The genes from Bt have been inserted into several genetically modified crops so that the plants produce pesticides themselves. The GM industry argues that this is no different from what organic farmers do when they spray Bt bacteria; however, this is a massive distortion of the facts. Organic farmers spray live bacteria onto the crop, not the Bt toxins. During the night and early morning, pests eat the bacteria, infecting them so that the bacteria release their toxins and eventually kill the pests. It is destroyed by ultraviolet light, so usually, none will survive more than a day or two, and consumers will not be affected by the toxins produced by Bt.

On the other hand, every cell of a Bt GMO plant and its produce contains the Bt toxin, so livestock and people are consuming these pesticide compounds. Despite assurances that they have been tested for safety, most Bt GMOs receive no or minimal testing. The assumption is that because the Bt toxin is considered safe for non-target species, the Bt in the GMO produce is also safe.

However, there are several published, peer-reviewed scientific studies showing that the process of inserting the Bt gene from the bacteria into the plant changes the way Bt works. These studies show that it causes organ damage and inflammatory diseases in the animals that consume the plant. A Canadian study published in the scientific journal Reproductive Toxicology found the pesticide toxin from GMO crops in the blood samples of women and their unborn babies. The GMO toxin was found in 93 percent of maternal blood samples and 80 percent of fetal blood samples. These women were eating the typical Canadian diet. The products of these pesticide-producing plants have been permitted in the diets of people, especially children, without any peer-reviewed, evidence-based testing to show that they are safe. An extensive body of published scientific studies shows that these toxins are linked to numerous adverse health events in animals.

GMO Myths & Facts: A Summary

By Melissa Diane Smith

For the past several decades, the public has been fed the rhetoric that genetically modified (GM) crops and foods are needed to feed the world’s growing population and to meet the challenges that farmers face, including climate change as well as pests and diseases. However, scientific research and real-world farming experience show that GM crops and foods have not delivered on their promises of increased yields or reduced toxic chemical inputs.

Instead, GM crops have presented farmers with new challenges of controlling herbicide-resistant superweeds and Bt-resistant superpests. In addition, GM crops have not been shown to be safe to eat, and existing research shows that some GM crops – and the pesticides that go hand in hand with them – pose worrying health risks.

These are the conclusions made in GMO Myths and Facts: What they don’t want to tell you about genetically modified crops and foods, a meticulously referenced, reader-friendly, 28-page booklet written by Claire Robinson, editor of GMWatch.org, and produced by the Sheepdrove Trust to educate and inform the public. Download your free copy of the booklet.

At-a-glance

In the booklet, you’ll learn vital facts in the following areas.

• Yield: Conventionally bred plants outperform GM crops in terms of:

• Yield
• Disease resistance
• Enhanced nutritional value
• Tolerance to extreme weather conditions and poor soils.

• Pesticide use: Most GM crops are tolerant to herbicides, enabling farmers to spray the field liberally with that herbicide, killing all plant life except the crop. The spraying of crops with herbicide such as glyphosate, the active ingredient in Roundup weed killer, has led to the development and spread of superweeds—weeds that adapt to and withstand the herbicide, resulting in yet more herbicide spraying.
• Massive rise in the use of glyphosate: Globally, the use of glyphosate, an herbicide that has been identified as a potential cause of cancer and is linked to other diseases including liver and kidney disease, has increased 15-fold since the introduction of GM glyphosate-tolerant crops.
• GM Bt crops: GM Bt crops have been genetically engineered to produce insect-killing Bacillus thuringienisis (Bt) toxins in their cells so that pests that eat the plants will die. The use of GM Bt crops has led to the development of “super insects” that have become resistant to Bt’s insect-killing effects.

1. GM Bt crops have been found to have harmful effects far beyond the specific pests they were designed to control, including in butterflies, beneficial pest predators, bees, aquatic organisms, and beneficial soil organisms. In feeding trials in mammals, GM Bt crops have been shown to have adverse effects including:

• Toxic effects in the small intestine, liver, kidney, spleen, and pancreas
• Disturbed functioning of the digestive system
• Altered weight gain compared with controls
• Male reproductive organ damage
• Blood biochemistry abnormalities
• Immune system disturbances

• Lack of GM food testing: People often assume that governments and their independent agencies rigorously test and ensure the safety of the foods we eat. This is not the case with GM foods. Governments have made GMO developer companies that stand to profit from the sale of GMOs responsible for ensuring their safety – a practice that many liken to leaving the fox in charge of the henhouse. 
• The risks of consuming GM foods: There are no safety studies in humans on the health effects of GM foods. But animal studies reveal worrying risks, including:

• Multiple organ damage
• Immune responses and abnormal allergic-type reactions
• Enlarged lymph nodes
• Liver and kidney damage
• Digestive disturbances
• Altered gut bacteria
• Severe stomach inflammation and heavier uteruses.

1. In addition, most feeding studies with GMOs are short- or medium-term, which may not reveal if changes in GM-fed animals could develop into serious disease in the longer term. Human health and life expectancy in the US are declining, and GM foods and the pesticides that are used with them cannot be ruled out as one cause among many.

• Gene-editing: Gene-editing technologies (including CRISPR-Cas9, TALENs and ZFNs) are being used to generate not only new varieties of food crops, but farm animals as well. Although proponents claim that these techniques are precise and controllable, a growing body of scientific research shows that gene-editing gives rise to unpredictable results, including unexpected mutations (damage to DNA) both at the site targeted for editing (“on-target mutations”) and elsewhere in the genome (“off-target mutations”). Just like earlier GM technologies, the “new GM” technology of gene-editing will use up valuable resources and distract from the existing proven solutions to the problems of food production and agriculture.
• Food security: The answer to ensuring food security and sustainably feeding the world’s population is not GMOs, which undermine seed saving and food security in developing countries. Instead, the answer lies in agroecology, a range of low-input and organic farming methods that preserve soil and water while minimizing the use of external inputs, such as pesticides and fertilizers. These methods have been proven to:

• Deliver safe and abundant food 
• Produce dramatic increases in yield
• Keep seeds within the control of farmers and free from patent restraints.

Melissa Diane Smith is a health journalist, respected author on the topic of GMOs, holistic nutritionist, and environmentalist. 

In a rat feeding study,^1,2 genetically modified (GM) Bt insecticidal corn caused altered blood biochemistry, organ damage (including damage to liver and kidney), and potential impacts on male fertility. The only difference in the GM corn versus the non-GM corn was the genetic modification. Thus the effects seen in the GM-fed rats were due to the GM process and not to other factors, such as differences in cultivation conditions.

In-depth analysis

Study design

This study by Egyptian researchers was reported in two separate publications: Gab-Alla and colleagues (2012)¹ and El-Shamei and colleagues (2012).² In the study, rats were fed the genetically modified (GM) Bt insecticidal corn MON810: Ajeeb YG (a variety developed by Monsanto for the Egyptian market) for 45 and 91 days. The corn was engineered so that its tissues contain a Bt toxin insecticide intended to kill insect pests that feed on the crop.
Thirty male rats were divided into three feeding groups of 10 rats per group. The first group was fed a standard laboratory corn-containing diet. A second group – the control group – was fed a diet containing 30% of non-GM Ajeeb corn. The third group was fed a diet of 30% of GM MON810: Ajeeb YG corn. The GM and non-GM corn grains were milled into flour before being incorporated into the feed.
The body weight of each rat was recorded weekly. Animals were sacrificed and examined after 45 days and 91 days of feeding the different diets. Organs were weighed, blood samples taken, and serum analyzed. The results were written up in the first publication.¹
Histopathological analysis (microscopic examination of tissues) was carried out on the liver, kidney, testes, spleen and small intestine of rats sacrificed at both time points to check for abnormalities. These results were written up in the second publication.²

Findings: Body and organ weights

The GM-fed animals showed differences in body and organ weights, compared with the control rats (see Tables 2 and 3 in the first publication¹):

• From the seventh week of the experiment, the body weight of rats in the GM-fed group was lower than that of rats in the non-GM-fed and standard lab diet-fed groups.
• After 91 days of feeding, the heart weight was significantly higher in the GM-fed group than the non-GM-fed group.
• Kidney weight was significantly higher in the GM-fed group compared with non-GM-fed and standard lab diet groups, in both study periods. Liver weight was significantly higher in the GM-fed group than the non-GM-fed and standard lab diet groups, in the 91-day period.
• Spleen weight was significantly different in the GM-fed group in both study periods (at 45 days it was higher, and at 91 days it was lower compared with the other groups).
• Testes weight of the GM-fed group was lower than non-GM-fed and control groups after 45 days but no difference was found at 91 days.¹

Such differences in body and organ weights can indicate that the GM diet was toxic. This was confirmed to be the case in the histopathological findings presented in the second publication.²

Findings: Differences in blood biochemistry

The GM-fed animals showed differences in blood biochemistry, compared with the control rats (see Tables 4 and 5 in the first publication¹):

• Serum levels of uric acid, urea and creatinine (a waste product from breakdown of muscle tissue) were significantly higher in the GM-fed group compared with the non-GM-fed and standard diet groups, at both 45 and 91 days. These substances are measurements of kidney function. The higher levels in the GM-fed group suggest impaired kidney function.
• Serum levels of triglycerides (a type of fat) were significantly higher in the GM-fed group compared with the non-GM-fed and standard diet groups after both 45 and 91 days. High levels of blood triglycerides can lead to heart disease, high blood pressure, diabetes, obesity, or non-alcoholic fatty liver disease.
• Serum albumin, which is generated from the liver, was significantly lower in the GM-fed group in both study periods compared with the non-GM-fed and standard diet groups. This suggests compromised liver function.
• Serum levels of the liver enzyme ALP (alkaline phosphatase) were significantly higher in the GM-fed group in both study periods compared with the non-GM-fed and standard diet groups. Serum levels of the liver enzyme ALT (alanine transaminase) were significantly higher at 91 days in the GM-fed group compared with the non-GM-fed and standard diet groups. These changes in ALP and ALT imply liver structural damage in the GM-fed group, since these enzymes leak into the blood circulation when liver cells die and break up.
• Serum levels of VLDL (very low density lipoprotein) and LDL (low density lipoprotein) were significantly higher in both study periods in the GM-fed group compared with the non-GM-fed and standard diet groups. Such alterations in blood lipid (fat) levels can lead to a variety of disorders, including cardiovascular disease.¹

The authors noted that these changes could indicate “potential adverse health/toxic effects”, which need further investigation.¹

Findings: Histopathological abnormalities

The same group of researchers performed histopathological (microscopic) investigations of the rats fed over the 45 and 91-day study periods and reported the results in a separate publication.² They found toxic effects in several organs of the rats fed the GM corn. Abnormalities found in the GM-fed animals (but not in the non-GM-fed or standard diet-fed animals) included:

• Vacuolation (formation of storage structures – for example, of fatty compounds) in liver cells, indicating liver damage
• Fatty degeneration of liver cells
• Congestion of blood vessels in kidneys and cystic malformations of kidney tubules – signs of possible impending kidney failure
• Excessive growth and necrosis (death) of intestinal structures called villi
• Examination of the testes revealed necrosis and desquamation (shedding) of the spermatogonial cells that are the precursors of sperm cells and thus the foundation of male fertility.²

The authors of the study concluded, “Due to these observations, we suggest that the risk of GM crops cannot be ignored and deserves further investigations in order to identify possible long-term effects, if any, of GM food consumption.”²

Q&A

Q: What is the relevance to human health?
A: Among the negative health impacts seen in the GM-fed rats that are relevant to humans were liver damage and impaired kidney function. Indications of liver damage included elevated serum triglycerides (a type of fat) and vacuolation (an abnormality consisting of the formation of storage structures) and fatty degeneration of liver cells. These are all signs of non-alcoholic fatty liver disease (NAFLD), a modern epidemic in humans that now affects one in three Americans. NAFLD is the most common form of liver disease in children and has almost doubled over the past 20 years.³ Chronic kidney disease affects 14% of Americans.⁴
The relevance to humans of the particular gut abnormalities found in the GM-fed rats is not known, except to say that excessive growth in the villi of the small intestine may pre-dispose a person to the onset of cancer. It is not known if the necrosis seen in the rats’ intestinal villi would translate in humans as a “leaky gut”, a condition involving intestinal permeability that some physicians link to inflammatory diseases.
Q: What caused the effects seen in the GM-fed rats?
A: In line with best practice for GMO feeding trials, the non-GM control corn was “isogenic” to the GM corn. “Isogenic” means having the same genetic background as the GM corn but without the genetic modification. Moreover, the two corn varieties were grown at the same time and under the same conditions, with the same field management practices.⁵ This means that the changes seen in the GM-fed rats were due to changes in the corn caused by the genetic modification, and not by different environmental conditions or field management practices during cultivation.
It is not known, however, whether the toxicity found from the consumption of the GM corn was due to the presence of the introduced Bt toxin or to some unintended changes brought about by the GM process. This is a limitation common to the vast majority of animal feeding studies that find harm from GMOs. For example, animal feeding studies on GM Bt crops are not designed to distinguish between toxicity arising from the Bt toxin and from other components of the GM crop that have been unintentionally altered by the GM transformation process.
In order to distinguish between whether the toxicity observed is due to the engineered Bt toxin or GM process-induced changes, a group of animals consuming a diet consisting of the non-GM corn with added Bt toxin at the same level as that found in the GM corn would need to be included. In addition, to ensure equivalence to the GM diet, this would require that the Bt toxin be isolated from the GM corn and then added to the non-GM corn. Such isolation of the GM Bt toxin is difficult, which is why such a control group is not included in animal feeding studies.
Q: How do the findings relate to those of other studies?
A: The abnormalities in the intestinal villi of the GM-fed animals are in line with the findings of other studies. For example, in one study, mice fed GM Bt potatoes had excessive cell growth and cellular abnormalities in the villi of the small intestine (Fares and El-Sayed, 1998).⁶ In another study, rats fed GM potatoes expressing a different insecticidal protein (Galanthus nivalis lectin or GNA for short) had excessive cell growth in the small and large intestines (Ewen and Pusztai, 1999),⁷ suggestive of a pre-cancerous condition.
Signs of liver and kidney toxicity were also identified in a review of 90-day industry-sponsored rat feeding studies on two GM Bt corn varieties (De Vendomois and colleagues, 2009).⁸ And in a three-generation study, rats fed GM Bt corn showed damage to liver and kidneys and alterations in blood biochemistry (Kilic and Akay, 2008).⁹
Q: Doesn’t the EU-funded GMO90+ study contradict the findings of this study?
A: An EU-funded study (Coumoul and colleagues, 2018) called GMO90+ tested GM MON810 corn in Wistar rats over a 6-month period and reported “no adverse effect” from the GM diet, compared with the non-GM isogenic variety.¹⁰
However, this study¹⁰ is different in design and interpretation from the study by Gab-Alla and colleagues¹ and El-Shamei and colleagues² and thus is not comparable. First, regarding design, although the two studies evaluated GM corn with the same GM transformation “event” (MON810), this was present in different background genetics of the corn varieties, which means that they are not comparable. Thus the results obtained from one study do not “cancel out” the results from the other.
Second, and most crucially, the difference in interpretation is that in the EU-funded study, a number of statistically significant differences were found in the GM-fed rats, but the authors dismissed them as not biologically relevant, without scientific justification.¹⁰ In reality, the only way to know if these changes were biologically relevant is to extend the study length beyond 6 months to two years or more. This would give time for any long-term health effects to fully manifest. In contrast, and in line with good scientific practice, Gab-Alla and colleagues¹ and El-Shamei and colleagues² did not dismiss significant differences in the GM-fed rats, but took them seriously.
In addition, in the EU-funded study, all of the feeds used, including the control feeds, were equally contaminated with residues of the herbicide ingredient glyphosate.¹⁰ This could add “data noise” to the results, meaning that any changes due to the GM element of the diet might have been masked.
Q: What are the limitations of the study length?
A. The study investigated the health of the rats over two periods: 45 days and 91 days. The latter is equivalent to only around 9 years in a human.¹¹ Significant damage to the GM-fed rats’ organs was found even in this relatively short period. However, people could eat a GM food over their entire lives, so long-term (2-year) animal feeding studies should be carried out to see if the changes found in the GM-fed rats in this experiment develop into even more serious illness or shortened lifespans.
Q: Was there an adequate number of rats in the study?
A: There is no agreed standard for the numbers of rats that should be included in each group in GMO feeding studies. However, the number used in this experiment (10 per group) is comparable to that in studies that are often used to claim that GMOs are safe.¹² It is also comparable to the number (typically varying between 5 and 20) used by GMO companies in studies to support regulatory approvals.¹³
The Organisation for Economic Cooperation and Development (OECD), which sets international standards for the animal testing of chemicals to support regulatory approvals, recommends 20 animals per sex per group for a medium-term toxicity study of the length of this one. However, only 10 animals per sex per group (50%) have to be analyzed for blood and urine chemistry¹⁴ – the same number that were analyzed in this study. Thus the study gathered data from the same number of rats as the OECD norm, but unlike the OECD recommendation, 100% of the animals were analyzed. This is a superior methodology to analyzing only 50% of animals, as “selection bias” (choosing which animals to analyze or record data from) is impossible.
Q: All the rats tested were male. Is this a limitation?
A: Ideally both sexes should be included, as GM corn has been found in industry-sponsored feeding studies to affect males and females in different ways.⁸ However, this study in males only still gives valuable information.
Q: Is the GM crop tested in this experiment typical of GM crops on the market today?
A: This experiment tested a single-trait GM crop, but most GM crops currently on the market contain multiple (“stacked”) traits – for example, several different Bt toxins and genes conferring herbicide tolerance. Future animal feeding studies should focus on the newer stacked trait crops, grown with the herbicides and other chemicals that are typically used in the cultivation cycle.
References

1. Gab-Alla AA, El-Shamei ZS, Shatta AA, Moussa EA, Rayan AM. Morphological and biochemical changes in male rats fed on genetically modified corn (Ajeeb YG). J Am Sci. 2012;8(9):1117–1123. https://www.academia.edu/3138607/Morphological_and_Biochemical_Changes_in_Male_Rats_Fed_on_Genetically_Modified_Corn_Ajeeb_YG_. Accessed January 14, 2014.
2. El-Shamei ZS, Gab-Alla AA, Shatta AA, Moussa EA, Rayan AM. Histopathological changes in some organs of male rats fed on genetically modified corn (Ajeeb YG). J Am Sci. 2012;8(10):684–696. https://www.academia.edu/3405345/Histopathological_Changes_in_Some_Organs_of_Male_Rats_Fed_on_Genetically_Modified_Corn_Ajeeb_YG_. Accessed January 14, 2014.
3. American Liver Foundation. ALF NAFLD and NASH Overview 2018.; 2018. https://liverfoundation.org/for-patients/about-the-liver/diseases-of-the-liver/non-alcoholic-fatty-liver-disease/.
4. National Institute of Diabetes and Digestive and Kidney Diseases. Kidney disease statistics for the United States. niddk.nih.gov. https://www.niddk.nih.gov/health-information/health-statistics/kidney-disease. Published 2016. Accessed February 18, 2019.
5. Shatta AA, Rayan AM, El-Shamei ZS, Gab-Alla AA, Moussa EA. Comparative study of the physicochemical characteristics of oil from transgenic corn (Ajeeb YG) with its non-transgenic counterpart. Austin Food Sci. 2016;1(5):1023. http://austinpublishinggroup.com/food-sciences/fulltext/afs-v1-id1023.php. Accessed February 3, 2019.
6. Fares NH, El-Sayed AK. Fine structural changes in the ileum of mice fed on delta-endotoxin-treated potatoes and transgenic potatoes. Nat Toxins. 1998;6(6):219-233. http://www.ncbi.nlm.nih.gov/pubmed/10441029.
7. Ewen SW, Pusztai A. Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine. Lancet. 1999;354(9187):1353-1354. doi:10.1016/S0140-6736(98)05860-7
8. De Vendomois JS, Roullier F, Cellier D, Séralini GE. A comparison of the effects of three GM corn varieties on mammalian health. Int J Biol Sci. 2009;5:706–26. http://www.ncbi.nlm.nih.gov/pubmed/20011136 http://www.biolsci.org/v05p0706.htm.
9. Kilic A, Akay MT. A three generation study with genetically modified Bt corn in rats: Biochemical and histopathological investigation. Food Chem Toxicol. 2008;46:1164–70. doi:10.1016/j.fct.2007.11.016
10. Coumoul X, Servien R, Juricek L, et al. The GMO90+ project: absence of evidence for biologically meaningful effects of genetically modified maize based-diets on Wistar rats after 6-months feeding comparative trial. Toxicol Sci. 2018. doi:10.1093/toxsci/kfy298
11. Sengupta P. The laboratory rat: Relating its age with human’s. Int J Prev Med. 2013;4(6):624-630. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3733029/. Accessed January 13, 2019.
12. Snell C, Aude B, Bergé J, et al. Assessment of the health impact of GM plant diets in long-term and multigenerational animal feeding trials: A literature review. Food Chem Toxicol. 2012;50(3–4):1134-1148. http://www.sciencedirect.com/science/article/pii/S0278691511006399.
13. Ricroch AE, Boisron A, Kuntz M. Looking back at safety assessment of GM food/feed: an exhaustive review of 90-day animal feeding studies. Int J Biotechnol. 2014;13(4):230-256. doi:10.1504/IJBT.2014.068940
14. Organisation for Economic Cooperation and Development (OECD). OECD guideline no. 408 for the testing of chemicals: Repeated dose 90-day oral toxicity study in rodents: Adopted 21 September 1998. 1998.

1. The reasons why the recommendations from the 2004 and earlier NAS reports have gone largely unheeded, and why state-of-the-art risk assessment science has not been applied to today’s GE foods.
2. The fact that in the years ahead, with the recent approvals of GE sweet corn, Bt eggplant, Arctic apples, Innate potatoes and AquaAdvantage salmon (although very few Americans have consumed these foods yet, with the exception of GE sweet corn which has been commercially significant in the US for only a few years), people will now begin to consume GE foods in forms likely to contain intact GE proteins.
3. The worrisome gap in knowledge regarding the potential for “cross-talk” between multiple regulatory genes and sequences created by stacking traits. For several years, most GE corn varieties, for instance, have contained multiple, “stacked” traits, and one popular brand, SmartStax, contains eight (two herbicide-tolerant traits, and six Bt traits). Such unintended impacts could increase the level of known or new allergens and/or toxins.
4. The importance of including the synergistic effects of the transgene(s), its expression, and the pesticides normally used on the crop – including the so-called inert ingredients incorporated in a given pesticide formulation – in safety evaluations and risk assessments.

The present acceptance of GE crops and foods rests on several questionable assumptions and assertions, including the belief that the FDA “approval” process is thorough and independent. It is neither. In fact, the FDA never really “approves” a GE food: it simply accepts assertions made by technology developers during the course of a “voluntary consultation.”

The FDA approval process

The FDA review process is based almost entirely on industry-sponsored studies. Information in the open, peer-reviewed scientific literature is often ignored or discounted.
The FDA does not conduct any original research or risk assessments on a newly proposed GE food. Nor does it conduct an independent assessment of the conclusions reached by technology developers and expressed in the “voluntary consultation” packages submitted to it.
When submitting a “voluntary consultation” package to the FDA, a company:

1. Summarizes their own safety assessment.
2. Asserts that the GE trait produces food that is “substantially equivalent” to the non-GE counterpart (often referred to as an “isoline”).
3. States their conclusion that the GE food poses no new or more serious food safety or nutrition-related risk compared to non-engineered food.

The FDA simply accepts the data that the company has generated, along with its conclusions regarding safety. The agency does alert technology developers that they are responsible for informing it if they become aware of any data suggesting that the GE food might not be “substantially equivalent” or as safe as non-engineered food.
One need look no further than the typical letter that the FDA sends to a technology developer when it closes out – i.e., “approves” – a new GE food technology. In a 1996 letter to Monsanto, for instance, the FDA states,
Based on the safety and nutritional assessment [Monsanto has] conducted, it is our understanding that Monsanto has concluded that corn grain and forage derived from the new variety are not materially different in composition, safety, or other relevant parameters from corn grain and forage currently on the market, and that they do not raise issues that would require premarket review or approval by FDA. (FDA website)
Because the technology developer has concluded that the FDA does not need to conduct a premarket review, and because the FDA accepts that conclusion, the FDA has no substantive basis on which to “approve” the technology. The FDA “approval” is really an exemption from the standard FDA risk assessment process, and is, regrettably, only a small step removed from a free pass.
These are among the key reasons that we hope the ongoing NAS report on the health and safety of GE crops will examine in detail the FDA review process and recommend ways to strengthen it. In the following, we propose alternatives and evaluate the likely impact of the solutions that others have suggested.
For example, the FDA needs to ensure that the toxicological tests conducted are of sufficient duration and quality to rule out, or identify, potential food safety risks. The process also badly needs, and will benefit from, a greater level of independence and oversight by scientists not affiliated with or supported by technology developers.

Have GE crops been thoroughly tested?

The claim is often made that GE-food technology has undergone extremely thorough testing. A simple comparison of the number of available health impact studies shows otherwise. More than 11,000 citations can easily be found on DDT, and more than 3,000 on the insecticides chlorpyrifos and parathion and on the herbicides atrazine and 2,4-D. There are more than 1,500 studies on glyphosate. There are hundreds of thousands of health-impact studies on “all pesticides,” a class of agricultural technology roughly equivalent to “all GE crops.”
In comparison, there are only a few hundred studies designed to identify and/or quantify human health risks from consumption of GE food. An exhaustive review of the health effects of transgenic foods published in 2011 yielded a total of 75 studies covering GE potato, corn, maize, soybeans, rice, cassava, cucumbers, tomatoes, apples, and many other crops. Most of these studies were carried out for fewer than 91 days. For each of the above crops, there are several commercially significant transgenic events, most of which have been studied by scientists working for technology developers.
There are other categories of agricultural technology that have been examined in much greater depth than GE crops. Indisputable examples are antibiotics used for disease prevention and growth promotion, food additives, hormones used to accelerate animal growth or production, and food colors.
It would be closer to the truth for the NAS to state that GE foods are among the least well-tested agricultural technologies ever adopted.
The testing of GE crops poses significant challenges, including difficulty in ensuring that control animals in fact receive feed that is free of GE ingredients and that the Bt proteins used in animal feeding studies are, in fact, identical to the ones expressed in Bt-transgenic crops (the latter is often not the case, because of the cost of extracting enough Bt proteins from plants to run an animal feed experiment).
In spite of these difficulties, some animal feeding studies to test GE crops have revealed worrisome adverse health impacts and evidence of progress toward chronic disease. However, the US government has never funded research to follow up on experiments reporting adverse impacts, nor has it pushed forward the boundaries of scientific knowledge by trying to develop new tools to understand the mechanisms in transgenic plants through which novel allergens or toxins might be formed, detected, and studied for potential toxicity.

Substantial equivalence

Although the term “substantially equivalent” has been repeatedly used to justify the paucity of nutritional and food safety research on foods from GE crops, it is not subject to a rigorous scientific definition, nor does it encompass careful research on all compositional parameters and nutrient levels that might impact animal health.
In fact, studies of GE crops and their isolines grown in properly designed, side-by-side trials in multiple locations often show statistically significant differences in the levels of many nutrients. Technology developers, however, have argued that these differences should be dismissed as “biologically not meaningful” because they fall within the range of natural variation for the crop in question. It is time to define the concept of “substantial equivalence” much more rigorously in order to gain a more reliable, science-based understanding of the impacts of genetic engineering technology on agriculture.

Crops with stacked traits

Most GE corn varieties contain stacked traits. However, we are aware of only very few studies designed to test the question of whether unique risks arise as a result of stacking traits in a given cultivar. The FDA has adopted the position that if each trait is presumed safe individually, then combinations of traits will also be safe.
Until much needed science is carried out to determine whether FDA’s position on this issue is reasonable, the FDA “approval” process for GE crops/foods with stacked traits rests more on wishful thinking than on science.

Increased availability of transgenic products

We raise specific concerns over the introduction of three-trait sweet corn in the US which contains three GE traits and Bt eggplant internationally (although not yet in the US). EPA approval of Bt corn, both sweet corn and field corn, is based on data showing that Bt endotoxins are not acutely toxic to mammals and suggesting that they could be rapidly broken down in the mammalian GI tract.
However, transgenic Bt toxins can and do enter the bloodstream intact before they get to the stomach, via the gums, tongue, and throat in ways similar to sublingual medications (e.g., a pill placed under one’s tongue).
Moreover, while Bt endotoxins break down in the human stomach, very little research has been done to assess the type of elements they break down into, and whether fragments of Bt toxins might irritate the inner lining of the human GI tract. Such concern is grounded in an appreciation of the way activated Bt toxins attach to, and then create holes in, the stomachs of susceptible insects.
Furthermore, the experiment used to demonstrate Bt toxin destruction in the stomach is an in vitro assay at a highly acidic pH that does not duplicate stomach conditions for the millions of Americans on certain acid-reducing medications.
Chronic exposure to Bt toxins via crops that are ingested in minimally processed forms (such as sweet corn and eggplant) is therefore more likely to result in Bt toxins, or fragments thereof, entering the bloodstream. These fragments may then reach vital organs that might be vulnerable to such exposures, the effects of which have not been studied. We cannot responsibly accept the assertion that the consumption of these foods is safe for all humans. Such assertions might well prove correct in many, or even most cases, but for some others, particularly among individuals dealing with other, chronic conditions, or who are much more heavily exposed to GE proteins occupationally or through their diet, they may well not.

Further considerations: weed and insect resistance

Weed resistance is emerging as a critical concern for farmers planting GE, Roundup Ready® crops. The seed industry has responded by creating corn, soybean, and cotton plants genetically engineered to be tolerant of both glyphosate (the active ingredient in Roundup ®) and 2,4-D, or glyphosate and dicamba. Glyphosate and 2,4-D have been combined by Dow AgroSciences into the new product Enlist Duo®. The EPA approved the registration of Enlist Duo® in late 2014, but recently asked a court to reverse the approval, in effect banning any commercial use of the product until a set of issues involving impacts on non-target plants and endangered species are resolved.
When the EPA was first asked to approve GE Bt corn and cotton, the agency immediately recognized the risk of triggering the emergence of Bt-resistant insects. The EPA was also well aware, as were farmers, environmentalists, and ecologists, that the many natural forms of Bt play an absolutely critical role in soil food webs and in microbial biocontrol in the soil.
Moreover, several natural strains of Bt are incorporated in liquid bioinsecticides that are the backbone of Lepidopteran insect-control programs on many conventional and organic vegetable farms. Industry, farmers, environmentalists, and the EPA all agreed that the loss of Bt efficacy to resistance would be extremely costly and damaging and that strong, preventive measures should be taken if and as transgenic Bt crops were planted.
Hence, the initial approvals of Bt corn and cotton were accompanied by mandatory resistance management practices recommended by independent, mostly academic entomologists. For many years, this proactive approach worked as hoped, and the effectiveness of transgenic Bt corn and cotton did not start breaking down until industry pressure convinced the EPA to relax the preventive measures.
But in the early 1990s, when considering the first applications to approve Roundup Ready® crops, the EPA did not feel that mandatory resistance-risk prevention measures were warranted, even though the agency recognized that herbicide-tolerant crop technology would greatly increase the risk of Roundup-resistant weeds becoming a serious problem for farmers—a situation analogous to the development of Bt-resistant insects.
Why the difference in the way the EPA addressed the risk of resistance in the case of Bt crops versus herbicide-tolerant crops? In the case of Bt crops, the concern was about the future efficacy of a natural bioinsecticide of enormous value to all farmers, and indeed humankind. Since it was clear to just about everyone at the time that no company had the right to jeopardize the biological utility of such an important natural resource, the EPA felt justified in imposing mandatory resistance management practices.
But in the case of Roundup Ready® crops and their associated herbicide, glyphosate, the EPA left the management of glyphosate resistance to the manufacturer, concluding that they would believe it in their best interest to preserve the efficacy of their product.
In retrospect, the decision to leave glyphosate resistance management to market forces was one of the most costly and damaging decisions made in the 40-year history of the EPA’s Office of Pesticide Programs.

Labeling

In the US, foods from GE crops are not labeled as such. This impedes efforts by doctors and epidemiologists to trace any possible connections between consumption of GE foods and adverse health outcomes. Some consumers support labeling because of religious or cultural norms, while others want labeling so they can preferentially seek out or avoid GE foods. Consumer surveys consistently show 85% or more support for GE-food labeling.
Labeling also comes into play in an important way in the flow of agricultural commodities in world markets. Nearly 70 countries have made international sales of non-labeled GE crops illegal. The decision by a country, or a company, to not label GE food fosters mistrust, which can be costly when trying to secure or hold export market share.
Because of the need for labeling to conduct post-approval market surveillance and secure and retain access to many sensitive foreign markets, it is only a matter of time before all foods derived from US-grown GE crops will be labeled. In the interim, expect a lively debate over what sorts of labels should be required, who should impose the requirements, and who should oversee compliance (public versus private entity; states vs. the federal government).

Overcoming objections to GE foods

Several major changes in the way GE crops and foods are tested, analyzed, regulated, and marketed are going to be necessary to improve market acceptance. Substantial progress will take time, consistency, and transparency. Essential building blocks needed to resolve lingering risk assessment issues and gain consumer trust and acceptance include:

1. Labeling of GE foods and associated public information campaigns.
2. Risk assessment that conforms to a high standard of excellence. Given our present understanding, such assessment ought to include cutting-edge techniques, e.g. genomics, transcriptomics, proteomics, metabolomics, immune system parameters, as well as siRNA/miRNA profiling.
3. Long-term animal-feeding studies. These should include multiple arms of investigation addressing toxicity, carcinogenicity, reproduction, and multigenerational effects, several physiologically relevant doses, and comparisons to isogenic, non-GMO-only controls. This testing should be based on real-world conditions, including the use of formulated pesticides where relevant.
4. Long-term studies that define toxicokinetics and produce information sufficient to complete a comprehensive anatomical, histological, physiological, and biochemical analysis of major organs, blood, and urine.
5. Post-market surveillance similar to that available for new medications. Until much more is known about the human health risks posed by GE crops, post-market surveillance must be carefully structured as part of government approval, and particular consideration should be accorded to the ways in which it will be carried out and paid for.

A transparent, comprehensive effort, demonstrating a real commitment to discovering harmful effects, if any, should be undertaken. In health care, we well understand the directive to “do no harm.” This should also pervade regulatory decision-making—especially when it comes to human food. Many members of the public erroneously believe that government agencies are acting in accordance with this directive in the case of agricultural biotechnology. We wish it were true and, because it is not, we will work to make it so.
For more information on this topic:
Druker, S. 2015. Altered Genes, Twisted Truth: How the venture to genetically engineer our food has subverted science, corrupted government and systematically deceived the public. Clear River Press.
© 2015 GMO Science. All Rights Reserved