Showing posts with label anti-GMO. Show all posts
Showing posts with label anti-GMO. Show all posts

Surprise! Many organic foods are GMOs, and they are transgenic

A new study finds that many common foods, including beer and tea, turn out to be "natural" GMOs. What's a health-food purist to do?

Even though no one has found any evidence that genetically modified organisms (GMOs) are harmful, anti-GMO activists have campaigned against them for years, with considerable success. As of this writing, 19 out of 28 countries in the European Union have voted to ban or severely restrict genetically modified plants, and many other countries impose similar bans.

But all of these restrictions may be in vain, because nature got there first. It turns out that many common foods have already been genetically modified, by a bacterium called Agrobacterium. (Read on to see the list.) And, in news that should be even more frightening to the anti-GMO crowd, these foods are transgenic: they contain genetic material from completely different species. Frankenfoods!

First, as I've argued before, genetic modification technology is just a tool, and a very precise one at that. Scientifically, claiming that GMOs are bad for you is nonsensical–it depends entirely on what the genetic modification is. Whether a food scientist modifies a tomato to taste better by traditional breeding or by using GM technology, you still end up with a tomato that has different genetic content. The only difference is that with traditional breeding, you have no idea what exactly you changed in the plant's DNA. And humans have already consumed billions of servings of GM foods with no ill effects. The GM foods we eat today are perfectly safe.

So back to my first point. What are all these natural Frankenfoods, and how did they get that way?

I'll start with the common sweet potato, or yam. Humans eat hundreds of varieties of sweet potatoes, and you can buy them in markets on every continent. Back in 2015, a group of scientists from Belgium, Peru, China, and the US (Tina Kyndt and colleagues) discovered that every cultivated variety of sweet potato has "foreign" DNA integrated into its genome, from a bacterium called (appropriately) Agrobacterium. They tested 291 different varieties, and found the bacterium 100% of the time. They also tested wild relatives of sweet potato, and found that the wild varieties (which humans don't eat) are missing the bacterial DNA.

Agrobacterium is a bacterium with special properties: it has evolved to be able to insert its DNA directly into the genomes of a wide variety of plants. (Don't worry, it doesn't infect humans.) In sweet potatoes, this happened naturally, centuries or millenia ago, long before humans were cultivating it. But then we came along, and (apparently) we liked the taste of these naturally transgenic sweet potatoes, so those are the ones that we chose to cultivate. As a result, all the sweet potatoes we eat are GMOs, although it happened naturally.

That was five years ago. But in a newly published study, scientists Tatiana Matveeva from Russia and Léon Otten from France discovered that Agrobacterium has made its way into dozens of other plants, including some of our favorite foods and drinks. Matveeva and Otten searched through the genomes (the DNA) of hundreds of plants, and found 39 natural GMOs, as they called them.

So without further ado, here are the natural GMO foods, all of them transgenic, with the common name followed by the formal species name in italics:

  • bananas (Musa acuminata)
  • beer (hops) (Humulus lupulus)
  • cranberries (Vaccinium macrocarpon)
  • date-plum (Diospyros lotus)
  • guava (Psidium guajava)
  • peanuts (Arachis hypogaea)
  • pomelo fruit (Citrus maxima)
  • Suriname cherry (Eugenia uniflora)
  • sweet potatoes (Ipomoea species)
  • tea (Camellia sinensis, which is used for most teas)
  • walnuts (Juglans species)
  • yams (Dioscorea alata)


That's right, beer and tea are GMOs–even if they are labelled as "organic." Keep in mind that this list is undoubtedly incomplete: the new study relied on current genome databases, which are still missing many common foods. 

If you're reading this, you've probably already consumed countless servings of transgenic, GMO foods. As I wrote above, there's no reason to believe that GMO foods are harmful in any way. Plenty of plants are naturally poisonous, of course (think hemlock), but widely-consumed foods got that way for a reason: people like to eat them, and they help sustain us.

If you believe the alarmist claims of the anti-GMO movement, then you're going to have to start avoiding many more foods, including everything on the list above. And yes, that includes beer. 

Does RoundUp cause cancer?

(Quick answer: probably not. See my update at the bottom of this post.)

For many years, environmental activists have been concerned about the herbicide glyphosate, which is the main ingredient in RoundUp®, the world's most widely-used weed killer. Since 1996, global usage of glyphosate has increased 15-fold, in part due to the widespread cultivation of "RoundUp Ready" crops, which are genetically modified to be resistant to RoundUp®. This allows farmers to use the herbicide freely, killing undesirable weeds without harming their crops.

RoundUp®'s manufacturer, Monsanto, has long claimed that glyphosate is safe, and they point to hundreds of studies that support their argument.

Nonetheless, a new study raises the question again.

First let's look briefly at another recent study. A bit more than a year ago, in November 2017, a large study in the Journal of the National Cancer Institute looked at nearly 45,000 glyphosate users (farmers and other agricultural workers who apply glyphosate to crops). These "users" have a much higher exposure to RoundUp® than ordinary people. That study concluded:
"no association was apparent between glyphosate and any solid tumors or lymphoid malignancies overall, including NHL [non-Hodgkin lymphoma]."
They did find, though, that there was a trend–not quite significant–towards an increased risk for one type of leukemia, AML. This trend appeared in users who had the highest exposure to RoundUp®.

In the new study, by a group of scientists from UC Berkeley, Mount Sinai School of Medicine, and the University of Washington, the authors (L. Zhang et al.) decided to focus exclusively on people with the highest exposures to glyphosate. They point out that including people with low exposure, who might have no increased risk of cancer, tends to dilute risk estimates. Statistically speaking, this is undeniably correct, but it also means that their results may only apply to people with high exposures, and not to ordinary consumers.

The punchline from the new study: people with the highest exposure to glyphosate had a 41% higher risk of non-Hodgkin lymphoma.

One caveat to this finding is that it's a meta-analysis, meaning the authors did not collect any new data. Instead, they merged the results from six earlier studies including over 65,000 people, and they focused on those with the highest exposure levels.

Meta-analyses can be prone to cherry-picking; that is, picking the studies that tend to support your hypothesis. However, I couldn't find any sign of that here. The authors include a frank assessment of all the limitations of their study, and they also point out that multiple previous studies had similar findings, although most found smaller increases in relative risk. In the end, they conclude:
"The overall evidence from human, animal, and mechanistic studies presented here supports a compelling link between exposures to GBHs [glyphosate-based herbicides] and increased risk for NHL."
A couple more caveats are important. First, this finding is all about relative risk. Non-Hodgkin lymphoma is one of the most common cancers in the U.S. and Europe, but the lifetime risk for most people, according to the American Cancer Society, is just 1 in 42 (2.4%) for men and 1 in 54 (1.9%) for women. A 41% increase in relative risk increases those numbers to 3.4% (men) and 2.6% (women).

Second, this higher risk only applies to people with very high exposure to glyphosate: primarily people who work in agriculture and apply RoundUp® to crops. Ordinary consumers (including people who eat "Roundup Ready" crops) have a far, far lower exposure, and dozens of studies have failed to show any increased risk of cancer for consumers. For most of us, then, this new study should not cause much concern, but for agricultural workers, it does raise a warning flag.

[Update 18 Feb 7:45pm] After I posted this article, the scientists at the Genetic Literacy Project pointed me to Geoffrey Kabat's piece about the Zhang et al. study. Kabat did a deep dive into the studies that Zhang et al.'s work is based on and uncovered a critical flaw in the study, one that I hadn't found. More than half of the "weight" of the meta-analysis by Zhang, and by far the largest number of cancer cases, come from a single study by Andreotti et al. published in 2018. That study reported risks for 4 different time points: 5, 10, 15, and 20 years. It turns out, as Kabat reports, that only the 20-year period showed any increase in risk of cancer. The relative risks of cancer at 5, 10, and 15 years were actually lower in the group exposed to glyphosate, and yet Zhang et al. didn't mention this fact.


Now, no one thinks that glyphosate lowers the risk of cancer, but Zhang et al. did not report that they had cherry-picked in this way. At a minimum, they should have reported what their findings would be if they used the other time periods. I suspect that they'd have found no increased risk of cancer–but this wouldn't make for such a catchy headline. This omission on their part is a serious flaw, indicating that they (and their results) might have been unscientifically biased.

The bottom line: even in those with very high exposures to glyphosate, the evidence that it causes any type of cancer is very weak. And for ordinary consumers, there's nothing to worry about.

Nobelists call for Greenpeace to drop its anti-science, anti-GMO activism

Golden rice is fortified with vitamin A to prevent blindness.
Has Greenpeace lost its way? I still remember my excitement about the Save the Whales campaign when I was in college, one of the first and most visible of Greenpeace's campaigns. These were the good guys.

In recent years, though, they have adopted as one of their causes a rigidly inflexible opposition to all genetically modified foods, a stance that has no basis in science and that threatens to block technology that has great potential for good.

This past Thursday, a group of 110 Nobel Laureates released a letter excoriating Greenpeace for its long-term campaign against genetically modified organisms (GMOs) and especially against “golden rice.” The Nobelists' letter points out that science has shown that GM foods are just as safe and healthy as any other foods, and that Golden Rice has the potential to relieve a great deal of human suffering.

Unfortunately, anti-GMO activists at Greenpeace and elsewhere are ignoring the science. Their opposition seems to rely on two arguments, both of them superficially appealing, but both wrong.

First, there's the argument that "natural" is always better, whether it be applied to your food or to other aspects of life. Many people find this idea very compelling; after all, we humans are part of nature, so why not consume foods in their natural state? This argument is wrong for many, many reasons, far too many to list here, but I'll just mention a couple. We can start with cooking: it sure isn't natural, but cooking allows us to extract far more nutrients from our food, and is one of humankind's greatest inventions. Or consider pasteurization, an unnatural process that has saved countless millions of people from death by killing the bacteria that are present in purely "natural" milk and other products.

Suffice it to say that there's nothing wrong with modifying our food to make it easier to digest, healthier (as with Golden Rice), or just tastier. The fact that some genetic modifications fail to do any of these things doesn't make GMOs bad, it just means that GM technology can be applied in other ways.

The other argument against GMOs, perhaps the more emotional one, is that they're just a stealth method to allow big agricultural corporations to sell more herbicides and pesticides. This isn't exactly wrong: Monsanto's RoundUp Ready® crops are engineered to allow farmers to use more of the herbicide glyphosphate. Regardless of the arguments about herbicides, the fundamental problem with this argument is that it's a gross over-generalization: just because you don't like RoundUp Ready® soybeans doesn't mean that all GMOs should be banned. As the National Academy of Sciences concluded in a report published earlier this year,
"it is the product, not the process, that should be regulated."
Greenpeace, pay attention. That same NAS report also concluded that GM foods are generally safe and just as healthy as non-GM foods.

Now consider Golden Rice, a variety of rice that has been genetically modified so that it naturally produces beta carotene, which humans metabolize to produce vitamin A. Golden Rice has the potential to reduce vitamin A deficiency, which has devastating effects in parts of the world where children struggle to get enough nutrition. As the Nobel Laureates' letter points out, vitamin A deficiency affects 250 million people worldwide, and
"Vitamin A deficiency is the leading cause of childhood blindness globally affecting 250,000 - 500,000 children each year. Half die within 12 months of losing their eyesight."
How could Greenpeace oppose something that could eliminate so much suffering? I can only conclude that the anti-GMO forces within Greenpeace are so consumed by their rigid opposition that they simply cannot see that GMO technology has the potential for great benefits.

GMWatch, an anti-GMO organization, published a lengthy response to the Nobelists' letter the day after the letter appeared. Their rebuttal contains two arguments: first, that Golden Rice isn't yet ready for widespread distribution (Greenpeace's response, printed in The Washington Post, made the same argument, saying "we are talking about something that doesn’t even exist"); and second, that the Nobel Laureates don't have the "relevant expertise."

Hmm. Neither of these arguments stands up to even a tiny bit of scrutiny. First, even if Golden Rice isn't ready for prime time, it's still a great idea. Would Greenpeace support Golden Rice if it were ready to be shipped to hungry children today? They don't say. And both GMWatch and Greenpeace fail to mention (or deny) the fact that one of the major reasons that Golden Rice isn't yet on the market is that anti-GMO groups have worked very hard to block it, lobbying hard for regulatory barriers and even ripping up a test field.

Second, the argument about relevant expertise is ridiculous. Sir Richard Roberts and Dr. Phillip Sharp, two of the Nobel Laureates who spearheaded the effort to write the letter, are among the world's leading geneticists and molecular biologists, as are many of the other Nobelists who signed the letter. I also have to point out that this is a classic ad hominem attack: rather than address the actual topic, GMWatch are attacking the messengers. (Also, somewhat bizarrely, GMWatch contradicts its own argument in an update they posted to their own article. In the update, they write that "[Dr. Phillip] Sharp is a biotech entrepreneur with interests in GMO research," essentially acknowledging that he is an expert in GMO technology.)

Ad hominem attacks may be entertaining, but they fail to support the Greenpeace argument that GMOs should be banned. Nowhere in GMWatch's article, or in Greenpeace's anti-GMO policy, is there any comment about the extensive scientific evidence that shows that GM foods are safe. As I've written before, you're far more likely to be harmed by being hit on the head by a corn cob than by some kind of deviant GMO corn gene.

I asked Sir Richard Roberts if he had any response to the arguments from Greenpeace, and he replied that:
“Greenpeace just reiterate the old arguments that are adequately debunked elsewhere. Why won't they just admit they got this issue wrong? Is it because they have consistently introduced roadblocks and then wonder why it is taking so long to introduce Golden Rice to the market? Are they serious?”
Greenpeace would do well to reconsider their position, as Dr. Roberts and his colleagues argue. They are flat wrong on the science of GMOs, and their dogmaticism is losing them the support of many scientists (and others) who are strong backers of Greenpeace's other causes. For example, Greenpeace's website features their "Save the heart of the Amazon" campaign, an admirable effort to protect a large swath of the Brazilian rainforest. They also have a major campaign to save the Arctic, a cause I support even more enthusiastically.

One last note: organic food stores, led (in the U.S.) by Whole Foods, have been eagerly promoting the "non-genetically modified" nature of their foods, and pushing for laws to require that all GM foods be labelled. First, I have to point out that this is nonsense. Virtually everything you eat has had its genes modified from their natural state, through centuries of breeding by farmers. The only difference with modern GM food is that we can precisely select the genetic changes we want, unlike the slow, incredibly inefficient methods of traditional agriculture.

Ironically (and this is delicious in more ways than one), Whole Foods does sell massive quantities of one GMO: sweet potatoes. It turns out that all sweet potatoes contain bacterial genes! As Tina Kyndt, Dora Quispe and colleagues reported last year, 291 different varieties of sweet potato all contain genes from a bacterium called Agrobacterium tumefaciens. This bacterium has the ability to insert bits of its own genome into its host, and it did exactly that to sweet potatoes sometime in the recent past, after humans started cultivating sweet potatoes (wild relatives don't have the foreign genes). Apparently, ancient human farmers preferred the sweet potatoes with the bacterial genes, and these were passed on to all modern varieties. So sweet potatoes are not only genetically modified, but they are transgenic: they contains genes from a completely different species.

I was at Whole Foods today, and I failed to notice any labels revealing that their sweet potatoes are transgenic. I'll keep checking.

[Full disclosure: I have been privileged to have collaborated scientifically with Sir Richard Roberts, one of the leaders of the group of Nobel Laureates who authored the letter on GMOs. I was not involved in the writing of that letter and I was unaware of it until it was published.]