Genetically-modified food is not going to give you cancer

Last week PSPG and the Penn Biotech Group hosted Dr. Val Giddings, President and CEO of the consulting firm PrometheusAB and Senior Science Policy Fellow at the Information Technology and Innovation Foundation. Dr. Giddings specializes in issues concerning genetically-modified organisms (GMOs) or as he prefers to call them, “biotech-improved” organisms, which have been genetically engineered to have certain beneficial traits. This usually means that a gene from one organism is inserted into the genome of a different organism to alter its properties or behavior in some beneficial way. GMO crops are frequently altered to improve tolerance to herbicides (think RoundUp) and resistance to insects and pathogens. They can also be modified to change their agronomic qualities (how/when they grow) which helps farmers to be more productive. Crops can also be modified to improve their quality: for example Golden Rice has been engineered to produce beta-carotene, the precursor to vitamin A, which is an essential nutrient that many children in developing countries don’t get enough of1,2.  GMO crops are quite prevalent within the US agriculture, with over 90% of soybeans, 80% of cotton and 75% of corn crops in the US being genetically modified in some way3. Outside of the US, GMO crops are grown in 27 countries by 18 million farmers, most of whom are smallholders in developing countries4. So what are the consequences of all these genetic modifications in our food supply?

The Pros: GMO crops with improved agronomic properties have allowed farmers to increase yield on less land, reducing CO2 output and allowing more wild habitats to remain untouched. GMOs have also decreased the need for pesticides because insect-resistant plants fight off pests on their own, which is good for the environment and good for you. GMO crops that have been modified to increase yield and produce essential nutrients could be a boon for developing countries where hunger and vitamin deficiencies are a serious problem.

The Cons: GMOs could lead to the overuse of herbicides like RoundUp because herbicide-tolerant plants can be sprayed more often with more chemicals. However, Dr. Giddings argued that herbicide-tolerant crops would have to be treated less often because the weeds could be killed off quickly in one fell swoop so there may be a trade-off there. I think the most serious concerns about GMO crops primarily relate to unintended ecological consequences. GMO crops, if they somehow escaped the farm and started growing wild, might out-compete other plants and reduce overall biodiversity. They could also seriously disrupt the food chain, especially considering that they can kill off insect species which are undoubtedly a food source for other animals. And then there’s the question of whether GMOs are safe to eat. There are concerns that GMO crops which produce foreign proteins (such as those that kill off insects) might trigger allergic reactions in some individuals; however there have never been any legitimate reports of this happening. There are also concerns that GM foods could cause cancer; however rigorous, peer-reviewed scientific studies have effectively ruled out this scenario. In fact the most prominent study to claim a link between GMOs and cancer had to be retracted because the sample size was too small to draw any conclusions and the authors used a rat strain which was known to have a high frequency of cancer to begin with5. The bottom line is that there is no evidence that GMOs are bad for you and the Food and Drug Administration has concluded that GMOs are safe to eat6.

Existing federal law requires food labels to be accurate, informative and not misleading. Nutrition labels must contain material information relating to health, safety and nutrition. The fact of the matter is that GMOs are considered safe so there is no reason for the FDA to force companies to identify their products as GMO. Basically the FDA decided that genetically modified foods are subject to the same labeling rules as any other food. Here are the highlights from FDA’s recommendations on how to label GM food7:

  •  If a bioengineered food is significantly different from its traditional counterpart such that the common or usual name no longer adequately describes the new food, the name must be changed to describe the difference.

  • If a bioengineered food has a significantly different nutritional property, its label must reflect the difference.

  •  If a new food includes an allergen that consumers would not expect to be present based on the name of the food, the presence of that allergen must be disclosed on the label.

However this doesn’t mean consumers are completely in the dark about what they’re buying. If you wish to avoid GM foods you can buy food labeled “USDA Organic” or “Non-GMO certified.” Otherwise it’s probably safe to assume a product includes some kind of bioengineered ingredient.
So why the big fuss over GMOs? It’s pretty clear that bioengineered foods are safe to eat and GMOs are probably more helpful than hurtful to the environment. Dr. Giddings offered a few explanations for the widespread resistance to GMOs in the Western world. Firstly, the organic/health food industry reaps big profits by distinguishing itself as a healthy, safe alternative to the Big Ag.  Secondly and more importantly, food is a huge part of every human being’s life and nobody likes the idea of it being messed with in ways they might not understand. It’s especially disconcerting when huge tentacle-y corporations are responsible for these changes.  So with all these considerations in mind, it’s up to you, the consumer, to decide whether genetically modified foods are worth the risks. Feel free to comment if there are any issues I omitted that you think are worth noting.

-Nicole Aiello 

1. Ye X, Al-Babili S, Klöti A, Zhang J, Lucca P, Beyer P, Potrykus I (2000) Engineering the provitamin A (β-carotene) biosynthetic pathway into (carotenoid-free) rice endosperm. Science 287:303-305.
2. Grune T, Lietz G, Palou A, Ross AC, Stahl W, Tang G, Thurnham D, Yin S, Biesalski HK (2010) β-Carotene is an important vitamin A source for humans. Journal of Nutrition doi: 10.3945/jn.109.119024.
3. US Department of Agriculture (USDA). Economic Research Service (ERS) 2013. Adoption of Genetically Engineered Crops in the US data product.
4. Clive James, ISAA Brief 46.
5. Séralini, Gilles-Eric; Clair, Emilie; Mesnage, Robin; Gress, Steeve; Defarge, Nicolas; Malatesta, Manuela; Hennequin, Didier; De Vendômois, Joël Spiroux (2012). "Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize". Food and Chemical Toxicology 50 (11): 4221–31.


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