momofthree's picture
I have read several articles and watched an alarming utube video that blame GMOs for many of the GI problems people are having. My husband has had issues for a few years and within the last year I have begun to have issues. How do you address these concerns? If a GMO can make a pests stomach explode how can you say it won't affect humans in similar ways?

A:Expert Answer

Sorry to hear about your husband’s problem.  One of my best friends has GI issues as does her daughter and it is not pleasant.  They’ve been looking for answers too, so I did some research and thought I’d chime in here. I’ll provide some thoughts on why it is not due to anti-pest measures in GMO food, then a bit on increasing celiac disease and then address potential causes, their tie to GMO, and finally a rather interesting twist on the future of GMO and celiac disease.


The anti-pest protein (we'll call it Bt from now on) does not make "stomachs explode" in any critter.  That's a little hyperbole.  Bt is natural and used in organic farming as a pesticide. In several GM crops scientists have simply added it to the plant cell-- no need to apply it-- the plant makes it on its own.  Pretty cool.  It's like if your body made a compound that made mosquitoes sick.  They'd take a bite and leave!


When engineered into corn, corn earworms (troublesome pests) nibble on the end of an ear, they eat the Bt, then they stop feeding.   It works because the Bt protein enters the gut, it is processed by enzymes in the larval insect gut to make the active Bt protein.  This protein binds a specific receptor on the gut wall.  The receptor interaction wth Bt is like a lock and key.  The interaction is so specific that a Bt protein working against moth larvae won't work on many other insects.  


When the receptor is bound these bound molecules get together and form a pore where the gut contents mix with the body cavity, which is bad news for the insect larvae.   We digest the protein just like any other protein and there are no consequences in vertebrates for sure.


This is good news for us.  Because the corn makes this protein farmers have to spray less.  Bt corn and Bt cotton cut pesticide applications by 50-60% according to the 2010 National Academies book on GM Crops (Figs 2-3 and 2-7).  That cuts farmer costs and brings fewer chemicals into our environment! 


But since GMO crops have been around there's the increase in GI ailments, primarily celiac disease.  What's up with that?  It is absolutely just a correlation. In fact, GMO might actually SOLVE the problem.


(I know there's a lot to read here, I really got into your question, so PLEASE get to the punch line!!!)


Reilly et al., 2013 report  that this problem is still relatively rare in the USA, although increasing.  The countries with the greatest incidence include Sweden, Mexico and Finland, but it is low in Italy and Germany. It is primarily a disease found in those of European origin, with some incidence in Chilean and Asian populations. Rubio-Tapia et al (2009) show that diagnosis increases with age. One study in Sweden showed that infants with several early-life illnesses and exposure to wheat products had a higher incidence later in life. There is broad subscription to the idea of the “celiac iceberg” that the disease is much more prevalent than reported because most symptoms are mild (Mustalati et al., 2010).


As it is seen right now the causes appear to be multi-factorial (Bizzaro et al., 2012), in other words, there’s not one cause that can be pinned down.  However, there is growing scientific consensus that it is a combination of factors including sensitivity to wheat proteins, a genetic component, and a pathogenic issue. 


The literature consistently reports gluten intolerance as a strong contributing factor.  Disease markers include irritation of the intestinal mucosa and production of antibodies toward transgultaminase, a protein complex arising from wheat. Van den Broeck et al (2010) show an increase in certain protein variants that may contribute to the disease in modern wheats that were not present in wild wheat, and suggest that these may be behind the problem.


Why wheat?  Modern wheat is a genetic complexity, where all of the genes from three types of wild wheat occur in one genetic background. It happens naturally. Talk about a frankenfood! It is common in plants, known as "polyploidy". There are specific wheat protein types (alpha gliadin) that appear to induce T-cells, the body’s defense cells that trigger autoimmune responses. As wheat has been bred (bread!) for higher protein content, perhaps so has the prevalence of this, and other proteins.  This was the conclusion of the aforementioned study.


Wait!  But what about GMO!  The big surprise is that commercial wheat is not “transgenic” or what we commonly refer to as GMO.  So while traditional breeding may be contributing to the problem, it is 100% NOT due to GMO.  Can't be.  There is no commercial GMO wheat.


Sorry for the long walk to your answer.


Here’s the neat part.  Could GMO’s stop celiac disease?  Probably.  Gil-Humanes et al., (2010) and Altenback and Allen (2011) report that they can use GM technology to remove, or substantially reduce, the problematic proteins.  By turning off, or silencing, the genes using wheat's own sequences, the wheat does not produce the deleterious proteins.


How cool is that? 


If you read websites critical to biotechnology they’ll tell you that wheat already is a GMO and that GMO wheat causes celiac disease.  My guess is that is why you are here.


But the reality is that it is likely due to traditional breeding, the non-GMO process that brought us all of the major varieties we have today.  In the future, GMO technology will likely contribute to removing the reactive proteins. 


Wouldn’t that be quite a twist if GMO technology actually ended celiac disease? My guess is that it is exactly what will happen.  Best wishes to your husband.  Science is moving fast in this area and new therapies, and perhaps new foods, may make his life a little more comfortable going forward.

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jtrav21's picture

Hello momofthree - you may feel better after doing some research on BT proteins, this detailed reference on the safe use of this technology for the past 100 years may help:

Transparency's picture

There are some really good insights here about modern wheat proteins. I sincerely hope biotech is able to turn off some of those auto-immune triggers that Kevin talks about. To Kevin’s credit, I never thought of that idea -- pretty cool indeed. I too personally suffer from wheat allergies.

Putting wheat aside for a moment, due to the lack of long-term animal studies, and absence of human-feeding studies, I am not convinced biotech has really explored the interaction between GMOs and gut bacteria/viruses in depth. Therefore, I am sharing Section 5 of the Institute for Responsible Technology’s write-up entitled, “The Documented Health Risks of Genetically Engineered Foods,” which makes quite a few intriguing points -- areas that I believe require additional research and/or discussion.

Section 5: Transfer of genes to gut bacteria, internal organs, or viruses

5.1 In spite of industry claims, transgenes survive the digestive system and can wander
1. Industry advocates claimed that genes were destroyed during the digestion of food and therefore gene transfer to gut bacteria or organs was extremely unlikely.
2. Studies now verify that genes can survive digestion, both in humans and animals.
3. Animal studies on non-GM DNA also verify that it can pass through the placenta into the fetus, from the digestive channels into the blood and organs, and even penetrate the blood brain barrier.
5.2 Transgene design facilitates transfer into gut bacteria
1. Genes can naturally transfer between species and even kingdoms, but it is uncommon.
2. GM crops may be especially suited to overcome the natural barriers of this transfer.
3. Short bacterial sequences and higher herbicide residues, for example, may significantly increase the transfer rate.
4. Transgenes may therefore readily travel from GM food into the DNA of gut bacteria.
5.3 Transgenes may proliferate in gut bacteria over the long-term
1. Once transferred into gut bacteria, transgenes may confer survival advantages, allowing them to endure and spread.
2. These advantages may be due to antibiotic or herbicide resistance, promoters that function in bacteria and genetic mechanisms that promote uncontrolled replication.
3. Having "infected" our gut bacteria, the foreign genes and the proteins they create may be harmful.
5.4 Transgene transfer to human gut bacteria is confirmed
1. The only human feeding trial ever published confirmed that genetic material from Roundup Ready soy transferred into the gut bacteria in three of seven human volunteers.
2. The transferred portion of the transgene was stable inside the bacteria and appeared to produce herbicide tolerant protein.
3. There is no known way to treat such a condition, which may be long-term.
5.5 GM foods might create antibiotic-resistant diseases
1. Antibiotic resistant marker (ARM) genes have been inserted into most GM foods on the market.
2. If ARM genes were to transfer to pathogenic bacteria inside the gut or mouth, they might create super diseases, untreatable with one or more types of antibiotics.
3. GM crops may therefore accelerate the rise of antibiotic-resistant illnesses, which are already responsible for death and disease.
5.6 The promoter can also transfer and may switch on random genes or viruses
1. Contrary to prior assumptions, the CaMV promoter does function in human, animal and bacteria DNA.
2. This promoter does transfer into the DNA of human gut bacteria and might also transfer into human DNA.
3. Once transferred, it may switch on genes that produce toxins, allergens or carcinogens, create genetic instability, and in higher organisms, switch on dormant viruses.
5.7 If Bt genes transfer, they could turn our gut bacteria into living pesticide factories
1. Transfer of the Bt transgene could cause our intestinal flora to produce Bt-toxin.
2. With increased exposure to Bt crops and through selective pressure, the number of gut bacteria producing Bt may increase over time.
3. Since Bt-toxin has been associated with immune responses and damaged cells in animal intestines, long-term exposure may cause significant health problems.
5.8 Genes may transfer to bacteria in the mouth or throat
1. Bacteria in the mouth have been shown to take up free DNA.
2. GM DNA might similarly transfer.
3. Not only might this impact human health, it might also be readily passed from person to person.
4. Breathing dust or pollen from GM crops might cause genes to transfer to microorganisms in the respiratory tract.
5.9 Transfer of viral genes into gut microorganisms may create toxins and weaken peoples' viral defenses
1. As discussed earlier, proteins produced from viruses can be toxic and disable viral defenses.
2. If viral genes inserted into GM crops transferred into gut microorganisms, they might produce large quantities of potentially harmful proteins.
3. Characteristics of viral transgenes make transfer to gut microorganisms much more likely.

ieatfood's picture

"When the receptor is bound these bound molecules get together and form a pore where the gut contents mix with the body cavity," I find this quote interesting because I remember my friend who suffers from gluten intolerance was telling me that the doctor told her that this might happen to her, and she will be able to tell because your skin goes gray. But wheat that we eat is not GMO! so it can not be GMOs fault. Ok lets go with that, and lets not even think that bt corn could be a part of the formula, wait but aren't they planted on the same field, in the same soil, in the same year? Are there any studies to show that there is no transfer of transgenes from plant to plant?

Joseph Najjar's picture

What you are proposing is feasible I suppose, but all research done in the area of horizontal gene transfer suggests that the chances of that occurring, in the soil or in our bodies. HGT happens at very, very low rates( 10^-4 to 10^-8) and were not even observed in any of the studies looking for HGT in the soil.

"Moreover, in the unlikely event that soil bacteria acquired the resistance to an antibiotic among those currently used in the laboratory to select GE plants, this would not affect the population of natural antibiotic resistant bacteria already present in the soil (D’Costa, 2006; Forsberg et al., 2012) or imply any additional risk for human and animal health."

That is a comprehensive look at research done on many of the issues raised with GMOs. Coming out of the EU, it should carry added weight, as they were once one of the harshest critics of GM technologies in the world

Gentile Clem's picture

To momofthree: I have bowel trouble & wish the best to all of you.
I have a gsatro Dr. that recommends I stop all sugar use + substitute use. I am replacing it with honey. I just had my coffee with honey & I have not used honey very long, so I am in trial, but honey can't hurt.

Sugar causes candida (yeast explosion in stomach) to multiply rapidly & get stomach out of kilter. Honey will help get candida back to normal.

Hope this helps your family & it does not help the pharmaceutical companies!!!