11 The 2016 National Academies Study
In March 1863, while the United States was immersed in its Civil War, President Abraham Lincoln signed legislation establishing a new type of organization. The National Academy of Sciences was chartered as a private, nonprofit institution whose members were expected to provide pro-bono technical consultation to the government. The act stated that
The Academy shall, whenever called upon by any department of the government, investigate, examine, experiment and report upon any subject of science or art, the actual expense of such investigations, examinations, experiments, and reports to be paid from appropriations which may be made for the purpose, but the Academy shall receive no compensation whatever for any services to the Government of the United States.1
The National Academy began with fifty charter members. Its first president, Alexander Dallas Bache, was the great-grandson of Benjamin Franklin. Over the years, it has expanded to include National Research Council (1916), the National Academy of Engineering (1964), and the National Academy of Medicine (1970), which became the National Institute of Medicine (2015). The name given to the overarching organization became the National Academies of Sciences, Engineering, and Medicine (NASEM) in 2015.
NASEM is the most eminent nonprofit, independent scientific organization in the United States. It is a self-governing, self-perpetuating organization with over 2,000 members and 400 foreign associates. New members are elected into the organization by existing members. Other than reimbursement for travel and lodging, members do not receive compensation for their consultation. NASEM also publishes the Proceedings of the National Academy of Sciences (PNAS), one of the most prestigious international scientific publications. Like the Royal Society in the United Kingdom, the National Academies of Sciences, Engineering, and Medicine, with its cadre of Nobel laureates and medal winners, ranks among the top scientific institutions in the world.
Between 1985 and 2016, the National Academies issued nine consensus reports on agriculture and biotechnology. The first report, titled New Directions for Biosciences Research in Agriculture: High Reward Opportunities, was sponsored by the U.S. Department of Agriculture (USDA) and provided recommendations for where molecular genetics can contribute to studies of animals, food, crops, plant pathogens and insect pests. Subsequent NASEM reports were released in 1987,2 1989,3 2000,4 2002,5 2004 (two reports),6 2010,7 and 20168 and cover human health and the ecological safety of bioengineered crops.
A consistent theme that runs through the reports is that there is no evidence that foods derived from genetically engineered crops pose risks that are qualitatively different than foods produced by conventional breeding methods. Nor is there any evidence that transgenic crops and the foods derived from them are unsafe to eat. The most recent NASEM report, published in May 2016, addresses the new body of animal feeding experiments that were designed to test the health effects of GMOs, epidemiological data on human health effects covering countries with different GMO consumption patterns, and new data on environmental impacts and yields of transgenic plants.9 Because this consensus report is the most recent and engages the widest body of literature on human health effects of GMOs, I discuss how the study covers the issues and what consensus recommendations came from the report.
The mandate given to the panel of the 2016 report was to look at the food safety, environmental, social, economic, and regulatory aspects of transgenic crops. The report defines genetic engineering as “the introduction of or change of DNA, RNA, or proteins manipulated by humans to effect a change in an organism’s genotype or epigenome.”10 It includes in its definition new gene-editing techniques such as CRISPR/Cas9. The report distinguishes between genetic engineering and biotechnology. Under biotechnology, the panel includes some methods that are usually classified within traditional breeding (such as chemical and nuclear induced mutagenesis) as well as some in vitro culture techniques that enable wide crossing of plants, which does not occur naturally. By establishing these definitions and distinctions, the NASEM panel revealed its judgment that a greater continuity exists between traditional breeding and molecular breeding than is usually recognized in the regulatory or nonprofit sector.
Crop Yields of Transgenic Crops
A widely heralded claim among pro-GMO advocates is that genetically engineered crops are necessary to keep pace with the world’s growing population and the declining marginal advances in crop productivity from the Green Revolution. The question that has been raised from the birth of the agricultural biotechnology industry is whether GMOs will increase farmer yield. The first crops were designed explicitly for productivity. Herbicide-resistant crops were expected to reduce the competition of food plants with weeds and thus provide crops with greater access to soil nutrients, water, sunlight, and space for crop growth. Insect-resistant crops were designed to reduce crop losses resulting from insect infestations and thus improve yields.
The 2016 NASEM report is consistent with past National Academies studies by distinguishing between potential yield and actual yield. The potential yield of a cultivar is the theoretical yield that the crop could have without any limitations of water or nutrients (such as nitrogen), without any losses to pests and disease, and with an ideal supply of environmental resources (such as sunlight, carbon dioxide, and temperature). The actual yield represents the farming conditions and limitations for achieving maximum (theoretical) yield, including insect pests, crop diseases, weeds, soil acidity, and water scarcity.
Scientists have theorized that genetically engineered crops can improve potential yield by modifying the crops’ biochemical pathways in order to utilize external resources (such as sunlight through photosynthesis) more efficiently or by improving the uptake of nutrients from the soil for plant growth. The 2010 National Research Council report concluded that “GE traits for pest management have an indirect effect on yield by reducing or facilitating the reduction of crop losses.”11 The NRC reported that there have been higher yields in many cases because of more cost-effective weed control and reduced losses from insect pests but that herbicide-tolerant crops have not substantially increased yield.12 Thus far, the advancement of improved crop yield directly through genetic engineering has been mixed. The one exception is the transgenic eucalyptus tree as a source of cellulose. The transgene causes more cellulose to be found on the cell walls of the plant, which gives the transgenic crop a significant yield boost of 20 percent.13
The 2016 NASEM report acknowledges that a number of factors are associated with changes in crop yield for both conventional breeding and molecular breeding that involve farming practices and environmental conditions. After reviewing all the evidence on crop yield changes over the past forty years, the report states that “the nation-wide data on maize, cotton or soybean in the United States do not show a significant signature of genetic-engineering on the rate of yield increase.”14 Although the yield of some genetically engineered crops has increased substantially since 1980, it is an open question whether GE will contribute to higher yields in the future.
With respect to Bacillus thuringiensis (Bt) crops, the NASEM report maintains that it is not totally clear whether transgenic crops contribute to higher yields. Other factors “could confound the estimation of the apparent yield advantage of the Bt varieties.”15 The National Academies panel debunks the overzealous and empirically deficient claims of GMO proponents that higher yield was one of the critical benefits of genetically engineered crops and was therefore integral to feeding a growing planet (a global population that the United Nations estimates will reach 9.7 billion by 2050).16 There were a few conditions under which the panel found yield increases: “Bt crops have increased yields when insect pressure was high, but there was little evidence that the introduction of GE crops were resulting in a more rapid yearly increase in on-farm crop yields in the United States than had been seen prior to the use of GE crops.”17 Cotton yields have been stymied by the ubiquitous bollworms. One study in the Punjab province in Pakistan found that Bt cotton used fewer pesticides, produced greater yields, and brought greater profits to farmers.18 The panel’s overall assessment of GMO yields is consistent with the scientific studies that show that GMO yield increases were idiosyncratic, circumstantial, and not systematic.
Health Effects of GMOs
The 2016 NASEM report devotes a chapter to the health effects of GMOs. It addresses the seminal issues that separate pro- and anti-GMO communities, such as “the assumption that a plant’s endogenous metabolism is more likely to be disrupted through the introduction of new genetic elements via genetic engineering than via conventional breeding or normal environmental stresses on the plant.”19 The National Academies panel investigated the scientific literature that evaluated the health effects of GMOs compared to non-GMOs. It began its investigation by summarizing what was known about natural toxins in food, which can result from traditional breeding. Breeders usually select against crops with high levels of natural toxins. Some conventionally bred varieties (such as a potato variety with high concentrations of glycoalkaloids) have been taken off the market.20 It reported what is widely understood and uncontroversial—namely, that “crop plants naturally produce an array of chemicals that protect against herbivores and pathogens. Some of these chemicals can be toxic to humans when consumed in large amounts.”21 A question that has persisted is whether GMOs will introduce an unanticipated class of new proteins or their metabolites from foreign gene inserts that will result in adverse health effects.
Substantial Equivalence and Food Safety
The 2016 NASEM study outlines three categories of testing for evaluating food safety—acute or chronic animal feeding toxicity testing that uses whole foods, compositional analysis that looks at proteins and other molecules in the food, and allergenicity testing that usually is done in vitro or on humans. If GMOs are assumed to be safe or as safe as crops traditionally bred, then until proven otherwise, safety testing ordinarily would not be required.
U.S. policy on GMOs depends largely on the adoption of the concept of substantial equivalence. The 2016 NASEM report acknowledges that “No simple definition of substantial equivalence is found in the regulatory literature on GE foods”22 and that its use has been debated. The National Academies committee affirms that “substantial equivalence” remains the cornerstone for GMO food-safety assessment by regulatory agencies and, without offering an argument, states as a finding that “The concept of substantial equivalence can aid in the identification of potential safety and nutritional issues related to intended and unintended changes in GE crops and conventionally bred crops.”23 What is missing is an independent criterion for substantial equivalence or at least an operational definition. We shall return to the NASEM committee’s use of omics analysis as a surrogate for substantial equivalence.
Animal Feeding Studies
The 2016 NASEM report discusses animal studies of whole GMOs extensively to underscore uncertainties about testing protocols. The NASEM panel asked, What are the appropriate doses? What types of special testing requirements are involved when testing whole foods compared to agricultural chemicals? What is the right number of animals to be used in a study? In animal feeding studies, what percentage of the animal diet should consist of the GMO? Should the proportion of the GMO in the animal diet reflect actual feeding practice or test hypothetical situations (such as accumulation over generations)? How many feeding days should be included in the short-term animal tests? What constitutes a long-term test, and should it include a multiple-generation test?
Because the study of GMOs has not been standardized, many of the above questions have been left unanswered. The 2016 NASEM report raises questions about the utility of whole-food animal studies: “The utility of the whole-food tests has been questioned by a number of government agencies and by industry and academic researchers … and they are not an automatic part of the regulatory requirements.”24
The NASEM study highlights the criticisms of animal feeding tests that were made by members of the scientific community and cites the fragility of any consensus on using a particular methodology for assessing GMO food risks. One group of scientists debunked whole-food animal studies because they are not sensitive enough to detect differences and there were other types of tests to evaluate safety. Another group of scientists believed that whole-food tests could be useful if their design were appropriate and if they could be performed objectively without a commercial bias.
In the 2002 National Research Council study titled The Environmental Effects of Transgenic Plants: The Scope and Adequacy of Regulation, the panel says that “With few exceptions, the environmental risks that will accompany future novel plants cannot be predicted. Therefore, they should be evaluated on a case-by-case basis.”25 This finding about environmental effects might be thought to apply to human health effects, too. Yet without a standard protocol and consensus on the testing requirements, there is not likely to be agreement on the interpretation of any particular test.
The 2016 NASEM report examines a number of animal feeding studies and in the process of reviewing them raises questions about their methodology and validity, especially for those that reported adverse effects. The report gives considerable attention to the 2012 toxicology study by Gilles-Eric Séralini and his colleagues, which initially was published in and then retracted by the journal of Food and Chemical Toxicology and then republished in a European journal. The NASEM panel echoed the criticisms of reviews and studies from Monsanto supporters. Although Séralini and his colleagues undertook the first long-term animal whole-food study for GMOs, the panel disagreed that “this one study should lead to a general change in global procedures regarding the health effects and safety of GE crops.”26 Other researchers have also called for long-term studies as recommended by Séralini et al.
Séralini and his colleagues responded to their critics in an eight-page “Answer to Critics” in Food and Chemical Toxicology.27 They noted that no guidelines exist for GMO toxicity studies in vivo, responding to critics who claimed that they had failed to satisfy the standard protocols. They chose to use the guidelines of the Organisation for Economic Co-operation and Development (OECD), which were the best available for European studies.
Séralini et al. were clear from the outset that their study was not a carcinogenesis study, which would have required fifty rats for each group, as recommended by OECD guidelines. Theirs was a chronic toxicity study, which according to the OECD required only ten rats in each group. The 2016 NASEM report focused on the tumor data because it received the most media attention. NASEM did not address the primary data from the experiment—namely, sex hormone imbalances, disabled pituitary function, disruptions of estrogen-related pathways, and the enhancement of oxidative stress. Séralini and his colleagues were clear throughout their original retracted paper and the republished study that long-term studies need to be conducted to confirm their results.
The 2016 NASEM panel acknowledged that Séralini et al. followed the OECD testing guidelines that called for ten male and ten female rats, even though the experiment was criticized by the European Food and Safety Authority (EFSA)28 for not having enough animals to report tumor incidence. Séralini et al. responded: “The criticism of the relatively low number of rats used in our experiment relies entirely on the misconception that it is a carcinogenicity study. It was not the case, as we stated clearly in the title and the introduction.”29
The NASEM report stated: “The current animal-testing protocols based on OECD guidelines for the testing of chemicals use small samples and have limited statistical power; therefore, they may not detect existing differences between GE and non-GE crops or may produce statistically significant results which are not biologically meaningful.”30
The EFSA published a paper in 2011 that outlines the distinctions between statistical significance and biological significance in animal testing experiments. The former is related to statistical concepts, and the latter is related to biological considerations. Results that turn out to be statistically significant (namely, that there is a 95 percent probability that the observed effect did not happen by chance) may not turn out to be biologically meaningful. EFSA notes that “Many researchers incorrectly conclude that any statistically significant effect is biologically relevant as it is supported by mathematics.”31 Statistical significance is calculated after the experiment. But biological relevance should be considered in the design stage of the experiment before the test is begun (see figure 11.1 for the sequence of events).
Power analysis and biological significance
A power analysis is an analytical method for determining the size of the researchers’ sample in animal testing in order to obtain statistical probability of a type II error or a false negative. It is used to estimate the chances of detecting an effect before the study is conducted to determine the sample size needed.
To carry out the power analysis, one needs to stipulate several key factors—(1) effect size, (2) standard deviation for variables with quantitative effects, (3) chosen statistical significance level, (4) chosen power, (5) alternative hypotheses, and (6) sample size. Investigators will specify the first five factors in order to determine the sample size. The power or effect size also can be calculated if the sample size is fixed.32 A power of 80 to 90 percent is usually considered good.
A power analysis is not done if there is no clear hypothesis or no prior data to enable a power determination. Séralini and his colleagues did not have a fixed hypothesis for their two-year test. It was a broad observational study with controls: “All rats were carefully monitored for behavior, appearance, palpable tumors, infections, during the experiment, and at least 10 organs per animal were weighted and up to 34 analyzed postmortem, at the macroscopic and/or microscopic levels (Table 1).” In their response to critics, the investigators encouraged others to repeat the study for any of their observed results: “We encourage others to replicate such chronic experiments, with greater statistical power. What is now urgently required is for the burden of proof to be obtained experimentally by studies conducted independent from industry.”33
Other than the statistical significance of an animal feeding study, like EFSA, the 2016 NASEM panel cited the importance of the biological relevance of the findings: “How large a difference is biologically relevant before designing an experiment to test a null hypothesis of no difference?” A study with statistical significance does not eliminate uncertainty. It is merely the first step in reaching a sound result. The panel wrote: “If a whole-food study with an animal finds statistically significant effects, there is obviously a need for further safety testing, but when there is a negative result, there is uncertainty as to whether there is an adverse effect on health.”34 The panel states that a positive outcome in an animal feeding study (adverse effect) does not mean there was sufficient statistical power in the test. Compare this with what EFSA wrote: “a statistically significant treatment effect may exist but be biologically irrelevant because, although statistically significant, it is smaller than the predefined biologically relevant effect size.”35
In addition to the study by Séralini and his colleagues, the 2016 NASEM panel cited other long-term rodent studies, some of which were intergenerational. Several of the studies found statistically significant differences between GMOs and non-GMOs, which the NASEM report did not consider “biologically relevant,” without providing data on the normal range of variation among non-GMO crops. The NASEM committee questioned whether the statistically significant results of a study should be dismissed without sufficient reason.
Aysun Kiliç and Mehmet Turan Akay conducted a three-generation rat study in which 20 percent of the diet was Bt maize or a non-Bt maize that otherwise was genetically similar.36 All generations of female and male rats were fed the assigned diets, and the third-generation offspring that were fed the diets were sacrificed after 3.5 months for analysis. The authors found that “although the results obtained from this study showed minor histopathological and biochemical effects in rats fed with Bt corn, long term consumption of transgenic Bt corn throughout three generation[s] did not cause severe health concerns on rats. Therefore, long-term feeding studies with GM crops should be performed on other species collaboration with new improving technologies in order to assure their safety.37
The 2016 NASEM report questioned Kiliç and Akay’s result, arguing that “there was no presentation of standards used for finding what would be a biologically relevant difference or what the normal range was in the measurements.”38 The NASEM report questioned whether the power of the study was sufficient and also surmised that “most if not all of the rodent studies are based on widely accepted safety evaluation protocols with fixed numbers of animals per treatment.”39
The NASEM committee raised other areas of uncertainty, such as whether the GMO and non-GMO sources were isogenic or were grown in different or unknown locations: “These problems in design make it difficult to determine whether differences [found in studies] are due to the genetic-engineering process or GE trait or to other sources of variation in the nutritional quality of crops.”40 With respect to the animal feeding studies, the most important message of the NASEM report calls for follow-up testing, not simply dismissal of some results: “In cases in which testing produces equivocal results or tests are found to lack rigor, follow-up experimentation with trusted research protocols, personnel, and publication outlets is needed to decrease uncertainty and increase the legitimacy of regulatory decisions.”41 Although some feeding studies with pigs showed no adverse effects, the panel did report statistically significant phenotypic differences (such as in conversion efficiency from the feed) between pigs that were fed Bt maize (GMO) and those that were fed non-GMO maize. No definitive conclusions can be drawn because of limitations in the studies, but NASEM could not discount the possibility that the genetically engineered food was responsible for the differences in animal effects.
The NASEM committee placed considerable value in the long-term animal feed data collected by the USDA. Comparison of livestock health and feed conversion ratios as reported in a review by Alison L. Van Eenennaam and Andrea E. Young42 found that no adverse effects were detected in farm animals after comparing animal health before and after the conversion to GMO feedstock.
With regard to animal feeding studies, the NASEM report recommended that such studies should be conducted with consideration for statistics that are biologically relevant, with a power analysis done for each characteristic (endpoint) and follow-up studies carried out when there are equivocal results on the health effects of GMO crops. The NASEM committee called for public funding in the United States for independent follow-up studies whenever there were equivocal results.43 Follow-up studies were rarely, if ever, conducted when there were adverse outcomes.
The Composition of GMOs Compared to Non-GMOs
Beyond animal studies, a second area of interest for evaluating genetically engineered crops is compositional analysis. Seed manufacturers can submit a compositional analysis of a new genetically modified cultivar to the FDA, but they are not required to do so. When they do submit the analysis, they select certain components of the GM crop (nutrients, antinutrients, toxicants), and the levels of expression of those components are measured and compared with similar components in the parental (or counterpart) variety from which the GM crop was developed. The analysis may report statistically significant differences between the level of the proteins in the GM and non-GM plants. This could be important if the GM plant had higher or lower levels of a toxicant or nutrient compared to its non-GMO parental or counterpart strain. Such a finding might suggest that the GMO is not materially equivalent to its isogenic non-GM strain.
But the 2016 NASEM report says that such a finding does not tell the whole story. The GMO protein may have a mean concentration of a protein that is 70 percent of what the non-GM plant yields. What is left out is the variation of the protein across a wide range of non-GM plants. Data from a wide variety of non-GM plants for the protein show a range of concentrations for each protein. If the 30 percent difference in the test samples is within the range of the natural variations that occur within the non-GM cultivar (under similar environmental conditions), then the differences found in comparing GMO and non-GMO cultivars, although statistically significant, are not biologically significant. Thus, the 2016 NASEM report states that statistical significance in compositional analysis may not reveal an important difference in test samples unless one knows the natural variations in a protein for the cultivar.
There is another caveat in trying to understand the differences in the compositional analysis: “It is difficult to know how much of the variance and range in values for the components is due to the crop variety, the growing conditions, and specific laboratory experimental equipment.”44 Head-to-head compositional studies for GMO and non-GMO cultivars could be done on isogenic crops grown side by side, and the results could reveal any compositional differences arising from the genetic engineering method. The panel also questioned whether the proteins that were selected for compositional analysis were the right choice. The current compositional analyses have not assessed whether the components measured are the appropriate ones to examine or whether differences found in measured components are indicators that there are differences in other unmeasured components. This suggests that the seed manufacturers should not choose the components for valid compositional analysis because there may be a selection bias.
After outlining the limitations in the current compositional analyses, the NASEM committee praises the importance of newly developed omics methods for understanding whether compositional changes occur in GMOs. These methods are not currently required to be used by regulatory authorities. Omics is a field of study in biology that examines distinct classes of molecules in cells, tissues, and organisms, including genes (genomics), RNA molecules (transcriptomics such as mRNA and tRNA), proteins (proteomics), and chemical metabolites or breakdown products (metabolomics). Some omics studies require mass spectrometry (liquid chromatography-tandem mass spectrometry), electrospidy ionization (ESI) (a technique used to produce ions using an electrospray and a high voltage applied to a liquid to create an aerosol), and electrophoresis (such as differential image gel electrophoresis, or DIGE).
The 2003 genetically engineered food guidelines of the Codex Alimentarius Commission—a body established in 1963 by the United Nations Food and Agriculture Organization and the World Health Organization to set standards for food safety and quality—includes some but not all of NASEM’s recommendations for omics analysis, including an examination of new metabolites, food composition analysis, food components, and proteins. Codex is an influential organization in Europe, where testing of GE foods is required. As previously noted, in the United States GE foods are not required to be approved as safe by the FDA before entering the commercial market.
The 2016 NASEM report concludes the section on compositional analysis by stating that without omics analyses of crop composition, we are left with uncertainty over whether the GMO and the isogenic parental (or non-GMO counterpart) strain are materially equivalent. Despite these uncertainties, the committee appears confident about the safety of GMOs for consumers. There are other reasons that give the panel confidence that the current GMOs in circulation are not unsafe, even as there are some adverse effects observed from certain animal feeding studies that have not been replicated for confirmation.
Global Health Data
The 2016 NASEM report surmises that if GMOs have a significant impact on human health, the effects would show up in global health data. The committee looked at global data on cancer, chronic kidney disease, obesity, celiac disease, and allergies before and after the introduction of GMOs and compared data from countries that had heavy consumption of GMOs with countries that had light consumption. Among the data consulted was cancer incidence in women and men in the United Kingdom (a country where GMOs generally were not consumed) and in the United States (where most of the soybean and maize were GMO varieties). The committee found that the patterns of change in cancer incidence in both regions were generally similar, even though European diets contain much lower amounts of feed derived from genetically engineered crops. There was no unusual rise in cancer incidence for specific types of cancers in the United States after 1996, when GMOs were first introduced. Because of this, the report states that global cancer data “do not support the hypothesis that GE foods have resulted in a substantial increase in the incidence of cancer” from the consumption of GMOs and that the findings are clear about no findings of cancer risk.
Although a few animal feeding experiments with GMOs had cancer endpoints, cancer was not a major postulated outcome of consuming GE crops. Based on the global data, kidney disease, autism, and food allergies were not attributable to GMOs. Overall, “the committee found no differences that implicate a higher risk to human health from GE foods than from their non-GE counterparts.”45 In its final conclusion on the health effects of GMOs, the NASEM committee wrote that “the research that has been conducted in studies with animals and on chemical composition of GE food reveals no differences that would implicate a higher risk to human health from eating GE foods than from eating their non-GE counterparts. The committee could not find persuasive evidence of adverse health effects directly attributable to the consumption of GE foods.”46
In 2015, I published a paper that examined eight systematic reviews of research on the health effects of GMOs published between 2008 and 2014.47 The reviews differed significantly in their conclusions about what the current science concludes about the health effects in animal feeding studies. One review states that GMOs may cause hepatic, pancreatic, renal, and reproductive effects on animals,48 and another review states that the research does not suggest any health hazards or any statistically significant differences between GMO and non-GMO crops in the parameters observed.49 I also found twenty-six studies that individually report adverse effects of GMOs in animal feeding studies.
After reviewing the 2016 NASEM report, several questions came to mind. Does the study cite the reviews that I cover in my 2015 paper? Does it cite the twenty-six studies? Does it dismiss the reviews and studies that reported positive effects from GMOs because of methodology, weak statistical power, or lack of replication?
In the chapter on health effects of GMOs in the 2016 NASEM report, there are 287 references. That report cites four of the eight systematic reviews that I cover in my paper. Of the four that it does not cite, some report that GMOs cause adverse effects, and others reported no differences between GMOs and non-GMOs in animal studies. The NASEM report cites or acknowledges only four of the twenty-six individual studies that I found that report adverse effects. Of the studies not cited in the NASEM review, many appeared in respected journals such as The Lancet, Journal of Anatomy, Journal of Agriculture, Food and Chemistry, Animal Science, Archives of Environmental Contamination and Toxicology, Journal of Biological Sciences, Reproductive Toxicology and Critical Reviews in Food, and Science and Nutrition.
This leaves me with more questions than answers. The NASEM panel gives no specific reasons for not acknowledging four reviews and twenty-two studies. Would these studies have shifted the weight of evidence? It does not seem likely that these additional studies would have shifted the outcome of the report, given the authoritative positions cited in the 2016 NASEM report—from past National Research Council studies, the American Association for the Advancement of Science, the American Medical Association House of Delegates, the World Health Organization, the FDA, and the European Commission—that have expressed confidence in the safety of GMOs for human and animal consumption. As for the results by Séralini and his colleagues, which were retracted after a year without the authors’ consent from the journal of the initial publication, the 2016 NASEM report cites the fact that no dose-response relationship was found and that the reanalysis by the European Food Safety Authority found no statistically significant differences between the GM and the non-GM crop. Séralini et al.’s work was labeled as undependable and, like most whole-food animal studies, not a credible way to assess the safety of GMOs.
The Integrity of the 2016 NASEM Study
It is now generally recognized that corporate funding of research can bias the outcome in favor of the financial interests of the funder. Most major journals have adopted financial conflict-of-interest (fCOI) disclosure policies for their contributors. Government agencies also require fCOI disclosure for members of advisory panels.
In the 1997 amendments to the Federal Advisory Committee Act (FACA), requirements regarding financial conflicts of interest were established for committees of the National Academies of Sciences, Engineering, and Medicine (then called the National Academy of Sciences). The new rules stated that federal agencies cannot utilize the scientific advice of NASEM unless two conditions are met. First, no individual appointed to serve on a NASEM committee can have a conflict of interest relevant to the functions to be performed unless NASEM determines that the conflict is unavoidable, in which case it must be promptly and publicly disclosed. Second, the committee membership must be fairly balanced.50
In response to the FACA requirements, NASEM developed its own conflict-of-interest guidelines. Some of the NASEM panels were criticized for having a high percentage of scientists (somewhere between 20 and 25 percent) who had ties to industry.51 The 2016 NASEM genetically engineered crop report states that there were no conflicts of interest among the twenty scientists who comprised the panel. A February 2017 study of the panel members for the report found that six out of the twenty had financial interests in genetically engineered crops, including patents and corporate research grants.52 The Academies dismissed the results of the 2017 study in the following news release:
The National Academies of Sciences, Engineering, and Medicine have a stringent, well-defined, and transparent conflict-of-interest policy, with which all members of this study committee complied. It is unfair and disingenuous for the authors of the PLOS article to apply their own perception of conflict of interest to our committee in place of our tested and trusted conflict-of-interest policies.53
In May 2017, the president of NASEM was quoted in The Scientist as stating that the organization would be revising its conflict-of-interest policy.54
In conclusion—notwithstanding the caveats expressed throughout the voluminous 2016 NASEM assessment about the uncertainties in the studies (both positive and negative), the limitations of the compositional analysis, and the importance of follow-up studies—the panel affirms that there is no evidence of health hazards from GMO food consumption. The report offers a comprehensive and nuanced analysis of genetically engineered crops, but it does not close the chapter on the health effects of GMOs. There needs to be a consensus on standardized tests (including compositional omics analysis, in vitro tests, and animal feeding studies), publicly funded research on molecular approaches for testing future products, and follow-up testing for any equivocal results. There is no evidence that the report changed the minds of the legions who remain skeptical about GMO products.
Notes
1. National Academies of Sciences, Engineering, and Medicine (NASEM), “Who We Are,” http://
2. National Research Council, Agricultural Biotechnology: Strategies for National Competitiveness (Washington, DC: National Academy Press, 1987).
3. National Research Council, Field Testing Genetically Modified Organisms: Framework for Decisions (Washington, DC: National Academy Press, 1989).
4. National Research Council, Genetically Modified Pest-Protected Plants: Science and Regulation (Washington, DC: National Academy Press, 2000).
5. National Research Council, The Environmental Effect of Transgenic Plants: The Scope and Adequacy of Regulation (Washington, DC: National Academies Press, 2002).
6. National Research Council, Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects (Washington, DC: National Academies Press, 2004); National Research Council, Biological Confinement of Genetically Engineered Organisms (Washington, DC: National Academies Press, 2004).
7. National Research Council, The Impact of Genetically Engineered Crops on Farm Sustainability in the United States (Washington, DC: National Academies Press, 2010).
8. National Academies of Science, Engineering, and Medicine (NASEM), Genetically Engineered Crops: Experiences and Prospects (Washington, DC: National Academies Press, 2016), 36.
9. NASEM, Genetically Engineered Crops.
10. NASEM, 58.
11. National Research Council, The Impact of Genetically Engineered Crops, 100.
12. National Research Council, 135.
13. Heidi Ledford, “Brazil Considers Transgenic Trees,” Nature, August 27, 2014, https://
14. NASEM, Genetically Engineered Crops, 102.
15. NASEM, 116.
16. United Nations Department of Economic and Social Affairs, “World Population Projected to Reach 9.7 Billion by 2050,” July 29, 2015, http://
17. NASEM, Genetically Engineered Crops, 154.
18. Khuda Bak, “Impacts of Bt Cotton on Profitability, Productivity and Farm Inputs in Pakistan: Use of Panel Models,” Environment and Development Economics 22, no. 4 (2017): 373–391, doi.org/10.1017/s1355770x17000080.
19. NASEM, Genetically Engineered Crops, 173.
20. NASEM, 175.
21. NASEM, 175.
22. NASEM, 176.
23. NASEM, 178.
24. NASEM, 185.
25. National Research Council, The Environmental Effect of Transgenic Plants, 15.
26. NASEM, Genetically Engineered Crops, 191.
27. Gilles-Eric Séralini, Robin Mesnage, Nicolas Defarge, Steeve Gress, Didier Hennequin, Emilie Clair, Manuela Malatesta, and Joël Spiroux de Vendômois, “Answers to Critics: Why There Is a Long Term Toxicity Due to a Roundup-Tolerant Genetically Modified Maize and to a Roundup Herbicide,” Food and Chemical Toxicology 53 (2013): 476–483.
28. European Food Safety Authority, “Review of the Séralini et al. (2012) Publication on a 2-Year Rodent Feeding Study with Glyphosate Formulations and GM Maize NK603 as Published Online on 19 September 2012 in Food and Chemical Toxicology,” EFSA Journal 10, no. 10 (2012): 2910.
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