Introduction to GMOs

By Layla Katiraee and Anastasia Bodnar

Walk down the food aisle and you’ll see dozens of labels. There’s one in particular that we SciMoms talk about often: non-GMO labels. Surveys show that many shoppers equate this label to healthier food. Studies have shown that the label increases the price of food. But surveys also show that most consumers don’t know much about what this label means. In this post, we’ll review some key terms and some common myths about GMOs.

The debate around GMOs entails far more than scientific facts: GMOs have become a proxy for many socio-economic issues such as patents, monopolies, food security, and others. We discuss these issues in a prior post. In this post, we focus on the science and safety of genetically engineered crops.

What is a GMO?

GMO stands for Genetically Modified Organism. GMOs are organisms that have had a gene or genes added or removed by scientists, giving or removing a characteristic or trait. For example, scientists could give a crop the ability to grow more quickly, withstand extreme weather, have a different color, or resist pests. Consequently, a GMO is not a single thing: there are many different types of GMOs. Different countries and different labels define GMO differently.

Why do GMOs exist?

Farmers and agricultural companies have long been improving crops to make them easier to grow, harvest, and store and to give consumers the tastes and qualities we desire. Many different techniques have been used over the years. Often, breeding can accomplish what scientists are trying to achieve. But sometimes, breeding would take too much time, or be ineffective, and other methods need to be used.

For example, if one variety of rice is long grain, and a second is short grain and resistant to a fungus, you could breed those two together hoping for a fungus-resistant long grain variety. As scientists learned more about DNA, they invented methods in the laboratory to take the gene that conferred resistance to the fungus and add it directly to the DNA of the long-grain rice. Not only that, but this method would work whether the fungus-resistance gene came from rice, corn, or even bacteria.

The scientific term for taking a gene from one organism and using laboratory techniques to add it to another is “transgenesis”.

different colored rice
Different types of rice from the collection of International Rice Research Institute (IRRI)’s International Rice Genebank. Image by IRRI via Flickr.

What crops are GMOs?

Few GMO crops are currently grown in the US, but the economic importance of these crops is very significant. Many experts consider GMOs to be critical to food security, both in the United States and in countries like India and Brazil. The GMO crops currently available in the US are:

  • alfalfa – for animal feed
  • apple – Arctic Apple variety, currently only available dried, not fresh
  • canola – for canola oil
  • corn – field corn for animal feed and processed foods, some sweet corn, but not popcorn
  • cotton – for clothing, cottonseed oil, and animal feed
  • papaya – Rainbow Papaya variety
  • potato – White Russett variety, only available in some locations
  • soy – for animal feed and processed foods, but not edamame or tofu varieties
  • sugar beets – for table sugar
  • summer squash and zucchini – only a small percentage of the US crop

Many of these genetically engineered crops are also available in countries around the world. Genetically engineered salmon is available in Canada. It has been approved by the FDA, but is not yet available for sale in the US.

In addition, many nutrients, enzymes, and other products used for food processing and fortification come from genetically modified bacteria or yeast. For example, rennet is an important enzyme for cheesemaking. Traditionally, cheesemakers extracted rennet from the stomach of slaughtered calves. With genetic engineering, the enzyme can be produced in microbes instead. Another example is soybean leghemoglobin, produced in yeast and used to make vegetarian Impossible Burgers taste beefier.

What traits or characteristics do GMOs have?

To date, biotech traits have been primarily of importance to farmers, through consumers see benefits as well. Here is an incomplete list of available traits:

  • insect resistance – Certain insects are killed when they feed on a Bt crop, while other insects remain unharmed.
  • herbicide tolerance – When farmers treat their fields with a certain herbicide, the crop will survive while susceptible weeds wither.
  • virus resistance – Allows crops to resist viruses that kill the plants or impact the quality of the crop. This trait has been incredibly important in Hawaii where the ringspot virus nearly destroyed the island’s papaya farms.
  • non-browning/bruising – Removes an enzyme that causes some crops to brown when they’re cut or bumped, such as apples or potatoes. This trait aims to reduce food waste – all of us SciMoms desperately want to see a non-browning avocado.

Are GMOs safe?

We must reiterate that GMOs are not just one thing. Viewed in this context, it’s strange to lump the safety of herbicide-tolerant corn with non-browning apples. Taken as a group, we can say that the methods used to create transgenic crops are safe.

Scientific groups around the world, such as the National Academy of Sciences in the US, the Royal Society in the UK, the European Food Safety Authority, the Australian Academy of Science, and dozens of others have reviewed published data about GMOs. More than 280 scientific and technical societies have reviewed the data surrounding transgenic crops, each concluding that GMOs are as safe as other crops. In other words, crops developed with transgenesis pose no greater risk than crops developed with other methods (article continues after infographic).

SciMoms Infographic listing types of GMOs, the most common GMOs, and a short list of organizations that have deemed GMOs to be safe.
SciMoms Infographic on GMOs

Are GMOs tested?

The regulatory framework for GMOs in each country usually requires the developer to conduct testing. In the United States, developers contact regulatory agencies and the agencies determine which tests are needed. Required tests may include allergenicity testing, animal feeding studies, and molecular tests to demonstrate that the transgenic crop has the same amount of nutrients as non-GMO crops.

Additionally, transgenic crops have been heavily studied outside of the regulatory framework by public and private sector scientists. These include animal feeding studies, studies examining environmental issues, even studies examining the microbiome.

What GMO safety studies have been done?

Thousands of studies, both privately and publicly funded, have examined different transgenic crops or GMOs. Multiple researchers reviewed the scientific literature, finding that studies are largely publicly funded with limited evidence of harm from GMOs.

In 2007, a researcher found a total of 31,848 records in the scientific literature on GMOs. While only 692 studies had to do specifically with safety (defined as detection, gene flow, nontarget effects, compositional, toxicological, and nutritional analyses) many of the other scientific studies examined differences between transgenic and non-transgenic crops. The researcher notes that many additional safety studies are conducted by industry as part of the regulatory process, but these studies are often not included in the scientific literature.

In 2013, researchers found 1,783 papers about GMO safety. These included “original research papers, reviews, relevant opinions and reports” from 2002 to 2012, about biodiversity, gene flow, substantial equivalence, food/feed consumption and traceability.

In 2015, a researcher considered only original studies about the safety of GMO food/feed. He found 698 peer reviewed papers with full text available, published from 1993 to 2014. Of these, fewer than 5% reported negative outcomes from GMO crops. He also found that most of the research had no conflicts of interest. Specifically, over 65% of papers related to allergenicity, processing, unintended effects, animal health, traceability, and digestion reported no financial or professional connections to industry.

In 2016, researchers determined that statistical errors accounted for many of the claims that GMOs had negative outcomes. Then, in 2017, researchers looked at the 5% of papers that reported negative outcomes about GMOs: 35 peer-reviewed papers from 1998 to 2016. All of them “violate at least one of the basic standards for assessment of GM food/feed safety”.

Have long term GMO studies been done?

Many long-term and multi-generational animal feeding studies have been conducted. When researchers looked at 12 long-term and 12 multi-generational studies, they found no evidence of health hazards from GMOs and concluded that “a 90-day feeding study performed in rodents, according to the OECD Test Guideline, is generally considered sufficient in order to evaluate the health effects of GM feed.”

Long-term and multi-generational feeding studies have been conducted on a variety of animal species, including pigs, cows, quail, rats, mice, and fish. Shorter-term GMO feeding studies have been conducted on sheep, goats, pigs, chickens, quail, cattle, water buffalo, rabbits, rats, mice, fish, and a variety of different insects. While a few studies have found isolated differences between groups fed GMO and non-GMO feed, the overwhelming evidence is that there is no difference in the health of the animals.

A 2014 study considered GMO crops in livestock feed. In the US alone, farmers raise over 9 billion food-producing animals annually. More than 95% of livestock eat feed that is 70 to 90% GMO crop biomass, generation after generation. The researchers looked at data on livestock health and productivity before and after the introduction of GMOs, and found no decrease after GMOs were introduced. Further, the nutritional profile of meat, milk, and eggs are the same whether they are from animals fed GMOs or those fed non-GMO feed.

The same is true when we look at lab animals: animals which are extensively studied for various reasons. Like livestock, their feed consists of mostly GMO crop biomass. Yet there has been no increase in health problems among these animals.

Some GMO critics highlight that trials have not been conducted on humans. However, with no hypothesis on how GMOs could impact human health and no ideas on what to measure, it would be impossible to conduct such a study. In its review of GMOs, the National Academies examined the incidence of cancer and other health-related illnesses since GMOs were introduced and found no association.

Where are GMOs grown?

According to the International Service for the Acquisition of Agri-biotech Applications (ISAAA), farmers in 24 countries grew GMOs in 2017. The US grows the most, with 75 million hectares in 2017, followed by Brazil with 50.2 million hectares, Argentina with 23.6 million hectares, Canada with 13.1 million hectares, and India with 11.4 million hectares. Each of the remaining 19 countries grew 3 million hectares or less of GM crops.

Most of the GMOs grown internationally are the same ones that are available in the US: primarily corn, cotton, soybean, and canola with insect resistance or herbicide tolerance traits. That said, some interesting crops are being grown now and more are on the horizon. For example, insect resistant Bt brinjal (eggplant) in Bangladesh has already reduced the amount of pesticide that farmers have to apply. In development are such diverse crops as drought tolerant sugarcane for biofuel production, disease resistance in many crops including citrus and chestnut trees, and vitamin-A enriched bananas.

ISAAA hosts a GM Approval Database that includes GMOs that have been approved for commercialization, planting, or importation for food and feed use. Many more crops that have been developed but languish on the shelf due to problems with regulation or consumer acceptance (article continues after infographic).

infographic showing where GMOs are grown
Infographic by the International Service for the Acquisition of Agri-biotech Applications (ISAAA).

Why has Europe banned GMOs?

Europe has not banned GMOs. Each country has different rules and regulations surrounding these crops. The type of approval that the crop developer seeks defines the type of testing that the crop has to undergo. Many GMOs are not approved for growing in Europe, but are approved for import. Farmers in other countries grow the crops which European food manufacturers then purchase.

Is GMO labeling mandatory?

In many countries, labeling of GMOs is mandatory, but each country’s implementation differs since there’s no clear definition for “GMO”. For example, in Australia and New Zealand, products derived from GMOs need to be labeled only if DNA and/or protein can be detected. This means that sugar or oil needn’t be labeled. In the EU, all products derived from GMOs are labeled regardless of whether an analytical test can determine whether the final product came from a transgenic crop or not.

In the US, the federal government recently mandated a GMO label under the National Bioengineered Food Disclosure Standard. This law and the subsequent regulation use the term bioengineered, bringing yet another term to the list of US GMO-related definitions. Response to the regulation has been varied, some groups are pleased while others are not. It remains to be seen how implementation will take place. In Canada, GMOs are not labeled.

There are also third-party non-GMO labels. Some companies simply label their products as non-GMO without using a third-party system. In the case of the Non-GMO Project, they have stated that their label does not imply that it is actually non-GMO.

Are there any concerns about GMOs?

As we’ve discussed before, there are many legitimate socioeconomic concerns about our food supply and unfortunately, GMOs have become scapegoats for many of these issues: patents, monopolies, monocultures, environmental concerns, and many others. However, these concerns are found across many industries and across all of agriculture. Narrowing the scope of these issues to “GMOs” will not find solutions.

GMOs are not one thing but there are legitimate concerns with specific traits. For example, proper stewardship is not always practiced with insecticide and herbicide-related traits. Over-reliance on glyphosate-tolerant crops has increased the number of glyphosate-tolerant weeds, although herbicide-tolerant weeds is a risk with any herbicide use, and the incidence of glyphosate-tolerant weeds is not as dire as widely reported. So far, use of refuges with insect-resistant Bt crops have mostly kept resistance in insects at bay but this depends on continued use of best practices.

Another problem we may see more of in the coming years is that some traits are associated with dubious health benefits. For example, the non-browning potato also has decreased amounts of acrylamide when cooked. The developer seems to have muted these claims, but earlier articles touted decreased cancer risk from fries made with these potatoes, though the actual risk from acrylamide is low. A pink pineapple with extra antioxidants will soon be available in the US. Although it will broaden our choice of fruits and will surely be enjoyable for many kids and grownups, the benefits of extra antioxidants has not been conclusively demonstrated.

Why do SciMoms discuss GMOs so often?

Surveys have examined public opinion vs opinion of scientists on various topics. The topic where there was the greatest discrepancy between what the public believes and what scientists believe is GMOs. Scientists generally find biotechnology to be a safe method of crop breeding, while non-scientists largely believe they are unsafe.

Our choice to shun safe food is a luxury. However, this has repercussions, particularly that we cannot afford to wait any longer before developing crops that are suitable for the growing number of pests and harsher weather that result from a changing climate. We must bear in mind that the people who will be impacted most are people who have little voice in these discussions.