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More on GMOs

I know some of you are already growing tired of my preoccupation with genetic engineering, a subject that until recently I knew very little about. There is still much I don't know, but I consider it an important topic, and will continue to educate myself. I'll probably be posting less about it in the future but for now I still have a few things to say.

Red, in the comments to a previous post raised some good questions about GM crops, concerns he has, dangers he feels need addressing. . I'm certainly no expert, but I've never let that stop me before so I'm going to try and address some of his concerns. He doesn't say whether he thinks existing GM crops need to be withdrawn, nor does he weigh in on specific GM crops that are under development like Golden Rice, he says he's basically in favor of biotech but still has concerns.

1. It's effect on biodiversity and its vulnerability to to potenital crushing effects on our food supply if disease strikes homogeneous plant or animal populations.

It seems to me that this isn't just a problem of GM crops, but is something that has been happening for a long time. Long before there were any GM crops the varieties of crops like apple, corn, etc were decreasing. When a farmer finds something that works well they tend to stick with it whether it's a GM crop or not. Biodiversity is important and I think that GM can play a positive role in increasing diversity in crops in significant ways, not just variety for varieties sake but for variety that meets the specific needs of farmers. I recently read a post at Biofortified that addresses this very issue.

2. Its economic effects. I think you like this technology because of its potential to feed more people. But the last 20 years have seen a giant spread of industrial food production and increased hunger. Economics are more complicated than cheaper food = more people eating. Many poor people have both their primary income and primary expense in the realm of food production. Nevada republicans think that you can still trade a chicken for medical service. What is a chicken worth in a market flooded with corn fed factory birds? $8? Not exactly going to cover a deductible. Corporate mass production has devalued one of the primary small business opportunities for the poor. Not to mention the small business around seed and family farms. You end up with the same argument that Wal-Mart uses to say that they are good for the economy.

As Red points out this problem not unique to GMO it is a problem that is inherent in our system. The solution is not to clamp down on GMO, but to support laws that regulate corporations in general.

3.Nutrition has been hurt by the cheapness of mass produced corn that is stuck into everything we eat. when they get done designing super corn, will I be able to get brown rice for an affordable price? We are plowing under fields of more nutritious foods to produce the highest profit product.

Once again this is not a problem unique to GM crops, but a problem with a system that promotes big. It is a problem of education, if consumers aren't educated then they will demand the products the big corporations. I recently watched the program Food Inc. One of the points it made was that even big corporations respond to consumer pressure. In the program they pointed out how Wal-Mart was now buying large quantities of organic foods. So again to blame GM crops is missing the point.

4. The need to protect the vulnerabilities in my number 1 (biodiversity) with chemicals on plants and drugs in animals. The first does us some potential minor harm and the second has the potential to create super bugs and kill lots of people. Not to mention that any farmer can tell you that corn is one of the most destructive crops when it comes to soil and requires much more fertilizers. also pretty bad for the environment.

Planting the same crop year after year is not good farming practice, but that really doesn't have anything to do with GM crops per se. I don't know what superbugs Red's referring too perhaps he could clarify in the comments.

5.The unintentional potential consequences of GM foods. There a number of foods that we eat, like peanuts that have trace amounts of known carcinogens and we don't really know how many proteins we are changing when we alter genetics. We could be increasing plants content of things that could have long term health effects. How do round-up ready crops resist the poison?

For the most part the unintentional potential consequences of GM foods are not greater than foods that grown from seeds subject to mutagenesis both chemical and radioactive. Even other so called standard plant breeding techniques have their risks. What they don't have is the same level of scrutiny that GM crops have. Actually modern genetic engineering of plants has a better idea of what the changes will do than other methods.

So there you go, I think there is way too much knee-jerk criticism of GM crops. It reminds me of the kind of arguments you hear from some of those that criticize big pharma and promote the so-called alternative medicines. GM crops have great potential, we should be cautious but not paranoid. We should be thoughtful and look at the evidence not the name-calling, the guilt by association. We should carefully look at the evidence and follow it where it leads. We need to be careful that we're not just confirming our biases and are evaluating the evidence fairly.

Your comments are an important part of the discussion so don't be shy, speak your mind.

Here are a couple of books I've found helpful in understanding the issues underlying GMOs


 

Comments

as a scientist whose training is specifically in the utility of GMOs I appreciate your rational rebuttals of the concerns about GM crops that stem from misunderstandings of very basic biological principles.

Thanks, Norm.

No thank you Todd, as you've noticed a view that see's anything good about GMOs is quite unpopular on a liberal blog like this one. I haven't felt quite this besieged since I supported Jon Edwards and then Hilary Clinton instead of the left-wing darling Barack Obama in the last election.

Well, imagine if Edwards had won and the pregnancy of his mistress had come to light while he was president. Now imagine if you're as wrong about GMOs as you were about Edwards.

I've noticed you have a tendency to get defensive when people disagree with you. I'm not knocking you; it happens to me too. But you're going to encounter disagreement from time to time. Edwards and Clinton have many admirable qualities, but they also have their weak points. The same can be said for GMOs. The moment I hear Tribe, Specter, Chassy, Scienceblogs, etc. admit they can understand some of the objections, rather than tarring everyone with the anti-science brush, is the moment we'll be on our way towards a rational consensus. I mean, is the Union of Concerned Scientists anti-science? What about Dr. Iganacio Chapela? Don't you think it would be more rational for Tribe et al. to say, "Hmmm. Roundup Ready weeds DO seem to be a problem. Good point," rather than, "You're anti-science! You're anti-science!"?

not all GMOs are created equal. GMOs that use use genes to boost endogenous (in other words, "native") processes of the plant (i.e. a supercharged orange that has twice the amount of vitamin C in it) has very little concern ecologically while engineering a plant to be resistant to a herbicide that it normally isn't resistant to requires us to have an understanding of the ecology of gene transfers in the wild (in other words, how common is it for a gene from a plant jump into a bacteria or insect...the answer is substantially less frequently than GMO fearmongers suggest).

You can "understand objections" while understanding that most people object because of misinformation, miseducation, and fear instead of because of the result of rational statistical inquiry and experimental support.

That isn't quite fair.

I am sure Daniel is preparing to eat his hat right about now. Thanks for the pointed response.

Again, I would say that I think genetic modification will produce us a large number of great foods that will be as common as the banana, as nutritious and tasty.

But I have concerned about what is being developed and how those products are currently being distributed, patented, and the business practices of those selling them. I would also agree that some certainly think baseless things about organics. I also think that the former use the latter to dismiss criticisms.

I hear little news of the future of the genetically modified leak, or the superbellpepper. Most of this research is used to mass produce the two least nutricious things in our diets sugar and starch. and then suddenly you need to pay 300% more to get salad dressing that doesn't contain more calories than a whopper jr.

Allow me to clarify the points I raised earlier and respond where appropriate.

  1. Your link is good and admittedly, GMO's can be diverse. I just don't think that is the way they are being developed, and since some don't reproduce and interbreed they aren't going to have as much diversity as any selectively bred crops. Managing this process and regulation can eliminate this issue.

  2. No, its not unique to GMO's. But it is significantly worse in a world where companies can patent a plant and prevent farmers from using their own seeds. I would also continue the Wallmart point. Cheaper products don't mean poor people are better off if the same economics reduce quality jobs. It's the net result that matters. Sure small farmers may get higher yields, but are their products getting lower prices? and are the corporations selling the seed also buying the corn or whatever, in order to say feed cattle for export rather than putting them on the local market where they can help local hunger issues. We have the right to regulate our food and should do so to the potential benefit of all.

  3. Agreed. I would just add that I hate the supposed "science" points on the matter of nutrition. They compare an organic steak to a conventional steak. Well no duh, but take say, organic ketchup made from tomatoes and heinz tomato ketchup made from corn syrup salt and red dye. I bet the results would be pretty striking. So when people say they are "eating Organic" they mean more that simply buying organic raw materials. Sometimes the best science in the world can mean nothing because you got the question wrong.

  4. From the Blog of David Tribe

Evidence from human studies suggests that children who consume organic fruits and vegetables and adults who consume organic cereal may significantly reduce their pesticide exposure compared with groups consuming conventional diets, although the levels of pesticide exposures in both groups is within accepted safety standards. There is no evidence of any other benefits of consuming organic food based on human dietary studies. Finally, although rates of bacterial contamination did not differ significantly between organic and conventionally grown meats, eggs, and milk, the antibiotic resistance of bacteria cultured from conventional meats, eggs, and milk was significantly greater than for organic products.

To pesticides, I would argue that within safety standards it does make sense to assume less is healthier than more.

And my point on "superbugs" was about antibiotic resistant bacteria, which is a growing threat as animals are kept in unsanitary conditions where they are fed large amounts of corn, the main focus of so much genetic development.

5.I don't think that similar amounts of genetic change are always equivalent. Plants have been shaped by evolution of millions of years not to poison their animal support, It would take a lot of selective breeding to make them harmful. On the other hand, bacteria don't necessarily have any problem killing folks. So inserting bacteria genetics into a plant certainly has more risks. I assume they can test to prevent us all from dying face first in our corn flakes, but companies should also be required to track the effects across decades to ensure they aren't doing more subtle damage.

And coming back to number 2, if these companies aren't producing food in a way that reduces hunger in a real way, than why should we let them patent plants and use a new technology to make a profit? even if the risks in all my other points are very minor risks or easily eliminated, or not really risks at all, I have no stake in their success.

I mean if car companies wanted to alter all our cars to run on another fuel that was just as bad for global warming but was maybe a little cheaper, I think I would oppose that change. It's a waste of our time, there is some small chance it will backfire in some way. and there are costs involved in research and production that will be passed onto consumers and governments and universities and the savings will largely be eaten up by profit.

Who gives a crap about the GM food issue? We have had the capacity to feed most of the world's hungry for the better part of a century, but 25,000 people (a majority of them children) die because of starvation every day.

I don't have an interest in the GM issue because GM foods only stand to benefit the rich corporations.

I haven't read most of the long threads on this topic here, but I agree with Norm. Not particularly based on any extensive knowledge I have on the issue, but of the types of arguments being made. Since I haven't read many of the comments on this blog, I'll just speak in general, but most of the arguments from the anti-GM crowd seem to overgeneralize, and misinterpret the science with catchy words like "poison" and "chemicals". And the "corporation making money = bad" angle also raises suspicion.

It was not long ago that people scandalized by GM propositions were pondering that a tomato with a certain fish gene inserted for resilience would make it taste like fish. I think we've moved past that, but I still feel that most people are motivated from unwarranted fear of the unknown.

Of course there are individual examples of GMO turning out to be detrimental in some way, but that's why the science needs to be rigorous. Instead of advocating against GMO as a whole, why not advocate for better regulation (if the current standards don't suffice)?

Well that was a response to the topic in general, not to you Frenetic. Reply got borked.

but I agree with Norm. Not particularly based on any extensive knowledge I have on the issue, but of the types of arguments being made.

My knowledge is also limited but not as limited as it was when the discussion of this topic started. Like you, It was the type and form the arguments against GMO had taken that made me suspicious.

I don't think that similar amounts of genetic change are always equivalent. Plants have been shaped by evolution of millions of years not to poison their animal support, It would take a lot of selective breeding to make them harmful. On the other hand, bacteria don't necessarily have any problem killing folks. So inserting bacteria genetics into a plant certainly has more risks.

Actually plants shaped by evolution and standard breeding methods may be more likely to contain harmful toxins for example:

In the late 1960s Wilford Mills of the Pennsylvania State University crossed the popular potato variety Delta Gold with a wild potato relative from Peru. He called the new variety Lenape. The wild genes made Lenape highly resistant to attack by insects and potato blight. “Lenape was a wonderful potato,” remembers Mills's colleague Herb Cole. “It chipped golden.” A Pennsylvania potato chip manufacturer earmarked it as a favorite. A potato breeder in Ontario thought Lenape would be a good variety for early potatoes, the kind harvested young and boiled with peas. “He cooked up a batch of potatoes and peas,” Cole said, telling the story in 2003, “and he got very nauseous. He figured it was just an accident, so he cooked up some more the next week. He got even sicker.” He asked a biochemist at his university to analyze the potatoes. It turned out that they were exceedingly high in glycoalkaloids, the potato's natural toxins. He reported the results to Mills, who enlisted Cole in analyzing the variety further. “The result was that Penn State recalled the Lenape potato,” Cole said. Lenape had been released as a public variety, not patented. Recalling it meant contacting every grower of seed potatoes and requesting that they not market Lenape seed tubers. Cole and Mills did so. “But some of Lenape's heritage has carried forward and been bred into other varieties used today,” Cole added. A list of potato cultivars compiled by the crop and soil science department of Michigan State University includes Lenape in the parentage of 13 varieties. “In making the cross,” Cole concluded, “Bill did what all the people opposed to biotechnology say you ought to do. He went back to the origins of the potato and brought along genes for insect and disease resistance. He also brought along genes for glycoalkaloids.” But he didn't know it. Mendel in the Kitchen (Nina V. Fedoroff)

It doesn't look like your fear of the bacteria in Btcorn is justified.

Bt-based pesticides have been used for more than 30 years to control a variety of insects, including gypsy moths. They are especially favored by organic farmers, who consider them natural, not synthetic. The toxins, which break down when exposed to sunlight, heat, or drying, come from a bacterium, Bacillis thuringiensis. “While commonly referred to in the singular as ‘Bt,' B. thuringiensis is actually a large group of subspecies,” writes entomologist Brian Federici of the University of California, Riverside. More than 70 subspecies (also called varieties or strains) have been identified. Each produces one or more types of “Cry” (for crystal-like) proteins in its spores. These proteins are not toxic until they come into contact with an insect's digestive juices, which are highly alkaline (with a pH reading of 8 to 10). Eaten by an insect larva, the crystal dissolves. The protein is then broken apart, producing a toxic fragment. The fragment binds to a receptor on the lining of the insect's gut. If the insect doesn't have such a receptor—and most don't—nothing happens. In insects that have these receptors, on the other hand, the cell immediately begins to swell until it bursts. The active toxin binds to proteins on the epithelial cells lining the insect's midgut, forming pores that let potassium ions escape. Lacking potassium, the insect's gut cells take up too much water. Within two hours the insect stops feeding; if it has eaten enough of the toxin it becomes paralyzed and soon dies. The bacterium in this way prepares its own habitat. Federici points out that while Bt is usually thought of as a “soil bacterium,” its true ecological niche is the dead insect. After the larva is dead, the bacterium feeds off its body, reproduces, and makes millions of spores. The toxin has no effect on humans because of the differences between our digestive system and that of an insect. A human's digestive juices are highly acidic (with a pH reading of 1 to 3), so the crystal is not dissolved and the toxic fragment is not released. Even if it were, it would still not be toxic to a human. Toxins work by interfering with, or changing, a normal part of a cell. Human cells lack the receptor that interacts with the Cry protein in the insect's gut. Mendel in the Kitchen (Nina V. Fedoroff)

very interesting examples. Potatoes aren't the most representative vegetable as in nature they are indeed evolved to be somewhat poisonous. My grandmother used to gouge out all the eyes from our potatoes to remove the poison.

We're getting thin here I'll post so more example in a comment at the bottom.

By taking them as examples I don't mean to say that I think GMO's nessecarily will have any side effects, but just as with the potato there will be some issues here in there. Bacteria splicing and other things I think may have some higher risk of problems from breeding but I am not a biologist. Still from what I have read, I think its safe to say that the industry should be regulated and tested.

The main problem I have with GMOs is that this is the only planet we have and rather than keep this technology the lab where it could be researched companies and individuals have disregarded the rest of us and foist this technology on us and our environment, along with its potential unforeseen consequences. And due to the nature of the technology we won't be able to put the genie back in the bottle. None of these people will be held responsible if something goes wrong. As usual any profits will be privatised and costs socialised.

GMO is an integral part of this diseased meme we call intellectual property. Frankly I don't give a toss if it's promising. As far as I'm concerned the whole Monsanto Canada Inc. v. Schmeiser thing was a declaration of war. The idea that we can't collect seed that blows onto our property makes me want to puke.

GMO is just another pollutant I need to deal with because the economic system we live in is not only incapable to accounting properly for externalities but actively thrives on them.

Come back and tell me how great GMO is when we have an economic and political system that can deal with it properly.

I would be more supportive of GMO if there were truth in labeling laws. I want to know what the modification was in the food I eat.

If vitamins were bred in, as in golden rice, then great.

If pesticides like Bt, were inserted in the produce (where they can't be washed off), then it is likely I would avoid it.

Plus, I figure that Monsanto works so hard to battle truth in labeling laws they might be hiding something.

And my point on "superbugs" was about antibiotic resistant bacteria, which is a growing threat as animals are kept in unsanitary conditions where they are fed large amounts of corn, the main focus of so much genetic development.

I'm still not sure what the relationship is you're making to GMOs

http://www.biofortified.org/2010/03/gmos-antibiotics/

That isn't the link I was making.

I see the connection that these industrial farmers are largely developing these crops to make raw materials like feed more efficiaent. More efficient feed production make CFO's more profitable and therefor more common.

That style of meat production has a number of environmental impacts including the potential healthrisk associated with resistant bacteria.

It's not so much that it is caused by GMO's but in arguement that seems to be framed as a battle between the "Organics" and the "scientific". This is one huge scientific advantage that organic food production has. And if we eventually get to the place where cfos are both unhealthy and inhumane, then the GMO strategy for producing cheaper feed and therefore cheaper meat is pointless.

You're right it's not caused by GMOs, I don't see it as an argument between scientific and organic. Organic has just as much to gain from science as any other kind of farming.

I think we eat too much beef. I also think that the beef we eat should be from grass fed cattle. So once again this is not a GMO problem per se but one of education of consumers with science based evidence.

I'm bumming that you've chose to explore this GMO subject right now, when spring farm chores are stacking up on me faster than I can get to them. I cannot enter the fray now, I'm just too busy. Maybe you will still be interested in GMO later when I have more time. A couple of items I might at least raise.

It is unconscionable that Monsanto/Adm are not required to label the food grown from their GM seed. We oughta have a choice about whether or not we want round-up residuals in the corn and soy we feed our kids, and whether or not we want to choose to believe Monsanto that it's all good.

Over and over, Monsanto and their lobbyists have tried to pass laws prohibiting individual counties and states from passing laws prohibiting GMO use in their jurisdictions.

Their lobbyists already own the Fed. Government policy on this subject, and so long as they can prevent, by fiat, any local community from objecting, there is no defense from drifted contamination.

The same is true of Federal foreign food relief programs being used as a bludgeon to force poor countries to let in these products to contaminate their native species. We live in a global economy, but food production is intensely local and choices about it ought to be as well.

Too often, by exclusive focus on crop yields, one ends up selecting traits that only thrive at all with more water and more artificial fertilizer than may small farmers world over can afford. An all too American focus on fast growth and yield is predicated on industrial agriculture techniques and environment.

You've heard, I know, that whatever it's cause, one effect of climate change is that glacial water sources are drying up. Fast growth is not always the right choice. Heritage seed stocks that have evolved over hundreds or thousands of years to thrive in a given environment are too readily cross pollinated with these manufactured seed products.

When spread through drift or government policy or predatory practices to non-industrial farming environments, traits (portions of the genome) ignored or neglected by the seed manufacturers, might well prove to be the ones best suited to a changing ecology.

Currently much activity in the Bio Engineering Plant world is focused on transgenic vaccine development. They say that flu vaccines can be created so much more quickly by injecting pig genes into plants instead of virus into egg yolks. Good grief. If I had the SLIGHTEST confidence that such research would not take place in open field trials with no supervision by ANY government agency charged with protection of our food, agriculture, health or environment then, well, maybe,..., but I don't. (Maybe they'll wait til those poor folks living next to the open field trial start developing an irresistible inclination to rub their butts against the fences, and then they'll hold hearings.)

Bill Gates and Stu Brandt might I suppose, be excused for presuming that since "advanced" technology is pretty clearly good in some areas of human endeavor, it must, by definition, be good for others.

But they don't understand that Organic processes are different than computing. We don't know enough about the genomes of multiple species to be manipulating then propagating them without control and rigorous followup.

It's our right to know when our food is GMO manufactured. Without GMO labeling laws, no followup is even possible since no one knows if they have consumed GMO food. It is fundamental to good science to build in test metrics. Without them, any scientific argument regarding either efficacy or harm is useless. Food grown from Genetically altered seed MUST be labeled as such.

We've heard this before Norm. Remember "Better Living Through Chemistry?" Wasn't that from the folks

who brought us Napalm?

I have no problem with labeling laws but am disturbed that the proponents of labeling want all GMO Foods labeled frankenfood :)

I'll work on some scientifically based answers to your concerns. It does occur to me that most African farmers are currently doing what we call organic farming, and that it's not working out all that well.

I'll probably continue addressing the GMOs, but my education on the subject is still a little lean. I'll continue to work on that, those basic classes in Biology, Chemistry, and Physics 40 years ago put me at a disadvantage, that said I find many commenting on the subject even less informed than I am.

"I find many commenting on the subject even less informed than I am."

Who, for example? I've read pretty much all of the comments here since this debate started, and I haven't seen very many ill-informed comments. Maybe you mean comments at other blogs.

No, I mean comments here.

I admit my ignorance, however diplomatically I present it.

Rather than eating my hat, I'd just like to take full credit for this post.

And as I've been saying since my first comment in response to this topic and has been restated here by Red among others: The problems many of us have with GMO have little to do with science. The science is the least of it. It's about all of the other issues that arise from their distribution and lack of regulation and so on.

But the thing is, at some point it's all inextricably linked. The "other issues" we're concerned about only come up because of the existence of the science. And there in lies the rub.

Also, if we have to choose sides between Monsanto or Friends of the Earth, I'm going to throw my non-eaten hat in with the NGO trying to protect our planet rather than the giant company trying to make money from it. Just sayin'.

Rather than eating my hat, I'd just like to take full credit for this post.

Credit given.

if we have to choose sides between Monsanto or Friends of the Earth, I'm going to throw my non-eaten hat in with the NGO trying to protect our planet rather than the giant company trying to make money from it.

I don't think we have to choose, for me I'll come down on the side of peer-reviewed science, to make my decisions. I'm not in either camp, Friends of the Earth with their well-meaning but sometime fear-mongering tactics or those greedy bastards from Monsanto bending the rules like pretzels and using all the dirty tricks in the book.

You aren't going to get rid of the Monsanto because you support Friends of the Earth. It never was an either or question. It's a question of the best science and then getting behind it.

I wonder if you know of the work of Vandana Shiva. She has a site and there are videos on youtube. She is also a scientist and she ably refutes the supposed benefits of GMO's, including arguments you made.

It is now legal for multinationals to patent life-forms. GMO's are about making money for them, not about feeding the world.

How do you expect third-world farmers to pay for these expensive seeds and the associated pesticides each and every year? As Shiva points out, there has been a rise in farmers' suicides in India because they cannot pay.

In the past, farmers around the world had a variety of crops including vegetable gardens which provided the nutrients they needed. GM0's push them to monocultures.

Frontline and Nova teamed up to address the GMO issue. It's an interesting, balanced approach. At the end of each segment, the reader is asked whether or not they agree with the use of GMOs. If the reader votes "yes," s/he is directed to to a counter-argument, and vice versa. Here is the link:

http://www.pbs.org/wgbh/harvest/exist/

At the end of the discussion, readers had been able to tally a final vote based on all that they had learned. PBS was forced to discontinue this function, however, because:

"In late May 2004, thanks in part to the vigilance of several outside readers who phoned in, we discovered that some person or persons had tampered with this feature's tally. Specifically, on May 16-17, 1,540,016 "Yes" votes and 33,641 "No" votes were cast via just four IP addresses. (Prior to May 16, a total of roughly 124,000 votes of any kind had been cast since the feature launched in April 2001.)

Deeming the credibility of the tally to have been compromised, we made this page unavailable for several days while we decided how best to address this problem. In the end, we threw out these suspicious votes and recalculated the remaining response numbers and percentages. Then we did a more thorough scouring of votes from before May 2004.

It appears that a lesser degree of multiple voting has been going on for some time, so we have decided to temporarily remove the final vote and tallying options from this feature until we can put a more secure system in place. The feature itself remains unchanged, and we encourage you to challenge your stance on GM foods by reading it. We apologize for any inconvenience, and we appreciate your readership.—The Editors"

Now, I wonder who would do such a thing. Anyway, the report itself hasn't been compromised, so I encourage you to read through the sections. Bear in mind that the report is a few years old, so some of the data may have changed a bit.

As political scientist Robert Paarlberg notes in his book The Politics of Precaution: Genetically Modified Crops in Developing Countries, “Eating any food can be dangerous.” Many familiar foods naturally contain toxic chemicals—poisons the plant uses to defend itself against insects and browsing animals. Lima beans contain a chemical that breaks down during digestion into hydrogen cyanide, which is poisonous. Toxic psoralens in celery cause skin rashes. Moreover, psoralen cross-links the strands of DNA to each other, which can cause cancer. A chemical in cauliflower can make the thyroid enlarge. Carrots contain a nerve poison and a hallucinogen. Peaches and pears promote goiters. Strawberries contain a chemical that prevents blood from clotting and can lead to uncontrollable bleeding. Peas, beans, cereals, and potatoes contain lectins, which cause nausea, vomiting, and diarrhea, as do the glycoalkaloids also found in potatoes. Mushrooms, squash, cucumbers, chickpeas, mustard, manioc, olives, coffee, and tea all contain chemicals that are toxic to humans. Yet people generally know from experience how to prepare and eat these foods safely. Few even know about the toxins, because they are present at levels too low to harm someone eating a varied diet. (You would have to eat 400 carrots at a time to receive a toxic dose of nerve poison.) But some foods contain enough of a harmful chemical to be toxic in the amounts ordinarily consumed. By trial and error over millennia, people have learned to eliminate the toxins while preparing the food. In the Andes bitter potatoes are detoxified through freeze-drying. In Mexico and the American Southwest they are dipped in clay. Both methods keep the glycoalkaloids from causing stomach pains and vomiting. Manioc, from which cassava meal is ground, “is more poisonous than the potato,” noted Jack Harlan in The Living Fields. “It contains cyanogenic glycosides which when broken down by enzymes release prussic acid, HCN, one of the most deadly compounds known to man.” To be safely eaten, a manioc tuber must be peeled, grated, and pressed to expel the juice. The meal must be sun dried, fermented, or heated overnight until all possible HCN is formed. Then, when the cassava cake is cooked, the HCN is destroyed by the heat. To eat olives or olive oil, the extremely bitter oleuropein must first be pressed out—the ancient Romans used it as a weed killer and insecticide; it is now considered a pollutant. Yet olive oil, cassava, and potatoes are not only considered to be safe foods, they are staple foods on which cultures depend. Because proving “a complete absence of danger is,” in Paarlberg's words, “beyond the capability of experimental science,” the practical definition of a safe food has long been based on experience. “If a food has been a familiar component of the human diet for some time without any known adverse effects,” Paarlberg explains, “it comes to be ‘generally recognized as safe'—or GRAS, to use the terminology of the United States Food and Drug Administration (FDA).”

IIRC you recently linked to a talk on the dangers of anti-science. In this talk, the speaker first lambasts those who take food supplements, saying all they do is darken your urine. In a later sentence he is praising genetically engineered crops for having more vitamin content. Is darkened urine saving the third world or not? WTF?

It's my understanding that vitamins that are consumed through eating food absorb better than tablets taken as supplements which pass through with little absorption, that's WTF.

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