Should We be Concerned about Genetic Modification of Our Food?

Industry Feeding Studies

The typical industry funded feeding study on GMOs follows a very predictable and consistent format. A number of rats are fed a certain percentage of a GE product, while a number of control rats are fed a non-GE variety for a period of 90 days. At the end of the 90 day period, blood, urine and tissue samples are taken from the rats. They are then sacrificed and a number of outcomes are measured. The findings of these studies are routinely reported as insignificant with the safety of the GE product verified. Upon approval by the FDA the product is released for widespread use and consumption.

Let’s discuss one of these types of studies performed with glyphosate-tolerant corn – one of the most common GE products that is designed to be resistant to Monsanto’s popular Roundup herbicide. It is also known as Roundup ready corn. This type of corn has a gene inserted that is derived from the bacterium Agrobacteria sp.(6) The gene codes for a version of an enzyme normally found in plants, enolpyruvylshikimate-3-phosphate (EPSP). EPSP is involved in the production of certain amino acids that are necessary for the continued growth and health of the plant.(6) Roundup normally block the action of this enzyme leading to death of the plant.(6) The GE version of this enzyme, however, is resistant to the effects of glyphosate.(6)

The study used 6-week old male and female rats.(6) The rats were split into ten groups of twenty rats consisting of two control groups, two experimental groups and six reference control groups.(6) One control group was fed a diet consisting of 11% conventional corn grain diets, while the other control group was fed a diet of 33% conventional corn for a period of 13 weeks.(6) The experimental groups were fed the same percentage of glyphosate-tolerant corn.(6) Reference controls were all fed a diet of 33% conventional corn.(6) During the 13 week period, the rats were observed twice daily to make sure they were still living and once daily to assess for overt toxicity.(6) Blood was drawn at 4 weeks and at the end of the study.(6) Urine was also collected at this time.(6) At the end of the study, the rats were sacrificed and a number of organ and tissue samples were collected.(6) As previously mentioned, outcomes such as weight, blood counts, serum electrolytes, liver & kidney function, organ weights and tissue pathology were assessed.(6) There were no statistically significant findings to show that rats consuming glyphosate-tolerant corn were in any way adversely affected by it.(6)


There are a number of concerns that arise using this type of study to verify that a GE product is safe for human consumption. I’ll mention two that should be easily recognized. The first and most blatantly obvious concern is with the test subjects – they are not human. Rat and other animal studies are commonly used as preliminary research in the medical field, but cannot be relied upon when assessing for true health effects in humans. The same can, and should, be said for GE products. The second matter is the length of the study. 13 weeks, or approximately 90 days, may be useful for assessing short-term, overt toxicity, but it is not a sufficient amount of time to assess for long-term risk of adverse health effects. No matter what assumptions are made regarding substantial equivalence, the general safety of proteins or the usefulness of animal studies, the only truly valid way to assess the safety of a GE product in humans is by studying humans consuming a product for a valid length of time to assess for chronic health effects.

Roundup Herbicide


There is a reason to choose glyphosate-tolerant corn as a prime example of a GE product. In 2012, 93% of soybean crops, 80% of cotton crops and 73% of corn crops in the US were of this variety – Roundup ready.(5) But, just how safe is Roundup?

As previously mentioned, glyphosate works by inhibiting the enzyme EPSP found in plants. Yet, there is much debate over possible health consequences of glyphosate in humans. There is research supporting both sides of the topic leaving the issue ultimately undecided. Often, however, it is forgotten that herbicidal formulations, such as Roundup, contain more than just glyphosate. They contain a whole host of other chemicals that are designed to assist glyphosate in achieving its herbicidal goal. Unfortunately, many of these other chemicals don’t get the same attention regarding safety as glyphosate does.


One such chemical found in many roundup formulations is a polyethoxylated alkylamine known as POE-15.(9) In a recent study performed by Mesnage, Bernay and Seralini, it was found that POE-15 may be much more toxic to human cells than glyphosate or other chemicals found in Roundup formulations. The LC50 (lethal concentration at which 50% of cells are killed) of POE-15 was found to be only 2 ppm (parts per million) for hepatic and embryonic cells and only 1 ppm for placental cells.(9) According to this research, POE-15 is vastly more toxic to human cells than glyphosate, yet has not receive nearly the same amount of attention or safety testing.

What does this have to do with GMOs? The answer is simple. Since Roundup ready crops were first introduced the use of Roundup herbicide has increased dramatically. This means our environment, our food and our bodies are much more likely to be exposed to the various chemicals found in Roundup formulations, including POE-15. Unfortunately, the chronic health effects of exposure to all these chemicals are not currently well understood.