Genetically-modified organisms (GMOs) which include both genetically-modified foods and genetically-engineered animals are a controversial topic.
GM crops may be beneficial to some farmers and consumers due to a variety of reasons but primarily involve financial impacts.
GM crops may negatively impact the environment and raise cancer risk. Increased allergenicity is less clear.
Purple tomatoes engineered to contain high levels of a specific antioxidant will hit the market in 2023. New GM crops and GE animals are currently in development around the world.
Whether you choose to include or avoid GM foods is a personal decision and will depend on your individual or family priorities.
Since the first GMO was introduced in 1994, and to this day, people remain divided on their opinions of GMOs. Here I’ve compiled research and answers to four important questions to help guide your future food decisions.
Are GMOs beneficial?
The answer depends on whether you are asking the farmer or the consumer.
To some farmers, specific GM crops appear to increase yield, improve grain quality and pest resistance, withstand high use of herbicides, and support agriculture and economic growth.
For the consumer, GM crops can be engineered to include specific nutrients for desired health outcomes. For example, supplementation of the seed oil from the GM Camelina sativa seed oil (false flax) plant resulted in similar improvements in the two primary omega-3 anti-inflammatory fatty acids, EPA and DHA, compared to fish oil. Seed oil represents a more cost-effective strategy for raising omega-3 fatty acid levels that may help to improve cardiovascular disease risk.
In addition, GMO corn has been shown to contain lower levels of mycotoxins, toxic compounds from fungus that exert both short and long-term effects on human and animal health.
GM crops are also significantly less expensive for consumers compared to organic and non-GMO crops due to government subsidies. These foods represent a strategy for reducing household food costs.
Are GMOs risky?
One area of concern for GM consumption is the potential increase in allergenicity – or the likelihood that a GM food’s new protein(s) can induce allergic reactions. Research finds an upward trend in food allergy diagnoses in the last few decades in both the US and the UK. This rise is reported to have started before the first GM food was introduced into the US marketplace in 1996 and before GM crops were commonly available in the UK.
Despite the gravity of potential health impact from GM crops, a review of 83 allergenicity-related studies conducted in 2017 found no human or animal randomized controlled trials in its search to help establish cause and effect relationships. However, the Annals of Allergy, Asthma and Immunology reported it found 3 studies that showed increased sensitization to GM crops - 2 to GM corn, and 1 human study to GM soy (that contained an introduced Brazil nut protein). The first two trials did not appear to result in increased clinical allergy reactions, whereas the third study did not test GM ingestion of the GM soy so clinical reactions are unknown. The investigators of the third study confirmed their belief that there is evidence of GM-induced potential of inadvertent allergen gene transfer. The lengthy review otherwise found no evidence in the remaining body of evidence to support the claim that GM crops are more allergenic than conventional crops. In fact, some studies found GM crops resulted in weaker IgE-binding than conventional crops, reducing allergy reaction potential.
Another study reports that many GM crops contain novel proteins in very low amounts, below common allergenic thresholds of 1mg. According to some experts, this limited novel protein content appears to reduce the potential of allergic reactions even in those with allergy history.
Genetically-modified herbicide-resistant crops are grown worldwide, currently in 29 countries. About 80% of GM crops were created with the intention of tolerating heavy use (up to 15-fold!) of herbicides or producing their own insecticide. GM crops can never be recalled once planted and have been found growing along highways, parking lots and wild fields after introduction into the environment. This has led to the development of “superweeds” - weeds that selectively survive because they survive use of herbicides. Superweeds have been shown to impact millions of acres in 22 states.
In addition, a GM corn variety – Starlink GM corn – only approved for use in US animal feed was found to inadvertently appear in the human food supply in 2001.
After review of close to 1000 studies, the World Health Organization’s International Agency for Cancer Research (IARC) officially classified glyphosate - the main herbicide used on GM crops - as “probably carcinogenic to humans” in 2015. It also stated there was “strong” evidence that glyphosate is genotoxic, which may induce genetic mutations leading to cancer. The most profound links reported with glyphosate exposure were incidence of non-Hodgkin lymphoma in humans, and tumors in animals.
The IARC’s conclusions were declared after their systematic review of all publicly available evidence. This position is in contrast to many regulatory agencies’ - such as the FDA’s - conclusions which heavily rely on industry-funded toxicological studies rather than analysis of publicly-available research.
Purple tomatoes now, what next?
After 14 years, the first genetically-modified purple tomato variety was approved by the USDA in September 2022 and may become commercially available in the spring of 2023. This is one of the first GM crops to insert genes for a specific health benefit rather than for an agricultural need or desire. These tomatoes contain higher levels of anthocyanins, the pigment-rich phytochemical in berries, which are associated with reduced risks of cancer and disease. To date, no randomized, controlled trials have been performed in humans to assess health outcomes from ingestion of this new tomato. A mouse study however found that this GM variety increased lifespan by 30% in cancer-susceptible mice.
Next on the horizon? Confined field trials are currently underway around the globe for new varieties of GM cotton, corn and other crops. Genetically-engineered (GE) Chinook salmon are engineered to triple weight rapidly and are already sold in Canada. In the US however, a long list of retailers with over 18,000 locations have made commitments to not sell the GE salmon.
Despite market concern, current development of genetically-engineered animals includes at least 35 other species of fish, as well as chicken, cows and pigs.
Should I eat or avoid them?
Only you can answer this question – and it depends on what your priorities are. If your goal is to reduce your food costs and enjoy increased food access, GM crops are likely a good purchase.
If you are concerned about unintended consequences of GM crops, cancer risk, and environmental impact, limiting or avoiding GM crops is likely ideal.
Limiting, avoiding, or embracing GMO foods is a personal choice. If you choose to limit your intake, eat more organic, fresh and whole foods and nonGMO Project Verified products to reduce your exposure and help preserve the environment.
- African Union Development Agency. Genetically Modified Crops in Development.
- European Commission. A Decade of EU-funded GMO Research (2001-2010).
- NIH. The allergenicity of genetically modified foods from genetically engineered crops: A narrative and systematic review.
- Friends of the Earth. Largest U.S. Retailers Reject Genetically Engineered Salmon Ahead of Potential First U.S. Sales.
- Ge-Fish. Genetically Modified Salmon.
Show all references
- WHO. IARC Monograph on Glyphosate.
- he New England journal of medicine. Identification of a Brazil-nut allergen in transgenic soybeans.
- NIH. Impact of genetically engineered maize on agronomic, environmental and toxicological traits: a meta-analysis of 21 years of field data.
- Molecular nutrition & food research. Review of the development of methodology for evaluating the human allergenic potential of novel proteins.
- NIH. Dietary supplementation with seed oil from transgenic Camelina sativa induces similar increments in plasma and erythrocyte DHA and EPA to fish oil in healthy humans.