GMO corn (maize) Toxicity

[DrDNA]

Have y'all seen this study?

 

A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health

http://www.biolsci.org/v05p0706.htm#headingA11

 

Int J Biol Sci 2009; 5:706-726

 

To summarize:

 

-Rats were fed three main commercialized genetically modified (GMO) maize (aka corn) (NK 603, MON 810, MON 863) used throughout the world. 1 is tolerant to herbicide Roundup. 2 are engineered to synthesize Bt toxins which are used as insecticides.

 

-All three of these GMO corn strains have been approved for consumption in the US and several countries in Europe.

 

-For the 3 GMO dietary products above, dose-dependent side effects were linked with their consumption after just 90 days.

 

- Effects included dietary detoxifying organs (kidney and liver function).Other effects noticed in the heart, adrenal glands, spleen and haematopoietic system.

 

-Conclusion = The study suggests that these GMO corn strains are linked to dose-dependent hepatorenal toxicity, possibly due to the pesticides specific to each GMO corn. Direct or indirect metabolic consequences of the genetic modification cannot be excluded.

 

 

 

"............We therefore conclude that our data strongly suggests that these GM maize varieties induce a state of hepatorenal toxicity. This can be due to the new pesticides (herbicide or insecticide) present specifically in each type of GM maize, although unintended metabolic effects due to the mutagenic properties of the GM transformation process cannot be excluded [42]. All three GM maize varieties contain a distinctly different pesticide residue associated with their particular GM event (glyphosate and AMPA in NK 603, modified Cry1Ab in MON 810, modified Cry3Bb1 in MON 863). These substances have never before been an integral part of the human or animal diet and therefore their health consequences for those who consume them, especially over long time periods are currently unknown. Furthermore, any side effect linked to the GM event will be unique in each case as the site of transgene insertion and the spectrum of genome wide mutations will differ between the three modified maize types. In conclusion, our data presented here strongly recommend that additional long-term (up to 2 years) animal feeding studies be performed in at least three species, preferably also multi-generational, to provide true scientifically valid data on the acute and chronic toxic effects of GM crops, feed and foods. Our analysis highlights that the kidneys and liver as particularly important on which to focus such research as there was a clear negative impact on the function of these organs in rats consuming GM maize varieties for just 90 days."

 

I find these results quit surprising since I was in the camp that believed that GMOs were safe for consumption.

I have been concerned about the potential for cross-pollination (to weeds, invasive species, etc) and the potential for tolerance (as with antibiotics).

 

It looks the EU has been right about GMOs all along.............and Monsanto and the USDA/FDA has been wrong.

 

BYW: This study conforms with a 2007 analysis published in Environmental Contamination and Toxicology.

 

Monsanto disputes the 2007 study (naturally) stating:

“The analyses conducted by these authors are not consistent with what has been traditionally accepted for use by regulatory toxicologists for analysis of rat toxicology data.”

 

Comments????

[Variola]

I think it is too early to say the EU have been right, there are a few holes in the research, as with most research you can't cover it all, and that is reflected by the authors in the discussion.

 

Briefly- a few points to bare in mind.

 

There are trace amounts of pesticides in most non-organic foods we consume. the ordinary levels need to be compared to those contained in GM crops.

 

The food we eat is usually processed, not many folk eat maize/corn straight from the field! Therefore the diet containing GM foods of a rat and a human would be very different. Processing can alter the structure and bioavailability of a chemical.

 

Following that is the level of GM crop fed to the rats, if it was an exclusive diet then it would contain levels much higher than in a normal rat, or human diet.

 

Despite being good animal models, there is still a vast difference between rat and human physiology.

 

This study needs proper biochemical analysis before it carries any real weight, saying there is a possible causal link, without the biochem to back it up is not enough, not to convince me personally anyhow.

The authors discussion is reflective of their study though.

 

 

I dunno..... maybe I am just erring on the side or caution..... or I am getting too obsessed with seeing Biochem..... lol!!

Edited June 19, 2010 by Variola

[CharonY]

As a rule of thumb there is quite some research needed to establish potential adverse effects of any given GMO strain. As extreme effects are usually rather unlikely the difficulty is of course to identify effects that are above background toxicity (and how to define that baseline). For instance GMO maize may have more negative effects than pristine WT maize, but have less or equivalent to those grown under normal agriculturally relevant conditions (including use of pesticides, environmental pollution etc.)

 

Unfortunately biochemistry will not be the ultimate answer either. Even if toxicity pathways are identified we will be stuck with BMD or similar parameters that do not necessarily apply to humans. But that is a current limitation of traditional toxicology.

[Variola]

As a rule of thumb there is quite some research needed to establish potential adverse effects of any given GMO strain. As extreme effects are usually rather unlikely the difficulty is of course to identify effects that are above background toxicity (and how to define that baseline). For instance GMO maize may have more negative effects than pristine WT maize, but have less or equivalent to those grown under normal agriculturally relevant conditions (including use of pesticides, environmental pollution etc.)

 

Unfortunately biochemistry will not be the ultimate answer either. Even if toxicity pathways are identified we will be stuck with BMD or similar parameters that do not necessarily apply to humans. But that is a current limitation of traditional toxicology.

 

 

Yes that is true, but some standard toxicology to prove x causes y which causes z will be a starting point, and presumably one of the next goals.

The paper in itself, despite the support of other research findings is not enough to make me start worrying just yet.

 

Some comparable tests to examine ordinary non-organic ( although BT is considered by some to be organic) maize grown in the traditional way against the GM maize would be more relevant I think.

[CharonY]

Interestingly enough, for many if not most toxic compounds only vague mechanisms are known. There are few for which all the involved pathways are elucidated. The reason is that many have unspecific effects. There is hope that systems biology approaches may be useful in identifying novel toxicity pathways, though.