Science Supports Safety of Genetically Modified Soybeans
By Mark Messina, PhD, Executive Director, Soy Nutrition Institute
Genetically modified (GM) foods generate a lot of heated discussion about safety and product labeling. Given that 94% of the soybeans grown in the United States are GM, these discussions, not surprisingly, usually include soybeans.1
Opinion polls since 1992 show an overwhelming majority of the American public support GM food labeling.2 However, polls also show that much of the public has little understanding of the technology involved in producing GM foods and that those with greater scientific knowledge tend to have less negative attitudes towards these foods.3 The US Food and Drug Administration doesn’t require that GM foods be labeled because the label is not intended to provide information about the process by which the food is made and because they are considered safe since they are not materially different from their non-GM counterpart. Only if a GM food is significantly different from its conventional counterpart does the food need to be labeled as such.
The process of genome manipulation involves the translocation of genes from multiple genetic sources, in a process widely known as recombinant deoxyribonucleic acid (rDNA) technology.4 Given the poor scientific background of many Americans, it isn’t surprising that GM technology is often misunderstood.
Safety concerns over GM soybeans focus on the bean itself and glyphosate, the herbicide to which GM soybeans are resistant. There is news on both fronts that should comfort those with doubts about the wisdom of consuming foods made from GM soybeans.
A just-released report from the National Academy of Sciences (NAS) concluded that GM foods were safe. The report said: “On the basis of detailed examination of comparisons between currently commercialized GE [genetically engineered] and non-GE foods in compositional analysis, acute and chronic animal toxicity tests, long-term data on health of livestock fed GE foods, and epidemiological data, that no differences were found that implicate a higher risk to human health safety from GE foods than from their non-GE counterparts.”5
The NSA report was written by “The Committee on Genetically Engineered Crops: Past Experience and Future Prospects.” The committee included 16 academics from US universities. In addition to examining the scientific literature, the committee listened to presentations from 80 people who had diverse expertise, experience, and perspectives on GE crops to augment the diversity represented on the committee. They also received and read more than 700 comments and documents sent to them from individuals and organizations about specific risks and benefits that could be associated with GE crops and their accompanying technologies.
What about the health effects of the herbicide glyphosate? Glyphosate (N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide and an organophosphorus compound, specifically a phosphonate. It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. It was discovered to be an herbicide by Monsanto chemist John E. Franz in 1970.6 Glyphosate kills plants by inhibiting the activity of an enzyme (5-enolpyruvylshikimate-3-phosphate synthase, EPSPS) involved in the synthesis of the aromatic amino acids phenylalanine, tyrosine, and tryptophan.7 Roundup Ready (RR) soybeans, as they are called, are able to survive glyphosate because they have been engineered to express an alternative form of EPSPS that functions normally even in the presence of glyphosate. The EPSPS gene used in RR plants comes from a bacterium.
Recently, the World Health Organization’s cancer authorities – the International Agency for Research on Cancer (IARC) – determined that glyphosate is “probably carcinogenic to humans” (Group 2A) despite the fact that neither the U.S. Environmental Protection Agency (EPA) nor the European Chemical Agency had classified glyphosate in this way. In fact, a report (marked final) that recently appeared on the website of the US EPA criticized the IARC conclusion about glyphosate and instead concluded that neither the epidemiologic data nor animal studies indicate glyphosate is carcinogenic. Also, in 2015, the German Risk Agency concluded: “The lack of a plausible mechanism, along with published epidemiology studies, which fail to demonstrate clear, statistically significant, unbiased and non-confounded associations between glyphosate and cancer of any single etiology, and a compelling weight of evidence, support the conclusion that glyphosate does not present concern with respect to carcinogenic potential in humans.”8
In conclusion, science supports the safety of GM soybeans. Nevertheless, soyfoods made from non-GM soybeans are widely available so, regardless of personal preference, there are plenty of options from which consumers can choose.