What is Nature Biotechnology good for?

The critics’ challenges to Dr Ermakova’s work are mostly reasonable (2). They rest on demonstrating flaws in her methodology and also on the assertion that her work is further contradicted by four mammalian feeding studies of Roundup Ready soy, even though, unlike Dr Ermakova’s, all of these are single generation studies (Zhu et al. 2004; Teshima et al. 2000; Cromwell et al. 2002; Hammond et al. 1996). As in their comparison with the Brake and Evenson work however, the criticisms create the impression that these papers do not themselves suffer from the flaws noted in Dr Ermakova’s work. This is not the case however and from a toxicological perspective, the limitations of all these studies (summarised in Tables A and B) are strikingly similar to those pointed out by Dr Ermakova’s critics.

Table A details for each study the preparation and selection of soybeans for consumption (e.g. whether Roundup Ready and control soybeans were grown under the same conditions, whether isogenic lines were used, whether the presence/absence of the transgene was ascertained, etc.) while Table B details key attributes of the feeding studies themselves (such as how many animals were used, what percent soy was included in the diet etc). Looking at Tables A and B it is plain to see that, as a result of their collective limitations (which include short study durations, small numbers of animals and lack of replication), while no adverse effects were reported (though see footnote 3), their individual and collective limitations are highly significant.

These inadequacies, which are fundamental to any discussion about whether Dr Ermakova’s data are in conflict with the published literature, appear to have been missed entirely by the Nature Biotechnology critics. It is not the only mistake they make however. They seem to have been unaware of the Malatesta papers, they cite Teshima et al. and Zhu et al. in stating that “Previous reports in the literature have shown no effects of Roundup Ready soy on birth weights or pup mortality” (p983) yet neither paper studied birth weights, pregnant rats or pregnant mice. In fact, Teshima et al. started their study on rats and mice that were both seven weeks old and Zhu et al. started theirs on 28 day old rats. None of these are trivial errors and they make the question-raised by Roland Fischer of WOZ-of why Nature Biotechnology failed to use truly expert referees, a highly pertinent one.

Ultimately, more important than any misrepresentation of the evidence by these four critics, is a question that is central for regulators who are asked to approve and consumers who are offered Roundup Ready soy: does the existence of these seven flawed studies tell us anything useful about the safety or otherwise of Roundup Ready cultivars? This question is also an interesting one purely from a scientific perspective because current scientific understandings (especially in regulatory science) are very frequently constructed from small numbers of highly imperfect studies. The answer would seem to depend on at least three parameters, all of which are mutually dependent. Firstly, the precise nature of those flaws, because some, such as failing to positively determine the presence of the transgene in the treatments, and equally its’ absence from the controls, ought to invalidate any experiment regardless of the subsequent quality of data collected (4). The second significant parameter is whether the flaws in each paper are the same or overlapping. Flaws in one paper, and usually these will be data gaps, can sometimes be made up for by the results of another. Lastly, an experiment may be perfectly useful, but nevertheless not support the conclusions which the authors draw. Failure to use isogenic lines and/or to grow them side-by-side means that, whatever the title of a paper may imply, any effect seen in the treatment group cannot be attributed specifically to presence of the Roundup Ready transgene. Using these criteria, any conclusions about the safety of Roundup Ready soy based on these data must be extremely limited and highly provisional, and consequently deeply unsatisfactory.

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