Genetic modification (GM) of foods has become a significant topic of discussion, debate, and research. This technology, which involves altering the genetic material of plants and animals, holds immense promise for improving crop yields, nutritional value, and resistance to pests and diseases. However, it also raises important questions about safety, environmental impact, and ethical considerations. This article delves into the science behind GM foods, examines the potential risks and benefits, and addresses public concerns surrounding their consumption.
What are Genetically Modified (GM) Foods?
Genetic modification is a specialized gene technology used to alter the genetic makeup of living organisms like plants, animals, or microorganisms. Recombinant DNA technology involves combining genes from different organisms, resulting in what’s known as a ‘Genetically Modified (GM)’, ‘Genetically Engineered’, or ‘Transgenic’ organism. Key GM crops grown commercially include soybeans, corn, cotton, and canola, which are engineered to resist herbicides and insects. Other GM crops include sweet potatoes resistant to viruses and rice with increased iron and vitamins.
GM Food Development
Scientists first discovered in 1946 that DNA could be transferred between organisms. The first GM plant was produced in 1983, using an antibiotic-resistant tobacco plant. China was the first country to commercialize a transgenic crop in the early 1990s with the introduction of virus-resistant tobacco. In 1994, the ‘Flavour Saver tomato’ was approved in the USA, allowing delayed ripening after picking. By 2011, the USA was a leading producer of GM crops, including cotton, soybean, canola, potatoes, eggplant, strawberries, corn, tomatoes, lettuce, cantaloupe, carrots.
Examples of GM Foods
Fruits and Vegetables
Papaya, engineered to resist the ring spot virus, saved Hawaii’s papaya industry in the 1990s. Currently, 80% of Hawaiian papaya is genetically engineered, as no conventional or organic method is available to control ring spot virus.
Papaya crop fields with farmers examining the produce.
The NewLeaf™ potato, protected from the Colorado potato beetle using Bacillus thuringiensis (Bt), was introduced by Monsanto in the late 1990s. However, it was withdrawn from the market in 2001 due to rejection by fast-food retailers and export problems. While transgenic potatoes are not currently marketed for human consumption, BASF has sought approval for its ‘Fortuna potato’ resistant to late blight. As of 2005, around 13% of zucchini grown in the USA is genetically modified to resist viruses.
Vegetable Oil
Vegetable oil derived from GM crops generally contains little to no protein or DNA. A significant portion of Canola produced in the USA is genetically modified, primarily for herbicide resistance and improved oil composition. Canola oil, the third most consumed vegetable oil globally, is used in cooking oil, margarine, shortening, and various prepared foods.
Corn and Sugar
In 2010, 86% of the maize crop in the USA was genetically modified. A good amount of the total maize harvested goes to livestock feed including the distillers grains. The remaining has been used for ethanol and high fructose corn syrup production, export, and also used for other sweeteners, cornstarch, alcohol, human food or drink. Corn oil is sold directly as cooking oil and to make shortening and margarine, in addition to make vitamin carriers, as a source of lecithin, as an ingredient in prepared foods like mayonnaise, sauces and soups, and also to fry potato chips and French fries.
Glyphosate-resistant sugar beet is widely used in the USA, with 95% of sugar beet acres planted with glyphosate-resistant seed after deregulation in 2005. The sugar produced from GM sugar beets is highly refined and contains no DNA or protein – it is just sucrose.
Are GM Foods Safe? Assessing the Risks
Safety tests on commercial GM crops are essential to ensure they do not pose risks to human health.
Maize and Soybeans
Studies on herbicide-resistant GM maize showed differences in fat and carbohydrate content compared to non-GM maize. However, toxicity tests were limited. Glyphosate-resistant soybeans were claimed to be “substantially equivalent” to conventional soybeans, although studies recorded significant changes in genistein content and trypsin inhibitor.
Potatoes and Rice
Studies on GM potatoes expressing the soybean glycinin gene found no differences in growth, feed intake, blood cell count, or organ weights in rats. However, other research indicated potential issues, such as villus epithelial cell hypertrophy in mice fed potatoes with a Bacillus thuringiensis toxin gene. GM rice expressing the soybean glycinin gene was claimed to have increased protein content, which was found probably due to a decrease in moisture rather than true increase in protein.
Cotton and Peas
GM cotton plants providing increased protection against pests were claimed to be “substantially equivalent” to parent lines in macronutrient and gossypol levels. GM peas expressing bean alpha-amylase inhibitor showed similar nutritional value to parent-line peas when fed to rats.
Allergenicity Concerns
Allergenicity is a significant concern with GM foods. It is crucial to determine whether genetic engineering affects the potency of endogenous allergens or introduces new allergens.
Farm workers exposed to B. thuringiensis pesticide were shown to have developed skin sensitization and IgE antibodies to the Bt spore extract. Patients allergic to Brazil nuts and not to soy bean then showed an IgE mediated response towards GM soy bean.
Controversy and Risks
Controversies surrounding GM foods include safety concerns, labeling requirements, and the role of agricultural biotechnology in addressing world hunger. Evolution of resistant pests and weeds, termed superbugs and super weeds, is another problem. The potential risks accompanied by disease resistant plants deal mostly with viral resistance. It is possible that viral resistance can lead to the formation of new viruses and therefore new diseases.
Health risks associated with GM foods are concerned with toxins, allergens, or genetic hazards. Insertional mutagenesis can disrupt or change the expression of existing genes in a host plant.
Public Concerns and Attitudes
Public concerns about GM foods have led to regulations on their production and trade. Issues related to traceability and labeling of GMOs are gaining interest worldwide.
Consumer acceptance depends on perceived risks. A study in Spain indicated that consumer-perceived risk is most influenced by concerns about health.
The Indian Perspective
The Indian government has been cautious about GM technology, particularly regarding food crops. GM mustard, a variety using the barnase-barstar-bar gene complex, has faced scrutiny due to concerns about its safety and potential impact on non-GM mustard varieties. Activists claim that GM foods are inherently dangerous and must not be cultivated in India.
Future Prospects
GM foods hold potential for addressing global hunger and malnutrition and reducing reliance on synthetic pesticides and herbicides. Future applications may include drugs in food, bananas that produce human vaccines, and plants that produce biodegradable plastics.
