AntiGMO activists claim that Tests on human cells have shown for the first time that the genetically modified GM toxins produced by Bt corn can have a toxic effect on human cells is this true? Who has done these tests?

Expert response from Community Manager

Moderator for GMOAnswers.com

Monday, 31/08/2015 18:33

Several government and health agencies have determined that Bt corn is safe for human consumption and human cells. Each Bt crop on the market, including Bt corn, must pass stringent regulatory tests. Bt is only toxic to specific “target” insects that feed on foliage, flowers, and grain. 

The Mezzomo study is one study performed on mice, and discussed that Bt is toxic to humans cells. This study has been discredited by the scientific community due to a lack of experimental controls.

Since your questions about Bt toxicity touch on several topics, we broke the answer down into a few sections to provide more details. 

Bt Basics

The Bt protein (also known as the Bt toxin) comes from the bacterium Bacillus thuringiensis. This naturally occurring bacteria and pesticide helps farmers protect their crops from target pests.

Even though Bt does not kill the insect immediately, treated plant parts will not be damaged because the insect stops feeding within a few hours after consuming Bt. Farmers have used Bt sprays on their crops since the 1920s. Bt is also one of the pesticides allowed for use in organic farming.

How Bt Works in 4 Steps:

• An insect, such as a corn rootworm, eats the Bt. 
• Bt is then activated by enzymes in the insect’s gut (or stomach).
• Once activated, the Bt binds to highly specific sites in the insect gut and the insect stops eating.
• These binding sites allow the Bt to form pores in the gut cells, leading to the death of the cells and eventually the death of the insect.

The Effect of Bt on Humans

Kevin Folta explains that many studies and evaluations have determined that Bt does not cause cellular changes that would cause cancer in humans.

“There is nothing about the Bt protein (used in insect resistance, also in organic pest control), the EPSPS enzyme (which confers herbicide resistance simply by substituting for the native enzyme in the plant) or the process itself that would induce such cellular changes in human cells that would lead to cancer. It is just not plausible.

“Some of the confusion comes from reports where the Bt protein or glyphosate (the herbicide used on some GM crops) is applied to cell lines in a petri dish, and the cells show changes associated with stress and perhaps abnormal proliferation. However, cells in a dish do not behave like cells in the body. Through years of careful evaluation, there is no reliable evidence that GM foods cause the same changes in a living organism.”

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