Contrary to industry claims, GMOs do not have a history of safe use, as they are subject to only short-term studies conducted by the companies that profit from them. In the 30 years since herbicide-tolerant and insect-resistant GMO crops entered the food supply, a substantial body of evidence has indicated their potential harm to human health. Credible studies that identify negative human health impacts have been actively discredited by agrochemical corporations.29,30 Learn more about the industry's role in GMO testing.
In multiple animal studies, "first generation" herbicide-tolerant and insect-resistant GMOs have been linked to serious adverse effects, including organ abnormalities and cell and tissue damage, as well as gastric and uterine disease, stomach inflammation and kidney and liver damage, with potential outcomes including a rise in tumor incidence and increased mortality.31,32,33,34,35,36,37,38,39,40,41,42,43
Additionally, herbicide-tolerant GMO crops have led to a dramatic increase in the use of accompanying herbicides.44 Exposure to these herbicides is widespread and can be harmful to human health at very low levels.45,46,47 Herbicide residue is linked to reproductive, developmental, neurological, metabolic, microbiome, digestive and urinary system damage, liver disease, GI tract damage, endocrine disruption, increased incidence of breast and other cancers, genotoxic effects and kidney disease.48,49,50,51,52,53,54,55,56,57,58
Newer forms of genetic engineering include a wide range of organisms and potential food ingredients that are entering the food supply without regulation or safety testing.59 While new genomic techniques such as gene editing are often described as a more precise method of creating GMOs, they can produce unexpected outcomes that are unlikely to occur with conventional methods, including off-target effects described by independent researchers as "chromosomal mayhem."60,61,62,63 The instance of off-target effects is likely wildly undercounted.64
With the expansion of biotechnology and the emergence of new genomic techniques, people encounter more GMOs with more complex genetic alterations from more food sources than ever before.