Sunday, December 14, 2014

Quit asking me to prove that GMOs are safe

So I'm writing this article out of frustration and it's probably going to be a long rant. It's inspired by several of the comments that I've received for articles I've written for the Genetic Literacy Project.

Quit asking me to prove to you that GMOs are safe. That's a ridiculous request which I won't be able to do. To explain why, we're going to do an exercise and try to prove that water is safe. The first thing to keep in mind is that there are many aspects to safety. In our example, we have to select an aspect of water safety that we want to examine: health impact, water transportation, water treatment, proper water storage, etc. For our example, we're going to select "health impact".

Then, we have to come up with a null hypothesis. Spouse, I know that it's counter-intuitive and the double negatives in these statements suck, but unfortunately, it's a key aspect of this whole article. The baseline for much of research is that there's no impact or no difference. It's the researcher's responsibility to disprove that hypothesis, ie. to show that there is a difference or that there is an impact. So for our exercise, our hypothesis will be "Drinking water does not cause cancer".

Next step, narrow down the hypothesis to a question, i.e what we're actually going to test. For our study, we're going to say "Individuals who have lived in the Alameda County of the San Francisco Bay Area for 10-20 years and drink 2-4 cups of tap water daily do not have a greater incidence of breast cancer than the national average".

We conduct our study and gather data which will probably take a few years. Then we apply the proper statistics. If our study finds a difference, then we've disproven our null hypothesis and much hoopla will be made. If there's no difference, then our null hypothesis still stands and our study will be published in a not-so-important journal and we won't win the Nobel prize.

So, let's say that we find no difference in breast cancer incidence in water drinkers. Have we "proven" that water is "safe"? No. All we've done is add data to the body of evidence that suggests that drinking water does not cause cancer and that it's safe to drink it. But you haven't "proven that it's safe". In fact, water can be considered downright dangerous. Drink too little and you die; drink too much and you die; if it's not properly purified you can diet; etc. The experiments that have been performed have helped identify the possible dangers inherent in water and how to minimize the risks.

Here are a few other examples of a broad hypothesis along with a more narrow question of what will be tested:

Broad: The MMR vaccine does not cause autism. Narrow: There is no significant difference in the incidence of autism between African-American children who have received Merck's MMR vaccine in the San Jose Bay Area and controls.

Broad: Eating transgenic crops does not harm the gut. Narrow: There is no significant difference in the relative abundance of X bacteria in the intestinal flora of pigs fed a diet consisting of 30% genetically modified Bt-corn for 30 days compared to a control diet.

Again, let's say that you are unable to disprove your null hypothesis. Does that mean that you've proven that the MMR vaccine doesn't cause autism? No. Have you proven that GMOs do not impact the bacteria in the gut? No. What you've done is add data to a body of evidence that suggests that the MMR vaccine doesn't cause autism and that GMOs don't cause harm.

Until someone comes up with a study showing that A causes B, then the null hypothesis is what we turn to: A does not cause B. Otherwise you can hypothesize that when you drop something, it's caused by a ghost who pushed it off your counter, or that earthquakes are caused by invisible dragons jumping all at the same time, and people have to "prove you wrong".... That's not the way it works. Dragons didn't cause the earthquake and ghosts didn't cause the bottle to fall, until you can prove otherwise.

So when you ask me to prove to you that GMOs are safe or to provide a paper that has this evidence, that is absolutely the wrong thing to be asking. Ask a specific question and then try to find the data showing that it DOES cause harm. And I can't provide you with that either because I haven't read a well-designed, well-executed study demonstrating that GMOs cause harm or have a negative health impact. If you have a study at hand, by all means, send it my way.

THIS is why scientists stress the number of studies that have examined GMOs. THIS is why scientists stress the statements made by academic and scientific societies about GMOs. Because no single study proves safety: its the sum of the studies, the body of data, the totality of research that's been done which suggest that the current GMOs on the market are safe.

My last point is this: as I noted above, negative data or being unable to disprove your hypothesis is not sexy. It doesn't really build a career for a research scientist in the current academic system, nor do you get big grants. So many researchers will not pursue a path where they don't see fruitful results. I don't agree with the system and think that it needs to change and its one of many reasons why I'm in the private sector. But for now, this is what scientists in the public arena have to deal with. So if you don't see a study being conducted, maybe that's why. Instead of thinking that it's because the big-fluoride cartel is paying off scientists, it's more likely that a scientist doesn't want to waste her time to figure out if fluoridation of water causes breast cancer when there's no logical way she could see that happening. Maybe the reason why no one has published a paper examining a link between Round-Up Ready corn and Alzheimer isn't because Monsanto is breaking scientists' kneecaps; rather, it's because the experts in the field have seen no reason to pursue that path based on the evidence at hand. Maybe the reason why you can't find data comparing the incidence rate of autism in African-American children in a population of vaccinated children vs a population of controls isn't because big-Pharma is paying off the big journals, but it's probably because such a study would never be approved by an ethics board because you're putting the un-vaccinated population at risk. 

If you want to see that data, by all means: spend 10 years of your life in school earning less than minimum wage, and then try to find a granting agency that will fund your study based on whatever evidence and reasoning you have. Best of luck to you in your future career path!!


  1. I think you are mistating the problem. It is not that you need to prove GM foods are safe. It is that you need to prove that the FDA approval process is robust enough to detect unwanted effects. The main safety net they seem to have is grossly underpowered toxicology studies (e.g. 14 rats per group) that would have difficulty detecting cigarettes as harmful. The sum total of a hodgepodge of (often underpowered) retrospective studies on individual modifications is a sorry substitute for proper systematic testing of every modification that enters the foodchain, and the safety of past modifications says very little about the safety of future modifications because they involve different chemicals, often introduced by different techniques.

    Also, you shouldn't compare the systematic randomized controlled testing in vaccines to the unscientific nonsense that is the doctrine of substantial equivalence. Those tests are rare in GM (golden rice seems to be the exception)

    If you tell people nonsense is science they won't believe us when we tell them to vaccinate their kids.

    1. Well, I agree with you in part: I think that there needs to be a systematic workflow that companies follow to gain the FDA's approval, based on the relative risk of the introduced transgene. I think it would be beneficial for all parties involved.
      I also agree with you when you state that the safety of the GMOs on the marketplace does not guarantee the safety of future modifications. Absolutely.
      But I'm curious as to why you'd state that substantial equivalence is nonsense? I examined substantial equivalence here:

  2. Incidentally water is almost certainly linked to cancer (or rather its precursors such as hydrogen peroxide and other reactive oxygen species):

    The rate of endogenous DNA damage has been estimated to be at least 20,000 lesions per cell per day. Such damage likely results from reactive oxygen species (ROS) that are generated as part of normal cellular metabolism.

    If any synthetic substance caused so much harm (which is almost entirely repaired) there would be mobs with pitchforks storming the doors.


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