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Genetically Modified (GMO) Foods – a Definition

Human beings have been making genetic modifications to food for generations. In fact, ever since man went from hunting and gathering to farming, he has altered the genetic make-up of food for his own convenience. Genetic modification has traditionally been done by selective breeding – a plant that exhibits traits you desire is the plant whose seeds you save, or from which you take a cutting to root. If you repeat this for enough successive generations of plants, you will get many plants with that desired trait.

For example, in the mid-19th century, most garden varieties of tomatoes were quite tart. Tomatoes were treated as a sour fruit and eaten with sugar and cream or made into preserves. Scientists began to work on increasing sweetness and yield of tomato plants, selecting those plants that were the sweetest and had the most fruits.

The seeds from the sweetest plants were saved and planted and those from the more sour ones were rejected. Over time, tomatoes changed from tart fruits to sweet-savory vegetables – although the tomato is, botanically, a fruit, we are more likely to eat tomatoes with salt than sugar. The selective breeding has produced tomato plants that give high yields and sweeter flavor.

But Genetically Modified Foods (GMFs or GMOs), also known as Genetically Engineered Foods, are not the result of selective breeding. Modern GMFs enter the realm of gene-splicing and the insertion of foreign genetic material into living cells. It is almost bizarre, the genes that can be inserted into plants to create once-unheard-of traits.

For example, a plant can be made to produce human insulin or have built-in pesticide or resistance thereto. Let’s look at the process in a bit more detail. Admittedly, the science of genetic engineering is a complex one. But it is important for laypeople to know as much as possible in order to understand what is being done to food. The best decisions, after all, are informed ones.

To understand how genetic engineering is done, watch this video (an illustrated explanation begins at the 2.20 minute mark).

The Nature of DNA

DNA stands for deoxyribonucleaic acid. As the name implies, DNA resides in the nucleus of living cells. Under magnification, a DNA strand looks like a twisted ladder, a shape called a double helix. Along this ladder-like shape are genes, those components of DNA that house instructions for the production of particular proteins. Scientists refer to this as the “coding” of proteins. These proteins join with other proteins in a vast, complex process. Your DNA is your personal blueprint, and so is a plant’s.

To genetically modify plants, scientists remove a gene from a strand of DNA. Then that gene is encased in a carrier, called a vector, that acts as a microscopic container. Often, scientists use viruses as vectors because of viruses’ ability to “sneak” into a cell and get into its DNA. Once the gene is in the vector, it is inserted into the cells of the host organism.

As a sort of flag or marker to help scientists distinguish between modified genes and non-modified ones, vectors are marked with antibiotic-resistant genes. All the cells are then bathed with antibiotics, and the antibiotic- resistant cells stand out. They multiply and the non-modified cells die.

The modified cells are sometimes aided by a “promoter.” A promoter is a protein found in all genes that sort of “jump starts” the protein-coding process. Scientists sometimes use viruses as promoters as well as vectors. As the modified cells multiply, the host organism takes on the characteristics encoded in the new DNA.

All of this cutting, pasting, and rearranging is quite complicated, and due to the complexity of DNA and the coding of protein, the whole realm of genetic engineering is imprecise. It is impossible to tell just where in a cell the foreign gene will land, and the results are often not pretty.

(It took 270 tries to clone “Dolly” the sheep – the 270 attempts were deformed, stunted, or born dead.) Genes do not necessarily act the same way twice; there are a great many variables that can affect the outcome. The potential for the creation of freakish organisms is very real.

What are the Positive Claims?

  • Solving World Hunger – Proponents of genetic engineering have made claims that GM foods will “feed the world.” GM foods are said to have much higher yields, and the resistance to disease and frost would translate into much less agricultural loss.
  • Frost resistance can be achieved via injection of arctic fish genes or special “ice-minus” bacteria. Once again, this means less loss and higher yields, and potentially more affordable food. (The price of a particular food always goes up when a frost destroys crops in southern areas.)
  • Crops that are genetically resistant to herbicides mean that farmers can spray herbicides (weed killer) where it’s needed, thus using less of these toxic chemicals. This also cuts down on a farmer’s costs.
  • Crops with internal pest resistance could mean farmers will not have to spray as much pesticide. Pest resistance also means high yields, lower production costs, and consequently cheaper food.
  • Some argue that genetic modification of foods is simply the next logical progression in agricultural evolution. After all, people have been modifying the genes of foods for centuries; this is just the next step.
  • “Farm”aceuticals, or plants that produce drugs, antibodies, vaccines, etc. are touted as a boon by some proponents of genetic engineering. Some of the medically-enhanced foods being explored are cranberries engineered to cure UTIs, rabies-vaccine corn, and insulin-containing soybeans for diabetics.
  • In addition to medicines, GM foods can be modified to contain greater amounts of vitamins and minerals, even those that do not occur naturally in that food. Advocates say this has great implications – for example, eating one piece of fruit could cover your vitamin and mineral needs for the day.
  • Constituents in plants that have been isolated as the “active” ones could be increased. For example, high-allicin garlic is being considered, as are extra-antioxidant blueberries. So-called “golden rice” – a rice with added beta-carotene – has already been developed. This is considered a great innovation for people suffering from starvation and Vitamin A in developing countries.

General Concerns

This process and its potential for harm are cause for concern. What has many people alarmed is not that the genetic modification of foods has been proven harmful; it’s the fact that this is a largely unresearched area of science, and yet genetically modified foods have made their way onto grocery shelves without a clear understanding of the risks.


Ecosystems are delicately balanced, self-contained community of organisms. To understand something about the potential effect that GM foods could have on ecosystems, let’s take a look at how GM foods go from laboratory to market.

Field trials are the means by which a GM food is “tested” for its ability to withstand natural conditions. Interestingly, it is not tested for safety in a field trial. When a new GM food is produced in the lab, it is subjected to a field trial. This means that the plant is grown outside in an environment that is as close as possible to the environment in which it will be grown for profit – wind, sun, rain, insects, etc. are all part of the conditions.

You may already have thought of the first potential problem – wind or insects can carry the pollen of this new GM plant into the surrounding environment. What if, after the field trial, the plant is found to be harmful, useless, or otherwise a “dud”? Its destructive genes could already be circulating in the environment, possibly affecting other plants.

Concerned people warn of the creation of “superweeds” from this indiscriminate dissemination of genetic material. Many of the GM plants are designed to resist herbicides. If an already-tenacious or invasive weed ends up with such resistant genes it could be catastrophic.

Or, if the GM plant is too weak to withstand natural forces, its DNA could effect useful – or even vital – plants and weaken their genetic structure, causing them to succumb to the elements. When plants are affected, animals are, too. If a particular species of plant becomes scarce due to its exposure to GM pollen, then the effects will be felt all the way up the food chain.


This refers to the diversity – or large variety – of plants and animal life. Genetic engineering of food reduces biodiversity by putting as much as possible into one plant. In other words, if scientists are going to jam vitamins, minerals, medicines, and healthful constituents into a few plants, why eat the others?

Also, farmers will want to produce those foods for which there is the greatest demand; government pressure on farmers to grow GM foods has the potential to reduce the variety of foods available.

This lack of biodiversity is sometimes called “monoculture,” and has its roots in the development of the hybrid. Farmers as far back as 100 years ago discovered that two purebred strains of corn, when interbred, produced an extremely robust result. Yield, disease-resistance, and life span were all increased in hybrid offspring.

Rather than natural selection, the means by which nature decides which species survive, farmers began to engage in “artificial” selection, whereby different (but still related) species are crossed that would never cross naturally. However, cross breeding was restricted to the species in question (i.e., fish were not being crossed with corn, but two strains of corn could be crossed or even corn and a related plant species).

In the 1930s, hybridization went beyond corn and major agricultural companies got in on the act. Feeling the economic pressure, farmers purchased genetically uniform hybrids from such companies, resulting in the farmer’s dependency on corporations and the reduction of biodiversity. This started the ball rolling toward monoculture and, ultimately, inter-species genetic modification of foods.

Disconnect from the Earth

Genetic modification – even early hybridization – connected the farmer intimately with his or her trade. The farmer had to know the nature of the plants in order to recognize which ones were doing better and which ones worse. Farmers had to observe their plants carefully, which required their physical presence in the field and their connection with the natural forces that affected their crops.

With genetic engineering, the farmer’s observant presence and active participation are no longer necessary. GM foods are developed and studied in the laboratory, and the farmer is simply a vehicle by which the plants are put into the ground and harvested.

Antibiotic Resistance

This is a growing concern even without GM foods, and anything that might exacerbate this growing problem needs close scrutiny. Bacteria possess the ability to communicate, and they “learn” resistance from one-another after being in contact. As mentioned above, antibiotic-resistant genes are used as “markers” to determine which genes have been altered.

From hence these antibiotic-resistant genes continue into the GM food itself, and then into the human digestive system. The “good” bacteria in the human gut could then learn antibiotic resistance – this may not seem to be so bad in itself, but if pathogenic (disease-causing) bacteria then learn antibiotic resistance from human gut bacteria, it could be disastrous. In the presence of a massive internal infection, antibiotics would not work.

Genes do not “stay put.” They jump from one organism to another both within a species and between species. The potential exists for an antibiotic-resistant gene (or any other gene) to jump from a plant to a person.


One of the concerns of GM foods is the potential lack of alternatives available. If GM foods become the most economically viable choice, and land is given over to their production, who will produce diverse, organic foods? Will there be land available to do so? And if cross-pollination and contamination of non-GM foods with GM foods get underway, could the very existence of “pure” and natural food be at risk?

Lack of Testing

The real problem, say contenders of GM foods, is the lack of clear, objective, proper testing. The implications and potential for harm are so enormous that concise, painstaking testing that does not “escape” into the surrounding ecosystems should be undergone before such foods enter the food supply.

Religious Concerns

Some faiths, such as Hindus and Adventists, do not eat meat. Jews and Muslims abstain from certain foods and eat foods prepared according to specific rituals. The Catholic Eucharist and the Jewish Seder combine food with worship. Some religions forbid certain food combinations.

These are all things to consider when thinking of GM foods, which certainly combine substances with abandon. Diet plays a role in many religious traditions, thus making labeling of GM foods and a better understanding of the process more vital than ever.

Health Concerns


Allergies are protein-based reactions. Thus, there is great potential for allergic reactions to the proteins introduced into plants via genetic modification. Allergic reactions vary significantly among individuals, so it is impossible to predict how much or what type of a substance may provoke an allergic reaction. Allergic reactions can be more than uncomfortable – they can be fatal.

Normally, labeling protects the allergic individual from ingesting a food to which he or she is allergic; but thus far, GM foods are not required to carry extensive labels. Those GM foods that are labeled need only state that the product contains GM foods. No other details are required, so the allergic person does not know with what substance the food was modified.

For example, in 1996 Brazil nut genes were experimentally inserted into soybeans, the intent being to increase the nutritional value of the soybeans. However, it was discovered (quite by accident while the scientists were testing for something else) that Brazil nuts tend to cause allergic reactions in people, and the research was abandoned.

Another potential allergy problem is from the injection of non-food genes into foods. Petunia DNA, for example, has been inserted into soybeans experimentally. Humans do not normally consume petunias, so the potential effects of such a modification are not known. Once again, it’s the lack of testing that has many contenders concerned.

Decreased Nutrition?

While proponents of GM foods claim they are higher in nutrients, there are indications that the opposite may be true. In 1999, the California-based Center for Ethics and Toxics (CETOS) did a study on GM soybeans and found a 12-14 percent decrease in phytoestrogens, important protective nutrients implicated in reduced risk of breast cancer and heart disease.

This study could have been a fluke; but the point is we don’t know. Soy products are in a great many foods, so this is potentially very bad news. What the CETOS study revealed is the tip of the iceberg, so to speak, and many people think it should have been followed up by rigorous nutritional tests of all GM foods and their non-GM counterparts.

Herbicides and Pesticides

What does it mean if these substances, intended to kill plants and animals, are injected into plant cells? A bacteria known as Bacillus thuringiensis, or Bt, is often used by organic farmers to spray crops. It is approved by the United States Environmental Protection Agency (EPA) for this purpose.

While this bacteria, used as a pesticide, is dangerous to humans in its pure form, it breaks down quickly after killing insects and no longer poses a threat to humans by the time the food is harvested. In 1995, field testing for plants genetically engineered with Bt was approved by the EPA. The implications are, once again, into the unknown but potentially devastating.

If B1 needs to break down before it is safe for human ingestion, what does that mean for the Bt present in the plant? Will is harm humans the way pure Bt would? What if leftover vegetables with Bt within their cells are tossed onto the compost pile in certain homes? Will the Bt kill beneficial organisms as it breaks down? Insects constantly exposed to Bt in plants may develop resistance to it, and organic farmers will be out of luck when spraying Bt no longer works.

Herbicide-tolerant crops, such as various foods in the Roundup Ready series (corn, soy, cotton, and canola), are engineered so that weed killers can be sprayed on and around the crop without harming the desired plant. While that may sound like a great way to reduce the use of herbicides and cut production costs, the herbicide-resistant genes in the Roundup Ready crops may find their way into the environment, producing the “superweeds” alluded to above.

Adding vitamins and minerals can complicate matters greatly – bodily needs differ according to age, gender, etc. Plus, inserting vitamins and minerals into foods ignores the synergy aspect of food consumption. For example, adding beta-carotene to rice, as mentioned above, may or may not be helpful.

Beta-carotene is a form of Vitamin A, which is fat-soluble, and rice is low in fat. In other words, unless other fatty foods are consumed with the rice, the Vitamin A will not be bio- available (readily used by the body). In starvation-plagued countries, high-fat foods are hard to come by; thus, the beta-carotene in “golden rice” may not even be absorbed by those who need it the most.

Are there Genetically Modified Foods Already in the Food Supply?

Once scientists started tinkering with the DNA of food plants, the genie was out of the bottle. There have been incidents of GM foods ending up in the human food supply by accident. StarLink corn, for example, is a type of GM corn that is used exclusively for animal feed due to its tendency to cause allergic reactions in people.

Oddly enough, in 2000, StarLink corn ended up on grocery shelves anyway, in the frm of taco shells and other food products. One wonders what other GM foods have sneaked into the food supply without anyone knowing about it – yet.

Are You Eating GMO Foods?

The Rise and Fall of the Flavr Savr

Have you ever heard of the Flavr Savr tomato? It was a genetically engineered tomato that the FDA approved for sale in 1994. By isolating and subsequently reversing a gene that codes for a ripening enzyme, the tomatoes took longer to ripen on the vine, thus improving flavor (hence the name) and extending shelf life. But the Flavr Savr was a bust – people did not want to pay more for a GM tomato, and the company that developed the Flavr Savr labeled the tomatoes clearly as GM foods, which spooked many customers away from purchasing it.

What we can learn from the Flavr Savr debacle? For one thing, we see the persistence of genetic engineers in the face of failure, because the potential for enormous profits – if one strikes that lucky genetic match – is great. Agricultural corporations seem to be hoping to hit upon the magical GM food that will increase crop yield and yield high dollars as well. So genetic modification of foods is probably not going anywhere.

Another lesson that corporations gleaned from the Flavr Savr is the dangers of labeling. Consumers are concerned with the dangers of not labeling, but agribusiness saw how the clear labeling of the genetically engineered origins of the Flavr Savr killed its sales. That makes businesses reluctant to label, creating a controversial situation.

Also, as noted above, arctic fish genes and “ice-minus” bacteria are regularly used in produce to make foods frost-resistant.

So yes, there are GM foods out there. Check out a complete list of invisible Genetically Modified ingredients. Check out a comprehensive list of GMO foods to avoid.

So What Does the Future Hold?

GMO Labeling Laws by StateClick here to learn more about state legislation and initiatives.

If genetic modification of foods continues unchecked, then the future could hold utopian food yields or a complete devastation of the food supply. People could be more nourished than ever, or victims of strange or deadly reactions to foreign proteins. This is the rub – GM foods are an unexplored realm.

Works Cited

photo credit: Waag Society GMO workshop (license)

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Dee Braun
Dee is an Adv. Certified Aromatherapist, Reiki Master, Adv. Color/Crystal Therapist, Herbalist, Dr. of Reflexology and single mom who is dedicated to helping others any way she can.

One way she chooses to help is by offering information on the benefits and uses of natural health and healing methods for the well-being of both people and pets.