Thursday, January 21, 2016

Are GMOs bad?


Are GMOs bad?
Multiple Responses:
GMOs are such a hot topic. With so many people debating pros and cons, it’s hard to know what to think. So let’s answer the question: Are GMOs bad for your health? Then let’s look at a few other important questions.

Vitamin A deficiency leaves up to half a million kids blind each year.

If I were to tell you that this is the most powerful statistic in the debate over GMOs, what would you think?

Would you wonder how vitamin A could possibly relate to those little “Non-GMO Project Verified” labels you see on cereal boxes at Whole Foods? If so, here’s the story.

Ingo Potrykus is a humanitarian and plant scientist in Switzerland who co-invented genetically modified rice. Yep, he makes GMOs, aka genetically modified organisms.

Is he a villain then? Or at least a shill for some multinational corporation?

Actually, his “golden rice” was engineered to fortify itself with vitamin A. By inserting a mere three genes into the plant’s DNA (out of around 50,000 total genes), Potrykus was able to create rice that carries the vitamin A in its grain instead of just in its inedible leaves.

Up to 500,000 children lose their sight each year due to vitamin A deficiency, with half of them dying within 12 months of going blind. Golden rice would prevent this.

Unfortunately, even though Potrykus finished his project about 15 years ago and made the seeds available for free to subsistence farmers around the world, malnourished children still can’t get golden rice. Because passionate opposition has blocked its development.

So here we have a cheap, nutritious crop. Seven years of extensive scientific research. An invention that could completely eliminate an unnecessary epidemic.

And that simple invention can’t reach the people who need it.

But aren’t GMOs evil?
I know, I know. “GMO” science can sometimes sound like comic-book stuff: crazy laboratories and mad geniuses, megalomanic super villains messing around with people’s food for their own entertainment and/or financial gain.

Fish mated with cantaloupe! Rice with eyeballs! Wheat that makes you grow a tail! Frankenfoods! Island of Dr. Moreau! Etc.

The whole issue has become synonymous with unchecked power, unethical tinkering, Monsanto, pesticides, contamination, and greed.

I get it. Nobody loves giant evil conspiracies (except for super villains). But this is real life. There are no superheroes and super villains. The truth, as usual, is much more complex. And less diabolical.

When it comes to GMOs, scientists — who are just highly educated regular folks, by the way, and rarely malevolent geniuses — are mostly working toward innovations in genetics that:
  • fight disease;
  • fight hunger and malnutrition;
  • improve animal and crop breeding practices; and
  • potentially even save lives.

Of course, scientists haven’t been all that great at explaining this to the average person. (That’s what happens when you’re sequestered all day at a fluorescent-lit lab bench trying to splice DNA from fungi or whatever, along with writing grant proposals.) So, naturally, the average non-scientist imagines scary stuff.

Allow me to speak for my people — the science geeks — and bridge the gap.

How “GMOs” became a four-letter word
If GMOs creep you out, you’re not alone.

A growing team of anti-GMO activists — including hundreds of reputable advocacy groups, state legislators, and big-name chains like Chipotle, Whole Foods, and Trader Joe’s — are questioning the safety of GMOs.

They say GM foods could cause major health problems like tumors, liver toxicity, allergic reactions, and death.

So it’s no surprise that over half of the U.S. public said genetically modified foods are unsafe to eat in a recent survey from Pew Research Center. One-quarter of those surveyed said they check product labels for GMOs every single time they shop.

GMOs sound scary and evil.

But do people really even know what they are? Or how they work?

What are GMOs?
A GMO, or genetically modified organism, is any living thing that’s been manipulated to evolve, whether via breeding, engineering, or mutagenics (something that purposely changes an organism’s genetic material).

Most of the time, people debating GMOs aren’t really talking about GMOs. Instead, they’re talking about GEOs: genetically engineered organisms, things that have somehow been constructed by scientists in a lab.

Genetically engineered (GE) plants, animals and microorganisms have had their DNA surgically altered for some specific purpose, such as increasing the vitamin A content of rice, making plants that need less water, or exploring genetic disorders.

For instance, you’ve probably heard of Roundup Ready® Wheat. This is a strain of wheat that resists a weed-killing herbicide known as Roundup.

Roundup is often sprayed on crop fields to kill off weeds. It works by attacking a plant enzyme called EPSP synthase. When EPSP synthase is attacked, weeds die. But so do other plants.

While Roundup Ready Wheat still has the EPSP synthase enzyme, it has a different version, which is invulnerable to that attack. So the weeds die while the wheat survives.

As simple as addition or subtraction

When we talk about altering an organism’s DNA, we may be talking about adding something in or taking something away:
  • You can add “programming” to the existing DNA system to make something new.

The product would be a transgenic organism (as in, you transferred in a gene), and that method has come to be known as gene “knock-in.”

For example, to create Roundup Ready Wheat, they added a gene for EPSP synthase from a bacteria.
  • Or you can stop the program of an existing portion of DNA.

This is called gene “knock-out.”

Interestingly, both knock-ins and knock-outs happen normally in nature.

For example, chickens used to have alligator-like teeth. (Creepy, huh?)

Oddly, they still carry talpid2, the gene that used to make the teeth, but over time the gene got knocked out by regular old evolution. Now it’s nonfunctional. Thankfully.

When engineered, knock-outs are usually done for research. They help us figure out what a gene does.

Did a GMO save your life today?
As I mentioned earlier, the vast majority of GMOs aren’t crops like corn and soy, but rather mice, bacteria, and viruses used to investigate diseases and cures in labs all over the world.

As a molecular biologist, I’ve made hundreds of GM bacteria, hundreds of GM yeasts and one GM mouse. They’ve helped me understand how muscle develops and fixes itself, and, from there, how we might develop treatments for muscular dystrophy.

Genetically modifying microorganisms has led to some of the most revolutionary, life-saving medicines of our time:
  • If you have type 1 diabetes, GM bacteria made your insulin cheap, safe, and accessible.
  • If you’ve suffered from a genetic growth disorder such as Turner’s syndrome or short bowel syndrome, GM bacteria made the Human Growth Hormone injections that help regulate your growth.
  • If you’re a hemophiliac, I’m sure you feel much safer with your treatment coming from GMO rather than from blood donations. Cells in a lab dish made recombinant human factor VIII.
  • If you ever suffer a stroke or heart attack, you might be treated with medication made by tissue plasminogen activator, a cellular GMO.
  • If you have multiple sclerosis, you’re perhaps thankful for interferon, also made by a cellular GMO.
  • If you have cystic fibrosis, the enzyme you take, Dornase alfa, is made by a GMO.
  • Undergoing chemotherapy for cancer? Two GMO drugs that help your bone marrow and blood counts are Erythropoietin (EPO — yes, that EPO) and granulocyte-colony stimulating factor (G-CSF or GCSF).
  • Lactose intolerant and taken lactase? It comes from GMOs thanks to genes from either a fungus or a yeast.
  • If (heaven forbid) you ever contract Ebola, you’ll be beyond grateful forZMap, a collection of antibodies grown from GM tobacco infected by GM viruses.

In the end, it’s kind of a shame that the debate over GM crops has led the general public to brand everything “genetically modified” as bad. Because GM crops only represent a teeny, tiny percent of what’s happening in the GM universe, most of which is geared toward helping people and saving lives.
“But they’re unnatural!”
Sometimes people say that GMOs aren’t natural. And, if they’re referring to genetic engineering, they’re correct.

Most of the evolution we’ve known on this planet has been the result of naturally occurring, random gene recombinations and mutations. In fact, that’s how you and I came to be.

Intentionally making a GMO on the other hand — again, that’s genetic engineering — is deliberate and strategic. And that may be a good thing.

Here’s why.

Farmers have been deliberately changing organisms by playing with DNA (whether they realized it or not) for millennia. More than 10,000 years ago, our ancestors domesticated hundreds of plants, inventing agriculture and cultivating crops that are still our main food sources today.

Through artificial selection — selecting specific traits over generations of crop or livestock — plants like corn and wheat have been bred for flavor, texture, size, and tolerance to environmental conditions.

Tomatoes, for example, used to be small and tart; if you want a bigger, sweeter tomato, then you only plant seeds from the biggest, sweetest tomatoes.

In the 17th Century, Dutch farmers bred carrots that were orange instead of yellow or purple — a nod, some speculate, to the Netherlands’ orange flag.

Today’s consumers typically want all of their produce to be bright with no blemishes, and seed-free. (Did you know that bananas used to have seeds?) The reason this is possible: Most produce has been bred (i.e. genetically modified through artificial selection) to be blemish and seed-free.

Artificial selection has been used with domesticated animals too: In 1950, an average chicken would produce 125 eggs a year. Decades later, we’ve bred them to lay 250 eggs annually.

Cows’ great-great-great-great (plus a bunch more “greats”) grandparents were aurochs. They were bigger and they were total jerks. After years and years and years of people picking the most agreeable aurochs, we ended up with creatures so docile you can tip them over (if you yourself are a jerk).

The point is:
Genetic modification isn’t some scary new science.

We’ve been doing it for a long time. However, we’ve been doing it in a very rough, imprecise, “chainsaw” sort of way.

Now, with genetic engineering, we’re able to do it in the best possible way — in a strategic, precise, “scalpel” sort of way. We also have a much better idea of what we’re changing and what impact it’ll have.

It’s true that with genetic engineering you can use any gene from anything — you could even make up your own DNA — potentially creating combinations that would never otherwise exist. But this isn’t really an argument against GE.

“Foreign” DNA inserts itself into other organisms in the wild all the time, likely yielding all manner of outcomes — positive, negative, and unknown.

For example, around 8 percent of human DNA is actually from viruses, which have invaded our bodies throughout history. This viral DNA has helped placental development during pregnancy, and for making more enzymes to break down carbs.

In general, corn is corn is corn

One major source of concern about GM foods is that genetic engineering might cause the DNA to go haywire, accidentally turning on nonfunctional genes (such as ones that could make the plant toxic), or creating genetic instability that would allow the plant to continue to evolve (in unintended, potentially scary ways) even after the scientists are “finished.”

Some of these concerns have to do with the aforementioned fear of inserting “foreign” genes into the DNA of the crops.

The truth is that GE foods really aren’t so different from conventionally bred plants and animals.

Look at Figure 1. We have wild corn alongside conventional corn artificially selected for hundreds of years. Notice how different the corn has become through non-GMO strategies (i.e artificial selection or “the chainsaw method”).
Teosinte ear (Zea mays ssp mexicana) on the left, maize ear on the right, and ear of their F1 hybrid in the center (photo by John Doebley.) Tracking Footprints of Maize Domestication and Evidence for a Massive Selective Sweep on Chromosome 10. Tian, Feng, Natalie M. Stevens, and Edward S. Buckler. Proceedings of the National Academy of Sciences of the United States of America 106.Suppl 1 (2009): 9979–9986.

Figure 2 compares conventional corn and genetically modified corn. Can you guess which is which?
Photo courtesy of Jason Haegele.
Photo courtesy of Jason Haegele.

And check out Figure 3. Is that bull on steroids, or what? (More on this to come).
Double muscling in cattle due to mutations in the myostatin gene. Alexandra C. McPherron and Se-Jin Lee PNAS 1997 94 (23) 12457-12461
Double muscling in cattle due to mutations in the myostatin gene. Alexandra C. McPherron and Se-Jin Lee PNAS 1997 94 (23) 12457-12461

Bottom line: Genetic engineering is a much more exact method that leaves less to chance than conventional breeding or artificial selection.

Both methods change genes in an organism. The difference is how muchchange, and how precise that change can be. A quick comparison:
Genetic engineering
Classical breeding
Modifies only a few genes (usually only one, in fact) leaving the rest untouched.
Shuffles hundreds of genes at once, changing their position in the DNA.
Allows strict control of each gene’s production — where (for example, in the seed but not the plant) and when (for example, during development but not once the plant is mature) genes are on.
Breeders have no idea where and when these genes will end up and how they’ll be expressed.
What this means:

Genetically modified corn is exactly the same as domesticated corn, with the exception of one or two genes.

In comparison, wild corn has many genes that differ (about 5 clusters of genes), each producing small variations in the plant.

These effects include:
  • How much starch corn makes, and what type
  • The type of environment and soil the corn will grow in
  • How long the cob is, and how many kernels are in each row
  • The size, shape, and color of the kernels
  • Resistance to pests (yes, even conventional corn can and does resist pests)

So, in most ways, conventional farming methods have had much more of an impact on our food than genetic engineering.

Oh, and by the way, Figure 3 is a not a GM bull, but one made from breeding. Again, artificial selection not genetic engineering.

Some fluke (there’s the chainsaw analogy again) mutated a gene (myostatin) and made this cow (Belgian blue). It has double the muscle and nearly no fat (less than boneless skinless chicken breast.)

With the precision of genetic engineering — what most people fear when talking about GMOs — this “accident” wouldn’t have likely happened. But with artificial selection — what most people seem okay with — you get this freaky cow.

The biggest threats posed by GMOs
There’s nothing intrinsically unsafe about genetic technology. As I argue above, it’s probably even safer than most of the approaches being used today.

However, there are some GMOs that could harm the world’s food supply.

First, certain kinds of GM crops could be wiped out by weeds or pests.

Humans and weeds are at war with each other. Crops go to the winner. As with many wars, this one has seen a military escalation, with more and better weapons.

Humans use herbicides (chemicals that are toxic to weeds and living things in general). The weeds retaliate by evolving to resist the herbicides. Humans then use more of a different herbicide. And on and on the escalation goes.

Problem is, the crops can only take so much herbicide exposure before they become collateral damage in the war.

Solution! Enter genetic engineering and its herbicide-resistant crops (remember Roundup?).

Great! War over, right?

It doesn’t work that way. The massive use of herbicides wiped out nearly all of the weeds — but the few that survived are now hyper-evolved, breeding herbicide-resistant strains.

Let’s use more herbicide! The war drags on.

Eventually, the weeds become resistant to these herbicides, and there’s major loss in crops.

Similarly, Bt-corn is programmed to make its own pesticide to wipe out the caterpillars that might munch on it. Good, right? But what if there are other, just as destructive pests just waiting for those weak and frail caterpillars to get out of the way so they can jump in to eat the leftovers?

The second big threat GMOs pose to our food supply is genetic erosion.

Genetic erosion happens when an already-small gene pool gets even smaller and more uniform.

Getting GM food to market is a strictly regulated process that takes up to 12 years.

One part of this process is ensuring that GM foods are 100 percent genetically uniform. Every single seed, every single ear of corn, has to have the exact same DNA.

This homogeneity — this genetic erosion — may mean that we lose diversity, which could make our food supply less robust.

With the same DNA, organisms have the same vulnerabilities. A plague, drought, fungus, or other pathogens could wipe out all our crops at once. Then we starve.

Don’t blame the GMOs
Herbicide escalation and genetic erosion should be taken seriously, to be sure. But in order to consider solutions, it’s important to recognize that these problems aren’t specific to GMOs.

For instance:
  • We’re well aware of the unacceptably high pesticide levels found in many of the fruits and vegetables at the grocery store.
  • Non-GMO crops can be the source of herbicide escalation, too (weeds simply become resistant through natural selection).
  • Genetic erosion isn’t a new worry: 100,000 years of breeding practices have led to a certain amount of uniformity already (though it’s prudent to make sure GM crops with advantages over conventional ones don’t further narrow the genetic pool).

No doubt that GM practices should be checked and strictly regulated. It’s a good thing that we have watchdog groups keeping the balance. Like everyone, scientists make mistakes and do the wrong thing sometimes!

But we have to look at the big picture. Focusing on GM foods means missing 99 percent of the problem.

So are GM foods safe?
I know you want to know — and I sympathize. GM ingredients and additives are used in so many of the foods we eat.

To begin with, there are 1500 published studies indicating that GM foods are safe. But I’m not going to rest a case on them. There are some animal studies that might raise red flags, but I won’t cite those, either.

Because here’s reality: While most scientists believe GM foods are probably safe, science will never prove it 100 percent unequivocally.

The answer is much more complicated than “yes or no,” “pro- or anti-.”

We need to get beyond that, to stop throwing studies at each other.

Nothing can be proved to be absolutely unequivocally safe. Pick anything, and somebody has died from it.

So let’s explore the grown-up questions and gray areas, and think about what trade-offs we’re willing to make, in a scientifically informed and literate way.

For instance:
  • What aspects of GM technology could be really good for the world? Why?
  • Which aspects should we be cautious about? Why?
  • What do we know to be true (or is probably true), and what is speculation? What’s the evidence?
  • How much is our discomfort with the unfamiliar driving the fears?
  • Are we correctly assessing risk and reward?
  • What’s an acceptable level of risk to get the benefits?

As a scientist, I would love people to embrace science, evidence, and the joy of discovery. Scientists grapple with some very difficult and complex questions. And most of them just want to make the world a better place.

What to do next
Short of going back to school for a Ph.D. in biology, what can you do right now?

1. Elevate your thinking game.
Almost no scientific question is about good versus evil. Even spacetime bends occasionally. Recognize that issues are complex.

If you’d like some practice with this, may we recommend our Level 1 and Level 2 Nutrition Certifications?

2. Be a critical consumer, learner, and listener.
Contrary to what the mainstream media might lead you to believe, the biggest threats posed by GMO crops on the market today are not to your individual health, and they’re not even specific to GMOs.

Picking a side — and assuming the other side is unreasonable — makes real communication impossible. Scientific findings presented as the “final word” are probably being misinterpreted; be wary of anyone who tells you something is “100 percent true” about GMOs.

Even as sciencey folks ourselves, we’re not going to give you The Big Definitive Answer either. Because there isn’t one.

3. Address specific issues. Don’t mix them up.
With GMOs and other food safety and regulatory issues, it’s important to think critically about our concerns.
  • Are you against pesticides? Great! But that’s different from being against GMOs, and to focus on GMOs here is to ask the wrong questions.
  • Want GM foods to be labeled as such? Great! But the importance of food labeling goes way beyond GMOs.
  • Worried about large companies controlling our food? I get that. Be against Big Food, not GMOs.

Both conventional farming and GMOs use herbicides and pesticides, narrow the genetics pool, and increase the risk of catastrophic loss of crops. Conflating these issues means change will never happen.

4. Focus on the big picture and real-life priorities.
The fourth-largest cause of death in the United States is accidents. Wearing your seat belt will lower your risk of early death much more than worrying about GMOs. (And quit texting and driving. You know who you are.)

Other leading causes of death are largely due to the toxic combination of sedentary lifestyles, stress, and poor nutrition. Never mind GM vegetables — people aren’t eating vegetables, period.

So start with the key behaviors that will really make a difference. (If you’re wondering what those are, check out our Nutrition Coaching Programs for menand women).

5. Keep things sane and sensible.
The world, in general, can feel scary. Things we don’t understand can feel even more so.

Control what you can control, as best you can. Make PN-friendly choices as consistently as possible, as well as possible.

Check out these infographics to get started.

Eat, move, and live… better.
The health and fitness world can sometimes be a confusing place. But it doesn’t have to be.

Do you know what’s in your food? Chances are it’s been genetically modified. Up to 80% of processed foods in the U.S. are. But what does that mean, and what’s all the fuss about GMOs these days?

“Like it or not, genetically modified foods are almost impossible to avoid,” says Sheldon Krimsky, PhD, an adjunct professor of public health and community medicine at Tufts Medical School in Boston.

Unless you eat only fresh, unprocessed foods that are marked as non-GMO or certified organic, you’re probably eating food that has been genetically modified. Is that a bad thing? It depends on who you ask.

What’s a GMO?
Genetically modified organisms (GMOs) may sound more like something out of Star Trek rather than anything you’d expect to find on your dinner plate. They are plants that have been changed by scientists. But they aren’t something new. They’ve been sold since 1994.

Want apples that won’t brown when you slice them? Potatoes that don’t get bruises from farm to table? The FDA has approved genetically modified versions of these foods that can do that.

People who are pro-GMO say they help farmers grow better crops faster. That means more, and cheaper, food for us.

But people on the other side of the GMO debate worry about their safety. They ask, "Do we know whether eating them over the long run can hurt people?"

How GMOs Are Made
Here’s how it works. Scientists take a plant. They change the plant by adding DNA from another plant, bacteria, or virus to it. DNA is what gives everything its special characteristics. So in this way, the original plant now has new qualities. The changes can make them more resistant to disease, bugs, or drought. It can give them other qualities too, like those that affect their taste or shelf life.

How is that different from the way we’ve improved crops for centuries? One big difference is that genetic modification speeds up the process.

Where it might take years to raise several generations of plants outside in fields to get all the right traits, inside, scientist can grow several generations in one year. Conditions are perfect in the lab. They don’t need to wait for the seasons to change.

How GMOs Are Made continued...
Genetic modification has made plants with extra vitamins, minerals, and other benefits. Swiss researchers created a strain of “golden” rice with a lot of beta-carotene. Thisantioxidant is good for the eyes and skin. And those bruise-free potatoes are supposed to cut down on cancer-causing chemicals created when potatoes are fried.

What's another benefit of using science to build better plants, according to people who are pro-GMO? You can combine plants that could never mate in the wild. An example of this is “Roundup Ready” corn. It can survive being sprayed by the weed killer. It is made of DNA from a few different types of plants.

Because of this, farmers can treat their entire field instead of just targeting weeds. Weeds die, but the corn is OK.

Are GMO Foods Safe?
Industry and health leaders cite hundreds of studies to support the safety of GMOs. That includes 20 years of studies in animals that have eaten modified food.

But experts like Krimsky say nearly two dozen studies show bad effects, like harm to thekidneys, liver, heart, and other organs. He says they should carry more weight as people judge the pros and cons.

People who are against GMOs do not like that Roundup Ready corn is sprayed with toxic chemicals. Even though the corn can survive, they worry about how it might affect people or animals that eat it.

An agency of the World Health Organization has classified the main chemical used in Roundup as a “probable carcinogen.” That means they think it probably increases the risk of cancer.

Monsanto, the maker of Roundup, disagrees and stands by the safety of its corn and GMO foods. The company is responsible for a lot of the world’s genetically modified crops.

“They’re the most thoroughly tested food on the market,” says Dan Goldstein, MD, senior science fellow at Monsanto.

How Can I Tell If My Food Has Been Genetically Modified?
China, Australia, and the European Union require GMO foods to be labeled. The U.S. does not.

If you choose organic foods, you may be able to avoid GMOs. You can also look for foods that are labeled as non-GMO. The makers of these foods volunteer to tag them, but that isn’t regulated by the government, so they may or may not be right.

More Pros and Cons
So are you good with GMOs? To make your decision, consider these other things.

The Pros
More food: Fans of GMOs say they will help us feed the extra 2 billion people that will fill the planet by 2050. Farmers can grow more food because these plants can live through a drought or cold snap. They aren’t as likely to die from disease.

“Not using these tools would push us back 40 to 50 years in food production,” Bradford says.

Less stress on the environment: Crops made so bugs won’t like them lower farmers’ need for toxic chemical pesticides, Goldstein says. Plants that resist weeds can live in fields that don’t have to be tilled as often. Tilling, or stirring up the dirt, gets rid of weeds, but it also causes dirt to be washed away into streams and rivers.

The Cons
More medical problems: Opponents say that besides possibly leading to cancer, GMOs can cause new allergies and hurt the effects of antibiotics. But no studies confirm this.

The rise of "superweeds": Crops built to survive weed killer could breed with weeds. These “superweeds” would also survive. Farmers would have to use more and more and stronger pesticide to keep up.

Inventing new weed killers is hard and expensive. Plus, people worry about the safety of new chemicals that haven’t been tested as much as older ones. On the other hand, people say this is nothing new.
Where Can You Find Non-Genetically Modified Food?
The movement to have non-modified food options is picking up some traction. Some food companies voluntarily label their foods as non-GMO. At least one fast food chain has pledged to take genetically modified foods off their menu. And at least one grocery store chain is working to label possible GMO foods in the coming years.

Activists often cite the alleged potential health risks of genetically modified foods. One recent example of this—”10 Scientific Studies Proving GMOs Can Be Harmful To Human Health“, posted on—outlines many familiar concerns and points in each case to “credible scientific studies that clearly demonstrate why GMOs should not be consumed”.

Are these concerns credible? What do the studies cited actually claim?
1) Multiple Toxins From GMOs Detected In Maternal and Fetal Blood.
The blog post sites a 2010 study that alleges to show this danger. The authors identified the Bt protein Cry1Ab in maternal and fetal blood, a protein found in some GMOs, but also commonly used as a pesticide in organic farming. The paper is flawed. The researchers’ measurements were based on an experiment/assay designed to detect Bt’s Cry1Ab in plants, not in humans. As this post in explains, the pregnant women in the study would have had to eat several kilos of corn in order to get the Bt measurements that were detected in their blood.

Additionally, there’s the “so what” factor. Humans lack the receptors for the protein, so it has no impact on us. Did you know that chocolate is toxic to dogs? Are you concerned that it might be toxic to you? Probably not (if you are concerned, then you’ve missed out on the greatest source of joy known to human taste buds…). Some chemical compounds behave differently among species, and both Bt‘s Cry1Ab and chocolate are examples of this.

2) DNA From Genetically Modified Crops Can Be Transferred Into Humans Who Eat Them
That’s not what the cited 2013 study concluded. The authors found that whole genes from our food can be detected in our plasma. That does not mean that they’ve integrated into our DNA; it means that they’ve been found floating in the space between cells. And that’s any food, not just GMOs. DNA from GMOs behave no differently than DNA from organic or conventional foods

If you aren’t concerned about the DNA from blueberries “transferring” into you, then you should not be concerned about DNA from GMOs either. The paper’s deepest flaw is that a negative control was not included in the sequencing experiments. Several recent papers (see here and here) have outlined the importance of including a negative control in experiments where there is very little DNA to account for possible contaminants from the environment and reagents. (For a lay introduction to the concept of contaminants in sequencing, seehere).

3) New Study Links GMOs To Gluten Disorders That Affect 18 Million Americans
The article quotes for an alleged “study” by the Institute for Responsible Technology (IRT). But there is no study on the link of GMOs to gluten allergies. There’s a link to a post on a webpage, but there isn’t a peer-reviewed article. IRT is a one-man band run by activist Jeffrey Smith. It is an NGO that advocates for the elimination of GMOs from our food supply. It’s not a university, college or research institution. It doesn’t do studies.

I’ve written about gluten allergies and GMOs. The Celiac Disease foundation hasspoken out against the IRT’s report. GMO wheat has not been commercialized, so any association of gluten allergies with the consumption of GMO wheat is on its face absurd. As for charts that track an increase in GMO consumption in general and gluten allergies, it’s a case of association with no causation (i.e. the incidence of gluten allergies have increased over the past decade and the amount of GMOs we eat have increased too. But, so have the number of plasma screens manufactured).

4) Study Links Genetically Modified Corn to Rat Tumors
This claim is the infamous Seralini paper, which was retracted, and recently republished, in a different journal without being peer reviewed. The paper identified tumors in rats that were fed GMOs and/or the herbicide glyphosate longterm. But the strain of rat used was predisposed to tumors. The paper did not perform statistical analyses and used too few rats, so it was not possible to determine if the tumors were due to the food, the chemical or to the fact that the strain of rats would get tumors regardless of what they were fed. Finally, the findings from Seralini’s paper are contrary to other long-term feeding studies. An overview of the criticisms regarding this paper can be found here.

5) Glyphosate Induces Human Breast Cancer Cells Growth via Estrogen Receptors
This claim relates to glyphosate, an herbicide used in tandem with herbicide resistant genetically modified crops. The cited paper examines the impact of glyphosate on breast cancer cell growth. In approximately 80 percent of instances of breast cancer, the diseased cells are hormone sensitive, meaning they need estrogen in order to proliferate and spread. These researchers took two breast cancer cell lines: one was estrogen sensitive and one was not, and they examined the impact of increasing amounts of glyphosate on cell growth. They found that glyphosate has similar impact on breast cancer growth as estrogen, although the relationship was not as strong, and it did not have an impact on the proliferation of the non-hormone sensitive breast cancer cell line.

The paper had numerous technical problems, including the absence of data on controls, a potentially critical omission. Additionally, there actually seems to be a protective effect at higher concentrations of glyphosate: instead of reaching a saturation point where the addition of glyphosate no longer has an effect on cell growth, there is no significant difference in cellular growth between the cells that received the highest doses of glyphosate and the controls  (which is why the data from the controls is an important factor).

This experiment was done with cells in a petri dish—what’s called an in vitro tissue-culture experiment. Such research is of limited real-world value. The cells are often finicky and need plenty of TLC in order to grow well; different cell lines can also behave very differently. The authors of the paper note some of these issues, along with the fact that their data doesn’t mesh with previous studies that have examined the impact of glyphosate on cellular proliferation (this previous paper suggests that glyphosate actually protects against cell proliferation in vitro in eight different cancer cell lines and that glyphosate might be developed into an anti-cancer drug!).

Monsanto wrote a response to the paper noting that many studies examined the potential carcinogenicity of glyphosate and none has found that the compound causes cancer. Some news reports misinterpreted the study, writing that researchers concluded that glyphosate causes cancer when that is not the researchers’ findings: they suggest glyphosate may cause breast cancer to proliferate. Monsanto pointed out that even this finding is contrary to the body of evidence that exists on the topic. The authors admit to this fact and discuss the appropriate next steps to examine this issue in mice/rats models for breast cancer. I think that that’s a great next step. I’d also look at a few more breast-cancer cell lines.

This is the most compelling research paper that I’ve read about that suggests a potential health risk surrounding glyphosate. But the study must be reproduced and its issues ironed out. However, as I mentioned, the paper isn’t really about GMOs as a class: keep in mind that only a fraction of GMOs are glyphosate resistant (i.e. Round-up Ready crops) and the use of glyphosate is not limited to GMOs.

Additionally, the paper does several experiments with a compound in soybean whose impact on breast cancer cell growth is very similar to that of glyphosate’s—meaning that there are “natural” compounds in our food that seem to have the same impact on breast-cancer proliferation that this paper’s findings suggest for glyphosate. There does not seem to be a scientific consensus on the topic of soy intake in breast cancer patients, although several publications have examined this issue without finding a positive correlation (examples here, here, and here).

6) Glyphosate Linked To Birth Defects
No peer reviewed, published scientific study makes such claims. The source of this health concern is a publication by Earth Open Source, an anti-GMO NGO co-founded by an individual who also owns a GMO-testing and certification company, and whose business would clearly benefit through the promotion of anti-GMO sentiments (see “About the Authors” in this document).

7) Study Links Glyphosate To Autism, Parkinson’s and Alzheimer’s
The paper that led to this health claim does not constitute research. It’s a hypothesis and no research was done to support the hypothesis. The paper was reviewed by science journalist Keith Kloor at Discover Magazine who aptly compared it to a Glenn Beck chalkboard drawing.

The claims were printed in a pay-for-play journal (also known as predatory journal), meaning that for a fee, one can get nearly anything published. There have been several exposés on pay-for-play journals, and many scientists believe that the phenomenon is eroding the quality of science (here’s an overview from; here’s an exposé of pay for play journals)

8) Chronically Ill Humans Have Higher Glyphosate Levels Than Healthy Humans
This claim is based on a paper published in the Journal of Environmental and Analytical Toxicology, owned by the Omics publishing group- a notorious predatory publishing company.

The authors examined glyphosate levels in humans and different animals. There’s no indication of what the animals were fed, how much, how they were kept or myriad other variables. Any of these could invalidate the study. The researchers do not say anything about the age, sex, weight, height, or genetic background of the humans, or how much they ate, if they washed their food, how long they had been eating organic/conventional diets and, most mind-blowing of all, there’s absolutely no definition for what constitutes being “chronically ill”. Any single issue that I’ve listed here would be considered a fatal flaw that would exclude the paper from publication in a more prestigious journal.

9) Studies Link GMO Animal Feed to Severe Stomach Inflammation and Enlarged Uteri in Pigs
In the study on which this claim is based, the researchers gave pigs GMO feed and non-GMO feed and identified the differences between the two groups. The paper has been thoroughly challenged by many journalists and scientists:
  • Journalist Mark Lynas highlighted the degree to which the data is cherry-picked. The difference in “inflammation” between the GM-fed and non-GM-fed pigs is apparent only when you break down the degree of inflammation into subcategories, but there’s no difference if you view it as a single category. Overall, there’s a high rate of inflammation for both groups, which is not explained in the paper. At the same time, there are several parameters where GM-feed could be argued as having a protective effect (there are 50 percent fewer heart-abnormalities in pigs fed GM-grain), but this isn’t discussed.
  • As explained by geneticist Anastasia Bodnar, the authors do not analyze the compositional differences in the feed between the two groups. Previous studies have determined that the environment (i.e., water, soil, geography) of a crop has a greater impact on proteins and metabolites than whether or not the crop is a GMO. As such, the differences seen in the pigs may not be due pesticides or presence/absence of the transgenic protein; rather, they are most likely due to differences in composition of the feed
  • Geneticist Val Giddings notes that the animals had abnormally high rates of pneumonia, which points to the possibility that something wonky was going on.

In conclusion, even if the paper’s findings are real, there’s no knowing whether that’s due to something associated with transgenes or not, because the researchers do not account for natural variation in the feed.

10) GMO risk assessment is based on very little scientific evidence in the sense that the testing methods recommended are not adequate to ensure safety.
Let’s set aside the fact that this isn’t a “Scientific Study Proving GMOs Can Be Harmful To Human Health,” which is the claim set out in the title. There are three papers associated with this bullet point. The first one is a review and I agree with a few of the points it makes. It highlights the need for standardized tests and statistics in animal feeding studies for GMOs, and anyone who followed the Seralini debacle would probably agree. It summarizes papers that have performed feeding studies and their results. However, the review does not remove flawed papers from their overview and nor does it distinguish between feeding studies for GMO crops that have been commercialized vs. crops that have never been submitted for regulatory approval. The paper does not conclude, “GMO risk assessment is based on very little scientific evidence”.

The second paper is also a review piece. The first author is affiliated with “Friends of the Earth,” an anti-GMO NGO. It does not constitute novel research and has a clear editorial slant.

The third paper does not even qualify as a review. It’s a commentary published in 2002 in Nature Biotechnology, which is a high caliber journal. It outlined possible unintended consequences that could happen with a GMO—none of which have ever been documented or identified since then, to the best of my knowledge.

In conclusion, despite the title of the article, none of these studies proves or even persuasively suggests that GMOs can be harmful to human health. The majority are either obviously flawed or are not scientific studies.

The current scientific consensus regarding GMOs remains unchanged: they are safe and do not pose a health risk to humans. However, a scientific consensus is subject to change if there is sufficient reproducible evidence that may impact it, but none of the studies reviewed here constitute such evidence.

You've probably seen food products boast GMO-free on their packaging and you've likely listened to someone talk about genetically modified corn. But do you really know why genetically modified organisms get so much hate?

In truth, most experts will argue that GMOs aren't all bad. As Hank Green explains in SciShow's video above, some plants are genetically modified simply for human benefit; the process has helped to feed the hungry and to amplify a crop's resistance to insects and harsh weather conditions, making more food available for consumption.

GMOs are often scrutinized not for their makeup, but for the control their production gives to a select group of companies that put more emphasis on profit than human health (and that put the little guys -- like local farmers -- out of work). With the ability to alter crops' genes, these companies can sell produce that can withstand trauma for a lower cost.  Even still, as Green explains, "There has been zero indication that genetically modified food poses a danger to human health." For now, the war against GMOs has more basis in economics and democracy than it does in physical health.

GMOs, a term that's thrown around all the time but rarely understood, have been taking a lot of flack lately. The latest confusion and controversy has prompted Whole Foods to pull Chobani yogurt from its shelves and General Mills to remove all GMOs from boxes of Cheerios. But how many people actually know what they are?

GMOs (Genetically Modified Organisms) are plants and animals that have had been created through gene splicing—the merging of DNA from different species to make a new one. Many strains of alfalfa, canola, papaya, zucchini, soy, sugar beets (a main source of white sugar), and corn (which is pretty much in everything) are genetically modified, according to the Non-GMO Project. And while we're really just starting to talk about GMOs, we've actually been eating them for more than two decades.

When food scientists first developed GMOs, they believed the technology would boost crop yields and profits, says dietician Jaime Mass, RDN, LDN. "Most GMO crops were created to be pest-resistant, or to survive herbicide use. If crops aren't killed by pesticides or little critters then we will grow more of that crop, make a lot more money, and potentially feed more people." However, recent findings published in the International Journal of Agricultural Sustainability show that conventional methods of breeding corn and soy actually increase yields more than genetic modification processes do. Still, the big question is: Are they safe to eat?

The government hasn't ruled one way or another, and the Food and Drug Administration doesn't have the authority to require approval before GM foods hit supermarket shelves, meaning that untested—and potentially unsafe—GMOs are free to fill grocery carts and American stomachs alike.

"The science is starting to reveal some major concerns, and it could be just the beginning," Mass says. Preliminary research published in the International Journal of Biological Sciences suggests that consumption of GM corn may contribute to weight gain as well as liver and kidney problems.

Some experts equate GMOs to genetic roulette. Gene splicing creates new, artificial species that have not evolved over time like "real" foods have. "We're consuming foods that contain, in simple terms, unnatural DNA," Mass says.

What's more, recent research has linked GMOs with a massive increase in herbicide use—an additional 527 million pounds between 1996 and 2011. The result? One major herbicide called glyphosate has been detected in high concentrations in genetically modified foods. "There's reason to continue studying GMOs to fully understand the impact they may have on our health over the long term," Mass says. "Until scientists can come up with a clear and unbiased safety profile for humans, many believe it would be responsible to start educating the public and labeling foods."

To complicate matters, foods containing GMOs are not currently labeled as such. So if you want to cut out genetically modified foods altogether, eating organic is a good place to start. However, more non-organic food manufacturers are also pledging to rid their products (like Cheerios) of GMOs. Last year, the U.S. Department of Agriculture approved a voluntary "GMO-free" label from the Non-GMO Project. To see all of the foods currently bearing the badge, check out the Non-GMO Project's list of approved GMO-free foods.

Additional sources cited: Journal of Biomedicine and Biotechnology, [Environmental Sciences Europe](, [Food Chemistry](

10 Reasons to Avoid GMOs
1. GMOs are unhealthy.
The American Academy of Environmental Medicine (AAEM) urges doctors to prescribe non-GMO diets for all patients. They cite animal studies showing organ damage, gastrointestinal and immune system disorders, accelerated aging, and infertility. Human studies show how genetically modified (GM) food can leave material behind inside us, possibly causing long-term problems. Genes inserted into GM soy, for example, can transfer into the DNA of bacteria living inside us, and that the toxic insecticide produced by GM corn was found in the blood of pregnant women and their unborn fetuses.

Numerous health problems increased after GMOs were introduced in 1996. The percentage of Americans with three or more chronic illnesses jumped from 7% to 13% in just 9 years; food allergies skyrocketed, and disorders such as autism, reproductive disorders, digestive problems, and others are on the rise. Although there is not sufficient research to confirm that GMOs are a contributing factor, doctors groups such as the AAEM tell us not to wait before we start protecting ourselves, and especially our children who are most at risk.

The American Public Health Association and American Nurses Association are among many medical groups that condemn the use of GM bovine growth hormone, because the milk from treated cows has more of the hormone IGF-1 (insulin-like growth factor 1)―which is linked to cancer.

2. GMOs contaminate―forever.
GMOs cross pollinate and their seeds can travel. It is impossible to fully clean up our contaminated gene pool. Self-propagating GMO pollution will outlast the effects of global warming and nuclear waste. The potential impact is huge, threatening the health of future generations. GMO contamination has also caused economic losses for organic and non-GMO farmers who often struggle to keep their crops pure.

3. GMOs increase herbicide use.
Most GM crops are engineered to be “herbicide tolerant”―they deadly weed killer. Monsanto, for example, sells Roundup Ready crops, designed to survive applications of their Roundup herbicide.

Between 1996 and 2008, US farmers sprayed an extra 383 million pounds of herbicide on GMOs. Overuse of Roundup results in “superweeds,” resistant to the herbicide. This is causing farmers to use even more toxic herbicides every year. Not only does this create environmental harm, GM foods contain higher residues of toxic herbicides. Roundup, for example, is linked with sterility, hormone disruption, birth defects, and cancer.

4. Genetic engineering creates dangerous side effects.
By mixing genes from totally unrelated species, genetic engineering unleashes a host of unpredictable side effects. Moreover, irrespective of the type of genes that are inserted, the very process of creating a GM plant can result in massive collateral damage that produces new toxins, allergens, carcinogens, and nutritional deficiencies.

5. Government oversight is dangerously lax.
Most of the health and environmental risks of GMOs are ignored by governments’ superficial regulations and safety assessments. The reason for this tragedy is largely political. The US Food and Drug Administration (FDA), for example, doesn’t require a single safety study, does not mandate labeling of GMOs, and allows companies to put their GM foods onto the market without even notifying the agency. Their justification was the claim that they had no information showing that GM foods were substantially different. But this was a lie. Secret agency memos made public by a lawsuit show that the overwhelming consensus even among the FDA’s own scientists was that GMOs can create unpredictable, hard-to-detect side effects. They urged long-term safety studies. But the White House had instructed the FDA to promote biotechnology, and the agency official in charge of policy was Michael Taylor, Monsanto’s former attorney, later their vice president. He’s now the US Food Safety Czar.

6. The biotech industry uses “tobacco science” to claim product safety.
Biotech companies like Monsanto told us that Agent Orange, PCBs, and DDT were safe. They are now using the same type of superficial, rigged research to try and convince us that GMOs are safe. Independent scientists, however, have caught the spin-masters red-handed, demonstrating without doubt how industry-funded research is designed to avoid finding problems, and how adverse findings are distorted or denied.

7. Independent research and reporting is attacked and suppressed.
Scientists who discover problems with GMOs have been attacked, gagged, fired, threatened, and denied funding. The journal Nature acknowledged that a “large block of scientists . . . denigrate research by other legitimate scientists in a knee-jerk, partisan, emotional way that is not helpful in advancing knowledge.” Attempts by media to expose problems are also often censored.

8. GMOs harm the environment.
GM crops and their associated herbicides can harm birds, insects, amphibians, marine ecosystems, and soil organisms. They reduce bio-diversity, pollute water resources, and are unsustainable. For example, GM crops are eliminating habitat for monarch butterflies, whose populations are down 50% in the US. Roundup herbicide has been shown to cause birth defects in amphibians, embryonic deaths and endocrine disruptions, and organ damage in animals even at very low doses. GM canola has been found growing wild in North Dakota and California, threatening to pass on its herbicide tolerant genes on to weeds.

9. GMOs do not increase yields, and work against feeding a hungry world.
Whereas sustainable non-GMO agricultural methods used in developing countries have conclusively resulted in yield increases of 79% and higher, GMOs do not, on average, increase yields at all. This was evident in the Union of Concerned Scientists’ 2009 report Failure to Yield―the definitive study to date on GM crops and yield.

The International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD) report, authored by more than 400 scientists and backed by 58 governments, stated that GM crop yields were “highly variable” and in some cases, “yields declined.” The report noted, “Assessment of the technology lags behind its development, information is anecdotal and contradictory, and uncertainty about possible benefits and damage is unavoidable.” They determined that the current GMOs have nothing to offer the goals of reducing hunger and poverty, improving nutrition, health and rural livelihoods, and facilitating social and environmental sustainability.

On the contrary, GMOs divert money and resources that would otherwise be spent on more safe, reliable, and appropriate technologies.

10. By avoiding GMOs, you contribute to the coming tipping point of consumer rejection, forcing them out of our food supply.
Because GMOs give no consumer benefits, if even a small percentage of us start rejecting brands that contain them, GM ingredients will become a marketing liability. Food companies will kick them out. In Europe, for example, the tipping point was achieved in 1999, just after a high profile GMO safety scandal hit the papers and alerted citizens to the potential dangers. In the US, a consumer rebellion against GM bovine growth hormone has also reached a tipping point, kicked the cow drug out of dairy products by Wal-Mart, Starbucks, Dannon, Yoplait, and most of America’s dairies.

NOTE: As an additional motivation to avoid GMOs, you may wish to take a lesson from the animals. Eyewitness reports from around the world describe several situations where animals, when given a choice, avoid genetically modified food. These include cows, pigs, geese, elk, deer, raccoons, mice, rats, squirrels, chicken, and buffalo. We’re pretty sure the animals didn’t read the above 10 reasons.

The Campaign for Healthier Eating in America is designed to achieve a tipping point against GMOs in the US. The number of non-GMO shoppers needed is probably just 5% of the population. The key is to educate consumers about the documented health dangers and provide a Non-GMO Shopping Guide to make avoiding GMOs much easier.

Please choose healthier non-GMO brands, tell others about GMOs so they can do the same, and join the Non-GMO Tipping Point Network. Together we can quickly reclaim a non-GMO food supply.

The Truth About GMOs: The Good, The Bad, and The Really Ugly
Genetically modified Organisms (GMOs) have been a hot topic among industries leaders and especially consumers as their desire to eat healthier has grown in recent years.

“Most Americans are eating GMOs in every meal, but until recently most have been unaware of this fact,” says Non-GMO Project Executive Director Megan Westgate.

According to the Grocery Manufacturer Association, 75% of conventional processed foods contain GMOs.

Westgate says the biotechnology industry (the creators of GMOs) is to blame for hiding this information from the public in the past.

“It has really backfired. People are outraged when they find out they are eating experimental products without their consent,” she adds.

Kate Hall, Managing Director for the Council for Biotechnology Information, and GMO Answers spokesperson says they support the consumers’ right to know but  are concerned that mandatory labeling of GMOs would actually be viewed as a warning label by many consumers.

“It’s important to remember that genetic engineering, or making a GMO, is a process by which a plant is developed, not an ingredient itself,” she said.

Monsanto (MON), one the largest pharmaceutical and agricultural companies that produce GMOs, say GMOs are identical to their Non-GMO counterparts in terms of nutrition, taste, and flavor.

“In thousands of independent studies since the 1980’s, not one health issue has ever been identified,” says Christi Dixon, Monsanto’s spokesperson.

“Many of us here at Monsanto are parents—we’ve spent a lot of time thinking about and studying GMOs, and we feel confident feeding them to our kids,” she adds.

Today, the majority of GMO crops are corn (88% of the U.S. crop), soy (94%), canola (90%), cottonseed (90%), and sugar beets (95%) according to the Non-GMO Project.

“We have not fed a group of humans GMO foods for their whole lives, and another group non-GMO foods for their whole lives, with sufficient numbers to determine statistically whether the two groups are different in their health status or development of illness,” says Martha Grout, M.D., President-Elect of the American Academy of Environmental Medicine.

“Nevertheless, I would urge caution, since we already appear to have initiated the biggest unfunded human experiment in history – The title of this experiment is: “What happens to animals and human beings when they eat crops genetically modified to contain herbicides/insecticides or to be resistant to herbicides/insecticides?” And the answer is very much unknown,” she adds.

Grout, who is also the Medical Director at Arizona Center for Advanced Medicine says it’s important that we educate people on what they are, and how they are produced.

“Let the people make their own decisions. The tricky part comes in whom we educate, who does the education, and how the information is slanted or spun,” she says.

The website “GMO Answers” is funded by the members of The Council for Biotechnology Information, which includes BASF, Bayer CropScience, Dow Chemical’s  (DOW) Dow AgroSciences, DuPont (DD), Monsanto and Syngenta (SYT).

“These are organizations that would appear to have stake in promoting the use of GMO crops,” says Grout. says scientific authorities from around the world, such as the U.S. National Academy of Sciences, United Nations Food and Agriculture Organization, World Health Organization, American Medical Association and the American Association for the Advancement of Science have analyzed thousands of scientific studies on GMOS.

“They concluded that GM (genetically modified) food crops do not pose any more risks to people, animals or the environment than any other foods, “ says Hall.

Genetic engineering allows plant breeders to take a desired trait, like resistance to a particular plant disease, from one plant or organism and transfer that trait to the plant they want to improve.

“We take our cues from farmers, who are incredible at what they do. They are faced with significant challenges such as unpredictable weather, soil erosion, pest, and plant disease,” says Dixon.

In 1960, each American farmer fed about 25 people. Today, the number is closer to 155. “We need to do more with the land we have available for farming, and in a sustainable way,” she adds.

Meanwhile, the global population is expected to increase by 38%, from 6.9 billion in 2010 to 9.6 billion in 2050. Biotechnology companies say GMO technology can help produce enough food safely and sustainably while preserving our natural resources.

Interestingly, Westgate says the U.S. the government has approved GMOs based on studies conducted by the same corporations that created them and profit from their sale.

“There is a well-documented revolving door between the biotechnology industry and government agencies. In the absence of mandatory labeling, the Non-GMO Project was created to give consumers the informed choice they deserve,” she says.

Westgate says their “Butterfly label” was created to give Americans a way to opt out of the GMO experiment if they choose.

In the end, both sides do agree that consumers need to do their research when it comes to GMOs and make their own decisions.

Genetically modified foods (GMOs) are highly controversial.

Yet, despite the debate, GMOs are found in all sorts of food products – often without labels.

Therefore, it’s important to understand the science behind these foods.

This article explains what genetically modified foods are, and how they can affect your health.

What is Genetically Modified (GMO) Food?
GMO stands for “genetically modified organism.”

The term is generally used for food that has had its genes changed using biotechnology.

Using genetic modification, scientists are able to produce new varieties of plants with certain qualities, such as being more resistant to viruses or pesticides.

To understand how this works, knowing some basic principles of genetics is required.

Basics of Genetics
Genetics is a scientific field that studies genes and heredity.

Genes contain instructions about how to make living organisms. These instructions are basically codes consisting of DNA, which is found inside cells.

Genes tell cells what to do, ultimately determining how organisms look and function. All living things inherit genes from their ancestors, which is why we look similar to our parents.

However, genes are not entirely stable. They are prone to changes called mutations.

This is part of the reason why each individual has unique physical features. The genes are slightly different between individuals of the same species.

Bottom Line: Genes contain information on how living organisms should look and function. Genes vary slightly among individuals of the same species.

Blue and Red DNA Helix
Evolution is a term that describes changes in organisms over many generations.

These changes happen because genetic makeup varies between individuals, even for organisms within the same species.

Evolution is usually a very slow process, and is determined by adaptations to specific environmental conditions.

Here is a simple example:
  • A species of plants is found on an island. The island has a wet climate and these plants have adapted to growing in wet conditions.
  • Gradually, over thousands of years, the climate changes from wet to dry.
  • Because of individual variability, some of the plants are, by chance, more tolerant to dry conditions than the others.
  • These plants survive, whereas the less drought-tolerant plants are more likely to die before they can produce seeds.
  • The end result is a plant population that has adapted to living in dry conditions.
  • This is called natural selection, and is where the phrase “survival of the fittest” comes from. The genes that are best suited for survival in the environment get passed on to future generations.

Bottom Line: Genetic variability drives natural selection. Some individuals are more likely to survive and reproduce, which over time may change the species.

Selective Breeding
Humans have used these natural principles to create various breeds of domesticated plants and animals. This is known as selective breeding.

Selective breeding is a faster process than evolution. It is based on choosing individuals that have desirable features and breeding them together.

For example, cows have been selectively bred to produce more milk, and apple trees have been selected to produce bigger fruit.

With genetic modification, this process has been made faster and more precise.

Bottom Line: Selective breeding involves choosing individuals with desirable features and breeding them together.

Genetic Modification
Fresh Soybeans
Genetic modification is a technique that allows scientists to alter the genetic material of an organism.

This is usually done by transferring a gene from one organism to another, giving it new traits.

For example, genetic modification can be used to make plants more resistant to diseases or pesticides.

It can also be used to increase a plant’s nutritional value, allow it to grow faster or make it taste better. The possibilities are endless.

Here are some examples of genetically modified (GMO) foods:
  • Herbicide-resistant corn and soybeans: Corn and soybeans were modified to tolerate the herbicide glyphosate, found in Roundup. This allows farmers to spray their fields with powerful herbicides to kill off weeds.
  • Virus-resistant papaya: In Hawaii, papaya was genetically modified to be able to withstand the ringspot virus.
  • Golden rice: Swiss scientists developed golden rice, a type of yellow rice that produces beta-carotene, an antioxidant that the body can turn into vitamin A (1).

Other crops that are often genetically modified include rapeseeds (used to make canola oil) and cottonseeds.

Bottom Line: Genetic modification allows scientists to transfer genes between organisms. This technique is more precise than selective breeding, and offers endless possibilities.

GMO Food is Very Common These Days
The amount of GMO food on the market is increasing worldwide.
Male Scientist Looking at Genetically Modified Tomato
However, the exact amount of GMOs you may be eating is difficult to estimate. This is because these foods are not always labeled as such.

In the US, GMO foods do not need to be labeled. Conversely, the European Union requires all GMOs to be labeled.

There are actually far fewer GMO foods available in Europe. These foods are much more readily available in US markets.

About 70–90% of GMO crops are used to feed livestock, and more than 95% of all food-producing animals in the US consume GMO feed.

If you eat soybeans, especially processed soy products, it is likely that they come from a GMO crop. More than 90% of all soybeans are genetically modified (2).

Keep in mind that soy, corn and canola are incredibly common in processed foods in the US. If you eat processed food, then you are almost definitely eating some genetically modified ingredients.

Bottom Line: GMO foods are generally not labeled in the US. Most processed foods in the US contain soy, corn or canola, so if you are eating processed foods then you are probably eating some amount of GMOs.

The GMO Controversy
GMO food is highly controversial.

People’s opinions of GMO foods are often based on ethical, philosophical or religious views.

Scientific misconceptions also frequently affect people’s beliefs (3).

However, there are plenty of unanswered questions regarding large-scale genetic modification and GMO agriculture.

Some scientists are concerned about the potential environmental impact and sustainability. Meanwhile, others believe that genetic modification may have beneficial environmental effects in the larger scheme of things.

Supporters of GMO foods also argue that genetic modification may be necessary to prevent food shortages as the world’s population continues to grow.

However, most people who avoid GMOs are doing so because they believe these foods to be unhealthy.

Bottom Line: Genetic modification is a very controversial subject and there are many unanswered questions.

Are GMO Foods Bad For Your Health?
GMO foods cannot be generalized as either healthy or unhealthy.
Woman Questioning Two Apples
It depends entirely on individual genetically modified crops, which should be assessed on a case-by-case basis (4).

Some people have pointed out that transferring a gene from an allergenic food crop, such as peanuts, could make the GMO food allergenic as well. While this is a possibility, safety testing should prevent such products from going on the market (5).

That being said, the risks associated with GMO foods are considered to be very low. They are no greater than those arising from traditional genetic manipulation through selective breeding (6).

To date, there is no evidence suggesting that GMOs cause harm in humans (7).

Likewise, most animal studies suggest that GMOs are safe (2, 8, 9).

Yet, despite the general lack of evidence against GMO foods, there is considerable public opposition to them and the debate continues.

This may be partly due to general distrust of biotech companies. There is also a potential conflict of interest in many scientific studies (10, 11).

Bottom Line: GMO food itself cannot be generalized as unhealthy or toxic. There is no good evidence saying these foods negatively impact human health.

The Herbicide Glyphosate (Roundup) May Cause Harm
Even though there is no good evidence showing that GMO foods themselves are unsafe, there are some other factors to consider.

A few animal studies suggest that herbicide-resistant crops sprayed with glyphosate(Monsanto’s Roundup herbicide) may cause adverse effects (12)

A notable study from 2012 showed that GMO corn that had been sprayed with glyphosate promoted the formation of cancerous tumors in rats.

The authors suggested that the tumors were a result of the toxic effects of glyphosate and/or the genetic modification itself (13).

The results of the study were controversial and heavily debated. In fact, the original paper was retracted, but published in a different journal later the same year (14, 15,16).

A few other animal studies and test-tube experiments have found signs of adverse effects when testing GMO corn and soybeans sprayed with glyphosate.

These studies suggest that trace amounts of the herbicide may be causing harm, rather than the genetic modification itself (17, 18).

Bottom Line: While GMO foods themselves cannot be classified as unhealthy, other related factors may cause adverse effects. The herbicide glyphosate (Roundup), which is sprayed on some GMO crops, may be harmful to health.

Take Home Message
The available evidence indicates that GMO food is not harmful to human health.

However, the health effects of spraying GMO crops with the herbicide glyphosate is still a matter of debate.

Nonetheless, there is no good evidence that genetic modification itself causes foods to become unhealthy or toxic.

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