Genetic engineering and GMOs are integral parts of the industrial food system and GMO ingredients are in most packaged foods. Many consumers are concerned about GMOs, but many do not truly understand the issues at play.
Published: 10/08/18, Last updated: 2/28/24
Genetically engineered (GE) or genetically modified (GM) foods are produced from plants and animals that have had changes made to their DNA, which introduce or modify genetic traits.
Most packaged foods contain genetically modified organisms (GMOs) engineered to be resistant to herbicides and pests; corn, soybeans and canola oil are prime examples. Concerns about GMOs range from their safety to how genetically modified plants’ pollen effects the environment, to the increasing use of herbicides associated with their use, with decreasing effectiveness. Polls show that consumers want mandatory labels on foods containing GE ingredients. 1
All living organisms are made up of cells, within which are strings of DNA molecules possessing instructions to make genes, which form a unique blueprint determining how an organism grows, develops, looks and lives. Genes make up about one percent of the DNA sequence; the rest is responsible for regulating when and how quantities of proteins are made. 2
Genetic engineering (GE) is the direct manipulation of genetic material (or the genome) by artificial means to alter the hereditary traits of a cell or organism. The process can involve the transfer of specific traits, or genes, from one organism to another, including across diverse species. Other types of genetic engineering include removing or “switching off” certain genes, adding new genes or introducing desired mutations. An organism that is created or modified by genetic engineering is called a genetically modified organism.
Genetic engineering in agriculture is different from traditional cross-breeding methods, which have been used for millennia. Traditional breeding more closely resembles accelerated evolution: breeders select organisms with a desired trait and then further select and breed whichever of its offspring most exhibits that trait. A breeder seeking a disease-resistant tomato, for example, will grow many tomatoes, but save the seeds of only the most disease-resistant plants. After several generations, offspring will be much more disease resistant than the progenitor. Traditional breeding is done between the same or closely related species and keeps strands of DNA and gene sequences intact — which can also mean that negative traits are reproduced alongside positive traits. Through genetic engineering, on the other hand, it is possible to isolate a single gene out of the whole genome and insert it into another organism.
The future of genetic engineering appears to be even more targeted than that: CRISPR technology (which stands for Clustered Regularly Interspaced Short Palindromic Repeat) allows scientists to isolate and essentially “cut and paste” very specific sections of DNA. This makes the process much more precise and efficient — and inexpensive, making it easier for many more scientists to experiment with the technology. As it becomes more common, many scientists also urge caution, as unintended consequences, whether at the cellular, human or ecosystem level, cannot be known in advance. 3
Genetically engineered crops have been adopted at an exceptionally rapid rate. In 1997, 17 percent of US soybean acres were planted with GE varieties; by 2014, that figure rose to 94 percent. GE cotton usage went from 10 percent in 1997 to 91 percent in 2014. GE corn acreage increased from 25 percent in 2000 to 92 in 2017. 45
The vast majority of these crops have been engineered to tolerate herbicides, allowing the plants to be sprayed with a particular chemical while the surrounding weeds die. Glyphosate, the active ingredient in Roundup, is the most common. Other crops are engineered to produce their own natural pesticide (primarily to produce Bacillus thuringiensis, or Bt, a naturally-occurring bacterium that is lethal to a number of agricultural pests), to increase drought resistance or improve nutritional content. The AquAdvantage Salmon, the first GE animal approved for human consumption, was engineered for faster growth, so that it reaches market weight more quickly than a natural salmon. 6
In addition to corn, soybeans and cotton, the other GE crops that are commercially available in the US are potatoes, papaya, squash, canola, alfalfa, apples and sugar beets. Several others are USDA approved but are not currently produced, including tomatoes, (non-sugar) beets, rice, roses, flax, plums and tobacco. 78 The controversial hormone rBGH (recombinant bovine growth hormone), which increases milk production in dairy cows, is genetically engineered as well.
The FLAVR SAVR tomato, engineered to retain real tomato taste after shipping, was the first GE food approved for human consumption by the US Department of Agriculture (USDA), in 1992, but has since been taken off the market. 9 Most recently, the Impossible Burger — a meatless “burger” that uses a genetically engineered yeast to make its signature ingredient known as heme (which accounts for its meat-like flavor) — has been popping up on menus and causing controversy because it does not have FDA approval. 10
In the US, regulatory approvals for GMOs are a complicated patchwork of the Food and Drug Administration for pharmaceutical developments, the Environmental Protection Agency for insecticide uses and the USDA for food crops.
For many farmers, GE crops require much less work and provide a larger yield, which offsets the substantially higher cost of GE seed. One 2014 metastudy found that globally, GE crops have reduced pesticide use by 37 percent, increased crop yields by 22 percent and increased farmer profits by 68 percent. 11 It is important to note that it was insect-resistant Bt crops that had much more advantage than herbicide-tolerant crops (from Roundup Ready seeds).
A 2014 analysis of USDA data had similar findings for insect-resistant crops in the US, but many more mixed results on herbicide resistance. 12 Certainly, when farmers start with GE seeds, yields and profits increase in the first few years. But some studies show that this tapers off. 13 For reasons discussed below, GMO technology is problematic for farmers and consumers alike.
On a larger scale, corporate interest plays an enormous role in the rapid growth of the technology. In 1980, the Supreme Court ruled that scientists could patent a GE bacterium developed to break down oil spills. This ruling — stating that life itself could be patented and owned — gave companies an incentive to develop GMOs that could be useful and profitable.
Monsanto (now part of Bayer), the largest manufacturer of GMOs, has a long history as a chemical maker, including as one of several makers of Agent Orange, the highly toxic defoliant used during the Vietnam War. 14 Following the war, the company turned to making agricultural chemicals, including its bestseller glyphosate herbicide, Roundup, and experimenting with genetically modifying seeds to resist the chemical so that pesticides could be liberally applied without fear of killing the crops. It introduced Roundup Ready seed in 1996 and spun off its chemical operations two years later to focus on biotechnology. 15
In 2017, Monsanto’s net sales of GE corn, soybean and cotton seeds and traits totaled $9.5 billion. 16 Most troubling, in the last two decades, is that Monsanto has bought many competitor seed companies, giving it control of a wide swath of the seed market and its accompanying genetic diversity. In 2018, Monsanto was bought by Bayer, further consolidating the production and ownership of seed stocks around the world.
The biotech industry claims that this chemical-based agricultural technology and biotechnology is necessary to feed a growing world population, increase crop yields and adapt to a changing climate. Herbicide-resistant crops do not require tilling, which leaves carbon in the ground and is better for soil structure, and proponents claim that they require less pesticide application than non-GE crops. However, this does not tell the whole story. These crops have actually driven up the use of herbicides like glyphosate, thereby increasing weed resistance and leading to the reintroduction of more potent herbicides. 17 These false narratives are perpetuated by biotech and other agribusiness corporations, but also by land grant universities (which receive more funding from agrochemical companies than public dollars, many agricultural scientists and farm organizations. 1819
However, technology and the industrialized food system are not currently feeding the world, so there is reason for skepticism about this claim. Globally, agriculture produces more than one and a half times the number of calories needed to feed the world population, yet one in nine people goes hungry. 20 The profit motive of Bayer/Monsanto and other agrochemical companies, as well as their long lack of support for small farmers, should subject their claims of working solely for the public good to scrutiny.
When it comes to increasing calorie production for the parts of the world that sorely need to feed a hungry populace, the International Assessment of Agricultural Knowledge, Science and Technology for Development report from the United Nations proposes that organic and sustainable agriculture is the best solution for countries like Africa and India, where the need is greatest. 21
Much of the debate around genetically modified food crops and animals focuses on potential threats to human health. But, long-term studies of the impact of consuming GM foods have yet to be done. Some independent studies have documented health effects on animals from eating GMO foods, which have become the subject of controversy. 22
Companies have determined that GE crops are different enough from those derived by conventional crops to get a patent, but not different enough to require adequate safety testing before they get to market. Additional independent studies and testing are needed. Ways in which GE foods can cause health problems are already documented, particularly in terms of allergens: genes from an allergenic plant can transfer the allergen to the new plant, causing it to provoke a reaction in those sensitive to the first plant. 23 It is also possible that new allergens could be created from combinations of genes that did not previously exist. 24 Overall though, we do not understand all of the potential health concerns, but that uncertainty is enough to warrant more oversight, not less.
Perhaps the most concerning consequence of herbicide-resistant crops is the huge increase in herbicide use and the evolution of herbicide-resistant “superweeds.” Weeds resistant to glyphosate, which have survived annual use of the herbicide, have become a problem. A 2016 survey across the Midwest found that one third to upwards of three quarters of fields showed resistant weeds. 25 To address the problem, seed and chemical companies have turned to older chemicals such as 2,4D and dicamba, engineering seeds resistant to these more toxic compounds and increasing their use in farmers’ fields.
Contrary to industry promises that GE crops would require less pesticide application, chemical use has increased steadily, particularly by farmers growing herbicide-resistant crops. Farmers growing Bt pest-resistant crops have been able to decrease their insecticide use, but scientists are concerned that the effect may not last, as pests also evolve resistance. 26
One of the major ways that GMOs have impacted the environment, therefore, has been in a mass of side effects stemming from increased pesticide use, including compromised water quality, loss of biodiversity and threats to human health.
While biotech seeds are touted as the only way to feed a growing world population, the data on yields are mixed. It should also be noted that GE crops rely on the promise of reduced pest and weed pressure to boost yields; no successful GE technique has yet increased intrinsic yields (such as more kernels per corncob).
A 2008 literature review by the Union of Concerned Scientists found that herbicide-tolerant GE crops produced no yield gain, while Bt crops produced marginal increases. 27 A 2013 New Zealand study found that average US GE corn yields were slightly lower than non-GE corn yields in western Europe in the same period. 28 2016 studies by both the National Academies of Sciences and the New York Times found no evidence that yield increases could be tied to GM technology. 2930
Meanwhile, traditional plant breeding techniques have increased yields significantly and have even outperformed GE technology in improving drought tolerance and other factors necessary for farming in a warming climate. 3132 But investment in GE research means less funding going to these more promising methods.
Farmers adopt GE seeds and their attendant herbicides ostensibly to make farming easier and more profitable. However, GE seeds cost a lot more than conventional seeds (up to $150 more per bag, according to one report) plus the cost of herbicides. An analysis by AgriWize farm business consultant Aaron Bloom found that GM corn costs an average of $81 more per acre per season than conventional. 33 For many farmers, the yield increase at harvest time makes the upfront costs worth it, but for others, the proliferation of superweeds or simply one bad harvest can put them in debt, with few options for how to get off the GE treadmill.
Congress passed the Plant Patenting Act in 1930, as the rise of hybrid seeds made the business of selling seeds (which since time immemorial have been freely reproducible) profitable for the first time. The law applied to certain plants only, but in 1985, it was expanded to include not only all crops but also their cells, genes and DNA. Seed patents, along with laws on intellectual property, seed marketing and more, have exploded in years since.
Humans have been breeding seeds for aeons, making plants more productive, tastier and better adapted to local conditions. In fact, adaptation has been bred into seeds throughout the ages by subsistence farmers; we take ancient farmer breeding ingenuity for granted. Today’s seed patents, meanwhile, bestow rights and profits on multinational companies for “discovering” the newest traits, ignoring the long and unsung contributions of farmers’ localized agricultural knowledge. 3435
Patents and other legal measures put control of this long heritage of seed development, and therefore our future food security, in the hands of a very few companies. The seed industry is one of the most concentrated in the US economy. Almost 80 percent of corn and more than 90 percent of soybeans grown in the US feature Monsanto/Bayer seed traits, while the top three seed firms control more than half of the total seed market, with Monsanto/Bayer alone controlling one quarter. 36 Up-to-date numbers on seed market control are difficult to come by, however, because huge mergers in the industry, including the 2017 Dow/Dupont and the 2018 Monsanto/Bayer mergers have shifted the landscape.
These companies value their patents and other intellectual property highly. Monsanto/Bayer has filed suit against 147 farmers for violating the terms of their planting agreement and has also at times threatened or intimidated farmers. 3738
Surveys consistently show that upwards of 90 percent of Americans support labeling of GMO foods, but unlike most developed countries — including 28 nations in the European Union, Japan, Australia, Brazil, Russia and China — the US had for many years no federal requirement for labels. 394041 States responded by taking the matter into their own hands. More than 70 labeling bills or ballot initiatives were introduced across 30 states, and labeling laws were passed in Vermont, Connecticut and Maine. 42 In high-profile cases in Washington State and California, bills were defeated due to aggressive lobbying efforts by big food and biotechnology companies to the tune of $63.6 million in 2014. 43
In 2016, a federal law was passed, mandating labeling of GE ingredients in foods, which strikes down or pre-empts state labeling laws. The federal law’s many critics dubbed it the Denying Americans the Right to Know (DARK) Act, because not only does it override state efforts (which in some cases, as in Vermont, are stringent), but because many GMOs would be exempted from being labeled. Further, the federal law states that labeling can be in the form of a digital QR code or toll-free phone number rather than a textual label that clearly marks the product as containing GMOs.
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