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Is Insecticidal GMO Corn Safe?

Recently, the prominent science journal Nature editorialized that we are now swimming in information about genetically modified crops, but that much of the information is wrong—on both sides of the debate. “But a lot of this incorrect information is sophisticated, backed by legitimate-sounding research and written with certitude,” adding that with GMOs, “a good gauge of a statement’s fallacy is the conviction with which it is delivered.”

To many in the scientific community, GMO concerns are dismissed as one big conspiracy theory. In fact, one item in a psychological test of belief in conspiracy theories asked people if they thought food companies would have the audacity to be dishonest about genetically modified food. The study concluded that many people were cynical and skeptical with regard to advertising tricks, as well as the tactics of organizations like banks and alcohol, drug, and tobacco companies. That doesn’t sound like conspiracy theory to me; that sounds like business as usual.

We must remember there is a long legacy of scientific misconduct. Throw in a multi-billion dollar industry, and one can imagine how hard it is to get to the truth of the matter. There are social, environmental, economic, food security, and biodiversity arguments both pro and con about GMOs, but those are outside my area of expertise. I’m going to stick to food safety. And as a physician, I’m a very limited veterinarian—I only know one species (us!). So, I will skip the lab animal data and ask instead: What human data do we have about GMO safety?

One study “confirmed” that DNA from genetically modified crops can be transferred into humans who eat them, but that’s not what the study found, just that plant DNA in general may be found in the human bloodstream, with no stipulations of harm (See Are GMOs Safe? The Case of Bt Corn).

Another study, however, did find a GMO crop protein in people. The “toxin” was detected in 93 percent of blood samples of pregnant women, 80 percent of umbilical cord blood samples, and 69 percent of samples from non-pregnant women. The toxin they’re talking about is an insecticidal protein produced by Bt bacteria whose gene was inserted into the corn’s DNA to create so-called Bt-corn, which has been incorporated into animal feed. If it’s mainly in animal feed, how did it get into the bodies of women? They suggest it may be through exposure to contaminated meat.

Of course, why get GMO’s second-hand when you can get them directly? The next great frontier is transgenic farm animals. A genetically modified salmon was first to vie for a spot at the dinner table. And then in 2010, transgenic cows, sheep, goats and pigs were created, genetically modified for increased muscle mass, based on the so-called mighty mouse model. Frankenfurters!

But back to children of the corn and their mothers. When they say it’s a toxin, it’s a toxin to corn worms, not necessarily to people. In fact I couldn’t find any data linking BT toxin to human harm, which is a good thing since it’s considered one of the few pesticides considered so non-toxic that it’s sprayed on organic fruits and vegetables.

For more on on the public health implications of genetically modified crops, see:

I did a similar “controversial issue” video series on gluten. See:

For those interested in the genetic engineering of livestock, I published a few papers myself on the topic:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

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