Pros and Cons of GMOs: Understanding Their Impact on Human Health

The debate surrounding genetically modified organisms (GMOs) and their potential impact on human health has been ongoing for decades. Genetically modified crops, such as herbicide-resistant soybeans and insect-resistant corn, have become increasingly prevalent in food production, sparking public concerns over their safety and regulation. While proponents argue that GMOs offer solutions to global food scarcity and nutritional deficiencies, opponents raise questions about potential health hazards, including toxicity, allergenicity, and unintended genetic changes.

This article delves into the pros and cons of GMOs, examining their implications for organ health, nutritional value, and environmental impact. It explores the regulatory landscape surrounding genetically modified food, virus-resistant crops, and the use of genetic engineering in animal feed. By analyzing the scientific evidence and public concerns, this comprehensive guide aims to provide a balanced perspective on the complex issue of GMOs' impact on human health.

What are Genetically Modified Organisms (GMOs)?

Definition and background on GMOs

Genetically modified organisms (GMOs) are plants, animals, or microbes whose genetic material has been altered using genetic engineering techniques. This involves introducing, enhancing, or deleting specific genes within a species or across different species and kingdoms in an attempt to modify the characteristics of an organism. GMOs can be used for various purposes, such as producing human insulin, fermenting beverages, and developing pesticide resistance in crop plants.

Genetic modification of crops has substantially focused on improving desirable traits, such as enhanced yields, quality, and tolerance to biotic and abiotic stresses. A genetically modified (GM) crop is defined as any plant whose genetic material has been manipulated using genetic techniques that do not occur naturally. Agriculture was the first sector to heavily invest in genetic modifications, enabling the development of suitable traits in plants for food production.

Genetic engineering techniques

Genetic engineering is a process that involves identifying the genetic information or "gene" that gives an organism a desired trait, copying that information from the organism that has the trait, and inserting it into the DNA of another organism. The new organism is then grown to ensure it has adopted the desired trait.

To produce a GMO plant, scientists first identify the desired trait, such as resistance to drought, herbicides, or insects. They then find an organism that already possesses that trait within its genes. For example, to create insect-resistant corn, scientists identified a gene in the soil bacterium Bacillus thuringiensis (Bt) that produces a natural insecticide. After copying the Bt gene, they inserted it into the DNA of the corn plant, giving it the insect resistance trait without changing its other existing traits.

Scientists are also developing new ways to create new crop and animal varieties using genome editing techniques like CRISPR, which can make changes more quickly and precisely than traditional breeding methods. These tools can be used to make crops more nutritious, drought-tolerant, and resistant to insect pests and diseases.

Prevalence and examples of GM crops

The global production of GM crops has increased significantly, from 1.7 million hectares in 1996 to 190.4 million hectares in 2019, a 112-fold increase. The United States is the world's largest producer of GM crops, with 71.5 million hectares (37.5% of global production) in 2019, primarily GM cotton, maize, and soybeans. Brazil and Argentina are the second and third largest producers, respectively.

Some examples of commercially grown GM crops include:

• Corn: Most GM corn is created to resist insect pests (e.g., Bt corn) or tolerate herbicides.

• Soybeans: Most GM soybeans are used for animal feed, making soybean oil, and as ingredients in processed foods.

• Cotton: GM cotton is resistant to bollworms and is used for textiles and cottonseed oil.

• Potatoes: Some GM potatoes are resistant to insect pests, diseases, and bruising/browning.

• Papaya: The Rainbow papaya was created to resist the ringspot virus, saving papaya farming in Hawaii.

• Canola: GM canola is used primarily for cooking oil, margarine, and animal feed.

• Alfalfa: GM alfalfa is primarily used as herbicide-resistant feed for dairy cattle.

• Apples: Some GM apples were developed to resist browning after being cut, reducing food waste.

• Sugar beets: More than half of granulated sugar is made from GM sugar beets resistant to herbicides.

• Pineapple: The GM pink pineapple has increased levels of lycopene, giving it a pink flesh color.

The entire process of bringing a GMO plant to the marketplace takes several years, involving extensive testing and monitoring in greenhouses and field trials before commercial release.

Health and Safety Concerns

Potential toxicity and allergenicity

There is growing concern among the general public and the scientific community regarding the potential toxicity of genetically modified organisms (GMOs). The use of biotechnology to enhance pest resistance or nutritional value has raised a number of fundamental questions, including the consequences of inserting reporter genes, the spread of resistance genes to surrounding plants, and the use of suicide genes to prohibit reuse of seed from engineered plants. Of particular interest is the ability of proteins from GMOs to elicit potentially harmful immunologic responses, including allergic hypersensitivity.

The lack of information on the potential toxicity of these products suggests a need to identify the critical issues and research needs regarding these materials and to develop testing strategies to examine the allergenicity of these compounds. Certain food proteins have been identified as allergens, and their stability to digestion in vitro has been proposed as a method to assess the potential allergenicity of newly expressed proteins in GMOs.

Effects on human digestive system

Gene transfer from GMOs to organisms in the environment, particularly the transfer of genes to pathogenic bacteria that could increase their virulence, is one of the main concerns. Gene transfer has been observed in the gastrointestinal (GI) tracts of mammals. However, several studies have shown that gene transfer in the environment, such as in the GI tract of rats and in wastewater treatment plants, occurs at rates that are 101- to 105-fold lower than the rates measured under laboratory conditions.

The presence of other bacteria and solid matter may also reduce the likelihood of a donor and a recipient meeting and, therefore, the likelihood of gene transfer in the GI tract. While the intestinal tract contains many naturally competent bacteria at concentrations greater than probiotic application rates, it is difficult to predict whether gene transfer to other bacteria occurs in the GI tract via transformation. The presence of DNases in the GI tract, however, reduces the likelihood of transfer by this mechanism.

Long-term impacts on human health

While safety studies have indicated that the use of GMOs presents no greater risk than the use of the original unmodified products, there are still public and scientific concerns about the safety of foods produced by gene manipulation technology. One of the major concerns in using genetically modified organisms in food production is the risk of gene transfer to other organisms in the environment, as naturally occurring gene transfer in the environment takes place relatively infrequently and is therefore difficult to measure experimentally with currently available techniques.

The potential long-term impacts of GMOs on human health are still being studied, and more research is needed to fully understand the implications of consuming genetically modified foods over an extended period. Concerns include the potential for unintended effects on human health due to the introduction of new proteins or changes in the nutritional composition of foods, as well as the potential for the development of resistance to antibiotics or other drugs.

Environmental Impacts

Effects on biodiversity and ecosystems

Genetic modification produces genetically modified organisms (GMOs) that, if introduced into the environment, can potentially affect biodiversity. Existing species may be overrun by more dominant new species, leading to a reduction in genetic diversity. Maintaining genetic diversity is crucial for the environment and agriculture, as it provides organisms with a better opportunity to adapt to changing environmental conditions.

One example highlighting the importance of genetic diversity is the Irish potato famine in the mid-1800s. At that time, Ireland heavily depended on potatoes for nutrition, and the potato crops were clones with identical genetic information. The lack of genetic variability proved detrimental when an invasive pathogen, P. infestans, wiped out the entire potato population. Had Ireland grown different varieties of potato crops with more genetic diversity, it is more likely that some populations would have contained genes providing resistance to the pathogen, potentially mitigating the catastrophic effects of the famine.

Assessing the impact of GMOs on biodiversity requires continuous research and knowledge updates. A major ecological research program, ERGO, aimed to amass ecological knowledge, such as the impact of new GMOs on their environment, and was coordinated by the Netherlands Organisation for Scientific Research (NWO).

Development of herbicide-resistant weeds

One of the major traits introduced into GMOs is resistance to specific herbicides, providing new tools for weed management in crop fields. Farmers can spray herbicides over the entire field, killing only the weeds while allowing the crop to grow without competition. The most prevalent example of this herbicide resistance trait is crops resistant to glyphosate, the world's most widely used herbicide.

However, weeds can adapt and evolve, developing resistance to herbicides over time. Weeds resistant to glyphosate, often referred to as "super weeds," have emerged, reducing the effectiveness of certain herbicide-resistant crops that were initially very effective at controlling weeds in combination with glyphosate.

Potential for gene transfer to non-GM species

A major concern regarding GMOs is the potential for gene transfer to other organisms in the environment, particularly the transfer of genes to pathogenic bacteria, which could increase their virulence. Gene transfer has been observed in the gastrointestinal (GI) tracts of mammals, although at rates significantly lower than those measured under laboratory conditions.

One example of gene transfer from GM crops to wild species has been documented in creeping bentgrass commonly used on golf courses. Scotts Miracle-Gro genetically engineered this grass to contain a gene conferring resistance to a common herbicide. Researchers found that the herbicide resistance gene had been transferred to wild grass up to 9 miles from its origin, just one year after the grass was planted. This distance is surprising, as most hybridization events have been reported between plants less than a mile apart.

Additionally, if advantageous genes are introduced into GMOs, it may allow them to become more fit than their wild relatives, enabling them to grow faster and reproduce more often, potentially taking resources away from non-GMO relatives if they inhabit the same environment. This concern has been raised regarding fast-growing Atlantic salmon engineered by AquaBounty technologies to reach market weight in half the time as their standard relatives.

Regulatory Landscape

Government policies and labeling requirements

Three federal agencies within the U.S. government work together to regulate most genetically modified organisms (GMOs). The U.S. Food and Drug Administration (FDA), U.S. Environmental Protection Agency (EPA), and U.S. Department of Agriculture (USDA) ensure that GMOs are safe for human, plant, and animal health, and monitor their impact on the environment.

The Coordinated Framework for the Regulation of Biotechnology, established in 1986, describes how these agencies collaborate to regulate GMOs. The FDA regulates most human and animal food, including GMO foods, ensuring they meet strict safety standards. The EPA is responsible for regulating pesticides, including plant-incorporated protectants (PIPs) that make some GMO plants resistant to insects and diseases. The USDA Animal and Plant Health Inspection Service (APHIS) sets regulations to ensure GMO plants are not harmful to other plants.

In 2016, Congress passed the National Bioengineered Food Disclosure Standard, preempting any state standards. This established requirements for labeling bioengineered foods, defined as those containing detectable genetically modified material. By 2022, food makers, importers, and certain retailers were required to label bioengineered foods or ingredients using text, symbols, or digital links.

Initially voluntary, mandatory labeling began in January 2022, with foods and packages including a small seal or text stating "bioengineered" or "derived from bioengineering". Enforcement is based on consumer complaints to the USDA regarding suspected non-disclosure.

International bodies and guidelines

Unlike the U.S., a major exporter of GMOs, Europe remains conservative on GMOs due to economic, political, and societal reasons. The European Commission (EC) and European Food Safety Authority issue harmonized rules, while EU member states have individual regulations. The EU's legal framework aims to protect human, animal, and environmental health, ensure risk assessment and authorization procedures, enable informed choice through labeling, and ensure traceability.

China's updated Food Safety Law in 2015 includes an article requiring mandatory GMO labeling, with fines or license suspension for violations. Japan takes a middle-of-the-road stance, with fewer GMO approvals than the U.S. but more than the EU.

Worldwide, countries have established GMO regulations based on their economic, political, and societal reasons, with the EU and Japan leaning toward more rigorous regulation and the U.S. representing a less preventive approach.

Public debate and controversies

While the USDA, EPA, and FDA agreed that the process of genetic modification is irrelevant to the safety of the product itself, some consumer activist groups argued there had been no long-term studies on the safety, particularly allergenicity, of GM-derived crops. They claimed consumers may be placed at risk against their wills, even if GM foods are safe under current guidelines.

Mandatory labeling is now the rule in other parts of the world, notably the European Union, and various pieces of legislation have been proposed in the U.S. Congress and state legislatures requiring some form of labeling.

Critics like the Center for Food Safety and some grocery stores and food advocacy groups challenged the USDA in court over the exclusion of many products from the labeling standard. They also complained that the term "bioengineered" would confuse and mislead consumers, and that electronic and digital forms of labeling, such as QR codes, would discriminate against consumers without smartphones. A federal court largely upheld the labeling standard in September 2022 but said the USDA needed to review the QR code and text message disclosure methods.

Benefits and Applications

Increased crop yields and resistance

Genetically modified (GM) crops have demonstrated significant potential in increasing crop yields and enhancing resistance to pests, diseases, and environmental stressors. On average, GM technology has increased crop yields by 21% (Figure 2). These yield increases are not due to higher genetic yield potential, but to more effective pest control and thus lower crop damage. Especially smallholder farmers in the tropics and subtropics suffer from considerable pest damage that can be reduced through GM crop adoption. Notably, yield gains of GM crops are 14 percentage points higher in developing countries than in developed countries.

GM crops may be modified to improve yield, enhance nutrition, or better adapt to environmental conditions. They can even be altered to resist pests or eliminate unwanted effects, like this type of onion that doesn't cause people to tear up when chopped.

Genetic engineering can improve crop yield, resulting in greater production of the target crop. Scientists can also engineer pest-resistant crops, helping local farmers better withstand environmental challenges that might otherwise wipe out a whole season of produce. Advances have also been made in developing crops that mature faster and tolerate aluminum, boron, salt, drought, frost, and other environmental stressors, allowing plants to grow in conditions where they might not otherwise flourish.

Nutritional enhancement

GM technology can help to breed food crops with higher contents of micronutrients; a case in point is Golden Rice with provitamin A in the grain. Such GM crops have not yet been commercialized. Projections show that they could reduce nutritional deficiencies among the poor, entailing sizeable positive health effects,.

Biofortified GM crops have been adopted, increasing micronutrient availability. Nutritionally enhanced foods improve an individual's nutrient intake, preventing and/or treating leading causes of death such as cancer, diabetes, cardiovascular disease and hypertension. Improving the nutritional content of daily food consumption certainly has day‐to‐day effects, but of significant importance are the long‐term effects that extend for decades over the course of an individual's lifetime.

In many instances, improving macronutrients (proteins, carbohydrates, lipids, fibre) and micronutrients (vitamins, minerals, functional metabolites) has significant childhood health improvements, such as reducing blindness due to the lack of vitamin availability. Improved food nutrient content, especially the increase in mineral availability, contributes to improved immunity systems and reduces stunting. In many developing countries, plant‐based nutrient intake accounts for one hundred per cent of an individual's nutrient diet, further highlighting the importance of nutritionally enhanced crop‐derived foods. As the later in life benefits from improved childhood nutrition are better understood, the full value of nutritionally enhanced GM crops and foods may not be realized for several decades.

Potential for addressing global food security

GM crops could contribute to food production increases and thus improve the availability of food at global and local levels. The results of this research confirm that the income gains through Bt cotton adoption among smallholder farm households in India have positive impacts on food security and dietary quality. GM crops are not a panacea for the problems of hunger and malnutrition. Complex problems require multi-pronged solutions. But the evidence suggests that GM crops can be an important component in a broader food security strategy.

For example, farmers whose livelihoods depend on production of commercial crops rather than food staples may be able to increase their income by growing GM crops, affording them the financial resources to purchase more or higher-quality food. Moreover, GM crops might better withstand certain natural disasters, such as drought.

Genetically modified (GM) crops represent the most rapidly adopted technology in the history of agriculture, having now reached 25 years of commercial production. Grown by millions of farmers, many in developing countries, the technology is providing significant economic and environmental benefits, such as reductions in chemical use of 37%, increased yields of 22% and improved farm profits of 68%. Genetically modified crops have made significant contributions to address the United Nations Sustainable Development Goals, in particular goals 1 (reducing poverty) and 2 (reducing hunger). While increased yields have contributed to higher household incomes, which reduce poverty, the increased yields have also enhanced household food security.

Conclusion

The debate surrounding the impact of genetically modified organisms (GMOs) on human health is multifaceted and complex. While proponents highlight the potential benefits of increased crop yields, enhanced nutritional value, and improved resistance to pests and environmental stressors, opponents raise concerns about potential toxicity, allergenicity, and long-term health consequences. Navigating this intricate landscape requires a balanced approach, guided by scientific evidence and rigorous regulatory oversight.

Ultimately, the decision to embrace or reject GMOs lies at the intersection of individual values, societal priorities, and responsible stewardship of our environment. As we continue to explore the frontiers of genetic engineering, it is imperative that we remain vigilant, fostering transparent public discourse, and prioritizing the well-being of both human and ecological systems. By maintaining an open and ongoing dialogue, we can collectively chart a course that harnesses the potential of biotechnology while mitigating its risks, ensuring a sustainable and equitable future for all.

FAQs

Q: What are the benefits and risks of GMOs for human health?

A: GMOs offer several benefits, including enhanced nutritional content in food. However, there are risks involved, such as the potential for developing new allergens from genetically modified (GM) crops and possible toxicity.

Q: Can you list some disadvantages of GMOs?

A: The disadvantages of GMOs include:

1. Altered interactions between plants and their living environment, which can lead to issues like persistence and invasiveness, and selective advantages or disadvantages.

2. Changed interactions between plants and their non-living environment, such as increased greenhouse gas emissions.

3. Potential toxicological effects on human and animal health.

Q: What are the primary advantages of GMOs for human life?

A: GMOs provide several advantages, including:

• More nutritious and tastier food.

• Disease and drought-resistant plants that require fewer resources like water and fertilizer.

• Reduced use of pesticides.

• Increased food supply with lower costs and extended shelf life.

• Faster growth in plants and animals.

Q: How do GMOs benefit the environment and human health?

A: GMOs contribute to environmental and health benefits by reducing the need for pesticides, as GMO crops resistant to insect damage require fewer chemical applications. Additionally, herbicide-tolerant GMO crops allow for more effective weed control without harming the crops themselves.