Please, do not make spurious claims about food and GMO safety on the basis of current science and an apparent lack of evidence about harm. We just do not know enough. We may be looking at things wrong – or looking at the wrong things. 

Image courtesy of Nat and Cody Photography.


Over the Thanksgiving Holiday our thoughts often turn to food, so I thought a post on that topic might be of interest.  Also, I just completed reading two books by scientifically minded individuals offering a defense of GMO food technology: Mark Lynas’ Seeds of Science (2018), and Stewart Brand’s Whole Earth Discipline [mostly Chapter 7] (2009). Both of these writers are known for their radical environmentalism, and I was hopeful that I would find new scientific evidence that would better inform my understanding of GMO foods. I was disappointed. The polemics were strong, but the scientific claims were exactly the same: (1) humans have been modifying food genetics for thousands of years (through horticultural practices) and (2) no harm from GMO foods has been documented. This drives me crazy! It is not rational to conclude from these observations that GMO foods are safe, particularly at the scale we are likely to see in this century.

Polemics is Not Evidence:

Lynas and Brand both provide fascinating accounts of the dramatic tensions within the environmental community on the issue of GMOs, and they both regard themselves as converts. They were wrong about GMO’s in the past, but they’ve seen the “evidence” and have reformed their views. This makes for highly entertaining reading, but it’s not particularly illuminating about the science of GMO foods.

For example, in the opening of his Chapter titled “What Anti-GMO Activists Got Right”, Lynas writes:  “When I began this project I intended it as an expose of sorts, a passionate polemic highlighting the sheer injustice and irrationality of the movement against genetic engineering and the damage I believe it had done in the world.”

The following 30 pages recounts some of the debates, including an excruciating encounter when he and Stewart Brand together faced a hostile anti-GMO audience of former colleagues and friends. However, Lynas cites no new revelations or evidence about the science of GMO. He has succeeded in writing a passionate polemic. But a polemic is not science. 

Rational Skepticism About GMO’s

Some of you may have read my previous article on the subject of GMO foods and the issue of food labeling in The Big GMO Debate. I noted then that the two primary arguments in favor of GMO foods were: (1) humans have been modifying food genetics for thousands of years (through horticultural practices) and (2) no harm from GMO foods has ever been scientifically documented. 

Lynas and Brand make the same arguments. Humans have been modifying gene stocks for millennia through horticultural practices. Moreover, GMO is more beneficial because it is just faster and more accurate. This is not convincing for several reasons. The first is scale – what we have done genetically to our food stocks in the last hundred years is several orders of magnitude MORE intensive that in the prior ten thousand years. GMO offers to ramp that up a couple more orders of magnitude.

The second is that it takes time for evidence of mal-adaptations between foods and physiology to appear, and orders of magnitude more time for biological adaptation to successfully respond to changes in foods. Dairy products (other than human milk) were introduced into the human food supply 10,000 years ago – yet many adult humans today still have problems with dairy. They do not have the genes (or no longer express the genes as adults) that produce enough of the enzyme needed to digest lactose. Is this a surprise? 10,000 years is only 400 or so generations, not enough time for the adaptation to lactose in the adult diet to spread through the entire population.

There is also scientific evidence that some of the pre-GMO genetic modifications to our food stocks have not been beneficial to our health. Tomatoes can be picked mechanically, shipped and stored around the world in the middle of winter. And they are tasteless. Many newer food varieties are less nutritious than they used to be.  Super sweet corn varieties are all derived from one of two genetic mutations found in corn seed stocks after they were irradiated during above ground nuclear testing. These mutations produced much higher sugar levels in corn, which appeals to our Paleolithic taste buds. But the higher sugar content also contributes, perhaps more through corn-sweetened drinks that anything else, to the epidemic of obesity and diabetes. 

We now know that plants under some stresses produce more phytonutrients and flavonoids. These contribute to both taste and nutrition and they are lower in industrially produced fruits and vegetables. It seems plants grown under stress are better for us than the pampered ones grown in pristine greenhouses and pest-free fields.

Wheat today is quite different from its ancient progenitors. Yields in the fields are way up, but the nutritional values have decreased. Modern wheat is also harder to digest. This has been identified as a potential contributor to the growing problem of gluten-intolerance, a milder form of the deadly celiac disease caused by inflammation in the small intestine from exposure to gluten. Another interesting fact is that the fermentation of wheat during the manufacture of bread helps break down gluten into more digestible forms. However, there was an industrial revolution in bread making in the 1960’s, when producers found ways to accelerate production with the addition of chemicals and enzymes. The bread is cheaper but the process shortcuts the fermentation of gluten – and, ironically, may have made bread harder to digest.

But These Arguments Apply to Pre-GMO Foods!

Yes! All of the above concerns apply to pre-GMO foods. GMO, like many powerful technologies, just turbo-charges the process. If traditional methods of modifying our foods have negative consequences, then GMO technology has the capacity to accelerate the harm significantly, particularly for harms that we are simply not aware of. At the same time, it is also true that there have been very positive consequences of pre-GMO food modifications. The Green Revolution brought the world to the point where it could produce enough protein and calories to feed the entire world (before GMO!). This positive benefit, however, is not an excuse for ignoring negative consequences. 

The kicker for me is to recall all of the times in the past when science said, “we know what we are doing – this is safe,” only to find that the science was inadequate. My father (a PHD chemist) died of pancreatic cancer in 1969 at the age of 54, most likely due to occupational exposure to aniline dies. His exposure occurred before anyone knew (or admitted) that these chemicals were carcinogenic.  At a certain point in time Thalidomide was safe. Widespread application of DDT was safe. Cigarette smoking was safe – and good for the nerves…

I still remember scientists claiming that since protein-coding genes were scattered across our chromosomes, some 90% of our DNA was “junk”. Now we know that this non-coding DNA can play other essential roles in our biology. Then there were the brain researchers who learned to map electrical activity in the brain. They found that a lot of the activity did not seem to relate to cognitive processes, so they concluded that 90% of the electrical activity in the brain was just “noise.” Subsequent research has found brain functioning to be far more efficient, and significantly more complex, that early researchers had posited. 

These mistakes occured because science had not yet discovered certain very important facts. We did not know what we did not know. In almost all cases of negative health and environmental impacts from technology, there were points where advocates of the technology could say – “we are only doing the same kind of things we have done before”, and “there is no evidence that this is not safe.” Hindsight has shown us otherwise.

Things are More Complicated Than We Think

Our knowledge of the biochemistry and health effects of foods is limited. The human body is an immensely complex and fascinating set of cells, organs, organisms and systems – easily the most chemically reactive thing in the universe. Everything we eat is broken down and processed in that human bioreactor – every molecule interacts with and is processed by the body. And it true that our scientific understanding of this human bioreactor has, in the past few decades, taken immense leaps forward.

Yet there is much left to be learned. The complexity of food science, plant biology and human physiology recently got vastly more complicated than anyone had ever suspected – with the discovery of the powerful symbiotic role of the micro biome to all living things. We are having to reconsider the established scientific consensus of germ theory, which postulated that germs cause disease and are therefor bad. The human body is, in fact, dependent upon an immense variety of microbial colonies, and we now know that there are far more non-human cells, and non-human DNA, in us, than there are human cells and human DNA. We are a multi-level, complex system of symbiotic organisms. What we eat affects the entire system.

I have no argument with those who want to research GMO or to apply it to address specific, isolated, documented probelms in a transparent and controlled program.  I have few concerns with synthetic biology in the laboratory.  But please, do not make spurious claims about food and GMO safety on the basis of current science and an apparent lack of evidence about harm. We just do not know enough. We may be looking at things wrong — or looking at the wrong things.

Image courtesy of Nat and Cody Photography.

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