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genetic engineering

Health risks of GE food

Dangers From Consumption of Foods Containing Transplanted DNA
Health risks of GE food

Dangers From Consumption of Foods Containing Transplanted DNA

by Hugh S. Lehman, Ph.D.


Genetically modified organisms (GMOs) are organisms that have been produced when DNA from other organisms is incorporated into the cells from which the GMO develops. The inserted DNA becomes part of the genome of the GMO and becomes active in the cells of the GMO. If this GMO is consumed, then the inserted DNA enters the digestive tract along with any products that result from the activity of that DNA. For example, if the inserted DNA produced a toxic substance then consumption of the GMO entails consumption of that toxin. There are many food products available to consumers in the United States that contain GMO's. Among these are corn and soybeans. Presumably there are many American consumers who consume significant amounts of food containing GMOs since, aside from the direct consumption of corn and soybeans, these foods are used in producing many other food products. The United States government regards these food products as safe for human consumption even though there were no experimental tests to determine that consumption of such foods caused no harm. [1]

There are good theoretical reasons to be concerned about the possibility of harm resulting from the consumption of GMOs. Some of these arise from the nature of the DNA that is inserted; some of these arise from the instability of inserted DNA generally. First let's talk about some questions that arise from the nature of the inserted DNA. Along with the DNA that is inserted to produce a desired trait in a plant or other organism there is additional DNA that is used to show that the insertion has succeeded and further more DNA that is used to activate the DNA that produces the desired trait. To show that the insertion of DNA into the organism was successful, DNA that produces antibiotic resistance is used. To activate the desired DNA, some DNA from the cauliflower mosaic virus is widely used. Possible harms that might result from consumption of inserted DNA include spread of antibiotic resistance to disease-causing intestinal organisms. In addition other foreign DNA, not described by the producer, has been found in GMOs. [2] This creates additional uncertainty regarding possible harms that could result from consuming the GMOs in question. Due to the instability of the inserted DNA there is also risk of harm to the organism from the cauliflower mosaic viral DNA.[3] Indeed, in 2002 a histopathologist, Dr. Stanley Ewen, warned that the DNA from the cauliflower mosaic virus could contribute to the growth of malignant tumors.[4] In the same year the Institute of Science in Society warned of such dangers from horizontal gene transfer[5].

There was a time when genetic researchers thought that consuming the DNA inserted into GMO's would not cause harm as the inserted DNA would be destroyed in the digestive tract. However evidence has been available for several years that the inserted DNA is not fully digested. As early as July 17, 2002, a report published in the Guardian in the United Kingdom asserted that research by British scientists, from Newcastle University, shows that transplanted DNA survived the digestive process and was able to enter bacteria resident in the human gut.[6] Our digestion depends on the wide range of bacterial organisms that inhabit our digestive tracts. We have evolved to live in commensal relationships with these microorganisms. The introduction of novel DNA could change those relationships in harmful ways. Were they modified by incorporation of novel DNA they could either fail to contribute to our digestive functioning or become toxic and produce injury or illness. While this is a significant consideration for young healthy adults, it is a consideration that should be taken7 even more seriously for people whose digestive system is compromised by illness or injury. The novel DNA produces proteins that may be toxic to humans, possibly causing problems only after prolonged exposures. Large populations are being exposed and potential toxicities aren't being studied; nor is there long-term surveillance or even labeling.

On June 13, 2003, The Institute of Science in Society (a group of scientists not affiliated with the agricultural industry) published a report calling attention to scientific evidence suggesting danger from consumption of GMOs. The report notes that genes for Bt toxin and the toxin that it codes for are taken up into bacteria in the human gut. As we have observed there is risk that such bacteria may become pathogenic. [8] The dangers posed by the consumption of GMOs may be more than theoretical.

Furthermore, even though GMO's were approved for human consumption in the United States without experimental tests to determine whether such consumption was safe, there is growing evidence from observations of animals that consuming GMOs may indeed cause injury or disease. While there has been subsequent research the most well known studies were performed by the distinguished food scientist Arpad Pusztai. Pusztai's research rats were fed GMOs and suffered modifications to many of their organ systems, e.g., liver, testicles, etc. More recently, in an April 2002 report of the British Broadcasting System it was asserted that research in which chickens fed genetically modified maize were compared with chickens fed on conventional maize. Twice as many of the chickens fed genetically modified maize died.[9]

In an article from the French newspaper Le Monde, reported by GM Watch in April 2004, rats suffered harm to their organs.[10] In an article in January 2004, the Institute of Science in Society noted reports of the death of cows fed genetically modified maize. In a report published May 27, 2004, GM Watch reported that the liver cells of mice fed on GMO's were abnormal.[11] That research was performed in Italy. In a report in April 2004 the Institute of Science in Society published a report concerning the deaths of chickens that had been feed genetically modified maize. Not only are there apparent dangers from the consumption of GMOs, there are reports of debilitating illnesses to farm workers who lived near fields containing a GM hybrid maize crop (reported in the April 28, 2004 report of the Institute of Science in Society.) Jeffrey Smith, author of Seeds of Deception: Exposing Industry and Government Lies about the Safety of the Genetically Engineered Foods You're Eating, has reported on much of the observational and experimental harms associated with the consumption of GMO's in that work and elsewhere.

We have discussed only some reasons for questioning the safety of consuming GMOs. While GMOs are consumed widely in the United States and Canada, to our knowledge there is no systematic effort to monitor the health of consumers to detect harms from such consumption. The health of consumers may already be affected but, since nobody is investigating, it is virtually certain that such harm will go undetected for a very long time.


1. Report of Institute of Science in Society, September 1, 2004.

2. Windels,P.et.al. European Journal of Food Research Technology, v.

213, Issue 2, pp. 107-112, 2001.

3. Report of Institute of Science in Society, October 23, 2003.

4. Press release from Crop Choice News, December 12, 2002.

5. Report of Institute of Science in Society, November 10, 2002.

6. John Vidal, Guardian Unlimited, Special Report, July 17, 2002.

See also report of Institute of Science in Society, June 13, 2003. See

also article by Jonathan Leake, Sunday Times Online, May 4, 2003.

7. The report of the Institute of Science in Society of March 23,

2004 mentions the existence of evidence of harm to mammals from the

toxins produced from inserted DNA constructs.

8. Report of the Institute of Science in Society, June 13, 2003.

9. BBC News, "GM Safety Tests Flawed", April 27,2002.

10. Report of the French Commission for Genetic Engineering (CGB),

October 28,2003.

11. Malaatesta, M., et.al., "Ulstructural Morphometrical and

Immunocytochemical Analyses of Hepatocyte Nuclei from Mice Fed on

Genetically Modified Soybeans", Cell Structure and Function, Vol. 27.

No.4, (2002), pp 173-181.

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