Wednesday, 14 December 2011

Genetically Modified Foods: Unanswered Questions

Genetic modification (GM) is a process commonly discussed but rarely defined. Without a clear definition of GM, how can we critically assess the benefits and costs of GM for human health and the health of the planet? At the very least, GM technology has increased our vocabulary. Nowadays, Transgenic, Genetic Engineering, Recombinant DNA, and Biotechnology are widely used in agricultural and political discourse. But, has this new lexicon led to a better understanding of how, why, and for whose benefit are we modifying our foods?

Starting with its most general definition, GM means altering an organism’s genetic make-up. GM is often synonymous with genetic engineering - a process whereby genes from one life form are transferred into the genes of another life form (a.k.a Recombinant DNA technology). If we understand GM as genetic engineering, the first commercially grown GM crop was tobacco. GM tobacco contained genes from other plants that were resistant to the common tobacco virus. GM crops were also created to prevent rotting. The “Flavr Savr” GM tomato was created in the 90’s to slow the ripening process to prevent it from pre-mature softening.

GM technology was revolutionized in the late 90’s. The creation of herbicide and insect resistant plants was made possible by inserting genes from other organisms into food crops. You may have heard of examples of these GM plants such as Bt Cotton and HT Alfalfa. Bt refers to the bacterium, Bacillus thuringiensis and a Bt crop contains a gene taken from this bacterium that confers insect resistance. HT means “herbicide tolerant” and an HT crop means it contains a gene that gives it immunity to a chemical weed killer. HT crops can survive spraying with weed killing chemicals, and thus HT crops are ideally used to maximize agricultural output. 

What distinguishes GM through engineering from human’s long history of domesticating plants?

Some have argued that GM through engineering is a continuum of the natural processes of plant modification in human history. This makes sense if we remember that indigenous peoples’ sustained efforts to cultivate multiple varieties of forest plants have resulted in the domestication of numerous foods we continue to eat. But, can we now equate the processes of domestication, trade, and exchange of wild plant varieties with the engineering of life forms by moving certain desirable genes into plants? 

Plant modification is part of human existence on earth. But, it is hard to assess the social and ecological impacts of gene-modification without an understanding of the bigger picture. Why are we manipulating plants? Who is doing the manipulation? What sectors of society benefit from the GM technology? Who are these new technologies excluding? Presently, we know that most GM crops being used have been modified to maximize agricultural profits. Very few initiatives to increase nutritional content of plants through genetic modification have reached marginalized peoples. To my knowledge, Golden Rice – a plant engineered to aid vitamin A production (critical for vision) and to be used where people are vitamin A deficient - was proposed in 2000 but has not yet reached the market.

Also, we know very little about how the successes of GM initiatives have been measured? For example, when the use GM crops are reported to have increased farmer’s yields, what are we comparing these numbers to? Are we improving crop yields compared to industrial monoculture or compared to long-standing traditions of organic and agro-ecological farming methods? Before we uncritically accept the widespread use of GM crops, these questions need to be addressed.

Different approaches to GM crops by country:


Stone, G. D. (2010). The Anthropology of Genetically Modified Crops Annu. Rev. Anthropol. , 39 (1), 381-400 : 10.1146/annurev.anthro.012809.105058


  1. The World Trade Organization has made a preliminary ruling that European Union restrictions on genetically engineered crops violate international trade rules. The United States, Canada, and Argentina together grow 80 percent of all biotech crops sold commercially, by which the EU regulates such crops. The countries argued that the EU's regulatory process was far too slow and its standards were unreasonable given that the overwhelming body of scientific evidence finds the crops safe.

  2. I'm wondering if any studies have been carried out on the effects of GM food on consumers' health. While the term "genetically modified" does seem scary to the public, what facts are there to support a cautious approach to widespread consumption of such food or to justify strict regulatory guidelines?

  3. Ehsan – Thanks for your comment and question.

    The impact of GM foods on human health is a hotly debated topic; I’m afraid to say I know very little on the existing research. What jumps out to me is that it has only been a little over 15 years that we have been consuming GM foods and the answers to these questions are not likely to be well known. I did a quick review of some journal articles and found that the existing research has focused on the impacts of feeding GM foods to pigs, sheep, cattle, etc. General trends are lacking and we need more research on GM foods on a case-by-case basis. There is concern that genes inserted into plant foods are not fully broken down through digestion and could be horizontally transferred to humans. For example the consumption of Bt crops (modified with bacteria genes) has been studied to determine if bacterial genes are horizontally transferred to the bacteria in an animals’ gut (results seem inconsistent). A similar concern exists for the use of viral DNA for GM crops. Other concerns include, 1) the potential that eating GM foods will lead to an increase in anti-nutrient levels in our body (anti-nutrients interfere with nutrient absorption among other things), 2) the possibility that novel genes will result in allergic responses, and 3) the possible transfer of antibiotic resistant genes to bacteria in the gut. I think the strongest argument for strict or precautionary regulatory guidelines is that our duration of exposure to GM foods is too short to fully evaluate potential health impacts.

    Here is a useful review I found:

    Dona, A., and Arvanitoyannis, I. S. 2009. Health Risks of Genetically Modified Foods. Critical Reviews in Food Science and Nutrition 49:164-175.

  4. James – Thank you for pointing this out. In addition to my above comment on human health, there are ecological and political rationales to support a more cautious approach to the widespread acceptance of GM crops. I enjoyed your site, a very useful resource for GM food news.

  5. As we genetically modify organisms (flora & fauna) we also risk exposure to the legal issues of 'patented' lifeforms. An example is the current patents held over soy, corn or canola and the politics involved in controlling the consumer demand for a specific 'patent' product - leading to not only restricted access to non-patent seed sources but also a limited and diminishing market for those who dare operate with non-patent seed.
    The only possible outcome is a very homogeneous single-seed product on a global scale. Nature will eventually re-teach the lessons of how a single disease or pest can easily wipe out entire crop-years based on the lack of variety in the disease's 'prey'.
    The eventual cost to human health will no longer be measured in terms of impact of prolonged consumption of 'alien' gene strings, but on the complete lack of any crop at all - mass global starvation!
    When Ethiopia (which at the time included the land now called Eretria)last experienced a drought, the news was focused on the fact farmers were resorting to eating their seed-grain - which had been handed down for centuries from generation to generation. The concern was surrounding the reduction of variety in the genetic make-up of these grains. Now, individual companies are capable of wiping out these seed varieties on a global scale. The exposure is frightening.
    I hope another possible outcome exists. Laws need to be changed to address this before it is too late.

  6. Hi Lester,

    Thank you for your comment. I apologize for not responding sooner. I received your comment as I began preparation for fieldwork in Costa Rica and I wanted to wait to respond until I had time to look into the information you provided.

    The homogenization of crop diversity is a critical part of the long-term impacts of genetic modification. And, as you mentioned, the scale to which this appears to be taking place is alarming.

    Similar to your Ethiopia/Eretria example, I recently visited an indigenous community in southern Costa Rica where people were concerned about the need to maintain varieties of seed used and maintained by their ancestors. In this community, one of the greatest challenges reported was that traditionally-cultivated plant species are now commercially produced. These commercial varieties are widely available to farmers at very accessible prices, and this has left little incentive for seed-saving of local landraces. An example of such a crop in south Costa Rica was the Pigeon Pea. I’m curious to know, was one of the plant(s) you referred to from the Ethiopian case millet?