Myth busting: Are synthetic pesticides, used with some GMOs, more dangerous than natural ones?

| July 15, 2016
pesticides
This article or excerpt is included in the GLP’s daily curated selection of ideologically diverse news, opinion and analysis of biotechnology innovation.

Plants and animals have evolved mechanisms to fight against their predators. Some of them are mechanical, like thorns or spines on a puffer fish, but some are chemical in nature. As a result, our food is full of natural pesticides and toxins.

It’s important not to let the term “pesticide” confuse you. We’re used to thinking of pesticides as the stuff we spray on plants or around our house to get rid of bugs. But the term “pesticide” is much broader than that: it’s any substance that gets rid of or repels a pest. The term encompasses many different -cides: herbicides (to get rid of plants), fungicide (to get rid of fungi), insecticides (to get rid of insects), etc. A natural pesticide can be toxic to the pest that its evolved to target, so I use the term “toxin” in this piece as well.

One of the more common natural pesticides that we ingest is solanine. This compound is present in different parts of the potato plant, which is a member of the nightshade family of plants. This paper from Lancet published in 1979 states that potatoes have small amounts of solanine in the peel and none in the flesh, but when the potato starts to green or sprout (i.e. the ‘eyes’ start growing), then the amount increases significantly. Solanine levels also increase in potatoes when they’re diseased, such as with the blight, and is probably part of the plant’s defense system.

The Lancet paper documents several cases of solanine poisoning from eating potatoes, but they were not typical cases (for example, individuals may have been malnourished). Current guidelines from the NIH state that eating solanine in very small amounts can be toxic and recommends throwing out spoiled potatoes or those that are green below the skin.

But solanine is just the tip of the iceberg when it comes to natural pesticides. Here are a few others:

The list is very long. In 1990, Bruce Ames published a paper entitled “Dietary pesticides (99.99 percent all natural)”. In it, he and his coauthors outline that we eat an estimated 1.5 grams of natural pesticides a day, which is about 10,000 times more” than the amount of synthetic pesticide residues we consume. This amount would be significantly higher in vegetarians and vegans. As an example, the authors provide a list of 49 different pesticides found in cabbage alone. The concentrations of these pesticides are in parts per thousand or parts per million, whereas the amount of synthetic pesticides we find on our food are in the parts per billion range.

Related article:  Is there gap in federal regulation of newer GMOs?

Despite the vast amount of toxins in our diet, only a handful of these have ever been tested (note that the paper was written in 1990, but the point still stands). Of all the chemicals tested for chronic cancer tests in animals, only 5 percent have been natural pesticides and half of these were carcinogenic.

Think about that for a moment. While there’s an uproar about parts per billion amounts of synthetic pesticide residues on our food, there are more concentrated compounds in fruits and veggies actually known to cause cancer. In addition, some of the more commonly used pesticides in agriculture have mechanisms of action that are specific to the pests their targeting, making them far safer than many natural pesticides, which is on reason why they’ve gained popularity in the past half century.

For example, glyphosate, which is often paired with herbicide resistant GMO crops, shuts down a biochemical pathway in plants that simply doesn’t exist in mammals. In contrast many of the natural toxins found in plants can be harmful to mammals. Yet we’re far more concerned about glyphosate residues than we are about natural formaldehyde in pears. Check out the graphic at the end of this article that highlights this point: we fear anything that’s synthetic because we assume that it’s “bad for us”, but there’s plenty of stuff that’s “natural” that can be harmful at a certain dose.

I’ve read a lot of arguments from anti-GMO groups about how transgenic crops that have the Bt-toxin will kill us all, because it’s a registered pesticide with the EPA. “Do you want to eat something that’s a pesticide?” is what I’ve read time and time again. But as I’ve noted above there are plenty of “natural chemicals” that are registered pesticides, but no one seems to be freaking out about basil and mustard seeds.

The final point that I want to highlight is that the cross-breeding and “natural” hybridizations we’ve been doing for centuries has undoubtedly impacted the levels of some of these natural pesticides by unknown amounts because no one examines them. Going back to solanine, in the ’60s a new strain of potato known as the “Lenape” potato was developed through “natural” methods, but was found to be toxic due to increased levels of solanine: it had ~2-4x the amount of solanine found in other potato varieties and it had to be pulled off the shelves. But no one seems to be making noise about “unintended consequences” of traditional crossbreeding.

This should be a nuanced discussion. Just because an agricultural pesticide has a benign toxic profile does not mean that we shouldn’t try to minimize its use when possible. Just because a transgene for a natural pesticide added to a crop has no impact on mammals does not mean that we should not study its impact on the environment. Yet we shouldn’t consider our food to be “unsafe” or shun traditional farming practices because of the use of synthetic pesticides.

Remember: it’s all in the dose.7x6q5yr9-1400349145

 

Layla Katiraee, contributor to the Genetic Literacy Project, holds a PhD in molecular genetics from the University of Toronto and is a senior scientist in product development at a genetic biotech company in California. All opinions and views expressed are her own. Her twitter handle is: @BioChicaGMO

The GLP featured this article to reflect the diversity of news, opinion and analysis. The viewpoint is the author’s own. The GLP’s goal is to stimulate constructive discourse on challenging science issues.

Outbreak
Outbreak Daily Digest
Biotech Facts & Fallacies
Talking Biotech
Genetics Unzipped
a a b b a f ac a

Video: Death by COVID: The projected grim toll in historical context

The latest statistics, as of July 10, show COVID-19-related deaths in U.S. are just under 1,000 per day nationally, which is ...
mag insects image superjumbo v

Disaster interrupted: Which farming system better preserves insect populations: Organic or conventional?

A three-year run of fragmentary Armageddon-like studies had primed the journalism pumps and settled the media framing about the future ...
dead bee desolate city

Are we facing an ‘Insect Apocalypse’ caused by ‘intensive, industrial’ farming and agricultural chemicals? The media say yes; Science says ‘no’

The media call it the “Insect Apocalypse”. In the past three years, the phrase has become an accepted truth of ...
types of oak trees

Infographic: Power of evolution? How oak trees came to dominate North American forests

Over the course of some 56 million years, oaks, which all belong to the genus Quercus, evolved from a single undifferentiated ...
biotechnology worker x

Can GMOs rescue threatened plants and crops?

Some scientists and ecologists argue that humans are in the midst of an "extinction crisis" — the sixth wave of ...
food globe x

Are GMOs necessary to feed the world?

Experts estimate that agricultural production needs to roughly double in the coming decades. How can that be achieved? ...
eating gmo corn on the cob x

Are GMOs safe?

In 2015, 15 scientists and activists issued a statement, "No Scientific consensus on GMO safety," in the journal Environmental Sciences ...
Screen Shot at PM

Charles Benbrook: Agricultural economist and consultant for the organic industry and anti-biotechnology advocacy groups

Independent scientists rip Benbrook's co-authored commentary in New England Journal calling for reassessment of dangers of all GMO crops and herbicides ...
Screen Shot at PM

ETC Group: ‘Extreme’ biotechnology critic campaigns against synthetic biology and other forms of ‘extreme genetic engineering’

The ETC Group is an international environmental non-governmental organization (NGO) based in Canada whose stated purpose is to monitor "the impact of emerging technologies and ...
Share via
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.
Send this to a friend