Thursday 14 November 2013

If it scares, it leads

I can't really blame the journalists. They're effectively in the infotainment business. And if punters are more likely to buy newspapers with scary stories about genetically modified crops than newspapers taking the consensus of scientists that the GMOs that have made it through the regulatory approval processes have had a far more thorough going-over than ones that have used other mutagenic techniques, well, we can't really blame them too much.

It can screw up policy though. There's a pretty serious externality through the political system where bogus scare stories whip up demand for regulatory regimes. Politicians cater to those demands.

I've spent a fair bit of time at Offsetting hitting on this kind of theme around bogus studies of the social costs of alcohol that do much to inflame public sentiment against consumption but little to inform.

Today's edition: GMOs. A paper in Cell Research last year suggested that bits of microRNA from food could migrate into people and so GMO bits could be dangerous. Canterbury biologist Jack Heinemann then put out a paper arguing, as I understand things, that if the Cell Research paper were right, then GMO wheat could also affect gene expression in people via the same mechanism. Most scientists working in the area thought this nonsense; the Science Media Centre put out a few rebuttals.

Paul Gorman at the Christchurch Press covered the controversy, highlighting all the scary bits.
The Heinemann paper and the reporting on it have yielded some pressure on the government to take action.

The latest issue of Nature Biotechnology features a replication of the Zhang et al paper in Cell Research on which Heinemann's results built. The Zhang paper didn't replicate. From the accompanying Nature Biotechnology editorial:
In contrast to these findings, the report on p. 965 finds no evidence for uptake of plant miRNA168a in the plasma and liver of mice fed a rice diet. Enzyme-linked immunosorbent assay data from the current study also contradict western blots from the Zhang paper that suggested miR168a directly suppressed levels of low-density lipoprotein receptor adapter protein 1 (LDLRAP1) in mice. Finally, the miRagen study suggests differences in diet composition, rather than miRNA-mediated cross-kingdom gene regulation, likely account for alterations in low-density lipoprotein in mouse plasma.
But why put the paper in Nature Biotechnology rather than Cell Research, where the original report was published? In fact, the miRagen investigators did submit their paper to that journal but were told that “it is a bit hard to publish a paper of which the results are largely negative.”
We differ with this assessment and believe the paper is worthy of publication precisely because it is a negative result throwing light on a key research question.
The original finding from Zhang and colleagues that plant miRNAs are capable of cross-kingdom gene regulation was an extraordinary claim. It went against a large body of research in which the systemic administration of double-stranded RNAs was shown incapable of triggering the RNA interference pathway in humans (and mice). It also raised concerns that plant miRNAs could pose health risks to humans. Indeed, last March, an article published in Environment International (5543552013) went so far as to claim that gene modification of plants using gene silencing mechanisms raises concerns for human health and that these concerns are not adequately considered in food safety assessments. This prompted the regulator Food Standards Australia New Zealand to undertake an assessment of the scientific literature on the issue and to publish a position statement on the regulation of genetically modified crops developed using gene silencing.
Bottom line seems to be that FSANZ and the Science Media Centre were right, the Greens (again) were latching on to fringe findings that supported their priors, and the media ran a scare campaign.

The whole Nature Biotechnology editorial is worth reading. They worry a lot about publication incentives and replication work.

Forbes comments on it here:
A great illustration of the challenge of controlling ‘metastasizing misinformation’ has emerged with the publication of a fascinating and important article in Nature Biotechnology that sharply challenges a study that had made controversial claims that dramatically raised the fear factor about GMOs.
The backstory provides an intriguing look at how the anti-GMO industry and sycophant journalists work—and the consequences of flogging single studies to score ideological points.
Since the publication of the original Zhang et al. study, similar research has appeared and the paper itself has been scrutinized—and the results are devastating. In May, researchers at Brigham and Women’s Hospital in Bostonfound that healthy athletes did not carry detectable levels of plant miRNAs in their blood after eating fruit filled with these molecules, and struck out in finding traces in mice or bees. “We conclude,” wrote the authors, “that horizontal delivery of microRNAs via typical dietary ingestion is neither a robust nor a frequent mechanism.”
Then in June, a research team from Johns Hopkins University writing in RNA Biology reported that the results were likely a false positive that resulted from the technique his group used, bolstering the case of skeptics who argued that genetic material from food would have little chance of surviving the digestive system, much less crossing the intestinal lining to enter the bloodstream.
The knockout blow came last week with the release of a replication study published in Nature Biotechnology. A team of scientists led by research scientist Brent Dickinson, using proper controls, could not detect the same microRNA reported by Zhang et al. Bottom line, there was almost none of the original culprit, miR168a, identified (one found in every million miRNAs).  Moreover, they repeated the rice feeding experiment, saw the decrease in LDL that Zhang et al. had found and the changes in LDL did not depend on the availability of miR168a. Instead, the authors added another treatment that corrected an energy/protein imbalance caused by the all-rice diet and the LDL effect went away. In turns out that the LDL effect was a nutrition effect. Mystery solved.”
Ignoring the basic science—few scientists embraced the original Zhang et al. study as it contradicted the logic of previous findings—professional antis will no doubt criticize the replication study as an industry apologia. “Many will dismiss this study because it was done with cooperation from Monsanto,”Folta wrote in his analysis of the newly released paper.  On the other hand, the other cooperator was miRagen [Therapuetics], a company interested in small RNAs for therapies.  They have a vested interest in identifying mechanisms to orally administer miRNA and detect physiological outcomes. If they repeated Zhang et al.’s work it would have been a positive finding for their company, as I’m sure they get plenty of criticism for the viability of their potential therapies.”
Don’t hold your breath for rollbacks of their disgraceful journalism and public comments by LeVeaux, Laskway, Gurian-Sherman, Hansen and others whose statements have ranged from credulous to intellectually dishonest to fraudulent manipulation and misrepresentation of results. Expect chief GMO demonizer Jeffrey Smith—who is a charlatan—to continue to hype this unproven danger in his “analysis” of the “dangers” of GMOs. They are single study syndrome sycophants. As a group—and this includes a sizable cadre of web activists, organic extremists, foodie journalists and campaigning scientists—they cherry pick the handful of papers that support their point of view and ignore the vast majority of research that disagrees. Some might call them professional fear mongerers.
I continue to see no scientific basis for demands that GMO foods be labelled. It just feeds the panic. And I continue to update my priors on those who take the GMO fearmongering seriously. There are real social costs to feeding this kind of nonsense. Jenny McCarthy has much for which to answer; so too do the GMO-worriers.


  1. I couldn't agree more Eric. This propensity towards confirmation bias is one of the more irritating aspect of the Greens and other anti-GM idealogues. It is a shame, because I am sympathetic to some Green policy, mostly around the environment. I just wish they would have a little more respect for science and the scientific method.

  2. Would that there were a version of the Greens that either stayed entirely away from economics (or proposed sensible policies towards their desired econ ends), didn't want to tell me what to eat, but otherwise were about where they are now.

  3. Only a few years ago we had Corngate. the socialists said we would grow two heads if we ate RNA. We managed to splice this corn food into a hungry labour party conference, but alas nothing happened

  4. Only a few years ago we had Corngate. the socialists said we would grow two heads if we ate RNA. We managed to splice this corn food into a hungry labour party conference, but alas nothing happened