Stawman Arguments Against Statements Related to GMO Safety

Previously I discussed how the World Health Organization, the American Medical Association, and the National Academy of Sciences have all issued statements regarding the safety of foods derived from genetically engineered crops.

In addition I discussed how critics have questioned these statements. One set of assertions supports the invocation of the precautionary principle.

I have written before about issues related to using the precautionary principle with respect to genetically modified vs conventional food crops.

In this post I would like to specifically discuss the assertion that  "There are no epidemiological studies investigating potential effects of GM food consumption on human health."

To those unfamiliar with modern crop science and genetics, that could sound like a very condemning statement. But that begs the question, have there been epidemiological studies investigating the potential effects of conventionally and mutagenically improved crops on human health?

Its also a true statement that there are no epidemiological studies investigating the relative safety of using the stairs vs. elevators vs. escalators vs. leaping out the top floor window with regard to human health. (although I am sure actuaries have assessed property/casualty probabilities associated with similar kinds of risks related to building design, we don't have people losing sleep over lack of publication in this area)

These last examples might seem extreme and unrelated, but they illustrate the point that for some things, conducting an expensive (and difficult) epidemiological study to assess impacts on human health makes little practical sense. 

What reasoning would make us think this is necessary for genetically modified foods? If we were discussing inclusion of traits known to impact metabolism or hormone levels or some other biological function this might make sense. But the types of crops approved for human consumption don't have traits known to behave this way. Some critics might assert that it is the unknown consequences (changes in DNA, changes in proteins, or metabolism) that we should be worried about. 

However, scientists know that these kinds of genetic disruptions are not any more proliferate with genetically engineered crops than those related to traditional and mutagenic crop improvement that have been consumed and accepted by consumers without question for hundreds (thousands) of years or more in some cases and decades in others. They are substantially equivalent in this regard.

It turns out that the statement about the absence of epidemiological studies is really irrelevant when it comes to assessing the risks associated with genetically engineered food consumption. Arguments using epidemiological studies to form a psychological baseline or frame of reference are akin to strawman statements that could raise unnecessary doubts and fears about a technology that actually exhibits characteristics beneficial to human health and the environment.

References:

No scientific consensus on GMO safety. Environmental Sciences Europe. 2015 27:4

Batista R, Saibo N, Lourenço T, Oliveira MM. Microarray analyses reveal that
plant mutagenesis may induce more transcriptomic changes than transgene
insertion. Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3640-5. doi:
10.1073/pnas.0707881105. PubMed PMID: 18303117; PubMed Central PMCID: PMC2265136

Baudo MM, Lyons R, Powers S, Pastori GM, Edwards KJ, Holdsworth MJ, Shewry PR. (2006). Transgenesis has less impact on the transcriptome of wheat grain than conventional breeding. Plant Biotechnol J. 2006 Jul;4(4):369-80

First citation:

Defining Consensus Regarding the Safety of Genetically Modified Foods

The World Health Organization, the American Medical Association, and the National Academy of Sciences have all issued statements regarding the safety of foods derived from genetically engineered crops. However, in a recent letter critical of the documentary film Food Evolution, the following paper is cited:

No scientific consensus on GMO safety. Environmental Sciences Europe. 2015 27:4
Link

This was the first time I had seen this paper so I spent some time going through it to see what kinds of arguments were being made. Below are a few excerpts and some discussion.

"the scarcity and contradictory nature of the scientific evidence published to date prevents conclusive claims of safety, or of lack of safety, of GMOs. Claims of consensus on the safety of GMOs are not supported by an objective analysis of the refereed literature."

"The health, environment, and agriculture authorities of most nations recognize publicly that no blanket statement about the safety of all GMOs is possible and that they must be assessed on a 'case-by-case' basis."

"There are no epidemiological studies investigating potential effects of GM food consumption on human health"

"an expert panel of the Royal Society of Canada issued a report that was highly critical of the regulatory system for GM foods and crops in that country. The report declared that it is 'scientifically unjustifiable' to presume that GM foods are safe without rigorous scientific testing and that the 'default prediction' for every GM food should be that the introduction of a new gene will cause 'unanticipated changes' in the expression of other genes, the pattern of proteins produced, and/or metabolic activities."

"We support the application of the Precautionary Principle with regard to the release and transboundary movement of GM crops and foods."

 I have not had a chance to check every single reference and citation made. However the general framework sketched out in the paper I am getting is this:

• there is no absolute or conclusive evidence that genetically engineered foods are safe or unsafe
• the risks are associated with unintended effects related to gene insertions (i.e. genetic disruptions)
•  invocation of the precautionary principle is used to obviate the statements often cited by the World Health Organization, the American Medical Association, and the National Academy of Sciences

This leads me to ask, can we make a blanket statement about the safety of all conventionally modified or organic foods that utilize plant breeding and mutagenesis? Have there been epidemiological studies investigating the effects of these methods on human health?

Suddenly this thinking brings up a question I have addressed before: why would we invoke the precautionary principle in the case of  food from genetically engineered crops and not for conventionally and mutagenically improved crops? 

From the literature:

“We found that the improvement of a plant variety through the acquisition of a new desired trait, using either mutagenesis or transgenesis, may cause stress and thus lead to an altered expression of untargeted genes. In all of the cases studied, the observed alteration was more extensive in mutagenized than in transgenic plants” - (Batista, et al; 2008)

With greater disruptions, critics might favor increased regulatory scrutiny. However, we do not have a framework in place for mutagenically improved crop varieties that have been safely used for decades and approved by the organic food industry and accepted by consumers, nor do we have anything like this for conventionally bred crops. If an argument for the precautionary principle holds for genetically engineered crops on this basis, then it should also hold for all types of crop improvement.

Therefore it seems tenuous to make a scientific risk based justification for special treatment of genetically engineered crops without further evidence. When many refer to a consensus on the safety of genetically engineered foods, this is what I have in mind.

Policies related to genetically engineered foods leveraging the precautionary principle could lead to increased risk of doing more harm than good to human health and the environment if policies prevent or delay adoption of traits that could decrease use of toxic pesticides, or reduce carbon emissions and improve soil conservation as some biotech traits have been shown to do in the literature.

See also:

Fat Tails, The Precautionary Principle, and GMOs
Comments on Rules for Gene Editing Technology
Organic Activists Realize Hypocrisy in Opposition to Gene Editing Technology

References:

Batista R, Saibo N, Lourenço T, Oliveira MM. Microarray analyses reveal that
plant mutagenesis may induce more transcriptomic changes than transgene
insertion. Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3640-5. doi:
10.1073/pnas.0707881105. PubMed PMID: 18303117; PubMed Central PMCID: PMC2265136

Baudo MM, Lyons R, Powers S, Pastori GM, Edwards KJ, Holdsworth MJ, Shewry PR. (2006). Transgenesis has less impact on the transcriptome of wheat grain than conventional breeding. Plant Biotechnol J. 2006 Jul;4(4):369-80

Are Soda Taxes Effective

Over at RealClearAgriculture I have been blogging about food subsidies and soda taxes.

Research from the American Journal of Clinical Nutrition finds no link to obesity and soft drink consumption.

"We showed no association between sugar-sweetened
beverage consumption, juice consumption, and adolescent weight
gain over a 5-y period. A direct association between diet beverages
and weight gain appeared to be explained by dieting practices.
Adolescents who consumed little or no white milk gained significantly
more weight than their peers who consumed white milk. Future
research that examines beverage habits and weight among adolescents
should address portion sizes, adolescent maturation, and dieting behaviors."

This corroborates previous findings from the journal Nutrition:

"Our analysis shows no evidence for an association between SSB consumption at age 5 or 7 y and fat mass at age 9 y in this cohort of British children"

A recent blog post (link) gets close to accurately reporting the issue of high fructose corn syrup- a sweetener chemically identical to table sugar found in soft drinks:

"Fructose and high-fructose corn syrup aren't the same. It appears that the writer, Lois Rogers, conflated the two and jumped to all kinds of incorrect conclusions. For example, that the research had anything at all to do with "the obesity epidemic." It didn't."

"The environmental site Grist tends to see everything through an ideological lens, and so is always on the hunt for evidence that high-fructose corn syrup is somehow more harmful than common sugar"

But then the article starts to get off track in stating:

"It is cheap (high fructose corn syrup) in large part because of farm subsidies. As a result, it is ubiquitous and is making a lot of people fat, diabetic, and prone to heart disease."

Research taking the claim of a connection between obesity and farm policy in a more direct fashion can be found here( from UC Davis).

"'The culprit here is not corn subsidies; rather,it is sugar policy that has restricted imports, driven up the U.S. price of sugar, and encouraged the replacement of sugar with alternative caloric sweeteners...Given that consumers generally show limited responses to retail food price changes, eliminating the corn subsidy would reduce corn-based food consumption by at most 0.2 percent.""

Similarly, this weak response of consumers to food prices undermines policies that advocate taxing soft drinks to reduce consumption and obesity. Research ( from the Mercatus Center at George Mason University) indicates that the taxes required to have any real affect on obesity would be in the 1200 percent range, and even if taxes eliminated ( in this case soda) consumption, the impact on obesity would be very small. The study concludes that "the sensitivity of individuals to changes in relative food prices is not sufficient to make “fat taxes” a viable tool to lower obesity."

These campaigns are nothing more than emotional appeals designed to solicit support for new taxes and regulations that ultimately undermine the agriculture industry and family farms.

References:

Media Gets Stuck in High-Fructose Corn Syrup
Dan MItchell
Daily Bread, The Business of Food Blog
The Big Money by Slate

Am J Clin Nutr doi: 10.3945/ajcn.2009.27573
Adolescent beverage habits and changes in weight over time:
findings from Project EAT1–3
Michelle S Vanselow, Mark A Pereira, Dianne Neumark-Sztainer, and Susan K Raatz

Nutrition July-August 2007, Volume 23, Issues 7-8, Pages 557-563
"Is sugar-sweetened beverage consumption associated with increased fatness in children?"

Taxing Sins: Are Excise Taxes Efficient
The Mercatus Center
George Mason University

Farm Subsidies and Obesity in the United States
Julian M. Alston, Daniel A. Sumner, and Stephen A. Vosti
Agricultural and Resource Economics Update
University of California
V. 11 no. • Nov/Dec 007