The very first crop submitted to the FDA's voluntary consultation process, the FlavrSavr tomato, showed evidence of toxins. Out of 20 female rats fed the GM tomato, seven developed stomach lesions.1
The director of FDA's Office of Special Research Skills wrote that the tomatoes did not demonstrate a "reasonable certainty of no harm,"2 which is their normal standard of safety. The Additives Evaluation Branch agreed that "unresolved questions still remain."3 The political appointees, however, did not require that the tomato be withdrawn.*
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Rats fed GM potatoes had excessive cell growth on their stomach wall. Photo credit Stanley Ewen, Ph.D.
According to Arpad Pusztai, Ph.D., one of the world's leading experts in GM food safety assessments, the type of stomach lesions linked to the tomatoes "could lead to life-endangering hemorrhage, particularly in the elderly who use aspirin to prevent [blood clots]."4
Pusztai believes that the digestive tract should be the first target of GM food risk assessment, because the gut is the first (and largest) point of contact with the foods; it can reveal various reactions to toxins. He was upset, however, that the research on the FlavrSavr never looked past the stomach to the intestines. Other studies that did look found problems.
Mice were fed potatoes with an added bacterial gene, which produced an insecticide called Bt-toxin. Scientists analyzed the lower part of their small intestines (ileum) and found abnormal and damaged cells, as well as proliferative cell growth.5 Rats fed potatoes engineered to produce a different type of insecticide (GNA lectin from the snowdrop plant) also showed proliferative cell growth in both the stomach and intestinal walls (see photos).6
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The proliferative cell growth in the intestines and stomach in GM-fed rats may be a precursor to cancer. Photo credit Stanley Ewen, Ph.D.
Although the guts of rats fed GM peas were not examined for cell growth, the intestines were mysteriously heavier; possibly resulting from such growth.7 Cell proliferation can be a precursor to cancer and is of special concern.
* Calgene had submitted data on two lines of GM tomatoes, both using the same inserted gene. They voluntarily elected to market only the variety that was not associated with the lesions. This was not required by the FDA, which did not block approvals on the lesion-associated variety. The FlavrSavr tomato has since been taken off the market.
After the FlavrSavr, no other biotech company has submitted such detailed data to the FDA. The superficial summaries they do present to the agency are dismissed by critics as woefully inadequate to judge safety.
References
1. Department of Veterinary Medicine, FDA, correspondence June 16, 1993. As quoted in Fred A. Hines, Memo to Dr. Linda Kahl. "Flavr Savr Tomato: ...Pathology Branch's Evaluation of Rats with Stomach Lesions From Three Four-Week Oral (Gavage) Toxicity Studies ... and an Expert Panel's Report," Alliance for Bio-Integrity (June 16, 1993) http://www.biointegrity.org/FDAdocs/17/view1.html
2. Robert J. Scheuplein, Memo to the FDA Biotechnology Coordinator and others, "Response to Calgene Amended Petition," Alliance for Bio-Integrity (October 27, 1993). www.biointegrity.org
3. Carl B. Johnson to Linda Kahl and others, "Flavr Savr™ Tomato: Significance of Pending DHEE Question," Alliance for Bio-Integrity (December 7, 1993) www.biointegrity.org
4. Arpad Pusztai, "Genetically Modified Foods: Are They a Risk to Human/Animal Health?" June 2001 Action Bioscience www.actionbioscience.org/biotech/pusztai.html
5. Nagui H. Fares, Adel K. El-Sayed, "Fine Structural Changes in the Ileum of Mice Fed on Endotoxin Treated Potatoes and Transgenic Potatoes," Natural Toxins 6, no. 6 (1998): 219-233.
6. Stanley W. B. Ewen and Arpad Pusztai, "Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine," Lancet, 1999 Oct 16; 354 (9187): 1353-4.
7. Arpad Pusztai, "Facts Behind the GM Pea Controversy: Epigenetics, Transgenic Plants & Risk Assessment," Proceedings of the Conference, December 1st 2005 (Frankfurtam Main, Germany: Literaturhaus, 2005).
This section on Consumer Health Concerns from genetically modified food crops is derived entirely from the work by Jeffrey M. Smith, director of the Institute for Responsible Technology and author of “Genetic Roulette: The Documented Health Risks of Genetically Engineered Foods” and “Seeds of Deception.” www.responsibletechnology.org
