Is GM corn toxic?

Question

According to Vendomois et al, 2009:

these data highlight signs of hepatorenal toxicity, possibly due to the new pesticides specific to each GM corn.

Monsanto, the manufacturer of two of the studied strains of GM corn, responded, dismissing the article, particularly by criticizing the statistical methods used. Is Monsanto's criticism valid?

Have there been additional studies done that either support or refute the claim that genetically-modified corn has toxic effects?

Related: http://skeptics.stackexchange.com/questions/68/what-risks-exist-with-gmo-but-not-with-selective-breeding — Sklivvz, Feb 29 '12 at 22:13
Every time I see an anti-GMO study, the first thing I check is if it was published by Séralini. :/ Not fair, but I'm just sick of arguing against his claims. — Mooing Duck, Jun 28 '15 at 07:34

score 12 · Answer 1 · edited Aug 23 '13 at 10:28

The simple answer is no.

GM corn has the BT gene that allows lower use of pesticides due to increased or the RR gene that allows the use of glyphosate for weed control. Neither of these alterations have any impacts upon the production of sugars or proteins in the plant. http://en.wikipedia.org/wiki/Genetically_modified_maize http://www.ca.uky.edu/entomology/entfacts/ef130.asp

The problem that can arise is from the pesticides that are now used on the crops and the timing of their application. These pesticides are known to harm mammals and if the dose is high enough can cause problems. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2793308/

Generally though, because you are removing pests and weeds the plants tend to be healthier so they are less impacted by pathogens, thus better for consumption. http://www.acsh.org/factsfears/newsID.962/news_detail.asp

There is an issue with using corn as a feed supplement in animals though. Corn is not a complete food source and is generally low in protein, especially tryptophan. This means that a feed mix is required, not just straight corn meal. http://www.ag.ndsu.edu/pubs/ansci/beef/as1238w.htm

Another issue is that corn can cause Pellagra. This is due to the niacin and B12 being bound in the corn starches and not being released in normal digestion. Tryptophan is also low in corn and can cause Pellagra. http://en.wikipedia.org/wiki/Maize#Pellagra

http://en.wikipedia.org/wiki/Pellagra

So the problems often cited with GM corn are actually just problems with corn itself. Neither are harmful, if used correctly in a balanced diet, but pesticide residues are of concern. For more see this: http://onlinelibrary.wiley.com/doi/10.1046/j.0960-7412.2002.001607.x/full

*The simple answer is no.*, to "Have their been additional studies done that either support or refute the claim that genetically-modified corn has toxic effects?", or to "Is GM corn toxic?"? — gerrit, Jan 16 '13 at 21:57
The ACSH source claims *Studies Indicate GM Crops Are Safer and Healthier*, but [last time ACSH reported their funding, they were co-funded by what are now GMO companies](http://www.sourcewatch.org/index.php?title=American_Council_on_Science_and_Health). Currently they are not open about their funding *at all*. Therefore, their independence cannot be established. Can you back up the claim by research where all funding sources are open and independent? — gerrit, Jan 16 '13 at 22:06
Gerrit - Of course there is plenty of independent data. gmopundit.blogspot.com/ regularly publishes the science on GMO. But that is beside the point, the underlying mechanism of the Bt is not one that works on humans (it is even sprayed in organic farms). We don't have an alkaline stomach to activate the chemical (ditto some insects it doesn't impact either) which means it can't do anything. So the concerns are completely misplaced. — Tim Scanlon, Jan 31 '13 at 10:55
@Sancho I’ve rolled back your edit – it placed undue emphasis on a dodgy hypothesis and completely changed the focus, and thus the statement, of the answer. — Konrad Rudolph, Aug 23 '13 at 10:29

score -3 · Answer 2 · edited Aug 07 '13 at 14:39

We don't know the long term effects that it might have. Feeding studies are generally 90 days long (and most are done by Monsanto, if you trust in the first place).

You also can't simply look at the specific protein produced by the transgene, as introducing a transgene affects the entire phenotype.

Monitoring the pattern of gene expression using microarray technology showed that mRNA levels for 5% of the genes were significantly upregulated or downregulated. Recent studies in transgenic plants showed that the over-expression of a gene involved in pectin synthesis had no effect in tobacco, but caused major structural changes and premature leaf shedding in apple trees [4]. Although these sorts of unpredicted changes in gene expression and function are frequently observed, they have received very little attention. Furthermore, they are not unexpected. The maintenance of a specific cell phenotype involves a very precise balancing act of gene regulation, and any perturbation might be expected to change the overall patterns of gene expression. The problem, as with secondary modifications, is that there is currently no way to predict the resultant changes in protein synthesis."

- Source: Commentary, A different perspective on GM food, David Schubert, Nature Biotechnology 20, 969 (2002) doi:10.1038/nbt1002-969

Please reference your claims that feeding studies are only 90 days long, that they are mostly done by Monsanto and that these are the only way we know about the potential effects. — Oddthinking, Aug 07 '13 at 14:33
The Nature Biotechnology commentary cited triggered [a number of disagreeing responses](http://sembremvalles.files.wordpress.com/2012/10/schubert02_5percent.pdf)) from the scientific community (which in turn had their conflicts of interest challenged.) — Oddthinking, Aug 07 '13 at 14:44

score -5 · Answer 3 · edited Aug 19 '13 at 05:18

-5

The simple answer is there is no simple answer. It is not appropriate to unequivocally say "no".

The FDA has stated they are not in the business of policing; rather, they put the onus on the seed corporations.

One only needs to look at history to have some serious questions and concerns. Sure genetic engineering hasn't been around very long so one would need to look at the biggest players in the Genetic Engineering Industry. Monsanto & Dow Chemical two chemical companies with an awful track record.

Yes Monsanto IS a big part of GE Food and wields power and influence like Big Tobacco in the 1970s. They do patent seeds and they now own an estimated 25% of the world seeds due to acquisitions. If you don't know about Monsanto's history check out the Monsanto Controls Your Diet article in Salon Magazine's April 2013 issue. Since 1901 they have been making chemicals that poison. Here is a link to the latest study showing a link of GMO food to leukemia

Yes, each study such as this is refuted by 100 Monsanto, Sygenta, etc. supported/funded studies. It is tough to put trust into studies from Univ. of Florida for instance that receives so much from Sygenta. I do not consider any such studies objective. For decades the tobacco industry did the same thing.

Whenever something is so one-sided (and the power and future profits are on that side) I often find myself skeptical. I am by no means against genetic engineering.

edited Aug 19 '13 at 05:18

Oddthinking

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answered Aug 19 '13 at 03:12

Charlie Brown

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Welcome to Skeptics. This currently reads like a rant, not an evidence-based answer. Please provide references to support your claims that the FDA said they don't police, Monsanto is part of GE food, Florida is receiving enough funding to be tarnished... I am going to clean up some of your more off-topic wanderings. – Oddthinking Aug 19 '13 at 05:15
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Your argument appears to be "Monsanto is evil. I don't trust any scientists who tell me otherwise. Therefore GM corn is unsafe." This seems to be an unfalsifiable position, and therefore not scientific. What would you accept as evidence that GM corn is safe? If there is no way you could be convinced, you are not applying skepticism. – Oddthinking Aug 19 '13 at 05:22
@oddthinking well based on the history of Monsanto starting w/saccharin in 1901 to DDT is good for me campaign to the PCBs which were sprayed on millions including our troops in vietnam *Monsanto had a heavier % of PCBs in Agent Orange than Dow & therefore tried w/war crimes, or the millions they paid out to an AL town where they knowingly dumped PCBs and finally creating rBst and Roundup. They have a history of nefarious business practices so I don't trust them. Did you read the Salon link and how integrated the are in all branches of our federal government? I can't say GM corn is unsafe. – Charlie Brown Aug 19 '13 at 06:09
@oddthinking I don't think being wary of Monsanto is biased. There is an old saying fool me once shame on you, fool me twice shame on me. There has been very little 'truly independent' scientific studies for me to make a decision either way. I know that it was sold to the public as the Flavr Savr tomato that failed miserably and ever since the majority of genetic engineering has focused on how to spray more pesticides and herbicides on the crops ie Round-up ready seeds. O'bama said he was going to get tough on GMOs, patents, etc. but then appoints an ex-Monsanto VP as the head of the FDA? – Charlie Brown Aug 19 '13 at 06:21
@oddthinking I purposely made note, although off topic I was not anti-Genetic engineering. I don't believe we are not to mess with Gods creations or something. I would like to see more objective scientific studies be done. I am skeptical of the scientific studies to date but not skeptical of the science itself. I do think it's odd for one of the most influential corporations on Capitol Hill to be in the chemical business for a century and then go into farming especially given their track record. They are not the only company out there in genetic engineering just the largest. – Charlie Brown Aug 19 '13 at 06:28
@Charlie Brown: Unless you **prove** that Monsanto has a strict policy of selling toxic things, what they have done in the past is fairly irrelevant to the matter at hand (the toxicity of GM corn). So please add references for all of the things that you claim. For instance: *Yes, each study such as this is refuted by 100 Monsanto, Sygenta, etc. supported/funded studies.*. So, again, this is an *ad hominem* attack. The studies are Monsanto funded so they must be false? Seriously? You should instead explain the problems with those studies. – nico Aug 19 '13 at 06:28
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I did not read the Salon article because you said it explained Monsanto's history. It may prove that Monsanto executive sweeten their coffee with the tears of baby orphans; that doesn't have any bearing on the question whether GM corn is toxic. Arguing otherwise is an "ad hominem fallacy". It might well cause you to spend more effort on checking the claims before accepting them, but it isn't an answer in itself. – Oddthinking Aug 19 '13 at 08:34
@Nico Please see the following [corporate backed publishings][2]. [non-profits with ties to industry][3] [the industry leader and it's ties to all facets of the federal government][5]. – Charlie Brown Aug 19 '13 at 12:59
@Oddthinking I don't see the logic and bandwagon jumping. It seems your mind is made up, so believe what you like. I refuted a number of items stated as fact on Mr. Scanlon's answer and the trouble making such claims while referencing them. I've been told what I think. – Charlie Brown Aug 19 '13 at 13:22
@Nico "Prove Monsanto has a strict policy of selling toxic things?" That sounds completely absurd. If there is long history and pattern of behavior is it not logical to question the intentions? Got to go to work would love to share more...already running late. – Charlie Brown Aug 19 '13 at 13:28
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It isn't a case of having my mind made up nor band-wagons. It is a case of requiring evidence - not name-calling, not speculation from history, not poisoning the well, but scientific evidence - before reaching a decision. – Oddthinking Aug 19 '13 at 14:00
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@Charlie Brown: *"Prove Monsanto has a strict policy of selling toxic things?" That sounds completely absurd.* Not more than saying that GM crop are toxic just because they are produced by Monsanto. Please provide biological proof that they are toxic. The economical strategy of a company does not have anything to do with the toxicity of a product. – nico Aug 19 '13 at 16:06
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Is GM really so new? It's at least 13,000 years old, in plants. http://en.wikipedia.org/wiki/Domestication#Plants – Aug 22 '13 at 20:54
Jon of All Trades This is not about crossbreeding, hybridizing, or genetic modification of a plant over the span of generations. The term GM is being referred to in the sense of genetic engineering. We did not know a thing about gene splicing 100 years ago let alone 13,000. We definitely were not trying to make them herbicide and pesticide resistant. – Charlie Brown Sep 26 '13 at 03:29
@oddthinking how can a society not take into account a pattern of behavior? It is done everyday in a court of law. I just don't see corporations = people but without accountability. I agree with the need for unbiased scientific evidence but do we differ because I prefer it prior to putting it into the populations food supply? – Charlie Brown Sep 26 '13 at 03:35
@oddthinking thanks for your editing & I don't think I was name calling, at least I hope I wasn't. Maybe misconstrued? I am not one to name call, especially debating a topic - usually I save that for the defenseless;-) If so, I don't know what got into me and it's rather weak on my part and I apologize to whomever. Although I don't agree with others points of view, I can appreciate them. What do I know? My answer wasn't well received. – Charlie Brown Sep 26 '13 at 03:50
@Nico wouldn't it be correct to put forth the unbiased results of scientific studies and decades of them, long term effects, etc. before putting the product in question into the population's food supply or am I being unrealistic in this approach. I tend to lean towards what would be ideal. I don't agree with the onus being on me or anyone else on proving something is safe after it is on the market. I guess that makes me against Milton Friedman's economic principles & unfettered capitalism. You know I'm a dreamer but I'm not the only one. – Charlie Brown Sep 26 '13 at 04:13
I am amazed there is not a single skeptic of the safety of Genetically Engineered crops for human consumption (& that people are indifferent with Nico's "The studies are Monsanto funded so they must be false? Seriously?") btw an example of twisting my words to discredit me, I merely stated it makes me question them - BIG difference. If one were to look @ my reason for skepticism stated through reason, logic & past history - & apply it to a different industry would we not be skeptical of studies funded by Big Tobacco or Big Pharma if profits of enormous proportion were at stake? – Charlie Brown Sep 30 '13 at 03:37
Also the very fact that I was criticized for talking directly about Monsanto makes zero sense to me. The question asks specifically about Monsanto "Is Monsanto's criticism valid?" Apparently one should directly address this question by side-stepping the company in question. I am skeptical of the skeptics group on stack exchange. – Charlie Brown Sep 30 '13 at 05:11
For skeptics to be so sure and have such a one-sided debate on something that remains unclear is pure irony. Environmental Working Group and other reputable non-profits question GE crops. It's not like this is coming from the Believers of Nephilim or even 10k Architects for truth about Bldg 7. Assessment: This is an emotional comment - ok fine I will agree with that. More importantly is there some validity to what I've stated? – Charlie Brown Sep 30 '13 at 05:26

Is GM corn toxic?

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