Review: GMOs Decoded

GMOs Decoded

Krimsky, Sheldon. (2019) GMOs Decoded. A Skeptic’s View of Genetically Modified Foods. Cambridge, Massachusetts: MIT Press. 161 pp. + 9 pp. References Cited. Forward by Marion Nestle. ISBN 9780262039192

Ellen Messer (Tufts University)

“What risks are acceptable and at what cost?” (p.14). These are the motivating questions of scientist-philosopher Sheldon Krimsky’s latest writings on GMOs, for which his findings can be summarized: much remains “uncertain.” As a corollary, he questions the widely touted “scientific consensus” of the benefits and safety of GMOs, rejected by European publics and policy makers who resist more widespread GMO approval and usage in the absence of greater certainty. This short book considers what additional evidence must be supplied before he and other skeptics would join the consensus.

The book is well organized. In an eight-page introductory overview, Krimsky lays out recurring questions that characterize the debate pitting GMO proponents against opponents, then chapter by chapter clarifies the logic of the frameworks, arguments, and evidence favoring one or the other viewpoint. Chapters 1 and 2 define and explicate, respectively, “traditional” vs. “molecular” plant breeding, and chapter 3 evaluates the “differences … and their significance for evaluating crops”. The next four chapters consider the evidence for qualities and safety of “early products in agricultural biotechnology” (Ch.4) and Herbicide-Resistant, Disease-Resistant, and Insect-Resistant crops (Ch’s 5-7). He explains how initial products included Calgene’s high-solids content, delayed ripening tomato, which was produced by “antisense technology … a small step in the move toward genetically engineered (GE) crops. No new genes were introduced into the tomatoes: the gene for one enzyme was removed and inverted” (p.34). The selected agronomic traits, by contrast, were constructed by engineering gene-transfers into multiple crops. Krimsky’s critical risk assessment comparing and contrasting molecular versus traditional breeding encompasses all GE.

Chapters 8 and 9, “Genetic Mechanisms and GMO Risk Assessment” and “Contested Viewpoints on the Health and Environmental Effects of GMOs” systematically probe the many uncertainties that still surround these manipulations of plant biology, genetics, and transformations, after more than thirty years of scientific evaluations. Krimsky is selective in citing sources for his skeptical analysis; for example, he finds particularly useful three points raised by David Schubert, a geneticist at the Salk Institute: (1) the same gene introduced into two different types of cells can produce two very different protein molecules; (2) the introduction of any gene can change gene expression and phenotype of the recipient cell (and by extension, organism); and (3) enzymatic pathways that synthesize small molecules (e.g., vitamins) can interact with endogenous pathways and produce novel molecules. All serve to question whether “generally recognized as safe” (GRAS) or “substantial equivalence” evaluations are adequate to judge identity and safety of GMOs (pp.69-70). Krimsky additionally uses Schubert’s uncontested scientific reasoning to argue that all products produced by molecular breeding, including gene editing that does not involve foreign gene transfers (GMOs), should be safety- regulated by method of breeding rather than final product. This is because molecular breeding entails potentially more unexpected changes in the new GE product; new molecules or enzymatic pathways resulting from genetic introductions or rearrangements may not be so easily recognized by the laboratory or commercial breeder who is not looking for such variants. U.S. and European authorities largely disagree on how to respond to all these uncertainties. U.S. regulators have moved more quickly in the direction of deregulation of additional plant varieties and products that involve processes and outcomes that have previously been judged GRAS or substantially equivalent to conventional products whereas European authorities have decided to withhold safety approval until risks, including GE procedures that do not involve foreign gene transfer, can be exhaustively evaluated. Such contradictory judgments call for additional chemical-component compositional and ecological analyses, animal feeding trials, or both.

There follow three short chapters summarizing: (10) the arguments for and against GMO labelling, (11) the carefully balanced evidence and concluding uncertainties of the largely pro-GMO 2016 National Academies Study on agricultural biotechnology, and (12) “The Promise and Protests of Golden Rice,” the one crop designed to meet micro-nutrient nutritional needs of low-income consumers in developing countries. Chapter 13 shows where “Science Studies” cultural-political arguments against GMOs diverge from the preceding science, and provides a good summary of the social issues in which conflicting views on GMOs are embedded. These public and social-science positions can be summarized that (1) there is no value-free science so “it is neither unreasonable nor irrational for there to exist disagreements because the value judgments are not premised exclusively on scientific authority”; (2) non-scientists appeal to religion, folk wisdom, family values, among other “non-scientific beliefs … “ in their judgments; and (3) “individuals who are inclined to follow scientific advice exclusively on matters of risk and health benefits may accept the knowledge claims or statements highlighting uncertainty by outlier scientists who(se) … views fall outside the mainstream.” (p.xviii). Krimsky throughout embraces the principle that “The history of science teaches us that minority positions sometimes become validated and should not be discarded at the outset, especially when questions remain unresolved.” (Ibid). Carefully and thoroughly, he shows how GMO proponents have done their best to squelch any negative findings reporting risks, either of gene transfers into non-target crops, health damages to experimental animals, or unanticipated gene products and outcomes.

The final chapter summarizes answers to his initial questions. Scientists and the general public and policy makers disagree with each other on the risks and implications of GMOs, he concludes, because they are asking different questions and framing the issues and requirements for supporting information in different ways. Critical public discourses are not based exclusively or mainly on authoritative science, but motivated by cultural and political-economic, including “food sovereignty” considerations and public opinion. It follows that “science-based” evaluations on the safety and advisability of GMOs in general or specific food-crops in particular, can never satisfy all scientists or the public at large.

As someone who began exploring agricultural biotechnologies in the mid-1980s, with the motivating question, “what opportunities might GMOs present for ending world hunger?” I found Krimsky’s presentation both lucid and frustrating. As scientist and philosopher, he carefully defined terms and analyzed ecosystem, organism, cellular, and molecular dimensions of transgenic processes and products in exquisite detail. These specifics showed the relative controllability of each step in the transformation process, and indicated how uncertainties arise in GE products, outcomes, and impacts. New transgenic seed varieties that have been extensively but not exhaustively tested are attractive to farmers because they promise higher yields with lower labor, chemical, and environmental costs, which potentially raise incomes. As anthropologists, among others, have shown, such alleged benefits appear to atrophy over the longer term, because the pests particular transgenics were designed to protect against develop resistance, or the introduction of new GE varieties paired with agricultural chemicals raise new ecological challenges. These foreseeable consequences put the farmers and the product developers on a dangerous treadmill that, in addition to making farmers dependent on additional products of ever more concentrated seed-chemical companies, may increase, rather than decrease, chemical loads, costs, and damages.

The thoroughness of his hypothetical questions and answers, however, offer the reader little guidance to answer the overarching questions. How much information is enough? Complete biochemical compositional analysis might be desirable; but would anything less suffice? Scientists and policy makers obviously disagree about how much uncertainty is tolerable, so what should non-experts think? For example, he insinuates that animal toxicity studies are always flawed. Yet his uncertainty assertions keep harking back to animal studies that indicated GMO toxicity, but which have never been replicated. Similarly, how valid are assertions that new allergens must always be considered a threat in GE products because the scientific community understands and has identified only a narrow range? Polarization on the dangers posed by known vs. unknown allergens continues; Krimsky gives no guidance on how to negotiate this divide.

Some arguments against GMOs, which Krimsky cites as worthy, can also be applied to non-GMO agricultural innovations. Changes in soil microbiome composition, for example, could be expected to accrue not only from GMOs, but from all new varieties and many of the new non-GMO seed dips, whose aim is to transform the microbial mix and benefit plant growth in expectable ways. Most frustrating, I wished that Krimsky had considered more carefully the management and monitoring issues. As a case in point, the virus-resistant papaya in Hawaii not only required development of protective seeding materials by molecular breeders, but also precise and vigilant management. Planting strategies kept ringspot viruses at bay by positioning more and less vulnerable and resilient varieties that successfully created buffers to virus co-evolution.

On balance, I finished the book with a clearer understanding of the debates, renewed skepticism about the scientific consensus, but the above frustrations. Ultimately, I think GE will be limited by the unsustainability of particular products and processes and farmer push-back against Big Ag industry strong-arm tactics and influence on farmer decision-making and management. In addition, health and environmental claims against the companies that produce GE seeds matched to ag-chemicals like glyphosate can be expected to multiply, along with damages connected to excessive, injudicious, wider-spread, and longer-term usage.

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Filed under agriculture, anthropology, farming, GMO food

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