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Genetically Engineered Foods May Cause Rising Food Allergies

Part 1: Genetically Engineered Soybeans

The huge jump in  childhood food allergies in the US is in the news often[1], but most reports  fail to consider a link to a recent radical change in America's diet. Beginning  in 1996, bacteria, virus and other genes have been artificially inserted to the  DNA of soy, corn, cottonseed and canola plants. These unlabeled genetically  modified (GM) foods carry a risk of triggering life-threatening allergic  reactions, and evidence collected over the past decade now suggests that they  are contributing to higher allergy rates.

Food safety tests are  inadequate to protect public health

Scientists have long known that GM  crops might cause allergies. But there are no tests to prove in advance that a  GM crop is safe.[2] That's because people aren't usually allergic to a food  until they have eaten it several times. "The only definitive test for  allergies," according to former FDA microbiologist Louis Pribyl, "is human consumption by affected peoples, which can have ethical considerations."[3] And it is the ethical considerations of feeding unlabeled, high-risk GM crops to  unknowing consumers that has many people up in arms.

The UK is one of the  few countries that conducts a yearly evaluation of food allergies. In March  1999, researchers at the York Laboratory were alarmed to discover that reactions  to soy had skyrocketed by 50% over the previous year. Genetically modified soy  had recently entered the UK from US imports and the soy used in the study was  largely GM. John Graham, spokesman for the York laboratory, said, "We believe  this raises serious new questions about the safety of GM  foods."[4]

Critics of GM foods often say that the US population is being  used as guinea pigs in an experiment. But experiments have the benefit of  controls and measurement. In this case, there is neither. GM food safety experts  point out that even if a someone tried to collect data about allergic reactions  to GM foods, they would not likely be successful. "The potential allergen is rarely identified. The number of allergy-related medical visits is not  tabulated. Even repeated visits due to well-known allergens are not counted as  part of any established surveillance system."[5] Indeed, after the Canadian  government announced in 2002 that they would "keep a careful eye on the health  of Canadians"[6] to see if GM foods had any adverse reactions, they abandoned their plans within a year, saying that such a study was too  difficult.

Genetic engineering may provoke increased allergies to  soy

The classical understanding of why a GM crop might create new  allergies is that the imported genes produce a new protein, which has never  before been present. The novel protein may trigger reactions. This was  demonstrated in the mid 1990s when soybeans were outfitted with a gene from the  Brazil nut. While the scientists had attempted to produce a healthier soybean,  they ended up with a potentially deadly one. Blood tests from people who were  allergic to Brazil nuts showed reactions to the beans.[7] It was fortunately  never put on the market.

The GM variety that is planted in 89% of US soy  acres gets its foreign gene from bacteria (with parts of virus and petunia DNA  as well). We don't know in advance if the protein produced by bacteria, which  has never been part of the human food supply, will provoke a reaction. As a  precaution, scientists compare this new protein with a database of proteins  known to cause allergies. The database lists the proteins' amino acid sequences  that have been shown to trigger immune responses. If the new GM protein is found  to contain sequences that are found in the allergen database, according to  criteria recommended by the World Health Organization (WHO) and others, the GM  crop should either not be commercialized or additional testing should be done.  Sections of the protein produced in GM soy are identical to known allergens, but  the soybean was introduced before the WHO criteria were established and the  recommended additional tests were not conducted.

If this protein in GM  soybeans is causing allergies, then the situation may be made much worse by  something called horizontal gene transfer (HGT). That's when genes spontaneously  transfer from one species' DNA to another. While this happens often among  bacteria, it is rare in plants and mammals. But the method used to construct and  insert foreign genes into GM crops eliminates many of the natural barriers that  stop HGT from occurring. Indeed, the only published human feeding study on GM  foods ever conducted verified that portions of the gene inserted into GM soy  ended up transferring into the DNA of human gut bacteria. Furthermore, the gene  was stably integrated and it appeared to be producing its potentially allergenic  protein. This means that years after people stop eating GM soy, they may still  be exposed to its risky protein, which is being continuously produced within  their intestines.

Genetic engineering damaged soy DNA, creating new (or  more) allergens

Although biotech advocates describe the process of  genetic engineering as precise, in which genes-like Legos-cleanly snap into  place, this is false. The process of creating a GM crop can produce massive  changes in the natural functioning of the plant's DNA. Native genes can be  mutated, deleted, permanently turned on or off, and hundreds may change their  levels of protein expression. This collateral damage may result in increasing  the levels of an existing allergen, or even producing a completely new, unknown  allergen within the crop. Both appear to have happened in GM soy.

Levels  of one known soy allergen, trypsin inhibitor, were up to 27% higher in raw GM  soy. In addition, although cooking soybeans normally reduces the amount of this  protein, the trypsin inhibitor in GM varieties appears to be more heat  resistant. Levels in cooked GM soy were nearly as high as those found in raw  soy, and up to seven times higher when compared to cooked non-GM soy.[8] This  suggests that this allergen in GM soy may be more likely to provoke reactions  than when consumed in natural varieties.

Another study verified that GM  soybeans contain a unique, unexpected protein, not found in non-GM soy controls.  Moreover, scientist tested the protein and determined that it reacted with the  antibody called IgE. This antibody in human blood plays a key role in a large  proportion of allergic reactions, including those that involve life-threatening  anaphylactic shock. The fact that the unique protein created by GM soy  interacted with IgE suggests that it might also trigger allergies.

The  same researchers measured the immune response of human subjects to soybeans  using a skin-prick test-an evaluation used often by allergy doctors. Eight  subjects showed a reaction to GM soy; but one of these did not also react to  non-GM soy. Although the sample size is small, the implication that certain people react only to GM soy is huge, and might account for the increase in soy  allergies in the UK.

Increased herbicides on GM crops may cause  reactions

By 2004, farmers used an estimated 86% more herbicide on GM soy  fields compared to non-GM.[9] The higher levels of herbicide residue in GM soy might cause health problems. In fact, many of the symptoms identified in the UK soy allergy study are among those related to glyphosate exposure. [The allergy study identified irritable bowel syndrome, digestion problems, chronic fatigue, headaches, lethargy, and skin complaints, including acne and eczema, all related to soy consumption. Symptoms of glyphosate exposure include nausea, headaches,  lethargy, skin rashes, and burning or itchy skin. It is also possible that glyphosate's breakdown product AMPA, which accumulates in GM soybeans after each  spray, might contribute to allergies.]

GM soy might impede digestion,  leading to allergies

If proteins survive longer in the digestive tract,  they have more time to provoke an allergic reaction. Mice fed GM soy showed  dramatically reduced levels of pancreatic enzymes. If protein-digesting enzymes  are less available, then food proteins may last longer in the gut, allowing more  time for an allergic reaction to take place. Such a reduction in protein  digestion due to GM soy consumption could therefore promote allergic reactions  to a wide range of proteins, not just to the soy. No human studies of protein  digestion related to GM soy have been conducted.

Soy linked to peanut  allergies

There is at least one protein in natural soybeans that has  cross-reactivity with peanut allergies.[10] That means that for some people who  are allergic to peanuts, consuming soybeans may trigger a reaction. While it is certainly possible that the unpredicted side effects from genetic engineering soybeans might increase the incidence of this cross-reactivity, it is unlikely  that any research has been conducted to investigate this. GM soy was introduced  into the US food supply in late 1996. We are left only to wonder whether this had an influence on the doubling of US peanut allergies from 1997 to  2002.

Eating GM foods is gambling with our health

The introduction  of genetically engineered foods into our diet was done quietly and without the  mandatory labeling that is required in most other industrialized countries.  Without knowing that GM foods might increase the risk of allergies, and without  knowing which foods contain GM ingredients, the biotech industry is gambling  with our health for their profit. This risk is not lost on everyone. In fact,  millions of shoppers are now seeking foods that are free from any GM  ingredients. Ohio-based allergy specialist John Boyles, MD, says, "I used to  test for soy allergies all the time, but now that soy is genetically engineered,  it is so dangerous that I tell people never to eat it-unless it says  organic."[11]

Organic foods are not allowed to contain GM ingredients.  Buying products that are certified organic or that say non-GMO are two ways to  limit your family's risk from GM foods. Another is to avoid products containing  any ingredients from the seven food crops that have been genetically engineered: soy, corn, cottonseed, canola, Hawaiian papaya and a little bit of zucchini and  crook neck squash. This means avoiding soy lecithin in chocolate, corn syrup in candies, and cottonseed or canola oil in snack foods.

Fortunately, the  Campaign for Healthier Eating in America will soon make your shopping easier.  This Consumer Non-GMO Education Campaign is orchestrating the clean out of GM  ingredients from foods and the natural products industry. The campaign will  circulate helpful non-GMO shopping guides to organic and natural food stores  nationwide. The Campaign will provide consumers with regular GM food safety  updates that explain the latest discoveries about why, Healthy Eating Means No  GMOs.

Safe eating.

This article is limited to the discussion of  allergic reactions from GM soybeans. The evidence that GM corn is triggering  allergies is far more extensive and will be covered in part 2 of this  series.

Jeffrey M. Smith is the author of the new publication Genetic Roulette: The Documented Health Risks of Genetically Engineered Foods, which  presents 65 risks in easy-to-read two-page spreads. His first book, Seeds of  Deception, is the top rated and #1 selling book on GM foods in the world. He is  the Executive Director of the Institute for Responsible Technology, which is spearheading the Campaign for Healthier Eating in America. Go to to learn more about how to avoid GM  foods.

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[1]  See for example, Charles Sheehan, "Scientists see spike in kids' food allergies," Chicago Tribune, 9 June 2006,

[2] See for  example, Carl B. Johnson, Memo on the "draft statement of policy 12/12/91,"  January 8, 1992. Johnson wrote: "Are we asking the crop developer to prove that  food from his crop is non-allergenic? This seems like an impossible  task."

[3] Louis J. Pribyl, "Biotechnology Draft Document, 2/27/92,"  March 6, 1992,

[4] Ibid.

[5] Traavik and  Heinemann, "Genetic Engineering and Omitted Health Research"

[6]  "Genetically modified foods, who knows how safe they are?" CBC News and Current  Affairs, September 25, 2006.

[7] J. Ordlee, et al, "Identification of a  Brazil-Nut Allergen in Transgenic Soybeans," The New England Journal of  Medicine, March 14, 1996.

[8] Stephen R. Padgette et al, "The Composition  of Glyphosate-Tolerant Soybean Seeds Is Equivalent to That of Conventional  Soybeans," The Journal of Nutrition 126, no. 4, (April 1996); including data in  the journal archives from the same study.

[9] Charles Benbrook,  "Genetically Engineered Crops and Pesticide Use in the United States: The First  Nine Years"; BioTech InfoNet, Technical Paper Number 7, October  2004.

[10] See for example, Scott H. Sicherer et al., "Prevalence of  peanut and tree nut allergy in the United States determined by means of a random  digit dial telephone survey: A 5-year follow-up study," Journal of allergy and clinical immunology, March 2003, vol. 112, n 6, 1203-1207); and Ricki Helm et  al., " Hypoallergenic Foods-Soybeans and Peanuts," Information Systems for Biotechnology News Report, October 1, 2002.

[11] John Boyles, MD,  personal communication,  2007.