Response to Ena Valikov Comments

Thank you again for responding. I really appreciate when people choose to comment and provide references. If you decide to post again I would appreciate if you make specific criticisms on any studies you disagree with. When you make statements such as “the Hammond studies cited: see if you reach the same conclusions” you are not telling me why their conclusions are invalid. Please be specific in your comments so you can indicate where the authors went wrong.

Now I will address your 2 points:

1)

In regards to the studies conducted by Hammond et al, I have found them to be of high quality and I agree with the conclusions of the authors. I will include a few quotes from these studies to illustrate this point.

(Hammond et al, 2006a)

This quote is found in the conclusion where they indicate that the EFSA (European Food Safety Authority) endorses their results and their conclusions.

“The summary prepared by the GMO Panel of the European Food Safety Authority best captures the prevailing scientific conclusion regarding the findings from this study. EFSA concluded that the results of the 90-day rodent study do not indicate adverse effects from consumption of maize line MON 863 (EFSA, 2004b)”.1

(Hammond et al, 2006b)

Here I will simply include a section from the results where some differences between the control and experimental groups are explained.

“Compositional, contaminant, and nutritional content of the experimental diets met the specifications for Certified Rodent LabDiet 5002 established by PMI. The levels of heavy metals, aflatoxins, and chlorinated and organophosphate insecticides were below detection limits. For chlordane, the analytical limit of detection was higher (250 ppb) than the maximum allowable concentration of 50 ppb, but was not considered to have an impact on the study. PCR analysis confirmed that the test diet contained MON 810 as it tested positive for the Cry1Ab transformation event. The control and reference diets did not test positive for the Cry1Ab transformation event. All of the 400 animals were healthy and appeared normal during the course of the study with the exception of one reference male that had to be sacrificed a few weeks prior to study termination due to injury. There were no changes noted during the duration of the study in behavior, activity, posture, gait, or external appearance that were considered to be test article related (data not shown).

3.1. Body weight and food consumption

Overall, body weight and weight gain were comparable for MON 810, control and reference groups (Figs. 1 and 2). Food consumption was generally similar between MON 810, control, and reference groups throughout the course of the study (Figs. 3 and 4).

3.2. Clinical pathology parameters

Clinical pathology parameters (hematology, blood chemistry, urinalysis) were generally comparable for all groups. There were a few statistically significant differences between the MON 810 and the control groups after 4 weeks and at study termination. None of these differences were considered test article related since they were of small magnitude and within ±2SD of the mean for the population of reference groups, and were either different from the control or the reference group but not both, or were not dose related (observed at the low dose but not at the high dose), and/or occurred after 4 weeks but not at study termination.

3.2.1. Hematology

Results for males and females, measured at study termination (week 13), are contained in Tables 2 and 3, respectively. There were no statistically significant differences between male and female MON 810 groups and the controls and reference groups for most of the parameters measured. There were two statistically significant differences (MCHC, PLT) observed in females that were not dose related and therefore not considered to be test article related.

3.2.2. Serum chemistry

Results for males and females, measured at study termination (week 13), are contained in Tables 4 and 5, respectively. There were no statistically significant differences between male and female MON 810 groups and their control and reference groups for most of the parameters measured. The few statistically significant differences observed were not considered to be test article related as they were of small magnitude and fell within ±2SD of the mean of the reference groups (Hammond et al., 2004b). The slight reduction in A/G (albumin/globulin) ratio for high dose MON 810 males was attributed to the slightly lower albumin and slightly higher globulin levels for MON 810 males, neither of which were individually statistically different from controls. The A/G ratio for MON 810 males also fell within ±2SD of the mean (1.79 ± 0.34) of the reference groups (Hammond et al., 2004b) even though it was slightly, but statistically significantly lower that both the control and reference groups. There were no differences in A/G ratio for females. This finding was not considered to be test article related.

3.2.3. Urine chemistry

There were a few statistically significant differences, but these occurred only in the males at the interim sampling period and none occurred at study termination (data not presented). None of the differences were concluded to be test article related.

3.3. Organ weights

There were no statistically significant differences noted in absolute or relative organ weights between treated and control animals. Table 6 presents organ weight data relative to body weights (absolute organ weights and organ weight relative to brain weight data are not shown).

3.4. Pathology

At necropsy, no gross or microscopic lesions were observed that were considered to be test article related(Table 7). The few spontaneous findings that were observed were generally of minimal to slight/mild severity, were randomly distributed among all groups and were the type commonly observed in control rats of this age and strain.”.2

(Hammond et al, 2004)

In regards to this study I would also like to refer you to the results section. In the results they give explanations of any statistically significant differences between treatment and control groups.

To reiterate my earlier point, if you want to criticize their conclusions you must specifically state what they did wrong.

2)

In regards to the papers produced by Malatesta et al., I would like to refer to the comments of the UK Advisory Committee on Novel Foods and Processes. This is what they had to say about their findings:

“The Committee was invited to consider a series of papers published by Italian researchers which examined the differences between the cells from mice given genetically modified (GM) and non-GM soya. Members were asked to identify any conclusions that could be drawn regarding the safety of GM herbicide-resistant soya.

Members noted that the papers did not state the origin of the GM and non-GM soya used in the feeding studies. There were no details of whether the soya had been grown in a field or under controlled conditions and whether or not the GM and non-GM soya were grown, handled and processed under similar conditions. It was also not clear whether the soya used in the control and GM experiments had a similar genetic background.

The Committee was unable to determine whether or not the GM and non-GM soya crops had been treated with the herbicide glyphosate, although the authors had suggested that differences in residual levels of glyphosate might be responsible for the observed differences.”3

Another paper was written in 2010 that further criticized the Malatesta paper that was written in 2008. They came up with 6 methodological problems that make this study invalid. They are as follows:

‘‘controlling for potential litter effect’’,

‘‘using an appropriate number of experimental animals per group and acquiring a sufficiently robust sample of independent observations’’,

‘‘establishing the representativeness of observations’’,

‘‘adhering to the principles for stereologic morphometry’’,

‘‘using appropriate statistical methods (for study design as well as for data analysis)’’,

‘‘controlling for potential confounding factors, including those related to differences in diet phytoestrogen contents’’.4

Considering all the criticism these studies have received and the obvious flaws they have; they do not indicate that GMO’s have metabolic harm. As you have said “The key to this, though, is to step back and examine the DATA to see if it supports the hypothesis”, I would suggest looking closer at the literature before you cite it in your argument.

Now I would like to address your comments in regards to the length of the triticale studies. I would agree that 90 days may not be long enough to examine all of the potential health impacts. I think that longer studies are needed so that we can truly know what effects GM foods have. I would also like to see a study done in human populations (although the logistics could be a nightmare). As I stated in my blog the most reliable evidence we have says that they are safe, that does not mean that more experiments wouldn't be helpful.

I do have institutional access to the primary literature, I could not comment on these issues without it.

Thank you again for commenting, I appreciate the discussion.

References

1. Hammond, B., Lemen, J., Dudek, R., Ward, D., Jiang, C., Nemeth, M., Burns, J., 2006a. Results of a 90-day safety assurance study with rats fed grain from corn rootworm-protected corn. Food Chem. Toxicol. 44, 147–160.

2. Hammond, B., Dudek, R., Lemen, J., Nemeth, M., 2006b. Results of a 90-day safety assurance study with rats fed grain from corn borer protected corn. Food Chem. Toxicol. 44, 1092–1099.

3. UK Advisory Committee on Novel Foods and Processes, 2006. Committee Paper for Discussion ACNFP/78/7 Advisory Committee on Novel Foods and Processes Ultrastructural Changes in Organs of Mice Fed GM and Non-GM Soya. Available at: <http://www.food.gov.uk/multimedia/pdfs/acnfp_78_7_.pdf>. Minutes of the Meeting Held on 20 July 2006, London, UK. Available at: <http://acnfp.food.gov.uk/meetings/acnfpmeet2006/acnfpjul06/acnfpminsjuly2006>.

4. Williams, A.L., DeSesso J.M. 2010. Genetically-modified soybeans. A critical evaluation of studies addressing potential changes associated with ingestion. The Toxicologist. 114, 1, 1154. Annual Meeting of the Society of Toxicology Salt Lake City, Utah March 7–11, 2010.