a company transfers a gene from a nonallergen source, the amino acid sequence must also be determined. If the sequence is found to be similar to a known allergen, additional specific allergenicity testing is required, as are digestibility tests to ascertain whether the GM protein was broken down in simulated digestive fluids. Should there be concerns about the rate with which the GM protein was split, serum screening tests would be called for to support or refute the results of the digestibility tests. If the serum screening results show that the GM protein does not react with antibodies in serum, it can be concluded that the GM protein does not raise allergenicity concerns.

Checking the source of the transferred genetic material is the safety assessment starting point. Two principles undergird allergenicity testing: (1) avoid transfer of known allergenic proteins, and (2) assume that all genes transferred from allergenic sources create new allergens until proven otherwise. With both the FDA and the food industry agreeing on these principles, the probability of introducing a new allergen, enhancing a toxin or antinutrient, is exceedingly small.

The second step requires the comparison of amino acid sequences of transferred proteins and those of known allergens, toxins, or antinutrients. If an amino acid sequence in a GM food is the same as or similar to one in an allergen or toxin, there ' s a reasonable likelihood that the GM food poses a risk. Sequence similarity tests can be fruitful in eliminating proteins of concern.

In vitro digestibility tests are a primary component of GM food safety tests. Rapid breakdown of a GM protein in simulated human gastric fluids indicate a high likelihood that the protein is neither allergic nor toxic. Safe dietary proteins are rapidly digested; allergens and toxins are not.

If a gene raises allergenicity issues, serum screening, used only for aller-genicity assessment, is required. Serum screening evaluates the reactivity of antibodies in the blood of individuals with known allergies to the plant that was the source of the gene. Serum screenings are valuable because they can expose allergens whose presence was only surmised in amino acid sequence similarity tests. Finally, nutritional and compositional profiles of GM foods are created to assess whether unexpected changes in nutrients, vitamins, proteins, fibers, starches, sugars, minerals, or fats have occurred as a consequence of genetic modification. While changes in these substances do not pose a health risk, obtaining a nutritional profile ensures that a GM food is comparable to its conventional peer.

As for long- t erm monitoring of potential health risks, the U.S. General Accountability Office, in its report on genetically modified foods, states that, "such monitoring is unnecessary because there is no scientific evidence, or even a hypothesis, suggesting that long-term harm such as increased cancer rates results from these foods" [59].

These many and varied tests notwithstanding, the question persists, are GM foods safe? That question appears to have been reasonably put to rest. For example, Professor Robert Paarlberg of Wellesley College reminds us that "Even in Europe, the epicenter of skepticism about genetic modification, the Research Directorate General of the European Union in 2001 released a summary of 81 separate scientific studies conducted over a 15-year period (all financed by the EU rather than private industry) finding no scientific evidence of added harm to humans or to the environment from any approved GM crops or food" [58]. Between 2002 and 2004, a clutch of European scientific organizations lined up in favor of GM foods. Professor Paarlberg informs us that "the French Academies of Sciences and Medicine drew a similar conclusion, as did the French Food Safety Agency." In May 2003, the Royal Society in London and the British Medical Association joined this consensus, followed by the Union of German Academies of Science and Humanities. Then in May 2004, the Food and Agriculture Organization (FAO) of the United Nations issued a 106-page report summarizing the evidence "that the environmental effect of the GM crops approved so far have been similar to those of conventional agricultural crops." Paarlberg goes on to say that, "as for food safety, the FAO concluded in 2004 that, 'lo date no verifiable untoward toxic or nutritionally deleterious effects resulting from the consumption of foods derived from genetically modified foods have been discovered anywhere in the world ' " [ 60 ].

The U.S. National Academy of Sciences and The Institute of Medicine added their voices to the growing chorus in 2004. In their report, Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects, they state unequivocally that "The most important message from this report is that it' s the product that matters, not the system you are using to produce it" [61]. They also noted that special food safety regulations are not needed just because foods are genetically engineered. Genetically modified foods have passed every test demanded of them. There is nothing Franken-steinish or malevolent about them.

What more surely can be provided? Not a great deal. Field trials and both human and animal testing will continue, and experience as with traditional food will provide continuing assurance—or it will not.

Are human health and food safety the real issues? I think not. For the Greens of Europe and the United States, the issue is political. Health and safety are smoke and mirrors, a way of keeping the public nervous, and the issue in the media. The Greens continue hoping to resolve their political concern, which is about—as they see it—nothing less than control of the world food supply. If plants are patentable, farmers could no longer save seeds from season to season. They would be forced to buy new seeds each year at increasing costs, if seeds were available to them. Farmers could be told when and what to plant. They would be captives of the seed owners. Furthermore, central Mexico has long been the world center of maize ' s genetic diversity. If wild Mexican maize becomes contaminated with modified genes and farmers in other countries who freely trade varieties, obtain modified maize from Mexico, will they be forced to pay royalties to the corporation that holds the patent on that modified gene, now in the maize? This patenting of genes could force farmers to lose control of their farms. In addition, many advances in gene modification were made at public universities with public funds and then given over to large corporations. For opponents of patents on DNA, the issue is, Who will control the food supply?—which is worth thinking about [62].

So, again, the biotech brouhaha is a political contretemps, not a scientific or safety issue. For the public, this cloak of invisibility would be better removed and the real case made on its merits—which appear to be considerable. Little is to be gained by frightening the public with fraudulent horror stories about the food supply. In fact, just what does the public know about genetically modified foods?

For several years the Rutgers University Food Policy Institute sought to take the pulse, as it were, of the American public's knowledge of GM foods. Sample surveys were conducted in 2001, 2003, and 2004. Here is a summary of their findings [ 63 ]:

Most Americans have heard or read little about it, are not aware of its prevalence in their lives, and are confused as to which types of GM products are available. Respondents struggled with the factual questions related to GM food and the science behind it; could not recall news stories related to the topic, and were not very knowledgeable about laws regarding the labeling and testing of GM food. Americans are also unsure of their opinions about GM food and split in their assessments of the technology when forced to take a position.

Not a terribly encouraging scenario. Furthermore, we learn that the responses changed little between 2003 and 2004, although there has been a small but significant increase in awareness since 2001. The numbers are dismaying: 44% of respondents had heard or read nothing about GM foods, while another 42% had read something, which suggests that 86% are poorly informed. This relates to the fact that 79% believed that GM tomatoes were available for purchase in supermarkets. Of course, the first and only GM tomatoes, the Flarsavr, were taken off the market in 1997. Yet 8 years later the belief remains. More disturbing was the fact that 32% believed that, or were uncertain as to whether, by eating a GM fruit, a person ' s genes could also become modified. And 40% either believed or were unsure as to whether tomatoes modified by a catfish gene would taste fishy. No, not at all encouraging. If the Rutgers survey is representative of the nation, it is readily understandable why environmentalist groups have such success purveying their brand of nonsense.

For too long the public has relied on others to make weighty decisions that affect them. It is time for the people to assume that responsibility and arm themselves with the knowledge vital for decisionmaking.

What kind of reception will the public accord cultured meat? Tissue engineering to produce edible meat may or may not be a form of genetic modification, but it is bioengineering, and is currently being developed at several universities. A collaborative team of researchers from the University of Maryland, South Dakota State, The Medical University of South Carolina, and Wageningen University of The Netherlands are pursuing an unimaginably new means of food production; mass-producing meat. These researchers from departments of cell biology and agriculture are using stem cells, undifferenti-ated cells, from animals or tissue specimens, and allowing them to grow in nutrient solutions in a rotating bioreactor, where they develop into muscle cells that form skeletal muscle tissue, myofibers. This tissue is then harvested and processed into a variety of meat products. If this method of producing sausages, meat patties, and beef and pork loins is perfected, waste would vanish, as would foodborne disease. World hunger would decrease markedly, and there would no longer be a need to slaughter cattle. "Remarkable" is an understatement. But it will require 10-15 years of further development to move from the laboratory to the marketplace [64]. Will the public accept so nontraditional a departure in a food? That's arguable, but what is not, is the fact of widespread scientific creativity and the availability of biologic and genetic engineering tools. Down the road expect a clutch of novel foods—to feed an escalating population.

Was this article helpful?

0 0
Allergic To Everything

Allergic To Everything

The human body And Todays chemical infested world. Here is a news flash You are not allergic to pollen, pet dander, or whatever it is that makes your body revolt Rather, your body just can not handle that one thing, what ever it is, anymore, due to the massive barrage of toxic chemicals you and everyone else are ingesting every single day.

Get My Free Audio and Ebook


Post a comment