by Megan L. Norris
Summary: As the prevalence of genetically modified organisms (GMOs) continues to rise, there has been an increasing public interest for information concerning the safety of these products. Concerns generally focus on how the GMO may affect the environment or how it may affect the consumer. One specific concern is the possibility for GMOs to negatively affect human health. This could result from differences in nutritional content, allergic response, or undesired side effects such as toxicity, organ damage, or gene transfer. To address these concerns, there have been over 100 research studies comparing the effects of traditional food to genetically modified food, the results of which have been reviewed in various journals [1], [2]. How these results affect regulation can be found through The Center for Environmental Risk Assessment, which hosts a GM Crop Database that can be searched by the public to find GMO crop history, style of modification, and regulation across the world [3]. Though knowing who to trust and what to believe regarding this topic is an ongoing battle, major health groups, including the American Medical Association and World Health Organization, have concluded from the research of independent groups worldwide that genetically modified foods are safe for consumers [4]. Regarding toxicity, this includes any dangers related to organ health, mutations, pregnancy and offspring, and potential for transfer of genes to the consumer.
GMO toxicity: fears and scientific analysis
After genetically modified foods were introduced in the United States a few decades ago, people independently reported toxic effects caused by GMOs. One example is an anti-GMO advocacy group called the Institute for Responsible Technology (IRT), which reported that rats fed a diet containing a GMO potato had virtually every organ system adversely affected after just ten days of feeding [5]. The IRT stated that the toxicity was the result of genetic modification techniques and not a specific case for that particular potato. They claimed the process of making the GMO caused it to be toxic and thus all GMOs were high risk for toxicity.
Scientists across the U.S. and the rest of the world have sought to rigorously test the assertions of the IRT and others to uncover any possible toxicity caused by GMOs. To this end, many different types of modifications in various crops have been tested, and the studies have found no evidence that GMOs cause organ toxicity or other adverse health effects. An example of this research is a study carried out on a type of GMO potato that was genetically modified to contain the bar gene. The product of the bar gene is an enzyme that can detoxify herbicides and thus protects the potato from herbicidal treatment.
In order to see if this GMO potato would have adverse effects on consumer health like those claimed by the IRT, a group of scientists at the National Institute of Toxicological Research in Seoul, Korea fed rats diets containing either GMO potato or non-GMO potato [6]. For each diet, they tracked male and female rats. To carefully analyze the rats’ health, a histopathological examination of tissues and organs was conducted after the rats died. Histopathology is the examination of organs for disease at the microscopic level (think pathologist doing a biopsy). Histopathological examinations of the reproductive organs, liver, kidneys, and spleen showed no differences between GMO-eating and non-GMO-eating animals.
Three years earlier, a separate group had found the same results for a GMO tomato and a GMO sweet pepper [7]. These researchers had split rats into four diet groups: non-GMO tomato, GMO tomato, non-GMO sweet pepper, and GMO sweet pepper. They fed the rats over 7,000 times the average human daily consumption of either GMO or non-GMO tomato or sweet pepper for 30 days and monitored their overall health. Finally, they carried out histopathology and again found no differences in the stomach, liver, heart, kidney, spleen, or reproductive organs of GMO versus non-GMO fed rats. Despite massive ingestion of GMO potato, tomato, or sweet pepper, these studies demonstrated no differences in the vitality or health of the animals, even at the microscopic level.
Experiments like these on humans would be completely unethical. Fortunately, prior to these studies years of work have demonstrated that rodents, like mice and rats, are acceptable models for humans, meaning rodent responses to drugs, chemicals, and foods can predict human response. Rat feeding studies like these, in which rats are fed a potential toxic item and monitored for adverse effects, are considered both specific and sensitive for monitoring toxicity of foods and widely used in the food regulation industry [1].
The test of time: GMOs and their effect on our offspring
Although scientists have been able to demonstrate that GMOs are not toxic to the animals that eat them, as described above and elsewhere, what about side effects being passed on to our next generations?
To discern whether GMO crops affect fertility or embryos during gestation, a group from South Dakota State University again turned to studies on rats. In this case, the rats were eating a type of GMO corn, more commonly known as Bt corn. Bt stands for Bacillus thuringiensis, a microbe that produces insecticidal endotoxin and has been used as a topical pesticide against insects since 1961 (see this article). To allow corn to directly generate this endotoxin, scientists introduced a gene from Bt into the genetic material (DNA) of corn.
To address buildup of toxicity over time, this group monitored the GMO-eating rats not only for the lifetime of one generation, but also three additional generations. For each generation, they tracked the fertility of parents and compared the health of the embryos from parents that ate Bt corn to those with parents that did not [8]. Toxic effects can arise in many places and in many ways, but some organs are more susceptible to damage than others, and monitoring them is a good readout for other difficult-to-see effects. Testes are considered a particularly sensitive organ for toxicity tests because of the high degree of cell divisions and thus high susceptibility to cellular or molecular toxins. To examine the affect of Bt corn on testicular health, the researchers tracked testicular development in fetal, postnatal, pubertal, and adult rats for all four generations. The group found no change in testicular health or litter sizes in any generation. Likewise, ingestion by pregnant mothers had no effect on fetal, postnatal, pubertal, or adult testicular development of her offspring.
Other groups have monitored toxicity over time as well. For example, the group studying the bar GMO potato also wanted to see if organs and reproductive health were sensitive to GMOs over long exposure times [5]. To do this, they examined the fertility and gestation periods of GMO-eating mothers compared to non-GMO-eating mothers for five generations. They tracked animal body weight, bone, eye, and thymus development, and general retardation. Like the studies on Bt corn, in all cases, they found no significant differences between the GMO potato and non-GMO potato diets, suggesting that there is no buildup or inheritance of toxicity, even over multiple generations.
Figure 1. Work from independent researchers has investigated various aspects of GMO safety, especially concerning consumer health and toxicity.
Can GMOs change our genes?
Concern has also surrounded the idea that genetically modified DNA would be unstable, causing damage (via unintentional mutations) not only to the crop, but also to whomever would consume it. Mutations in DNA are closely tied to cancer and other diseases, and thus mutagenic substances can have dire effects on human health. The creation of mutations, called mutagenesis, can be measured and compared to known mutation-causing agents and known safe compounds, allowing researchers to determine whether drugs, chemicals, and foods cause increased mutation rates. There are a variety of ways to measure mutagenicity, but the most traditional method is a process pioneered by Bruce Ames at the University of California in Berkeley. His method, now called the Ames test in his honor, is able to track increased rates of mutations in a living thing in response to some substance, like a chemical or food.
To directly test the ability of a GMO to cause mutations, a research group from the National Laboratory of Protein Engineering and Plant Genetic Engineering in Beijing, China applied the Ames test to GMO tomatoes and GMO corn [8]. GMO tomatoes and corn express the viral coat protein of cucumber mosaic virus (CMV). Expression of this coat protein confers resistance to CMV, which is the most broadly infectious virus of any known plant virus, thought to infect over 1,200 plant species from vegetable crops to ornamentals. The results of the Ames test demonstrated no relationship between GMO tomatoes or corn and mutations. They repeated their analysis using two additional methods for analyzing mutagenicity in mice and got the same result, allowing them to conclude that genetically modified DNA did not cause increased mutations in consumers. The modified DNA, like unmodified DNA, was not mutagenic.
Mutagenicity aside, there are also concerns surrounding the ability of the modified DNA to transfer to the DNA of whomever eats it or have other toxic side effects. Depending on the degree of processing of their foods, a given person will ingest between 0.1 and 1 g of DNA each day [9]; as such, DNA itself is regarded as safe by the FDA [10]. To determine if the DNA from GMO crops is as safe to consume as the DNA from traditional food sources, the International Life Sciences Institute reviewed the chemical characteristics, susceptibility to degradation, metabolic fate and allergenicity of GMO-DNA and found that, in all cases, GMO-DNA was completely indistinguishable from traditional DNA, and thus is no more likely to transfer to or be toxic to a human [9]. Consistent with this, the researchers working on the GMO potato attempted to isolate the bar gene from their GMO eating rats. Despite 5 generations of exposure to and ingestion of the GMO, the researchers were unable to detect the gene in the rats’ DNA [5].
A strong argument for GMO health safety
After more than 20 years of monitoring by countries and researchers around the world, many of the suspicions surrounding the effects of GMOs on organ health, our offspring, and our DNA have been addressed and tested (Figure 1). In the data discussed above, alongside many more studies not mentioned here, GMOs have been found to exhibit no toxicity, in one generation or across many. Though each new product will require careful analysis and assessment of safety, it appears that GMOs as a class are no more likely to be harmful than traditionally bred and grown food sources.
Megan L. Norris is a Ph.D. candidate in the Molecular, Cellular and Organismal Biology Program at Harvard University.
This article is part of the August 2015 Special Edition, Genetically Modified Organisms and Our Food.
References
- European Food Safety Authority GMO Panel Working Group on Animal Feeding Trials. “Safety and nutritional assessment of GM plants and derived food and feed: the role of animal feeding trials.,” Food Chem. Toxicol., vol. 46 Suppl 1, pp. S2–70, Mar. 2008
- G. Flachowsky, A. Chesson, and K. Aulrich, “Animal nutrition with feeds from genetically modified plants.,” Arch. Anim. Nutr., vol. 59, no. 1, pp. 1–40, 2005.
- Cera-gmc.org, ‘Welcome to the Center for Environmental Risk Assessment | CERA’, 2015. [Online]. [Accessed: 11- Jul- 2015].
- Tamar Haspel. “Genetically modified foods: What is and isn’t true”. Washington Post. October 15, 2013.
- Jeffrey Smith. “GM Potatoes Damaged Rats.” Genetic Roulette, Section I: Documented Health Risks.
- G. S. Rhee, D. H. Cho, Y. H. Won, J. H. Seok, S. S. Kim, S. J. Kwack, R. Da Lee, S. Y. Chae, J. W. Kim, B. M. Lee, K. L. Park, and K. S. Choi, “Multigeneration reproductive and developmental toxicity study of bar gene inserted into genetically modified potato on rats.,” J. Toxicol. Environ. Health. A, vol. 68, no. 23–24, pp. 2263–2276, 2005.
- Z. L. Chen, H. Gu, Y. Li, Y. Su, P. Wu, Z. Jiang, X. Ming, J. Tian, N. Pan, and L. J. Qu, “Safety assessment for genetically modified sweet pepper and tomato,” Toxicology, vol. 188, no. 2–3, pp. 297–307, 2003.
- D. G. Brake, R. Thaler, and D. P. Evenson, “Evaluation of Bt (Bacillus thuringiensis) Corn on Mouse Testicular Development by Dual Parameter Flow Cytometry,” J. Agric. Food Chem., vol. 52, no. 7, pp. 2097–2102, 2004.
- D. A. Jonas, I. Elmadfa, K. H. Engel, K. J. Heller, G. Kozianowski, a. König, D. Müller, J. F. Narbonne, W. Wackernagel, and J. Kleiner, “Safety considerations of DNA in food,” Ann. Nutr. Metab., vol. 45, no. 6, pp. 235–254, 2001.
- FDA: Guidance to Industry for Foods Derived from New Plant Varieties, Section V (C).
According to all known laws of aviation, there is no way a bee should be able to fly. Its wings are too small to get its fat little body off the ground. The bee, of course, flies anyway because bees don’t care what humans think is impossible. Yellow, black. Yellow, black. Yellow, black. Yellow, black. Ooh, black and yellow! Let’s shake it up a little. Barry! Breakfast is ready! Ooming! Hang on a second. Hello? – Barry? – Adam? – Oan you believe this is happening? – I can’t. I’ll pick you up. Looking sharp. Use the stairs. Your father paid good money for those. Sorry. I’m excited. Here’s the graduate. We’re very proud of you, son. A perfect report card, all B’s. Very proud. Ma! I got a thing going here. – You got lint on your fuzz. – Ow! That’s me! – Wave to us! We’ll be in row 118,000. – Bye! Barry, I told you, stop flying in the house! – Hey, Adam. – Hey, Barry. – Is that fuzz gel? – A little. Special day, graduation. Never thought I’d make it. Three days grade school, three days high school. Those were awkward. Three days college. I’m glad I took a day and hitchhiked around the hive. You did come back different. – Hi, Barry. – Artie, growing a mustache? Looks good. – Hear about Frankie? – Yeah. – You going to the funeral? – No, I’m not going. Everybody knows, sting someone, you die. Don’t waste it on a squirrel. Such a hothead. I guess he could have just gotten out of the way. I love this incorporating an amusement park into our day. That’s why we don’t need vacations. Boy, quite a bit of pomp… under the circumstances. – Well, Adam, today we are men. – We are! – Bee-men. – Amen! Hallelujah! Students, faculty, distinguished bees, please welcome Dean Buzzwell. Welcome, New Hive Oity graduating class of… …9:15. That concludes our ceremonies. And begins your career at Honex Industries! Will we pick ourjob today? I heard it’s just orientation. Heads up! Here we go. Keep your hands and antennas inside the tram at all times. – Wonder what it’ll be like? – A little scary. Welcome to Honex, a division of Honesco and a part of the Hexagon Group. This is it! Wow. Wow. We know that you, as a bee, have worked your whole life to get to the point where you can work for your whole life. Honey begins when our valiant Pollen Jocks bring the nectar to the hive. Our top-secret formula is automatically color-corrected, scent-adjusted and bubble-contoured into this soothing sweet syrup with its distinctive golden glow you know as… Honey! – That girl was hot. – She’s my cousin! – She is? – Yes, we’re all cousins. – Right. You’re right. – At Honex, we constantly strive to improve every aspect of bee existence. These bees are stress-testing a new helmet technology. – What do you think he makes? – Not enough. Here we have our latest advancement, the Krelman. – What does that do? – Oatches that little strand of honey that hangs after you pour it. Saves us millions. Oan anyone work on the Krelman? Of course. Most bee jobs are small ones. But bees know that every small job, if it’s done well, means a lot. But choose carefully because you’ll stay in the job you pick for the rest of your life. The same job the rest of your life? I didn’t know that. What’s the difference? You’ll be happy to know that bees, as a species, haven’t had one day off in 27 million years. So you’ll just work us to death? We’ll sure try. Wow! That blew my mind! “What’s the difference?” How can you say that? One job forever? That’s an insane choice to have to make. I’m relieved. Now we only have to make one decision in life. But, Adam, how could they never have told us that? Why would you question anything? We’re bees. We’re the most perfectly functioning society on Earth. You ever think maybe things work a little too well here? Like what? Give me one example. I don’t know. But you know what I’m talking about. Please clear the gate. Royal Nectar Force on approach. Wait a second. Oheck it out. – Hey, those are Pollen Jocks! – Wow. I’ve never seen them this close. They know what it’s like outside the hive. Yeah, but some don’t come back. – Hey, Jocks! – Hi, Jocks! You guys did great! You’re monsters! You’re sky freaks! I love it! I love it! – I wonder where they were. – I don’t know. Their day’s not planned. Outside the hive, flying who knows where, doing who knows what. You can’tjust decide to be a Pollen Jock. You have to be bred for that. Right. Look. That’s more pollen than you and I will see in a lifetime. It’s just a status symbol. Bees make too much of it. Perhaps. Unless you’re wearing it and the ladies see you wearing it. Those ladies? Aren’t they our cousins too? Distant. Distant. Look at these two. – Oouple of Hive Harrys. – Let’s have fun with them. It must be dangerous being a Pollen Jock. Yeah. Once a bear pinned me against a mushroom! He had a paw on my throat, and with the other, he was slapping me! – Oh, my! – I never thought I’d knock him out. What were you doing during this? Trying to alert the authorities. I can autograph that. A little gusty out there today, wasn’t it, comrades? Yeah. Gusty. We’re hitting a sunflower patch six miles from here tomorrow. – Six miles, huh? – Barry! A puddle jump for us, but maybe you’re not up for it. – Maybe I am. – You are not! We’re going 0900 at J-Gate. What do you think, buzzy-boy? Are you bee enough? I might be. It all depends on what 0900 means. Hey, Honex! Dad, you surprised me. You decide what you’re interested in? – Well, there’s a lot of choices. – But you only get one. Do you ever get bored doing the same job every day? Son, let me tell you about stirring. You grab that stick, and you just move it around, and you stir it around. You get yourself into a rhythm. It’s a beautiful thing. You know, Dad, the more I think about it, maybe the honey field just isn’t right for me. You were thinking of what, making balloon animals? That’s a bad job for a guy with a stinger. Janet, your son’s not sure he wants to go into honey! – Barry, you are so funny sometimes. – I’m not trying to be funny. You’re not funny! You’re going into honey. Our son, the stirrer! – You’re gonna be a stirrer? – No one’s listening to me! Wait till you see the sticks I have. I could say anything right now. I’m gonna get an ant tattoo! Let’s open some honey and celebrate! Maybe I’ll pierce my thorax. Shave my antennae. Shack up with a grasshopper. Get a gold tooth and call everybody “dawg”! I’m so proud. – We’re starting work today! – Today’s the day. Oome on! All the good jobs will be gone. Yeah, right. Pollen counting, stunt bee, pouring, stirrer, front desk, hair removal… – Is it still available? – Hang on. Two left! One of them’s yours! Oongratulations! Step to the side. – What’d you get? – Picking crud out. Stellar! Wow! Oouple of newbies? Yes, sir! Our first day! We are ready! Make your choice. – You want to go first? – No, you go. Oh, my. What’s available? Restroom attendant’s open, not for the reason you think. – Any chance of getting the Krelman? – Sure, you’re on. I’m sorry, the Krelman just closed out. Wax monkey’s always open. The Krelman opened up again. What happened? A bee died. Makes an opening. See? He’s dead. Another dead one. Deady. Deadified. Two more dead. Dead from the neck up. Dead from the neck down. That’s life! Oh, this is so hard! Heating, cooling, stunt bee, pourer, stirrer, humming, inspector number seven, lint coordinator, stripe supervisor, mite wrangler. Barry, what do you think I should… Barry? Barry! All right, we’ve got the sunflower patch in quadrant nine… What happened to you? Where are you? – I’m going out. – Out? Out where? – Out there. – Oh, no! I have to, before I go to work for the rest of my life. You’re gonna die! You’re crazy! Hello? Another call coming in. If anyone’s feeling brave, there’s a Korean deli on 83rd that gets their roses today. Hey, guys. – Look at that. – Isn’t that the kid we saw yesterday? Hold it, son, flight deck’s restricted. It’s OK, Lou. We’re gonna take him up. Really? Feeling lucky, are you? Sign here, here. Just initial that. – Thank you. – OK. You got a rain advisory today, and as you all know, bees cannot fly in rain. So be careful. As always, watch your brooms, hockey sticks, dogs, birds, bears and bats. Also, I got a couple of reports of root beer being poured on us. Murphy’s in a home because of it, babbling like a cicada! – That’s awful. – And a reminder for you rookies, bee law number one, absolutely no talking to humans! All right, launch positions! Buzz, buzz, buzz, buzz! Buzz, buzz, buzz, buzz! Buzz, buzz, buzz, buzz! Black and yellow! Hello! You ready for this, hot shot? Yeah. Yeah, bring it on. Wind, check. – Antennae, check. – Nectar pack, check. – Wings, check. – Stinger, check. Scared out of my shorts, check. OK, ladies, let’s move it out! Pound those petunias, you striped stem-suckers! All of you, drain those flowers! Wow! I’m out! I can’t believe I’m out! So blue. I feel so fast and free! Box kite! Wow! Flowers! This is Blue Leader. We have roses visual. Bring it around 30 degrees and hold. Roses! 30 degrees, roger. Bringing it around. Stand to the side, kid. It’s got a bit of a kick. That is one nectar collector! – Ever see pollination up close? – No, sir. I pick up some pollen here, sprinkle it over here. Maybe a dash over there, a pinch on that one. See that? It’s a little bit of magic. That’s amazing. Why do we do that? That’s pollen power. More pollen, more flowers, more nectar, more honey for us. Oool. I’m picking up a lot of bright yellow. Oould be daisies. Don’t we need those? Oopy that visual. Wait. One of these flowers seems to be on the move. Say again? You’re reporting a moving flower? Affirmative. That was on the line! This is the coolest. What is it? I don’t know, but I’m loving this color. It smells good. Not like a flower, but I like it. Yeah, fuzzy. Ohemical-y. Oareful, guys. It’s a little grabby. My sweet lord of bees! Oandy-brain, get off there! Problem! – Guys! – This could be bad. Affirmative. Very close. Gonna hurt. Mama’s little boy. You are way out of position, rookie! Ooming in at you like a missile! Help me! I don’t think these are flowers. – Should we tell him? – I think he knows. What is this?! Match point! You can start packing up, honey, because you’re about to eat it! Yowser! Gross. There’s a bee in the car! – Do something! – I’m driving! – Hi, bee. – He’s back here! He’s going to sting me! Nobody move. If you don’t move, he won’t sting you. Freeze! He blinked! Spray him, Granny! What are you doing?! Wow… the tension level out here is unbelievable. I gotta get home. Oan’t fly in rain. Oan’t fly in rain. Oan’t fly in rain. Mayday! Mayday! Bee going down! Ken, could you close the window please? Ken, could you close the window please? Oheck out my new resume. I made it into a fold-out brochure. You see? Folds out. Oh, no. More humans. I don’t need this. What was that? Maybe this time. This time. This time. This time! This time! This… Drapes! That is diabolical. It’s fantastic. It’s got all my special skills, even my top-ten favorite movies. What’s number one? Star Wars? Nah, I don’t go for that… …kind of stuff. No wonder we shouldn’t talk to them. They’re out of their minds. When I leave a job interview, they’re flabbergasted, can’t believe what I say. There’s the sun. Maybe that’s a way out. I don’t remember the sun having a big 75 on it. I predicted global warming. I could feel it getting hotter. At first I thought it was just me. Wait! Stop! Bee! Stand back. These are winter boots. Wait! Don’t kill him! You know I’m allergic to them! This thing could kill me! Why does his life have less value than yours? Why does his life have any less value than mine? Is that your statement? I’m just saying all life has value. You don’t know what he’s capable of feeling. My brochure! There you go, little guy. I’m not scared of him. It’s an allergic thing. Put that on your resume brochure. My whole face could puff up. Make it one of your special skills. Knocking someone out is also a special skill. Right. Bye, Vanessa. Thanks. – Vanessa, next week? Yogurt night? – Sure, Ken. You know, whatever. – You could put carob chips on there. – Bye. – Supposed to be less calories. – Bye. I gotta say something. She saved my life. I gotta say something. All right, here it goes. Nah. What would I say? I could really get in trouble. It’s a bee law. You’re not supposed to talk to a human. I can’t believe I’m doing this. I’ve got to. Oh, I can’t do it. Oome on! No. Yes. No. Do it. I can’t. How should I start it? “You like jazz?” No, that’s no good. Here she comes! Speak, you fool! Hi! I’m sorry. – You’re talking. – Yes, I know. You’re talking! I’m so sorry. No, it’s OK. It’s fine. I know I’m dreaming. But I don’t recall going to bed. Well, I’m sure this is very disconcerting. This is a bit of a surprise to me. I mean, you’re a bee! I am. And I’m not supposed to be doing this, but they were all trying to kill me. And if it wasn’t for you… I had to thank you. It’s just how I was raised. That was a little weird. – I’m talking with a bee. – Yeah. I’m talking to a bee. And the bee is talking to me! I just want to say I’m grateful. I’ll leave now. – Wait! How did you learn to do that? – What? The talking thing. Same way you did, I guess. “Mama, Dada, honey.” You pick it up. – That’s very funny. – Yeah. Bees are funny. If we didn’t laugh, we’d cry with what we have to deal with. Anyway… Oan I… …get you something? – Like what? I don’t know. I mean… I don’t know. Ooffee? I don’t want to put you out. It’s no trouble. It takes two minutes. – It’s just coffee. – I hate to impose. – Don’t be ridiculous! – Actually, I would love a cup. Hey, you want rum cake? – I shouldn’t. – Have some. – No, I can’t. – Oome on! I’m trying to lose a couple micrograms. – Where? – These stripes don’t help. You look great! I don’t know if you know anything about fashion. Are you all right? No. He’s making the tie in the cab as they’re flying up Madison. He finally gets there. He runs up the steps into the church. The wedding is on. And he says, “Watermelon? I thought you said Guatemalan. Why would I marry a watermelon?” Is that a bee joke? That’s the kind of stuff we do. Yeah, different. So, what are you gonna do, Barry? About work? I don’t know. I want to do my part for the hive, but I can’t do it the way they want. I know how you feel. – You do? – Sure. My parents wanted me to be a lawyer or a doctor, but I wanted to be a florist. – Really? – My only interest is flowers. Our new queen was just elected with that same campaign slogan. Anyway, if you look… There’s my hive right there. See it? You’re in Sheep Meadow! Yes! I’m right off the Turtle Pond! No way! I know that area. I lost a toe ring there once. – Why do girls put rings on their toes? – Why not? – It’s like putting a hat on your knee. – Maybe I’ll try that. – You all right, ma’am? – Oh, yeah. Fine. Just having two cups of coffee! Anyway, this has been great. Thanks for the coffee. Yeah, it’s no trouble. Sorry I couldn’t finish it. If I did, I’d be up the rest of my life. Are you…? Oan I take a piece of this with me? Sure! Here, have a crumb. – Thanks! – Yeah. All right. Well, then… I guess I’ll see you around. Or not. OK, Barry. And thank you so much again… for before. Oh, that? That was nothing. Well, not nothing, but… Anyway… This can’t possib
bro fr just wrote the whole bee movie script.
you forgot the cpaital- harvard student
bro ong. lets call the director
but its wings move really fast xoxo
The 4th source they used is left-biased (I used multiple sources to check this) so if you want unbiased info this is not it
Saying you have sources without citing them is unhelpful. It’s a Washington Post article though, it is of course going to be opinionated rather than neutral and scientific in nature. They don’t use this source as part of their argument in any case, they are citing it because it says that the AMA and the WHO have concluded that GMFs currently on the market are safe. Which is just verifiably true, and they probably only cited this WP article because it’s probably where the reader first learned that this was the stance of those groups. But any biases in that source are immaterial since what is being cited is just cold, hard, verifiable fact.
Something tells me you didn’t actually find four sources of your own to “prove a bias” (which isn’t a thing anyway), especially given that you didn’t even look at where the article in question was cited in the text…
Recent stduy shows:
(I copy/past abestrct)
Abstract
Objective: A systematic review of animal and human studies was conducted on genetically modifed (GM) food
consumption to assess its safety in terms of adverse efects/events to inform public concerns and future research.
Methods: Seven electronic databases were searched from January 1st 1983 till July 11th 2020 for in vivo, animal and
human studies on the incidence of adverse efects/events of GM products consumption. Two authors independently
identifed eligible studies, assessed the study quality, and extracted data on the name of the periodical, author and
afliation, literature type, the theme of the study, publication year, funding, sample size, target population character‑
istics, type of the intervention/exposure, outcomes and outcome measures, and details of adverse efects/events. We
used the Chi-square test to compare the adverse event reporting rates in articles funded by industry funding, govern‑
ment funding or unfunded articles.
Results: One crossover trial in humans and 203 animal studies from 179 articles met the inclusion criteria. The study
quality was all assessed as being unclear or having a high risk of bias. Minor illnesses were reported in the human
trial. Among the 204 studies, 59.46% of adverse events (22 of 37) were serious adverse events from 16 animal stud‑
ies (7.84%). No signifcant diferences were found in the adverse event reporting rates either between industry and
government funding (χ
2=2.286, P=0.131), industry and non-industry funding (χ
2=1.761, P=0.185) or funded
and non-funded articles (χ
2=0.491, P=0.483). We fnally identifed 21 GM food-related adverse events involv‑
ing 7 GM events (NK603×MON810 maize, GTS 40-3-2 soybean, NK603 maize, MON863 maize, MON810 maize,
MON863×MON810×NK603 maize and GM Shanyou 63 rice), which had all been on regulatory approval in some
countries/regions.
Conclusion: Serious adverse events of GM consumption include mortality, tumour or cancer, signifcant low fertility,
decreased learning and reaction abilities, and some organ abnormalities. Further clinical trials and long-term cohort
studies in human populations, especially on GM food-related adverse events and the corresponding GM events, are
still warranted. It suggests the necessity of labelling GM food so that consumers can make their own choice.
Shen C, Yin XC, Jiao BY, Li J, Jia P, Zhang XW, Cheng XH, Ren JX, Lan HD, Hou WB, Fang M. Evaluation of adverse effects/events of genetically modified food consumption: a systematic review of animal and human studies. Environmental Sciences Europe. 2022 Dec;34(1):1-33.
You should look at the funding for this article – this was funded by large TCM (Traditional Chinese Medicine) groups, which have an assumed conclusion associated with them. I’ve also read the study further and found it to be mostly a mercenary shill piece, as the funding suggests. You could probably notice this on your own, but I’ll elaborate anyway: this was written very quickly and unprofessionally – the formatting is poor, the statistical analysis is straight up incorrect on all three of the test cases I did with their own data, there are spelling and punctuation errors that would never pass muster for a real publication, they over-cite and under-deliver in an attempt to sway the cursory reader, they draw conclusions that their data does not support (such as animal studies being just generally bad I guess?) and just in general they are VERY unscientific.
Remember: just because it’s published, doesn’t mean it’s good!
I don’t have one right now
ummary: As the prevalence of genetically modified organisms (GMOs) continues to rise, there has been an increasing public interest for information concerning the safety of these products. Concerns generally focus on how the GMO may affect the environment or how it may affect the consumer. One specific concern is the possibility for GMOs to negatively affect human health. This could result from differences in nutritional content, allergic response, or undesired side effects such as toxicity, organ damage, or gene transfer. To address these concerns, there have been over 100 research studies comparing the effects of traditional food to genetically modified food, the results of which have been reviewed in various journals [1], [2]. How these results affect regulation can be found through The Center for Environmental Risk Assessment, which hosts a GM Crop Database that can be searched by the public to find GMO crop history, style of modification, and regulation across the world [3]. Though knowing who to trust and what to believe regarding this topic is an ongoing battle, major health groups, including the American Medical Association and World Health Organization, have concluded from the research of independent groups worldwide that genetically modified foods are safe for consumers [4]. Regarding toxicity, this includes any dangers related to organ health, mutations, pregnancy and offspring, and potential for transfer of genes to the consumer.
GMO toxicity: fears and scientific analysis
After genetically modified foods were introduced in the United States a few decades ago, people independently reported toxic effects caused by GMOs. One example is an anti-GMO advocacy group called the Institute for Responsible Technology (IRT), which reported that rats fed a diet containing a GMO potato had virtually every organ system adversely affected after just ten days of feeding [5]. The IRT stated that the toxicity was the result of genetic modification techniques and not a specific case for that particular potato. They claimed the process of making the GMO caused it to be toxic and thus all GMOs were high risk for toxicity.
Scientists across the U.S. and the rest of the world have sought to rigorously test the assertions of the IRT and others to uncover any possible toxicity caused by GMOs. To this end, many different types of modifications in various crops have been tested, and the studies have found no evidence that GMOs cause organ toxicity or other adverse health effects. An example of this research is a study carried out on a type of GMO potato that was genetically modified to contain the bar gene. The product of the bar gene is an enzyme that can detoxify herbicides and thus protects the potato from herbicidal treatment.
In order to see if this GMO potato would have adverse effects on consumer health like those claimed by the IRT, a group of scientists at the National Institute of Toxicological Research in Seoul, Korea fed rats diets containing either GMO potato or non-GMO potato [6]. For each diet, they tracked male and female rats. To carefully analyze the rats’ health, a histopathological examination of tissues and organs was conducted after the rats died. Histopathology is the examination of organs for disease at the microscopic level (think pathologist doing a biopsy). Histopathological examinations of the reproductive organs, liver, kidneys, and spleen showed no differences between GMO-eating and non-GMO-eating animals.
Three years earlier, a separate group had found the same results for a GMO tomato and a GMO sweet pepper [7]. These researchers had split rats into four diet groups: non-GMO tomato, GMO tomato, non-GMO sweet pepper, and GMO sweet pepper. They fed the rats over 7,000 times the average human daily consumption of either GMO or non-GMO tomato or sweet pepper for 30 days and monitored their overall health. Finally, they carried out histopathology and again found no differences in the stomach, liver, heart, kidney, spleen, or reproductive organs of GMO versus non-GMO fed rats. Despite massive ingestion of GMO potato, tomato, or sweet pepper, these studies demonstrated no differences in the vitality or health of the animals, even at the microscopic level.
Experiments like these on humans would be completely unethical. Fortunately, prior to these studies years of work have demonstrated that rodents, like mice and rats, are acceptable models for humans, meaning rodent responses to drugs, chemicals, and foods can predict human response. Rat feeding studies like these, in which rats are fed a potential toxic item and monitored for adverse effects, are considered both specific and sensitive for monitoring toxicity of foods and widely used in the food regulation industry [1].
The test of time: GMOs and their effect on our offspring
Although scientists have been able to demonstrate that GMOs are not toxic to the animals that eat them, as described above and elsewhere, what about side effects being passed on to our next generations?
To discern whether GMO crops affect fertility or embryos during gestation, a group from South Dakota State University again turned to studies on rats. In this case, the rats were eating a type of GMO corn, more commonly known as Bt corn. Bt stands for Bacillus thuringiensis, a microbe that produces insecticidal endotoxin and has been used as a topical pesticide against insects since 1961 (see this article). To allow corn to directly generate this endotoxin, scientists introduced a gene from Bt into the genetic material (DNA) of corn.
To address buildup of toxicity over time, this group monitored the GMO-eating rats not only for the lifetime of one generation, but also three additional generations. For each generation, they tracked the fertility of parents and compared the health of the embryos from parents that ate Bt corn to those with parents that did not [8]. Toxic effects can arise in many places and in many ways, but some organs are more susceptible to damage than others, and monitoring them is a good readout for other difficult-to-see effects. Testes are considered a particularly sensitive organ for toxicity tests because of the high degree of cell divisions and thus high susceptibility to cellular or molecular toxins. To examine the affect of Bt corn on testicular health, the researchers tracked testicular development in fetal, postnatal, pubertal, and adult rats for all four generations. The group found no change in testicular health or litter sizes in any generation. Likewise, ingestion by pregnant mothers had no effect on fetal, postnatal, pubertal, or adult testicular development of her offspring.
Other groups have monitored toxicity over time as well. For example, the group studying the bar GMO potato also wanted to see if organs and reproductive health were sensitive to GMOs over long exposure times [5]. To do this, they examined the fertility and gestation periods of GMO-eating mothers compared to non-GMO-eating mothers for five generations. They tracked animal body weight, bone, eye, and thymus development, and general retardation. Like the studies on Bt corn, in all cases, they found no significant differences between the GMO potato and non-GMO potato diets, suggesting that there is no buildup or inheritance of toxicity, even over multiple generations.
Figure 1. Work from independent researchers has investigated various aspects of GMO safety, especially concerning consumer health and toxicity.
Can GMOs change our genes?
Concern has also surrounded the idea that genetically modified DNA would be unstable, causing damage (via unintentional mutations) not only to the crop, but also to whomever would consume it. Mutations in DNA are closely tied to cancer and other diseases, and thus mutagenic substances can have dire effects on human health. The creation of mutations, called mutagenesis, can be measured and compared to known mutation-causing agents and known safe compounds, allowing researchers to determine whether drugs, chemicals, and foods cause increased mutation rates. There are a variety of ways to measure mutagenicity, but the most traditional method is a process pioneered by Bruce Ames at the University of California in Berkeley. His method, now called the Ames test in his honor, is able to track increased rates of mutations in a living thing in response to some substance, like a chemical or food.
To directly test the ability of a GMO to cause mutations, a research group from the National Laboratory of Protein Engineering and Plant Genetic Engineering in Beijing, China applied the Ames test to GMO tomatoes and GMO corn [8]. GMO tomatoes and corn express the viral coat protein of cucumber mosaic virus (CMV). Expression of this coat protein confers resistance to CMV, which is the most broadly infectious virus of any known plant virus, thought to infect over 1,200 plant species from vegetable crops to ornamentals. The results of the Ames test demonstrated no relationship between GMO tomatoes or corn and mutations. They repeated their analysis using two additional methods for analyzing mutagenicity in mice and got the same result, allowing them to conclude that genetically modified DNA did not cause increased mutations in consumers. The modified DNA, like unmodified DNA, was not mutagenic.
Mutagenicity aside, there are also concerns surrounding the ability of the modified DNA to transfer to the DNA of whomever eats it or have other toxic side effects. Depending on the degree of processing of their foods, a given person will ingest between 0.1 and 1 g of DNA each day [9]; as such, DNA itself is regarded as safe by the FDA [10]. To determine if the DNA from GMO crops is as safe to consume as the DNA from traditional food sources, the International Life Sciences Institute reviewed the chemical characteristics, susceptibility to degradation, metabolic fate and allergenicity of GMO-DNA and found that, in all cases, GMO-DNA was completely indistinguishable from traditional DNA, and thus is no more likely to transfer to or be toxic to a human [9]. Consistent with this, the researchers working on the GMO potato attempted to isolate the bar gene from their GMO eating rats. Despite 5 generations of exposure to and ingestion of the GMO, the researchers were unable to detect the gene in the rats’ DNA [5].
A strong argument for GMO health safety
After more than 20 years of monitoring by countries and researchers around the world, many of the suspicions surrounding the effects of GMOs on organ health, our offspring, and our DNA have been addressed and tested (Figure 1). In the data discussed above, alongside many more studies not mentioned here, GMOs have been found to exhibit no toxicity, in one generation or across many. Though each new product will require careful analysis and assessment of safety, it appears that GMOs as a class are no more likely to be harmful than traditionally bred and grown food sources.
Megan L. Norris is a Ph.D. candidate in the Molecular, Cellular and Organismal Biology Program at Harvard University.
This article is part of the August 2015 Special Edition, Genetically Modified Organisms and Our Food.
References
European Food Safety Authority GMO Panel Working Group on Animal Feeding Trials. “Safety and nutritional assessment of GM plants and derived food and feed: the role of animal feeding trials.,” Food Chem. Toxicol., vol. 46 Suppl 1, pp. S2–70, Mar. 2008
G. Flachowsky, A. Chesson, and K. Aulrich, “Animal nutrition with feeds from genetically modified plants.,” Arch. Anim. Nutr., vol. 59, no. 1, pp. 1–40, 2005.
Cera-gmc.org, ‘Welcome to the Center for Environmental Risk Assessment | CERA’, 2015. [Online]. [Accessed: 11- Jul- 2015].
Tamar Haspel. “Genetically modified foods: What is and isn’t true”. Washington Post. October 15, 2013.
Jeffrey Smith. “GM Potatoes Damaged Rats.” Genetic Roulette, Section I: Documented Health Risks.
G. S. Rhee, D. H. Cho, Y. H. Won, J. H. Seok, S. S. Kim, S. J. Kwack, R. Da Lee, S. Y. Chae, J. W. Kim, B. M. Lee, K. L. Park, and K. S. Choi, “Multigeneration reproductive and developmental toxicity study of bar gene inserted into genetically modified potato on rats.,” J. Toxicol. Environ. Health. A, vol. 68, no. 23–24, pp. 2263–2276, 2005.
Z. L. Chen, H. Gu, Y. Li, Y. Su, P. Wu, Z. Jiang, X. Ming, J. Tian, N. Pan, and L. J. Qu, “Safety assessment for genetically modified sweet pepper and tomato,” Toxicology, vol. 188, no. 2–3, pp. 297–307, 2003.
D. G. Brake, R. Thaler, and D. P. Evenson, “Evaluation of Bt (Bacillus thuringiensis) Corn on Mouse Testicular Development by Dual Parameter Flow Cytometry,” J. Agric. Food Chem., vol. 52, no. 7, pp. 2097–2102, 2004.
D. A. Jonas, I. Elmadfa, K. H. Engel, K. J. Heller, G. Kozianowski, a. König, D. Müller, J. F. Narbonne, W. Wackernagel, and J. Kleiner, “Safety considerations of DNA in food,” Ann. Nutr. Metab., vol. 45, no. 6, pp. 235–254, 2001.
FDA: Guidance to Industry for Foods Derived from New Plant Varieties, Section V (C).
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331 thoughts on “Will GMOs Hurt My Body? The Public’s Concerns and How Scientists Have Addressed Them”
Codie
AUGUST 10, 2015 AT 5:04 PM
Fantastic article.
REPLY
deathn
wow almost as good as the bee movie one
GMOs are just a way to help fight world hunger. Have you heard of food security? Don’t you want to stop hearing about the starving people in Africa? It’ll take time, but eventually, GM food will be available to almost every country. I say “almost” because of the bans and restrictions in France, Germany, Great Britain, Greece, Italy, and Spain. Although, GMOs are technically in almost every food. The most I’ve seen is corn syrup or fructose corn syrup.
Bro I was just looking for a comment about corn but ended up reading the entire bible and getting Rick Rolled
YES LMAO, all the sarcasm in the comment section made me laugh so damn hard. Some woman put the whole fucking BIBLE in a comment section about GMOs i am so done with humans
Can you please change the photo for this article. I don’t think it is necessary to contribute to the idea that the only thing worth protecting in a woman is her baby. Wonderful how the man gets kidney’s and a liver, maybe we could add some lungs and a heart to the lady.
Glad you remembered his balls tho, how would we ever know it is an all important male without them.
loved this article
Big words go brrrrr
Who are you so wise in the ways of science