orphanblack's picture
Why has there never been a clinically controlled independent human feeding trial? If I were to come down with some unknown, inexplainable, or highly unlikely health condition, is anyone looking for cause and effect from consuming GMOs. If no one is looking for connections - does that mean connections don't exist? Also why are animal trials only conducted for 3 months, whereas humans, as another kind of animal, are being fed GMOs long term and not even followed for 3 months!

A:Expert Answer

The composition of GM crops and foods derived from them is carefully studied.  Using our knowledge of toxicology, food allergy, and nutrition, it is possible to predict if a food will have an adverse effect based on composition alone.  The study of composition is a better indicator of safety than are animal studies on whole foods.  Many scientists in fact question if whole food studies in animals are useful and have suggested they not been done.  Studies in humans are even more difficult to do and would likely yield little useful information since the diets' composition is the same, the outcome would be the same.  Since these are whole foods, with animal studies animals can be fed diets containing large amounts of the food ingredient being tested every day, which would be very difficult to do with humans.  Moreover, at the end of a study with animals, post-mortem examinations are performed that allow for a careful pathological examination of most all tissues to understand the pathologies that resulted from consuming large amounts of the whole food tested.


It's a general scientific principle that to do a good animal or human study a clear hypothesis and a means to test it are required.  Whole food feeding studies lack an hypothesis.  The underlying problem with whole food studies is that foods are complex mixtures of thousands of compounds rather than single pure chemicals.  Toxicologists use animal studies with single chemicals to test their toxicity (remember that virtually every chemical including nutrients required in the human diet can be toxic if we ingest too much). Foods are of course generally safe to eat so new varieties of crops are not tested in animals or humans.  There is a significant scientific consensus, based on quite a few composition studies, that demonstrates that GM crops composition is more similar to the parental strain from which they were bred than are other varieties of the same crop.  So, if we were going to ask for human or animal studies on whole foods, we should be asking for the on crops bred by non-GM methods.

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Steve Walach's picture

Dear Bruce --

This post of yours is an textbook-excellent non-answer. Lots of avoiding the issues while seeming to address them.

You have not addressed in the slightest "orphanblack's concern about the length of animal studies -- only 90 days. Why the avoidance?

You write: "Using our knowledge of toxicology, food allergy, and nutrition, it is possible to predict if a food will have an adverse effect based on composition alone."

In essence, you are declaring that your infallible knowledge makes your predictions 100% accurate, and therefore it is not necessary to conduct an actual, five year scientific study on, say, the effects of a GMO corn-based diet on the micro-biome of elementary school-aged children whose carbohydrate intake is 30% GMO corn because you already know the answer. Really?

Control groups could consist of children whose carbohydrate intake was also 30% corn but one group non-GMO corn, another group organic corn and lastly (for now) a group that consumed no corn at all but whose carbohydrate intake was a grain that has never been genetically engineered, like rice or wheat.

Your write: "Whole food feeding studies lack an hypothesis." Only if researchers fail to provide one.

The hypothesis is this instance would center on the effect of various diets on the human micro-biome, and if that were too general, I am sure specialists could pre-select the target bacteria to be tested. Or the hypothesis could be to determine the effects of GMO corn on the human gut.

Monsanto GMO corn varieties Obsession, Temptation and Passion contain the insecticidal Bt protein in every cell. These varieties are being sold to consumers. The EPA has done in vitro tests of Bt corn protein using human saliva and stomach acid but why not design a study that studies the effects of Bt corn on the digestive systems of children?

Prior to GMO technology, in all of human history there has never been crop that has had a section of its DNA specifically engineered to create a protein that is also a registered poison. Shouldn’t such a poison be scrupulously tested?

Proponents of GMO technology should not be in the business of making excuses for the absence of long-term studies on human beings. Your credibility would be greatly enhanced if the biotech industry took the initiative to conduct such studies. Because you haven't, the concerned public is left with this unsettling conclusion:

You don't want to know because you're afraid the answer might raise unwanted concerns.