One of the criticisms I hear about the movement to label genetically modified organisms (GMOs) is that it's anti-science. Some even go so far as to say it's an assault on science. While I can't speak for the entire movement, I can say that the lack of research in humans and troubling findings in some animal studies is enough to make me question the safety and necessity of GMOs.
The research related to GMOs can be hard to sort through. One study may find health problems in animals, but then proponents and biotech scientists say the study is flawed. But are there any scientists that question the safety and effectiveness of GMOs?
Over the past few months, I have spoken with scientist Michael Hansen, PhD, who is an expert on genetically modified crops. Dr. Hansen works for the Consumers Union, the safety and advocacy arm of the organization Consumer Reports. Consumers Union is not funded by agribusiness, or other multinational companies tied to the biotech or food industry. Therefore its opinions are not influenced by industry money.
Dr. Hansen has testified at many hearings in support of GMO labeling both nationally and internationally. And he has been interviewed on a lot of television and radio shows, including the Dr. Oz Show, which aired on March 26, 2013. He is willing to answer some of my questions about GMOs, also known as genetically engineered crops.
1. Does the Food and Drug Administration (FDA) do safety testing on genetically modified crops?
No, they do not. Nor do they require any companies to do safety testing of their genetically engineered (GE) crops. The FDA policy on GE was introduced as a deregulatory initiative in 1993. It is based on the notion that genetic engineering is an extension of traditional plant breeding and should be regulated in the same way. In other words, no requirement for human safety testing; instead there are voluntary safety consultations.
2. What are voluntary safety consultations?
The companies that create GE crops do their own food safety assessments, which the FDA reviews. At the end of the consultation process the FDA sends a letter to the company. Here is an excerpt from one letter which says, "Based on the safety and nutritional assessment you have conducted, it is our understanding that Monsanto has concluded that corn grain and forage derived from the new variety are not materially different in composition, safety, or other relevant parameters from corn grain and forage currently on the market, and that they do not raise issues that would require premarket review or approval by FDA." [emphasis added]. A version of this sentence is in all 97 "safety" consultation letters.
In other words, the FDA does not state its own opinion about the safety of GE crops. It only states what the company believes.
3. What are the potential health risks associated with Genetically Engineered Crops?
Human safety concerns may arise from genetic engineering due to the introduction of new allergens, an increased level of naturally occurring allergens, plant toxins, or changes in nutrition. GE crops may also have a negative effect on the gut and peripheral immune response. A meta-analysis of animal feeding studies involving GE crops suggests that they cause liver and kidney problems. And a new well-designed, long-term feeding study has found that pigs consuming GE corn and soy had significantly higher rates of severe stomach inflammation and females had significant thickening of the uterus.
In addition, GE plant material is finding its way into the human body with unknown health effects. A study found the toxin from GE corn in 93 percent of maternal and 80 percent of fetal blood samples. Clearly, more research is needed.
4. The Séralini study published in October, 2012, has gotten a lot of criticism. Do you think it has merit?
Yes, I do. The study was a follow-up to Monsanto's 90-day feeding study on its NK603 corn. The Séralini study, which continued for 2 years, found that female rats fed this GE corn died 2-3 times more quickly, and developed mammary tumors more often than controls that ate non-GE corn. Male rats fed the GE corn had liver and kidney problems at higher rates than controls, and more large tumors than rats fed non-GE corn.
The study received a lot of media attention. It was viciously attacked in the media by pro-GE and industry-affiliated scientists in what appears to have been an orchestrated campaign.
The two main criticisms were that they used too few rats per group and that they used a strain of rat that is prone to mammary tumors as they age. Both criticisms are off base.
The Séralini study used 10 rats per group, the same number of rats that Monsanto used in their 90-day feeding study to look at key biological parameters. If ten rats are too small a sample size to demonstrate health problems, how come ten rats are a sufficient sample size to demonstrate no safety concerns?
As for the type of rat used, Séralini used the same strain, Sprague Dawley (SD), that was used in the Monsanto feeding study on its NK603 GE corn and its 2 year feeding study looking at the safety of glyphosate. Why is use of SD rat's bad when Séralini uses them, but okay when Monsanto and other biotech companies use them?
If Séralini's study is flawed, then so is Monsanto's, and the safety of their GE corn should be reassessed.
5. Have GMOs helped to feed the world, reduce the use of pesticides, or increase yield as proponents have promised?
No. Dr. Charles Benbrook's work has shown that GE crops in the U.S. have led to a dramatic expansion in pesticide use, particularly herbicides. Indeed, over the past 16 years there has been an increase of about 404 million pounds more herbicides used on GE crops, compared to non-GE crops. Work by Dr. Doug Gurian-Sherman has shown that genetic engineering doesn't really increase crop yield.
6. Why do you think foods with GMO ingredients should be labeled?
There are a lot of uncertainties related to genetically engineered crops including potential allergens and unknown health risks. If these foods are not labeled, it will be very difficult to identify an unexpected health effect resulting from eating a genetically modified food. For more information, see here.
Bernstein, I.L., Bernstein, J.A., Miller, M., Tierzieva, S., Bernstein, D.I., Lummus, Z., Selgrade, M.K., Doerfler, D.L. and V.L. Seligy. 1999. Immune responses in farm workers after exposure to Bacillus thuringiensis pesticides. Environmental Health Perspectives, 107(7): 575-582. At: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1566654/pdf/envhper00512-0103.pdf
Gupta, A. et al. 2006. Impact of Bt cotton on farmers' health (in Barwani and Dhar District of Madhya Pradesh). At: http://www.lobbywatch.org/archive2.asp?arcid=6265 and http://www.lobbywatch.org/archive2.asp?arcid=6266
Gendel, S.M. 1998. The use of amino acid sequence alignments to assess potential allergenicity of proteins used in genetically modified foods. Advances in Food and Nutrition Research, 42: 44-61.
Vazquez-Padron, R.I., Moreno-Fierros, L., Neri-Bazan, L., de la Riva, G.A. and R. Lopez-Revilla. 1999. Bacillus thuringiensis Cry1Ac protoxin is a potent systemic and mucosal adjuvant. Scandinavian Journal of Immunology 49: 578-584.
Finamore, A., Roselli, M., Britti, S., Monastra, G., Ambra, R., Turrini, A. and E. Mengheri. 2008. Intestinal and peripheral immune response to MON810 maize ingestion in weaning and old mice. Journal of Agriculture and Food Chemistry, 56: 11533-11539. At: http://www.giovannimonastra.info/documenti_pdf/Monastra_J_Agr_Food_Chem_2.pdf
Séralini, G-E, Mesnage, R., Clair, E., Gress, S., de Vendômois, JS and D. Cellier. Genetically modified crops safety assessments: present limits and possible improvements. Environmental Sciences Europe, 23: 10. At: http://www.enveurope.com/content/pdf/2190-4715-23-10.pdf
Kuiper, HA, Kleter, GA, Notebom, HPJM and EJ Kok. 2001. Assessment of food safety issues related to genetically modified foods. The Plant Journal, 27(6): 503-528.
Carmen, JA. et al. 2013. A long-term toxicology study on pigs fed a combined genetically modified (GM) soy and GM maize diet. Journal of Organic Systems, 8(1): 38-54. At: http://www.organic-systems.org/journal/81/8106.pdf
Aris, A and S Leblanc. 2011. Maternal and fetal exposure to pesticides associated to genetically modified foods in Eastern Townships of Quebec, Canada. Reproductive Toxicology, 31(4): 528-533.
Séralini, G-E. et al. 2012. Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food and Chemical Toxicology, 50: 4221-4231. http://www.sciencedirect.com/science/article/pii/S0278691512005637
Bardocz S, Clark A, Ewen S, Hansen, M, Heinemann J, Latham J, Pusztai A, Schubert D and A Wilson. 2012. Séralini and science: An open letter. Independent Science News. At: http://independentsciencenews.org/health/seralini-and-science-nk603-rat-study-roundup/
Benbrook, C. 2012. Impact of genetically engineered crops on pesticide use in the U.S. -the first sixteen years. Environmental Sciences Europe, 24:24.
Gurian-Sherman, D. Failure to Yield: Evaluating the Performance of Genetically Engineered Crops. Union of Concerned Scientists, 2009.