Are GMOs safe and are the nutrients in our crops declining?

Please discuss GMOs and decreased nutrition in our foods.

Mary Ellen / Originally posted on Nutrition education in medicine: A doctor a day keeps the apples away


This answer is from 2012. Please see our more recent videos on GMOs here:

For a discussion on how much the nutrient content of food crops has declined over the last 50 years please see my video Crop Nutrient Decline. In terms of GMOs, I’ve published a few papers on the inclusion of genetically modified animals in the food supply (for example here and here), but the relative risks and benefits of genetic engineering in crop agriculture is less clear.

Unfortunately, the latest review on the safety of plant GMOs is not freely available, but an earlier review is. If one is interested in the two extremes of the debate I’d suggest Health Risks of Genetically Modified Foods on the “anti” side and Why Genetically Modified Crops? on the pro.

Image Credit: Peter Blanchard / Flickr

  • Changeisgood

    What are your thoughts on the Monsanto Bill that was just passed???

  • Merio

    We’ve just begun to understand the real power of food(fruits and vegetables) and Monsanto tries already to “enhance” it… i think it’s like to play with fire…
    There are too many bias with GMO…

    • Eskil J.

      We’ve been “playing” with it for thousands of years. As long as we keep to cisgenic GM crops for now; there should be no more health risks than from conventional crop production, as has been demonstrated to be the case for over 25 years by hundreds of independent research teams.

      As for Monsanto, most of what is being told about them are just plain myths. They’re just like any other corporation out there but they have expressed concern for both environment and health. Dr. Steven Novella has a logical stance on this that I think you should hear out:

      And of course Dusty does a pretty funny non-professional review:

      And of course be sure to avoid the flawed anti-GM studies:

      As for GM animals I would say that’s definitely an ethics question, one that I deeply oppose for several reasons.

      • Malia

        by GL Woolsey
        September 13, 2012
        Source article

        GMO foods are such an embedded part of our food system these days, but it’s not difficult to think back to a time when food was simpler and healthier. How did we get to the point that genetically modified organisms infiltrate so much of what we eat? GMO expert GL Woolsey took a look at the history of
        GMOs. We present that for you here now.

        1935 – DNA Discovered

        Russian scientist Andrei Nikolaevitch Belozersky isolates pure DNA.

        1973 – Recombinant DNA Created

        The idea for man-made DNA, or rDNA, comes from a grad student at
        Stanford University Medical School. Professor Herbert Boyer and a few of his biologist colleagues run with it.

        1975 – Asilomar Conference

        A group of biologists get together with a few lawyers and doctors to
        create guidelines for the safe use of genetically engineered DNA.

        1980 – First GMO Patent Issued

        A 1980 court case between a genetics engineer at General Electric and the U.S. Patent Office is settled by a 5-to-4 Supreme Court ruling, allowing for the first patent on a living organism. The GMO in question is a bacterium with an appetite for crude oil, ready to gobble up spills.

        1982 – FDA Approves First GMO

        Humulin, insulin produced by genetically engineered E. coli bacteria, appears on the market.

        1994 – GMO Hits Grocery Stores

        The U.S. Food and Drug Administration approves the Flavr Savr tomato for sale on grocery store shelves. The delayed-ripening tomato has a longer shelf life than conventional tomatoes.

        1996 – GMO-Resistant Weeds

        Weeds resistant to glyphosate, the herbicide used with many GMO crops, are detected in Australia. Research shows that the super weeds are seven to 11 times more resistant to glyphosate than the standard susceptible population.

        1997 – Mandatory Labels

        The European Union rules in favor of mandatory labeling on all GMO food products, including animal feed.

        1999 – GMO Food Crops Dominate

        Over 100 million acres worldwide are planted with genetically engineered seeds. The marketplace begins embracing GMO technology at an alarming rate.

        2003 – GMO-Resistant Pests

        In 2003, a Bt-toxin-resistant caterpillar-cum-moth, Helicoverpa zea, is
        found feasting on GMO Bt cotton crops in the southern United States. In less than a decade, the bugs have adapted to the genetically engineered toxin produced by the modified plants.

        2011 – Bt Toxin in Humans

        Research in eastern Quebec finds Bt toxins in the blood of pregnant
        women and shows evidence that the toxin is passed to fetuses.

        2012 – Farmer Wins Court Battle

        French farmer Paul Francois sues Monsanto for chemical poisoning he claims was caused by its pesticide Lasso, part of the Roundup Ready lineof products. Francois wins and sets a new precedent for future cases.

        2014 – GMO Patent Expires

        Monsanto’s patent on the Roundup Ready line of genetically engineered seeds will end in two years. In 2009, Monsanto introduced Roundup 2 with a new patent set to make the first-generation seed obsolete.

  • Sandra Price

    Dr. Gregor: I recently ran across an interview of MIT scientist Stephanie Seneff discuss glyphosate in our foods and it’s affect on gut bacteria and amino acids as a possible cause of autism. The interview can be googled using her name, glyphosate and autism. Here are the slides from a talk she gave recently on this subject.

    I wondered what you think of this as a possible explanation for large increase in autism cases worldwide.

    Thank you for this excellent site. It’s outstanding.

    Sandra Price

    • e

      the paper actually proposes that glyphosate is cause for a whole myriad of diseases, not just autism–very interesting–some novel re cholesterol– hypotheses in this work–we need to wake up and get all genetic engineering stopped.

  • Martha Helene Jones

    No researcher can completely assess the potential of harm to those allergic to the protein in a genetic modification since allergies are so specific to the individual but here is a link to an article citing a good deal of research suggesting an association of the extreme rise in allergies with GMOs:

  • MMR

    There is no objective scientific reason that genetically modified foods should be harmful. If we take out the issue of pesticides, which may take advantage of the benefits of GMO but shouldn’t be an argument against genetic modification per se, they should theoretically be like any other plants. Species are always genetically modifying themselves naturally at random, so for a scientist to go in and speed up the process, or make it more beneficial to humans, and then let the plants grow naturally without chemicals, does not make the plants less “natural”. Of course, safety assessments should be done on such plants as they are new species and may have different levels of the compounds in them, but any food that evolves on it’s own would be the same. Therefore, to indiscriminately oppose ALL genetic modification of food on the basis of health effects (as opposed to the use of pesticides, the ethical standings of the companies that produce them, effects on the environment, etc) is ridiculous and may be detrimental to all the amazing advancements that could come out of this research.

  • Barbara

    Why would the latest review on GMO plants not be freely available? If it were all good, wouldn’t it be made available immediately? Even if its inconclusive, it could be presented as such, I would think. To be on the safe side, I avoid it as much as possible. It’s labeled here in Europe…

    • b00mer

      That is simply the nature of scientific publishing. Once a study is published, the publishing house (in this case Elsevier) owns the article and can charge for access to it. In fact, if you publish an article while you’re in grad school, and later want to include that material in your dissertation, you have to ask the publisher for permission, since you don’t own it anymore, they do. There is a push towards open access publishing, but unfortunately it is harder on the individual researcher financially, and there is also the issue of the “impact factor” associated with already existing journals. To opt to publish in the newer open access journals, a researcher loses the status and impact factor associated with the traditional journals. Hopefully the situation will improve in the future; personally I find it abominable that publicly funded research is not available to the public.

      So, while you don’t have access to this article on your own, you may try a local university library, particularly a research-oriented one, and if that library has a subscription to that particular journal (these can cost in the tens of thousands of dollars per year), then you will be able to access it on the library computers freely.

      I can access this particular review at my work, and what they say basically is that there was only enough new information to genuinely reassess three plants: maize, soybeans, and rice. Among these plants, there are studies showing that they are harmful, and studies showing that they are harmless, and so the debate continues.

      They also make reference to this summary published by the European Food Safety Authority, which you should have access to:

    • Susan

      Monsanto and their allies are very aware that Europeans and others who have the right to know will not willing eat or buy their crops.
      The way they fed the Europeans gmo corn and soy was through the livestock feed shipped from Brazil and Argentina. The EU boycotted the same product from the USA, according to Friends of Earth-Europe.

      They do not want to lose control of the U.S.A. marketplace. Plus, they are growing food in the USA and through Obama’s trade agreements forcing the entire world to eat this potentially toxic food. Hence, we will all die of the same or similar diseases, and no single herbicide or gmo will be singled out.

      Monsanto and allies have also BLOCKED anyone from studying their seeds, they have blocked journals from publishing data, and they have appointed one of their approved scientists to the independent CRIIGEN.

      • Eskil J.

        They’re just your average american corporation and there are a lot of myths surrounding them as well as they have become the icon of corporate evil. Yet that is hardly the case.

        Seralini has been so severely debunked for not following standard procedures. As an easy wiki reference read will teach you:

        “The conclusions that Séralini drew from the experiments were widely criticized, as was the design of the experiments.[3][4] Scientists claimed that Séralini’s conclusions were impossible to justify given the small sample size and the known high incidence of tumors in Sprague-Dawley rats. The paper was also refuted by food standards agencies.[5] Other long term studies, which were publicly funded, have uncovered no health issues.[4][5] The release of the book and movie in conjunction with the scientific paper, and the requirement that journalists sign a confidentiality agreement, were also criticized and negatively peer reviewed.[3]”

  • TR M

    When you eat GMO foods you are eating glyphosate. That poisons you gut bacteria by the same shikimate pathway that kills plants and leads to autoimmune and inflammation based conditions.

    Do you have any information on what if any the safe level of glyphosate is for human consumption? How to get rid of it if when you are exposed?


    • e

      how could there be any safe level when it works as you yourself state??

      • TR M

        That is a very valid question. Along with a few others.

        1) Why don’t they test Roundup (the finished product) rather than just the single so called active ingredient?

        2) Is there an additive or synergistic effect with the adjuvant chemicals used with glyphosate?

        3) Why do they raise the allowable levels when each new generation of GMO crops get released?

        4) Now that super weeds are resistant to glyphosate what levels of 2-4D are safe for long term consumption? That is the next wave of GMO crops coming.

        • Susan

          How would one know which of the many ingredients in Roundup may be causing the problem? The active ingredient, glyphosate, is the only ingredient off-patent now.

          2,4-D, which unintentionally contains 2,3,7,8-tetrachlorinated diobenzo-p-dioxin (the same chemical responsible for severe birth defects/developmental disorders in Vietnam, and major chemical spills or explosions, PVC plastics, and more, is a component of the herbicide, which was sparingly approved on cereal grains, but will now be used on soy and corn that have been genetically engineered to be herbicide resistant.

          It’s a good reason to eat low on the food chain, low fat foods, and also have a whole house and at least a kitchen carbon filter water purifier.

          My Multi-Pure 750 sb (below the sink) will reduce both 2,4-D and dioxin from my tap water if it is in there.

          It has been in the past, but the city changed water sources and last testing showed it was not present. This was confirmed by tests which I also paid for.
          Have your water tested by a reliable lab. If it contains 2,4-D, by all means, get the best water filter you can afford.

          But, remember. If spraying is occurring near you, as it is within 15 miles of where I live, nothing can prevent airborne emissions- drift from drifting down on my organic homegrown crops or coming down with the rain.

          Monsanto says GE broccoli and tomatoes are coming.

          I buy those grown by the organic method, until I can grow my own.

    • Susan

      When you are eating gmo foods, you are eating MORE THAN glyphosate. Monsanto also uses 2,4-D (a dioxin contaminated chemical of the worst kind). Roundup may also be contaminated with dioxin, but no one knows for certain because the testing has not been done.
      As someone who has been poisoned with pesticides, who has found that physicians are taught to treat the symptoms not cure a disease, let me say there are no safe levels. So much can go wrong with your health in addition to cancers…and then, there are synergistic effects.
      Do you even know a water company that is certified by NSF to reduce glyphosate in your tap water? Or, are there any testing procedures that show glyphosate may be in your tap water? I suggest Monsanto has blocked that pathway, as well..

  • Eskil J.

    I would say there is no reason to oppose GMO’s based on the supposed health issues because there are none as any complete review of the scientific literature demonstrates:

    In fact most researchers against GMO’s have routinely had an agenda and misrepresented their studies for selfish gains. Here’s some examples:

    And when it comes to Monsanto they’re no worse than your average corporation and they have just become the icon of corporate evil. Yet most of the claims about them are just outright false:

    As for environmental concerns, it varies greatly between climates and in some cases GM crops are better for environment and use less hectares, pesticides, etc.

    The problem is monoculture in general and not GM crops. Although GM crops do pose solutions for this and Monsanto did as well, but… (watch the video)

    “It’s all just big agro conspiracy mongering that’s just part of an anti-GMO ideological agenda.”

  • Susan

    I have severe osteoporosis and keep breaking bones. I have refused to take genetically engineered Boniva or other recombinant DNA pharms which use E-coli bacteria to make the product. Look at the side effects of the bisphosonate drugs at the National Library of Medicine.

    It’s not only pharms that use organisms from other species, food crops use the same. I intercepted an posting by a major player in the contamination of our food that will be using a Superbug — antibiotic resistant bacteria for its GE corn and soy. No wonder hospitals have so many cases of antibiotic resistant bacteria!

    The Environmental Working Group using data from the CDC and USDA compiled a report of antibiotic resistant bacteria identified in livestock found in supermarkets throughout the country.
    When I had an infection last year, nothing my physician prescribed worked until I suggested that he use an older antibiotic because I’ve eaten vegan for the past 2 years, and only ate certified organic for a decade previous to that. The older drug worked.
    More recently, another physician who treated me for a pelvic fracture (due to a bad fall). Viewing the x-ray at the time of the injury, and the comparison tone done 3 weeks later, he said he had never seen anyone grow bone so fast. At the next visit, two months from the onset of the injury, he declared my bone totally healed. Perhaps, it was because I only eat certified organic and only from companies I trust and now only eat healthy vegan!

    When I stop healing quickly, it may be because our food is contaminated with mineral chelators –herbicides. Roundup is patented as a mineral chelator, binding minerals in the soil and keeping them from being assimilated by plants and animals.
    I DO NOT LOOK FORWARD TO being forced to eat genetically engineered foods, given what has been learned about Roundup from abstracts of scientific studies, and the severe clinical health effects of the process of genetic engineering itself as told go us with genetically engineered “biological” pharmaceuticals.

    • Malia

      Eskil must work for Monsanto or has another financial concern. My advice: Don’t eat one GMO! It isn’t easy. I buy ONLY organic, eat ONLY vegan since watching Dr. Greger, never EVER go out to eat (and I won’t until they have a GMO-free option on the menu.. not just Vegan as I asked a waiter if the Vegan Portuguese Soup was GMO free but in fact they had used Canola Oil— Big One Not to Eat). So my life has gotten pretty restrictive but my Multiple Sclerosis has not gotten any worse in 5 years and I wonder what would happen if I had been on a GMO/Glycosphate/agent orage/whateverthecrap they want to feed us. I feel totally let down by my government NOT EVEN labeling them. Fortunately the money I save from not eating at restaurants has helped me to afford my organic food. It makes me ashamed to be an American, frankly.

  • Ilana

    Is there any update to the GMO debate? :-(

  • Veg-E

    After watching the documentary ‘Genetic Roulette’ like what the good Dr. Don Forrester M.D. suggested. I don’t ever want to eat GMOs products again and I’m not alone in that line of thought. You can see clearly in the movie that there is plenty to be worried about and thus GMOs should be avoided. At the very least labeled like gluten and nuts are. GMOs labeling needs to happen and the fact that Monsanto spent 43Mil in deceptive advertising here in California to defeat labling speaks volumes about the companies deceptive ways. What are they hiding? Scary stuff GMOs… again, just watch ‘Genetic Roulette and make up your own mind. Don’t listen to the paid shills like a few people in this thread defending GMOs. Watch the documentaries and maek up your own mind. Knowledge is power.

  • Malia

    I am anxiously awaiting the GMO discussion Dr. Greger promised us. I know it will be informative! Thank you Dr. Greger.. You have become my answer to life. I have never followed or trusted anyone as much. I do not think you can be bought by anyone although I was afraid the GMO industry would contact you because of your up-coming discussion on it. Malia

  • nicolestier

    Unrelated: Can you advise if people need to or should take a baby aspirin daily? If so, who should take it and at what age? Thanks!