Series: The Benevolent Side of GMOs
I promised that the science was coming and here it is! If you just came to Sleuth4Health or haven’t been here for awhile, I recommend that you read the last two posts so you know what is happening with my new series called The Benevolent Side of GMOs.
I begin with two questions I posed to Dr. Folta early on in our emails, very basic questions about bacillus thuringiensis (Bt) followed by glyphosate, the active ingredient in Roundup which is used on Roundup Ready crops. I believe these to be some of the most maligned, detested and feared words in the anti-GMO vernacular.
In the anti-GMO world we hear that Bt splits open the guts of insects and that it could very well be doing the same to us when we eat food from a Bt crop – causing, among other things, leaky guy syndrome, which could in turn be a reason for the increase in life-threatening food allergies, especially among children.
These food allergies can be pretty scary and this is where I do very much sympathize with parents who have an allergic child, and why Bt might be thought to be a culprit, even if it is not the real culprit. I teach in a public school and there are several staff members in the building who have EpiPen training (epinephrine is used to treat or avoid the onset of anaphylactic shock). If a highly allergic student eats something they shouldn’t, we must be ready. I get stacks of documents about these student allergies every year. They have increased dramatically even in the last decade.
S4H: How is Bt active in insects but not in humans? What if the ‘dose’ in humans were extrapolated to mimic the same ratio the corn borers get when they bite Bt corn?
Folta: This is the absolute miracle of Bt. It is a small peptide, a little chain of amino acids. In order to be active it has to be cleaved by an enzyme (which only certain insects have). Once active, it binds to specific receptors in the larval gut. The receptors bind like a lock and key. It is remarkably specific. Once bound, the receptors cluster and form a pore. The pore allows contents of the gut to mix with the body cavity and the insect larvae dies.
Humans do not have the receptors at all. Even if they did, the mechanism is so specific that the Bt peptide that affects moth larvae does not work on beetles, and vice versa. It is amazingly specific.
In the guts of humans or other animals the Bt peptide is just another peptide. It is digested in the stomach and broken down into amino acids. Even if the dose were increased to straight Bt, nothing would be expected to happen, at least in terms of how it affects the larvae.
Bt has been used in organic cultivation for a long time and has been studied in depth for over 60 years. No evidence of harm on animals. Reports that claim this are usually just in tissue culture cells, which are not a suitable proxy for an animal system.
Ok, so now we move on to the glyphosate, or Roundup question. In addition to learning a bit about how Roundup Ready crops work, I received a bonus fact which really surprised me. The crop duster, (mentioned in this question, and also on my “Why Do I Care So Much?” page) which I mistakenly thought was dropping Roundup all over a corn field, was likely dropping a MUCH worse pesticide. And now the shocker: it would not drop pesticide on to a Bt corn field because it would not be necessary. Wow!
S4H: For the sake of my question, I’ll assume that eating RR (Roundup Ready) soy, corn, cotton, rapeseed (canola), all of it, is safe. But how is it that the application of Roundup on the crops is also safe? I’ve been next to an Iowa cornfield when that stuff came pouring out of a crop duster and it’s some pretty strong stuff. My breathing got shallow because my lungs were super irritated. My eyes burned… and hours afterward, the Roundup “scent” still hung in the air and I still experienced irritation and found it uncomfortable to breathe deeply. I can’t imagine living next to that. I was just passing through.
Folta: That’s interesting. Roundup is usually applied by tractors because specific applicators are used to limit dispersal. You want the active ingredient evenly applied on the soil. It is applied early when seeds germinate and then maybe a few weeks later. The idea is to get crops to out compete the weeds. It is not applied during the food production window.
The stuff is pretty safe too. Sure, the difference between medicine and poison is dosage, but all things considered it is relatively inert. It works again in a specific fashion. It binds an enzyme in plants needed for amino acid synthesis. If the enzyme is blocked, no proteins, plant dies. Again, this is a specific interaction. The enzyme (call it EPSPS) has been extensively studied for its interaction with glyphosate (Roundup’s active ingredient).
Bacteria have an enzyme that does the same exact thing in amino acid synthesis– but it does not bind glyphosate. You see where this goes… the bacterial one is installed in plants. It does the same job, but is unaffected by glyphosate. The plant lives through the chemical treatment. Pretty cool.
My guess is that you got a lung-full of a pesticide. The Neonictinoids, organophosphates, etc are just awful.
In any conventionally-grown corn field, during ear-set the spray planes go back and forth to the airport, dumping thousands of pounds of pesticides on to corn while it is on the plant. It is just awful to see.
They do not fly over the Bt field. (The bold is a S4H edit, for emphasis.)
Just seeing this makes me wonder how any environmentalist could hate this technology.
My Conversation With a Scientist, Part One ends here. I think these two answers are HUGE and deserve their place at the head of the pack. Notice also that Folta implicates the neonicotinoids, (allegedly linked to the bee die-offs), as possibly being what irritated my lungs and eyes that day I strolled along an Iowa corn field. He doesn’t like them either! ~JuleeK@Sleuth4Health
5/5/2013 update: The website biofortified.org includes a subheading called GENERA, which stands for GENetic Engineering Risk Atlas. This is THE place to go for mainstream science around the topic of GE plants. Both public and privately funded research is included.
Down the Pike: My Conversation With a Scientist continues. Watch for Scientific Reports for Dummies.