|EXTRACT FROM OUR
RECENT LETTERS TO ADVISORY
COMMITTEE ON NOVEL FOODS AND PROCESSES (ACNFP)
|The following points are relevant, and have been
made by a number of scientists who have looked at both studies:
1. Brake and Evenson had a completely different - and highly specific - focus in their GM soya study (testicular development in young male rats) and aspects of their study were very poorly described. The authors may know a lot about sperm and testes analytical techniques, and male fertility issues, but it does not follow that they are experts in nutritional studies.
2. Ermakova used rats while Brake and Evenson used mice.
3. Ermakova was focussing on female reproduction and the growth of offspring of both sexes. We are trying to find out what happened to the female offspring in the B and E study -- we know that they were culled early, and we suspect that they may have been treated as irrelevant.
4. The two research groups used RR soybeans from two totally different sources. Ermakova gave its source in contrast to B and E who did not (apart from saying that it was by a seed dealer and taken from the middle of fields in South Dakota). Ermakova used whole (undefatted) soybeans as a paste and gave it to the rats in addition to the normal rat chow while B and E used extruded and dried meals and formulated diets with these, incorporating about 21% of the transgenic soya into the diet but without specifying how much conventional soya was put into the control diet. Neither of the two groups specify the amount of diet consumed by their respective animals. Basically, both studies lack essential nutritional details, and this is particularly true of the B and E study.
5. You say that the B and E study was "well controlled". Where is the evidence for this? On the contrary, because of the poor nutritional design of the study (or lack of a study design), the authors' conclusions probably cannot be justified. We have no idea what happened to their male mice once they were born; there is no feeding protocol, no data, no weights, no feed intake, and no data on growth patterns related to feed intake.
6. In a comparison of the biological properties of animals any differences in feed intake can have immeasurably greater effect than whether the animals are fed GM- or non-GM feed. Without strict pair-feeding of a group of animals of very similar starting weights one has virtually no chance of finding significant differences. So when B and E say that the testicular development of their male mice was not influenced by feeding them on GM soybean or non-GM soybean they have wasted a lot of money, work and effort to come to a conclusion that would not stand up to proper scientific scrutiny.
7. As indicated above, Brake and Evenson are not experts in animal nutrition, and their published output shows that they are specialists in fertility issues and reproduction. It is therefore foolish to assume that their 2004 study is somehow "superior" to that of Ermakova simply because it was peer-reviewed prior to publication. The peer review process is not in itself a guarantee of either scientific rigour or meaningful results.
8. As far as the Brake and Evenson affiliations are concerned, South Dakota Agricultural Experiment Station does a large amount of field testing of Roundup Ready soya for Monsanto and compares yield etc with conventional soya. So there are clearly very close relations with at least one GM multinational. We do not know where their research grant money comes from, since the trail is very difficult to follow. But caution about "sponsor pressure" would certainly be in order.
9. Ermakova was so surprised by her own results re offspring mortality rates that she repeated the experiment three times, with similar results. This is not the action of a slapdash or biased scientist. She also asked histologists to perform analyses of some of the organs of "Non-GM" rats and "GM rats". They investigated testes and liver and found great changes in the cells of these organs similar to those found by the Italian scientist M.Malatesta.
What we are saying is this: there are even more problems and uncertainties associated with the Brake / Evenson study than there are with the Ermakove study.
COMMENT FROM JOE CUMMINS ON THE B&E STUDY:
"My thinking is that it is ridiculous to claim that negative results (on tissue/organ damage) with mice, somehow make positive results with rats invalid. Years of studies such as the cancer feeding studies have always taken positive studies seriously even though there are many instances where chemicals cause cancer in either rats or mice but not in both. I find it shocking that qualified scientists might make claims that obfuscate positive findings that endanger people.
Turning to the two mouse studies, both follow testicular cell kinetics using flow cytometry but they do not look into instances of chromosome damage or rearrangement. Agents that cause, say, dominant lethality, were not even considered. Even if the diet did not visibly affect testicular development it is my understanding that many genotoxic agents may not disrupt cell kinetics. Hydroxyurea, used as a positive control in the studies as a chemical that disrupts cell kinetics, is a chemical used in cancer chemotherapy. However, micro nuclei were studied in neither report even though they are more sensitive indicators of gene damage. It is safe to say that the gross cell kinetic studies reported are useful but full studies of genotoxicity are needed.
Extrapolation of the two mouse studies to humans and concluding "Bt is not harmful to human reproduction" is a stretch, and cannot be taken seriously from a scientific point of view. The statement is clearly there simply for public relations purposes."
A generational study of glyphosate-tolerant soybeans on mouse fetal, postnatal, pubertal and adult testicular development. Food Chem Toxicol. 2004 Jan;42(1):29-36. Brake DG, Evenson DP.
Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA.
The health safety of transgenic soybeans (glyphosate-tolerant or Roundup Ready) was studied using the mammalian testis (mouse model) as a sensitive biomonitor of potential toxic effects. Pregnant mice were fed a transgenic soybean or a non-transgenic (conventional) diet through gestation and lactation. After weaning, the young male mice were maintained on the respective diets. At 8, 16, 26, 32, 63 and 87 days after birth, three male mice and an adult reference mouse were killed, the testes surgically removed, and the cell populations measured by flow cytometry. Multi-generational studies were conducted in the same manner. The results showed that the transgenic foodstuffs had no effect on macromolecular synthesis or cell growth and differentiation as evidenced by no differences in the percentages of testicular cell populations (haploid, diploid, and tetraploid) between the transgenic soybean-fed mice and those fed the conventional diet. Additionally, there were no differences in litter sizes and body weights of the two groups. It was concluded that the transgenic soybean diet had no negative effect on fetal, postnatal, pubertal or adult testicular development.