The medical establishment takes a stand on GMOs that enable more herbicide use

The majority of the scientific community has, until recently, considered genetically modified (GM) food safe to eat.  The Pew Research Center conducted a survey in which they compared the opinions of scientists regarding GM food to the opinions of the general public.  The scientists in the survey were members of the American Association of the Advancement of Science, an elite group of scientists.  Eighty-eight percent of the sampled scientists considered GM food safe to eat, compared to only 37% of the general public.  This survey was published in January 2015, reflecting recent attitudes toward GM food.

That opinion has changed, at least among some medical professionals, according to an article recently published by the New England Journal of Medicine (NEJM). (1)  NEJM is America’s premier medical journal, with the highest standards of journalistic ethics for the studies they choose to publish.  The article in NEJM was co-authored by a professor of preventive medicine and a professor of crop and soil science.  They conclude that GMOs have enabled huge increases in the use of herbicides by agriculture, posing hazards to public health.  The genetic modification itself is not to blame.  Rather it is the increased use of herbicides that are a matter of concern.

The authors trace the sequence of events that changed their opinion of GM foods from benign to a public health hazard.

What is “genetic modification?”

Genetic modification of plants and animals occurs naturally and has as long as life has existed on Earth.  When two closely related species interbreed, the result is a hybrid, which sometimes persists in nature and often ultimately results in a new species.  For example, there are hundreds of species, sub-species, and varieties of Manzanita in California because it is a species that freely hybridizes.  Sycamore trees are another plant that hybridizes freely.  Historically, such hybridizing events were not considered harmful.

Genetic modification is not fundamentally different from selective breeding in which humans have been engaged since the advent of agriculture and domestication of animals thousands of years ago.  Individual plants and animals with characteristics considered valuable were bred by humans to enhance the usefulness of plants or animals to humans.  Ancestor plants of corn were barely edible, but corn has become one of our staple foods as a result of breeding.

DNA analysis greatly enhanced the ability of humans to genetically modify plants and animals to make them more useful to humans.  Now scientists can import DNA into plants and animals from virtually anywhere in the biosphere.  Some of those modifications have been very beneficial, such as increasing crop yields, or enabling plants to survive in warmer climates, etc.  In 2000 and 2004, the American Academy of Sciences evaluated GM foods and concluded that they did not pose any unique hazards of human health.

Genetic modification becomes the enabler of herbicides

So what has changed that makes the medical establishment decide that GM foods are a matter of concern?  Beginning in the 1990s genetically modified crop seeds were developed that enable the crop to tolerate unlimited amounts of herbicide, particularly glyphosate (AKA Roundup).  Ninety percent of corn and soybeans grown in the United States is grown from these seeds.  Consequently, glyphosate use in the United States has increased from .4 million kilograms in 1974 to 113 million kilograms in 2014.

Rare ears of organic corn.  Courtesy A Really Small Farm
Rare ears of organic corn. Courtesy A Really Small Farm

Unfortunately, weeds are smarter than we are.  The more herbicide we use, the smarter the weeds get.  The evolutionary pressure of the chemical onslaught on the weeds has produced glyphosate-resistant weeds on nearly 100 million acres in 36 states.  There is always enough genetic variation in any large population of plants and insects to ensure that a few individuals will survive whatever we spray on them.  Those survivors will breed to produce the next generation, which ensures that the next generation will be more likely to survive the next onslaught of chemicals.  Over time, the population of weeds and insects capable of surviving our chemicals gets bigger and stronger.

One bad decision begets another

You might think we would abandon this chemical warfare in favor of a less poisonous, more effective long-term strategy.  You would be wrong because you’re not thinking like a corporation which manufacturers chemicals and the seeds that ensure their use.  Of course, their strategy is to make the chemicals stronger and stronger.  That strategy might make sense if we weren’t living on the same planet with all that poison or eating the food that has been sprayed with them.

The medical profession draws the line

In response to herbicide-resistant weeds, the manufacturers of pesticides have developed a new herbicide which combines glyphosate and 2,4D into a product called “Enlist Duo.”  You may recognize 2,4D as one of the ingredients in Agent Orange, used during the Vietnam War to defoliate the battle field and incidentally to poison our troops and generations of Vietnamese.  Enlist Duo was approved by the Environmental Protection Agency in 2014.  In 2015, the World Health Organization (WHO) classified glyphosate as a “probable human carcinogen” and 2,4D as a “possible human carcinogen.” 

US Army helicopter spraying Agent Orange over Vietnam. Public Domain
US Army helicopter spraying Agent Orange over Vietnam. Public Domain

This escalation of chemical warfare on America’s food supply has sent some members of the medical community over the edge:

“These developments suggest that GM foods and the herbicides applied to them may pose hazards to human health that were not examined in previous assessments.  We believe that the time has therefore come to thoroughly reconsider all aspects of the safety of plant biotechnology.  The National Academy of Sciences has convened a new committee to reassess the social, economic, environmental, and human health effects of GM crops.  This development is welcome, but the committee’s report is not expected until at least 2016.” (1)

In view of these concerns, the authors of the article in NEJM advise the EPA to withdraw its approval of Enlist Duo, a decision which “was made in haste…based on poorly designed and outdated studies and on an incomplete assessment of human exposure and environmental effects.” The authors also suggest that we “revisit the United States’ reluctance to label GM foods.”  They suggest that it is time to join 64 other countries around the world that require labeling of GM foods.


(1) Philip J. Landrigan, M.D., and Charles Benbrook, Ph.D., “GMOs, Herbicides, and Public Health,” New England Journal of Medicine, August 20, 2015.

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