The Truth About Genetically Modified Foods

Precise and safe or out of control and deadly? The shocking truth behind GM foods and how they pose a serious health risk.

The Truth About Genetically Modified Foods
By author of Seeds of Deception, Jeffrey M. Smith

Are you confused about genetically modified organisms (GMOs)? There’s good reason. The official policy of the US Food and Drug Administration is that genetically modified (GM) foods are not substantially different, and therefore no special safety tests are required. But the official policy of the American Academy of Environmental Medicine is that GM foods pose a serious health threat, and therefore all doctors should advise patients to avoid them.

Monsanto, the largest producer of GM seeds, claims that their gene-spliced crops increase yield and will feed the hungry. The Union of Concerned Scientists’ report, Failure to Yield, shows that GM seeds do not increase yield; and the International Assessment of Agricultural Knowledge, Science, and Technology – a three-year collaboration of more than 400 scientists, 30 governments, and 30 civil society organisations – concludes that GM foods offer nothing to feed the hungry world.

Save the world or destroy it? Precise and safe, or out of control and deadly? This report helps you navigate the contradictory claims and make sense of one of the most powerful and far-reaching technologies ever introduced.

Breaking the species barrier
For centuries, farmers saved the best seeds from their crops for replanting, improving the quality and reliability year after year. They also crossbred pairs of crops with desirable traits in the hopes that the offspring carried the best of both. Early last century, scientists realized that those traits were stored in genes, found within the DNA.

In the 1970s, scientists made a radical discovery. They could remove a gene from one species and force it into the DNA of another. No longer was sexual reproduction needed to create new types of offspring. And by transferring genes across the species barrier, the possible combinations became virtually infinite.

Scientists put spider genes into goats, in the hopes of milking the goat to get spider web proteins to make bullet proof vests. They’ve put genes into corn so the crop makes a spermicide. They’ve used jellyfish genes to make fish and puppies glow in the dark, created pigs with cow hides, and salmon that grow up to five times faster.

Nature became man’s playground, with a more profound and lasting impact than ever before.

GMO crops designed to drink or produce poison
There are nine genetically modified (GM) food crops on the market. The five major ones are soy, corn, cotton, canola, sugar beets, and alfalfa. All five are engineered with the trait called herbicide tolerance. Here’s the back story: Scientists discovered bacteria growing in a chemical waste dump near Monsanto’s factory. The bacteria was surviving in the presence of glyphosate –the active ingredient in Monsanto’s herbicide Roundup – which normally kills bacteria. The company figured “Great! Let’s put it into the food supply.” So they took out the bacterial gene that allowed it to survive, and forced it into the DNA of soybeans. Now you can spray Roundup Ready soybeans with Roundup, and not kill the crops. Just the weeds die. Each of the five crops have a Roundup Ready version. Some also have Liberty Link variety, which survives otherwise deadly doses of Liberty, from Bayer CropScience.

Although the biotech industry claimed that herbicide tolerant crops would reduce the use of herbicides, the opposite happened. Over the first 13 years, there was an increase of 383 million pounds, or 10%. But now weeds are getting wiser, they too are developing resistance to Roundup, and farmers are spraying lots more. So the rate of herbicide use is now growing in the range of 30% per year or more. And this means that we consume more herbicide residues in our food. And so do the animals.

The second popular trait, found in some corn and cotton varieties, is pesticide producing. These crops produce a pesticide in every cell, which breaks open the stomach of certain insects and kills them. The plants’ DNA is outfitted with a gene from the soil bacteria called Bt (Bacillus Thuringiensis), which makes Bt-toxin. Hence these plants are called Bt crops.

Nearly all GM crops in the world (more than 99%), are either herbicide tolerant, pesticide producing, or both. In other words, they either drink poison or produce poison.

Three minor crops are Hawaiian papaya, and a little courgette and yellow squash. They have viral genes added that allow the crop to resist a particular plant virus.

GMOs are inherently unsafe
When you cross plants through natural breeding, there’s a lot of random re-sorting of genes from each parent, causing wide variations among the offspring. Because genetic engineering allows scientists to isolate a desired gene and transfer it into a host plant, the industry likes to say that it is a more precise technology. This simplistic statement, however, is misleading.

The process of genetic engineering itself creates unpredicted alterations, irrespective of which gene is transferred. Gene insertion, for example, is accomplished by either shooting genes from a “gene gun” into a plate of cells, or using bacteria to infect the cell with foreign DNA. They don’t guide the “transgene” into a particular location in the plant DNA. Sometimes it will be imbedded in the middle of a native gene, changing its function. It can also delete natural genes, permanently turn them on or off, and cause mutations in and around the insertion site and elsewhere [1].

The “transformed” cell is then cloned into a plant through a process called tissue culture, which results in additional hundreds or thousands of mutations throughout the plants’ genome. In the end, the GM plant’s DNA can be a staggering 2-4% different from its natural parent [2]. Furthermore, one study revealed that up to 5% of the natural genes significantly altered the amount of protein they were producing, as a result of a single gene insertion.

This means that GM crops may have new or higher levels of allergens, toxins, carcinogens, and anti-nutrients. Natural corn, for example, has a gene designed to create a known allergen, but it’s permanently switched off. However, in Monsanto’s MON 810 Bt corn, the gene was accidentally switched on – and now the GM corn has a dangerous allergen not found in natural corn. Similarly, cooked Roundup Ready soybeans contain as much as seven times the amount of trypsin inhibitor (a known soy allergen) compared to cooked natural soybeans.

This massive collateral damage that occurs in the crops is largely ignored by biotech industry scientists and regulators, who still operate as if genes were like Lego that cleanly snaps into place.

The FDA’s “non-regulation” of GM foods
In 1992, the US Food and Drug Administration claimed they had no information showing that GM foods were substantially different from conventionally grown foods. Therefore they were safe to eat – absolutely no safety studies were required. Companies like Monsanto, that told us Agent Orange, PCBs, and DDT were safe, are in charge of determining if their GM foods are safe. This is the current FDA policy.

But internal memos made public by a 1998 lawsuit reveal that their position was staged by political appointees who were under orders from the White House to promote GMOs. In addition, the FDA official in charge of creating this policy was Michael Taylor, Monsanto’s former attorney, later their vice president, and now the FDA’s US Food Safety Czar.

In reality, FDA scientists had repeatedly warned that GM foods can create unpredictable, hard-to-detect side effects, including allergies, toxins, new diseases, and nutritional problems. They urged long-term safety studies, but were ignored.

Pusztai’s Hot Potatoes
In the UK, however, the Pro-GMO government decided to commission safety studies in 1996 – perhaps to convince a skeptical public to accept the new gene-spliced wonders. Hungarian born chemist Dr Arpad Pusztai succeeded out of 27 competing scientists for a £1.6 million grant to develop a safety testing protocol; it was supposed to eventually be required for all GM food approvals in Europe.

Pusztai’s team was working with a potato, outfitted with a gene from the snowdrop plant, that produced ‘GNA lectin’, a protein that kills insects. Dr Pusztai knew that the GNA lectin was harmless to mammals. Dr Pusztai was the world’s leading expert on lectin proteins, and the GNA lectin was the one he knew most about. He had studied it for nearly seven years.

But when Dr Pusztai fed the GM potato to rats using his new safety testing protocol, he got a shock. Nearly every system in the rats’ bodies was adversely affected – several in just ten days. Their brains, livers, and testicles were smaller, while their pancreases and intestines were enlarged. The liver was partially atrophied. Organs related to the immune system, including the thymus and the spleen, showed significant changes. Their white blood cells responded to an immune challenge more slowly, indicating immune system damage.

In all cases, the GM potato created proliferative cell growth in the stomach and small and large intestines; the lining was significantly thicker than controls.  Although no tumors were detected, such growth can be precancerous.

Dr Pusztai and his team knew that the GNA lectin had not caused the damage. Other rats had been fed natural potatoes spiked with the lectin and did fine. The damage to the rats, it appeared, came rather from the unintended side effects of the genetic engineering process.

Biotech Damage Control Kicks In
The television show ‘World in Action’ asked Dr Pusztai for an interview. With permission from his Institute’s director, he spoke generally about his concerns with GMOs based on the findings.

His 150-second interview was aired on August 10, 1998. The European Press went wild and Dr Pusztai was propelled to the status of hero at the Rowett Institute. The Institute’s director, Professor Phillip James, took over all the publicity efforts, described the research as a huge advance in science, and wrote in a press release, “a range of carefully controlled studies underlie the basis of Dr Pusztai’s concerns.”

On the afternoon of August 11th, two phone calls were allegedly placed from the pro-GMO Prime Minister’s office, forwarded through the Institute’s receptionist, to Professor James. Dr Pusztai’s hero status was revoked.

The next morning, the director suspended Dr Pusztai after 35 years of service. He was silenced with threats of a lawsuit and his twenty member research team disbanded. The government never implemented their GMO safety testing protocol.

The Institute released numerous statements, some contradicting each other, others misrepresenting the research, but all designed to discredit Dr Pusztai and the implications of his findings.

Seven months (and one heart attack) later, Dr Pusztai’s gag order was lifted when Parliament invited him to testify. As the true details of the study began to emerge, the media responded. About 750 articles on GMOs were circulating within the month. By the end of April 1999, just 10 weeks after Dr Pusztai’s gag order was lifted, the public’s distrust of GMOs reached a tipping point. Use of GM ingredients had become a marketing liability. Within a single week nearly every major food company committed to stop using GMOs in Europe.

GMO health dangers, and continued attacks on scientists
The attack on Dr Pusztai was just the beginning. For years, whenever a scientist discovers adverse findings or even criticizes the technology, according to Nature, they face a “large block of scientists who denigrate research by other legitimate scientists in a knee-jerk, partisan, emotional way that is not helpful in advancing knowledge and is outside the ideals of scientific inquiry.” As such, numerous scientists refuse to do any more research in this field, putting the number of independent studies perilously low. And industry funded studies are widely criticized as superficial and rigged to avoid finding problems. Nonetheless, GMO research does point to serious dangers.

Compromised immune system and allergies
Numerous GMO animal feeding studies show immune system problems, such as inflammatory and immune reactions, impaired immune responses, damage to organs associated with immunity, and altered parameters in the blood.

No tests can guarantee that a GMO will not cause allergies. Although the World Health Organization recommends a screening protocol, GM soy and corn fail those tests – because their GM proteins have properties of known allergens.

Soon after GM soy was introduced in the UK, soy allergies skyrocketed by 50%. Although there was no follow-up to see if GM soy was the culprit, there are many reasons why it might be. GM soy, for example, contains higher levels of trypsin inhibitor, a known soy allergen; contains higher residues of herbicide; and may contain an entirely new allergen.

The biotech industry claims that Bt-toxin is harmless to humans and mammals because the natural bacteria version has been used as a spray by farmers for years. In reality, hundreds of people exposed to natural Bt spray had allergic and flu-like symptoms. Now, farm workers throughout India are getting those same symptoms from handling Bt cotton. Likewise, mice fed natural Bt had powerful immune responses; now mice and rats fed Bt corn also show immune responses.

GMOs may make you allergic to non-GM foods
Since GMOs were introduced in the US, food allergies have become a huge problem, especially for children. Some of the foods that trigger reactions, however, are not genetically engineered. But studies show how GM foods might create sensitivity to other foods, and may in fact be contributing to this national epidemic.

GM soy, for example, drastically reduces digestive enzymes in mice. If our ability to breakdown proteins was impaired, we could become allergic to a wide variety of foods.

Mice fed Bt-toxin not only reacted to the Bt itself, they started having immune reactions to foods that were formerly harmless. The Bt-toxin in the corn we eat may have a similar impact. Mice fed experimental GM peas also started reacting to a range of other “safe” foods.

GMOs and liver problems
The liver is a primary detoxifier. Its condition can indicate if there are toxins in our food. Mice and rats fed GM feed had profound changes in their livers. In some cases, livers were smaller and partially atrophied. Some were significantly heavier, possibly inflamed. And certain cellular changes indicated a toxic insult from the GM diet.

Reproductive problems and infant mortality
Both male and female animals showed horrific problems when fed GM soy. More than half the babies of mother rats fed GM soy died within three weeks, compared to 10% of the non-GM soy controls. The GM babies were also considerably smaller, and were unable to conceive in a subsequent study. Male rats and mice fed GM soy had changed testicles, including altered young sperm cells in the mice. And when both mouse parents ate GM soy, the DNA of their embryos functioned differently. When hamsters were fed GM soy for two years, by the third generation most lost the ability to have babies. The GM group also grew slower, had a 4-5 fold increase in infant mortality, and some had hair growing in their mouths. GM corn also had an impact.  The longer mice were fed the corn, the fewer babies they had and the smaller their babies were.

Livestock sterility, disease, and death
Many of the problems seen in laboratories are also reported by farmers and investigators in the field.

o Thousands of sheep, buffalo, and goats in India died after grazing on Bt cotton plants after harvest. Others suffered poor health and serious reproductive problems.
o Farmers in Europe and Asia say that cows, water buffaloes, chickens, and horses died from eating Bt corn varieties.
o About two dozen US farmers report that GM corn varieties caused widespread sterility in pigs or cows.

Genes transfer to our intestinal bacteria
The only published GMO human feeding experiment found functioning soy transgenes inside human gut flora [3]. The subjects had Roundup Ready gut bacteria. This means that long after we stop eating GMOs, we may have dangerous GM proteins continuously produced inside us [4]. Although it was never evaluated, if Bt genes were to transfer from corn, for example, it might turn our intestinal flora into living pesticide factories.

A trail of failed promises
In addition to the claims that GMOs are healthy, they fail on other fronts as well.

Reduction of yields: According to the most comprehensive independent test data, including reports by the Union of Concerned Scientists and the US Department of Agriculture, GMOs do not increase average yields. In fact, they typically reduce yields.

Closed export markets: When GM corn, soy, canola, and papaya was introduced in various regions, key export markets such as Europe and Japan reduced or eliminated imports. This reduced commodity prices and also forced non-GMO farmers to pay extra for segregation and testing.

Farmer/peasant losses: GMOs have negatively impacted farmers and peasants in several ways:
• Studies show that average farmer income does not increase with GMOs, and can decrease in many instances;
• Farmers lose the ability to save seeds and become more dependent on multi-national corporations for both seeds and chemicals;
• Multinationals that buy local seed companies often eliminate non-GMO seed varieties from their catalogues, forcing farmers to purchase GMOs (and the associated weed killer in the case of herbicide tolerant crops).
• Once they control seed markets, multi-nationals typically increase seed prices;
• Herbicide tolerant crops such as Roundup Ready soybeans allow large land owners in Argentina and elsewhere to spray their fields by plane. As a result, they have forced peasant laborers, many of whom have worked the fields for decades, to leave the area and migrate to the city;
• Peasants in South America who remain in the agricultural areas are regularly exposed to GMO-related agricultural chemicals and report higher incidence of birth defects, cancer, and other conditions;
• Bt cotton has proven extremely unreliable. Nearly 200,000 Indian farmers committed suicide when their GM cotton harvest was insufficient to pay back high interest loans.

Environmental harm: New reports each year show how GM crops and their associated chemicals cause unexpected harm to insect populations, soil ecology, biodiversity, and biological balance.

Roundup causes multiple problems: Roundup herbicide, which accumulates in the food portion of the Roundup Ready crop, has now been linked with many serious health problems – from birth defects to cancer. Roundup also deprives plants of healthy nutrients, promotes soil-borne pathogens, harms beneficial microorganisms, lingers in the soil for months or years, leads to a reduction in the nutrient quality in food and feed, and promotes herbicide tolerant weeds.

Irreversible contamination: GMOs impose a self-propagating pollution that can survive and expand indefinitely. Pollen and seeds from GM plants can travel via wind, floods, insects, and accidental mixing to contaminate non-GMO crops and wild relatives. There is no technology to fully clean up this pollution of the gene pool.

Skewing agriculture for corporate benefit: The biotech industry’s strategic use of investments, advertising and research money, organizational sponsorships, and academic and political partnerships, has resulted in unprecedented control of agriculture. The result has been a promotion of the high-input industrial technologies that benefit corporations, and the widespread rejection of technologies that benefit the land, farmers, local culture, and nutrition. And it is that massive control of information that has allowed it to continue to promote the myths that have propped up this failing technology.

We’re the guinea pigs
It’s likely that GM foods are contributing to the deterioration of health in the United States, Canada, and other countries where it is consumed. But without post-marketing surveillance, the chances of tracing health problems to GM food are low. The incidence of a disease would have to increase dramatically before it was noticed, meaning that millions may have to get sick before a change is investigated. Tracking the impact of GM foods is even more difficult in North America, where the foods are not labelled.

Regulators at Health Canada announced in 2002 that they would monitor Canadians for health problems from eating GM foods. A spokesperson said, “I think it’s just prudent and what the public expects, that we will keep a careful eye on the health of Canadians.” But according to CBC TV news, Health Canada “abandoned that research less than a year later saying it was ‘too difficult to put an effective surveillance system in place.’” The news anchor added, “So at this point, there is little research into the health effects of genetically modified food. So will we ever know for sure if it’s safe?” [5]

The doctors at the American Academy of Environmental Medicine insist that we shouldn’t wait for more studies. People should stop eating GMOs now, to protect their health.

‘GMO-Free’ is the third fastest growing new label claim for all products, as companies rush to appeal to an increasingly large number of consumers unwilling to participate as guinea pigs in this uncontrolled experiment. The tipping point may not be far off.

Here in the UK, products derived from GM ingredients must be labelled as containing GMOs. However, this does not apply to food produced from animals fed with GMOs. This loophole means that some 20 million tonnes of GMOs enter the EU food chain in a totally invisible manner. The Conservative Party manifesto pledged to “ensure that consumers have the right to choose non-GM foods through clear labelling”, yet Conservative MEPs voted down an opportunity to introduce labelling of GM-fed animal products across the EU in July 2010.

In Sweden, a consumer-led coalition has played a leading role in lobbying for change, despite the pro-GM stance taken by the Swedish government. This move proves that a food chain that excludes GM animal feed is entirely possible, regardless of the official government position. Germany, France, Austria and Ireland all have government-backed voluntary labelling schemes which allow consumers to choose meat and dairy products fed GM-free feed. Why are we, in the UK, lagging behind? Our supermarkets should switch to non-GM feed so that we are not left in the dark about what animal feed is being used.

Visit to find out more about how to lobby your supermarket into taking action – helping to get GM out of our food chain. The biotech industry’s last profitable outlet for these crops is animal feed, if we make it clear we do not want these products, the industry will lose a significant part of its market.

Jeffrey M. Smith is the Executive Director of the Institute for Responsible Technology. For more information, see his books Seeds of Deception and Genetic Roulette, and sign up for the Institute’s free electronic newsletter at There you can also find a fully referenced version of this article.


1. J. R. Latham, et al., ‘The Mutational Consequences of Plant Transformation, The Journal of Biomedicine and Biotechnology (2006), Article ID 25376: 1-7; see also Allison Wilson, et. al., ‘Transformation-induced mutations in transgenic plants: Analysis and biosafety implications,’ Biotechnology and Genetic Engineering Reviews, (2006), vol 23.

2. P. H. Bao, S. Granata, S. Castiglione, G. Wang, C. Giordani, E. Cuzzoni, G. Damiani, C. Bandi, S. K. Datta, K. Datta, I. Potrykus, A. Callegarin and F. Sala, ‘Evidence for genomic changes in transgenic rice (Oryza sativa L.) recovered from protoplasts’, Transgen Res 5 (1996): 97-103.; M. Labra, C. Savini, M. Bracale, N. Pelucchi, L. Colombo, M. Bardini and F. Sala, ‘Genomic changes in transgenic rice (Oryza sativa L.) plants produced by infecting calli with Agrobacterium tumefaciens,’ Plant Cell Rep 20 (2001): 325-330.

3. Netherwood et al, ‘Assessing the survival of transgenic plant DNA in the human gastrointestinal tract,’ Nature Biotechnology 22 (2004)

4. Promoters may permanently switch on other genes within bacterial DNA, causing unknown effects.

5. “Genetically modified foods, who knows how safe they are?” CBC News and Current Affairs, September 25, 2006.