A Synthesis of Studies Regarding GM Foods and Feeds with Focus on Safety Analysis

Although it is still a relatively new technology, it seems as if genetic modification has developed as quickly as the microprocessor. First, the world saw Genentech's groundbreaking laboratory production of human proteins manufactured in bacteria in the late 1970's. Then, in the early 1990's genetically modified foods were declared not inherently dangerous for consumption by the FDA. However, recently, there has been an uproar across America by the so called "health conscious" who attempt to return to the natural methods of food production because they fear the impact of consumption of unnatural chemicals and also the unknown consequences of genetic modification. The purpose of this paper is to examine existing studies regarding GM foods with special attention to the safety and risks conclusions that are drawn.

Before studies are examined it is important to understand the current standards and guidelines. Therefore the first paper studied is by Harry A. Kuiper, it is an analysis of current methods for evaluating the safety of GMOs. The paper primarily focused on the concept of substantial equivalence. Substantial equivalence is considered the starting point for safety assessment of GMO's (genetically modified organisms). It also provides for the identification of intended and unintended differences on which further safety assessment should be focused. With this standard, a GMO is compared to the closest traditional counterpart. After the comparison the GMO obtains one of three labels; substantially equivalent, substantially equivalent except for the inserted trait, or not equivalent at all. If a GMO is deemed substantially equivalent then there is typically no further testing required; However, if a GMO is labeled not equivalent then it is suggested that rigorous case-by-case testing be imposed. If a GMO were to be considered substantially equivalent except for the inserted trait then testing centered about the specific trait is required. The paper concluded that, "No alternative, equally robust strategy is available." Although the paper detailed the procedures of many of the profiling techniques that are used, two of the most important conclusions to be drawn from the paper are the analysis of unintended effects and the final integrated approach for safety and nutritional assessment of novel foods.

In the analysis of unintended effects, scientists take a top down approach. First phenotypic alterations are considered (for both plant and tissue), followed by a DNA sequence analysis at the place of insertion. Then the mRNA, proteins and metabolites are analyzed to detect alterations in their respective profiles. In the integrated approach, two tiers of analysis will provide a robust safety-nutrition profile. In the first tier, biochemistry, toxicogenomics, nutrigenomics, metabolism/kinetics, toxicology, and clinical/nutrition are considered. The second tier goes in depth to provide info about dose-response, bioavailability, ranges for toxicity and functionality, nutrient gene interactions, polymorphism, and food matrix interactions.

With these standards and procedures in mind the scientific community has published a plethora of studies related to GMO safety testing. One such study, titled, Genetically Modified Feeds In Animal Nutrition 1^st Communication: Bacillus Thuringiensis (Bt) Corn In Poultry, Pig and Ruminant Nutrition, by Karen Aulrich, was aimed to clear up recent unusual findings of a few other studies. As the title implies, the study tested Bt corn based diets against a control diet in three different animal populations. The experimenters controlled for every possible factor from the growth and processing of the corn to the collection of excreta from the animals. Aulrich's study concluded that there was no significant difference in animal feeds that used Bt corn and traditional animal feeds; Bt corn was deemed safe for use in animal feed. The researchers did note that they felt further studies should be conducted on other varieties of GM foods in animal feeds to determine if GM feeds are safe in general. The sister study, Genetically Modified Feeds In Animal Nutrition 2^nd Communication: Glufosinate Tolerant Sugar Beets (Roots and Silage)and Maize Grains for Ruminants and Pigs, followed the recommendations of the first study. Since glufosinate tolerance is a first generation transgenic crop trait it was hypothesized that varieties of foods with this GM trait should be substantially equivalent to their counterpart. The experimenters followed the same control processes as in the first study. They also used the same statistical software to analyze the data. The results of the study stayed on par with the hypothesis and other published articles; specifically, that the insertion of the Glufosinate tolerant trait had no significant effect on the nutritional value, chemical composition, or digestibility of the sugar beets and maize grains. Both communication's experiments were conducted at the FAL facility in Germany. The experiments mentioned are described in greater detail with the same conclusions by Flachowsky.

Another paper focused on the safety concerns of GM feeds is, The relevance of gene transfer to the safety of food and feed derived from genetically modified plants. This article by G. van den Eede et al. provided a full explanation of the role of horizontal gene transfer in GM crops. The article also describes the basic process of creating a GM plant. The authors included these explanations so they could illustrate in depth the specific safety risks concerning food derived from GM plants. One of the major controversies that the paper discussed is the use of antibiotic resistant genes in GM plants. It was noted in the article that there is evidence that the GM plants can transfer DNA to microorganisms but that there was no evidence to show that bacteria can become antibiotic resistant. Furthermore, there are a number of factors that vastly decrease the probability that bacteria become antibiotic resistant due to transfer of DNA from GM plants. First, the DNA in GM foods is broken up into small pieces because they are typically heat processed. This means that if gene transfer were to occur that it is still a gamble if the transfer results in a dangerous outcome. Also, such transformations would require homology between the bacteria's DNA and the GM food's DNA. In general, the article concluded that horizontal gene transfer was a naturally occurring process so "there is very little reason to assume that consumption of transgenic food or feeds adds any particular generalized risk."(Eede) Another important fact the study noted was that once the modified DNA had been inserted into a host organism it is indistinguishable from the original DNA.

After reading the above articles, it may appear as if the GM community is continually reaching the same conclusions in experiments without progressing forward. On the contrary, Kleter, concluded that genetically modified animals will most likely enter the market in the near future. Research suggests that scientitst have reached ageneral conclusion that genetic modification of plants is safe; they have pushed their limitations to include genetic modification of animals. Since safety is of primary concern it is necessary to conduct rigorous case studies before new GM animal products enter the market. Substantial equivalence has been established for GM plants and can be adapted and applied to GM animals.

In conclusion, much of the current research on the subject of GM foods and feeds supports the argument for GM crops. The ideas and standards of substantial equivalence was developed to be a robust precautionary measure to insure that risks are minimized. The majority of conclusions of the various research articles all concur that there is little reason to believe that genetic modification adds any extra generalized risk; the scientists of these articles, also, tend to insist that every precaution be taken with respect to the genetic modification of foods and that further case studies will only improve the support.

References

Kuiper, Harry A. et al. (2001) Assessment of the food safety issues related to genetically modified foods.

The Plant Journal, 27(6),503-528.

Aulrich, Karen et al. (2001) Genetically Modified Feeds In Animal Nutrition 1^st Communication: Bacillus Thuringiensis (Bt) Corn In Poultry, Pig and Ruminant Nutrition.

Arch. Animal Nutrition. 54, 183-195.

Van den Eede, G. et al. (2004) The relevance of gene transfer to the safety of food and feed derived from genetically modified (GM) plants.

Food and Chemical Toxicology. 42, 1124-1156.

Bohme, H. et al. (2001) Genetically Modified Feeds In Animal Nutrition 2^nd Communication: Glufosinate Tolerant Sugar Beets (Roots and Silage)and Maize Grains for Ruminants and Pigs.

Arch. Animal Nutrition. 54, 197-207.

Flachowsky, G. et al. (2007) Studies on feeds from genetically modified plants (GMP) - Contributions to Nutritional and safety assessment.

Animal Feed Science and Technology. 133, 2-30.

Kleter, Gijs A. et al.(2002) Considerations for the assessment of the safety of genetically modified animals used for human food or animal feed.

Livestock Production Science. 74, 275-285.