What is the problem with genetic modification of food crops?
Critics point to the gene splicing technology used to create GM crops.
But that technique changes a plant's genome much less than the methods used to create commercial seed strains ... including some certified organic crops.
Instead, most independent scientists cite two potential eco and health risks from GM food crops.
First, the technology could introduce genes that would produce toxic or allergenic compounds in foods.
Why we reject GM foods
People worldwide have consumed copious amounts of GM foods over the past two decades, without any evidence of harm.
With regard to the animal research most widely cited by anti-GM authors, many independent scientists find it scientifically unpersuasive ... but other studies seem credible (see “Genetically Modified Corn Found Toxic to Animals”).
Despite the apparently clean human-safety record of GM foods so far, we have little confidence that U.S. laws and regulators are up to the task of ensuring ongoing safety.
Examples of sloppy, distorted science abound on the pro-GM side, with most independent scientists dismissing a recent U.S. safety review of proposed GM salmon as astonishingly lame. (See “GM Salmon Hit by Consumers Union, Congress”.)
At Vital Choice, we've supported labeling of GM foods, and declined to carry them ... mostly because of lax safety testing laws, the secrecy surrounding patented GM food crops and animals, the risk of “gene flow” from GM crops and animals to non-GM counterparts, and the notably irresponsible and/or obnoxious behavior of some biotech companies.
This writer recommends two books that present credible, nuanced views of the GM-foods debate:
Food, Inc.: Mendel to Monsanto–The Promises and Perils of the Biotech Harvest by Peter Pringle, an investigative journalist who's written for The New York Times, the Washington Post, the Atlantic, and others. (This book bears no relationship to the documentary film of the same name.)
Tomorrow's Table: Organic Farming, Genetics, and the Future of Food, by husband-wife team Pamela C. Ronald (a plant geneticist at UC Davis) and R. W. Adamchak (an organic farming professor at UC Davis).
(The makers of GM crop seeds must tell regulators which genes they will introduce, and certify that none can produce toxic or allergenic compounds.)
A second concern is that the DNA changes produced by gene splicing can “flow” to other food crops or wild plants, causing undesirable changes in their genomes.
(This second risk applies as much or more to the many non-GM crop strains created by making random, chemical- or radiation-induced gene mutations in seeds.)
Both fears are supposed to be allayed by existing U.S. laws and regulations ... but those rules are notably weak, and underfunded, politically pressured regulatory agencies often perform poorly.
For more on GM foods, and the fight over labeling, see the Genetic Engineering & Modification section of our news archive.
Is glyphosate (Roundup) the real risk?
The heated debate over the inherent safety of foods produced using GM technology may distract attention from a related risk.
Glyphosate (gly-foh-sate) is the active ingredient in Monsanto's Roundup product, and is now the most heavily used herbicide in the world.
(Monsanto's last patent expired in 2000, and Roundup is just one of hundreds of herbicidal products containing glyphosate.)
According to the U.S. Environmental Protection Agency (EPA), American farmers applied some 185 million pounds of glyphosate in 2007 … double the amount in 2001.
Monsanto's Roundup Ready widely planted (and consumed) corn and soy are genetically engineered to resist glyphosate.
Monsanto and other glyphosate makers say it has proven far safer than standard herbicides … thus, adoption of Roundup Ready crops should reduce the toxic burden on soil, water, animals, insects, and people.
The authors of a 2000 review concluded that “under present and expected conditions of new use, there is no potential for Roundup herbicide to pose a health risk to humans”, and a 2002 review by the European Union came to a similarly sanguine conclusion (Williams GM et al. 2000; EC 2002).
Monsanto also claims that the combination of Roundup Ready crops and Roundup (glyphosate plus additives) allows farmers to kill weeds with less mechanical tillage – which damages soil – and less risk to the crops being protected.
Over the past decade-plus, accelerating use of glyphosate by farmers, golf courses, commercial lawn services, and private consumers has steadily created more weeds resistant to it … see “Monsanto's GM Herbicide Failing”.
And Roundup-treated soil apparently fosters growth of a mystery pathogen that's been linked to increased crop disease and reduced fertility in livestock … see “GMO-Linked Herbicide Begins to Backfire”.
Evidence continues to mount suggesting that glyphosate products like Roundup may pose more risks than GM crops themselves … due in part to the toxic effects of “inactive” ingredients, including the detergents used in many glyphosate-based herbicidal formulas.
The authors of a new evidence review claims that Roundup could be harmful in ways different from – and more insidious than – the harm caused by the older herbicides it's displacing.
But are they right?
One observer – who possesses far greater expertise in human biology – deemed the report “a tissue of assertions and allegations, a tendentious brief for the prosecution that never should have been published in … any scientific journal.” (Lowe D 2013)
New report asserts unique health risks from Roundup
April of 2013 witnessed the release of a report that reviewed studies on Roundup, looking for possible effects on human health.
The authors were MIT electrical engineer Stephanie Seneff, Ph.D., and retired environmental scientist Anthony Samsel, Ph.D. Neither author is an expert in human biology or chemical toxicity.
Their report appeared in the open-source journal Entropy, and claims to reveal evidence that glyphosate residues in food could harm beneficial gut bacteria and a key class of enzymatic processes (cytochrome P450 or CYP).
The authors infer that glyphosate might kill bacteria in the human gut, including the beneficial bugs essential to health and disease protection. (Monsanto reportedly holds a patent for glyphosate's use as an antimicrobial agent.)
If eating food laced with Roundup damages our intestinal bacteria, and/or disrupts a critical class of enzymes, that could promote major health problems.
Frankly, it's not clear that glyphosate poses the risks the authors say it may.
Those who read their paper carefully may find it hard to disagree with the thrust of an April 30, 2013 critique by pharmaceutical chemist Derek Lowe, Ph.D., titled “Is Glyphosate Poisoning Everyone?”:
“This paper is a tissue of assertions and allegations, a tendentious brief for the prosecution that never should have been published in … any scientific journal.”
That may sound harsh, but the authors consistently ignored, overlooked, misinterpreted or over-interpreted evidence in papers they cite … including evidence clearly contradicting their claims about glyphosate and CYP enzymes.
What's next for glyphosate/Roundup?
The EPA is conducting a standard registration review of glyphosate and has set a deadline of 2015 for determining if glyphosate use should be limited.
Perhaps its use should be limited ... but not on the basis of farfetched claims based on sloppy research.
Given the known toxicity of the herbicides glyphosate has largely replaced, caution is in order before we trade the frying pan for the fire.
Of course, the best course is to minimize or eliminate all toxic pesticides, and publicly subsidize organic farming the way our society subsidizes big agribusinesses.
In the meantime, it seems obvious that only the least damaging agri-chemicals should be permitted, only for sparse use, and only with ongoing independent testing required.
  • Bradberry SM, Proudfoot AT, Vale JA. Glyphosate poisoning. Toxicol Rev. 2004;23(3):159-67. Review.
  • European Commission (EC). Review report for the active substance glyphosate. Glyphosate 6511/VI/99-final. 21 January 2002. Accessed at http://ec.europa.eu/food/fs/ph_ps/pro/eva/existing/list1_glyphosate_en.pdf
  • Lowe D. Is Glyphosate Poisoning Everyone? Accessed at http://pipeline.corante.com/archives/2013/04/30/ is_glyphosate_poisoning_everyone.php
  • Williams GM, Kroes R, Munro IC. Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans. Regul Toxicol Pharmacol. 2000 Apr;31(2 Pt 1):117-65. Review.