BioScience Productions, an organization promoting bioscience literacy, has commissioned Dr Arpad Pusztai, one of the world's formost expert's on nutritional studies with close to 300 primary peer-reviewed scietific papers published plus 12 scientific books, to do a short review of all the published studies on GM food safety.

This is an excellent resource and finally lays to rest the myth promoted by biotech proponents that GM foods are well tested and that there is a significant body of scientific literature supporting their safety. Dr Pusztai's review shows that GM crops and food are being grown and consumed by the public, even though:

- there is little scientific study about their health risks

- safety test technology is inadequate to asses potential harm

- they can carry unpredictable toxins

- they may increase the risk of allergenic reactions

The complete article is available online (url below). Here we give only a summary via:

-the article's headings - shown between * *

-BioScience Productions' summarising statements - shown in []

-quotations from the text, including the full conclusion.

We hope to make a full version of the article, complete with references, available shortly, in the meantime we recommend reading the full text at: http://www.actionbioscience.org/biotech/pusztai.html
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Genetically Modified Foods: Are They a Risk to Human/Animal Health?
By Arpad Pusztai, Ph.D.
BioScience productions

*Scarcity of safety tests*

[Information is scarce about health hazards, such as toxicity in GM crops.]

How can the public make informed decisions about GM foods when there is so little information about its safety? The lack of data is due to a number of reasons, including:  

It's more difficult to evaluate the safety of crop-derived foods than individual chemical, drug, or food additives. Crop foods are more complex and their composition varies according to differences in growth and agronomic conditions.  

Publications on GM food toxicity are scarce. An article in Science magazine said it all: "Health Risks of Genetically Modified Foods: Many Opinions but Few Data".1 In fact, no peer-reviewed publications of clinical studies on the human health effects of GM food exist. Even animal studies are few and far between.  

The preferred approach of the industry has been to use compositional comparisons between GM and non-GM crops. When they are not significantly different the two are regarded as "substantially equivalent", and therefore the GM food crop is regarded as safe as its conventional counterpart. This ensures that GM crops can be patented without animal testing. However, substantial equivalence is an unscientific concept that has never been properly defined and there are no legally binding rules on how to establish it.2  

[GM foods may cause bacteria to become resistant to antibiotics.]

DNA does not always fully break down in the alimentary tract.3,4 Gut bacteria can take up genes and GM plasmids5 and this opens up the possibility of the spread of antibiotic resistance.  

[They can also produce allergies.]

 [Current testing methods need radical improvements.]

Insertion of genes into the genome can also result in unintended effects, which need to be reduced/eliminated by selection, since some of the ways the inserted genes express themselves in the host or the way they affect the functioning of the crop's own genes are unpredictable. This may lead to the development of unknown toxic/allergenic components, which we cannot analyze for and seriously limiting the selection criteria.  

*Safety tests on commercial GM crops*

[Some rats died within a few weeks after eating GM tomatoes.]

GM tomatoes: The first and only safety evaluation of a GM crop, the FLAVR SAVR[TM] tomato, was commissioned by Calgene, as required by the FDA. This GM tomato was produced by inserting kanr genes into a tomato by an 'antisense' GM method. The test has not been peer-reviewed or published but is on the internet.8 The results claim there were no significant alterations in total protein, vitamins and mineral contents and in toxic glycoalkaloids.9 Therefore, the GM and parent tomatoes were deemed to be "substantially equivalent."  

No histology on the intestines was done even though stomach sections showed mild/moderate erosive/necrotic lesions in up to seven out of twenty female rats but none in the controls.However, these were considered to be of no importance, although in humans they could lead to life-endangering hemorrhage, particularly in the elderly who use aspirin to prevent thrombosis.

Seven out of forty rats on GM tomatoes died within two weeks for unstated reasons. These studies were poorly designed and therefore the conclusion that FLAVR SAVRTM tomatoes were safe does not rest on good science, questioning the validity of the FDA's decision that no toxicological testing of other GM foods will in future be required.  

GM maize: Two lines of Chardon LL herbicide-resistant GM maize expressing the gene of Phosphinothricin Acetyltransferase Enzyme (PAT-PROTEIN) before and after ensiling showed significant differences in fat and carbohydrate contents compared with non-GM maize and were therefore substantially different.  

[Rats'ability to digest was decreased after eating GM corn.]

...GM maize expressing PAT-PROTEIN may present unacceptable health risks.

*Compositional studies*

[Allergen content increased when soybeans were genetically modified.]

[The toxin level of GM cotton is unpredictable.]

*Nutritional/toxicological studies*

[Rats had meager weight gain when fed GM soybeans.]

[GM peas seem to have no harmful effects on animals but that doesn't mean they are safe for humans.]

[Toxins were found in mice after eating GM potatoes.]

 [[Pusztai's own research]]

When the health risks of GM potatoes were revealed in some studies, a debate ensued.  

...most of the adverse comments on this Lancet paper were personal, non-peer reviewed opinions and, as such, of limited scientific value. The findings, on the other hand, were published in a peer-reviewed publication25 and the criticism replied to.7 The work, however, has not been repeated nor results contradicted and it is therefore imperative that the effects on the gut structure and metabolism of all other GM crops developed using similar techniques and genetic vectors should be thoroughly investigated before their release into the food chain.  

*Allergenicity studies*

Allergies are a major concern with GM food, especially if ingredients are not labeled in packaged food.

There are no reliable ways to test GM foods for allergies.

*In conclusion*

[We need more and better testing methods before making GM foods available for human consumption.]

One has to agree with the piece in Science1 that there are many opinions but scarce data on the potential health risks of GM food crops, even though these should have been tested for and eliminated before their introduction. Our present data base is woefully inadequate. Moreover, the scientific quality of what has been published is, in most instances not up to expected standards. If, as claimed, our future is dependent on the success of the promise of genetic modification delivering wholesome, plentiful, more nutritious and safe GM foods, the inescapable conclusion of this review is that the present crude method of genetic modification has so far not delivered these benefits and the promise of a superior second generation is still in the future.

Although it is argued by some that small differences between GM and non-GM crops have little biological meaning, it is clear that most GM and parental line crops fall short of the definition of "substantial  equivalence." In any case, this crude, poorly defined and unscientific concept outlived its possible previous usefulness and we need novel methods and concepts to probe into the compositional, nutritional/toxicological and metabolic differences between GM and conventional crops and into the safety of the genetic techniques used in developing GM crops if we want to put this technology on a proper scientific foundation and allay the fears of the general public. We need more science, not less.6,7

 © 2001, BioScience Productions, Inc., an organization promoting bioscience literacy. Educators have permission to reprint articles for classroom use; other users, please contact editor for reprint permission.