Saturday, January 24, 2015

Review of "Gamma-Glutamyl Transferase Activity in Kids Born from Goats Fed Genetically Modified Soybean"

My article debunking Collective-Evolution's viral article about "10 studies proving that GMOs can be harmful to human health" has been cross-posted to other sites. This week, the article led to this exchange:
I was curious to see if there were any papers that outlined a genuine health risk, so I followed up with @GMOTruths and was pointed to an open-access paper entitled "Gamma-Glutamyl Transferase Activity in Kids Born from Goats Fed Genetically Modified Soybean".

So, I'm going to review this 2013 paper here.

First, let's examine the quality of the journal that it was published in: Food and Nutrition Sciences. The journal is not indexed by the NIH's database of scientific publications, which immediately raises a red flag because it indicates that the journal does not meet the NIH's criteria for a quality publication. Next, I searched for the journal in Beall's list of predatory publications: sure enough, the publisher "Scientific Research Publishing" is listed. Predatory journals will publish nearly anything, as long as you pay their hefty publication fee. There have been several exposes on these journals (see here and here) and the crazy papers that they've accepted for publication (my favorite one: the journal accepted a paper entitled "Get Me Off Your F*ing Mailing list". I particularly enjoyed the diagrams from the paper).

So right off the bat, there's something fishy going on. Otherwise, the authors would have published their paper in a better journal.

Let's get to the paper itself.

The authors start by outlining and defining RoundUp Ready Soy (please see this post about the gene and trait in this crop). They state that "the majority of animal feeding trials using GM feeds indicated no clinical effects", but that there is data indicating liver and kidney problems. Their reference for this last statement is the infamous Seralini paper, which was retracted and later republished. They also point to a few other papers as the basis for their study:
  • a paper which "hypothesized that cell metabolism of several enzymes was altered in rabbits fed GM soybean"
  • a paper (from the same authors as above) that found pieces of DNA from the transgene in "goat milk but also the kids organs when mothers are fed GM soybean". The paper also found higher levels of an enzyme in these animals which serves as an indicator of injury and disease (LDH).
So, the aim of the paper is to find out if there are a) DNA fragments from the GM soybean and b) changes in the activity of an enzyme named gamma-glutamyltransferase (GGT) which can serve as an indicator of liver disease, in the kid goats whose mothers were fed RoundUp Ready soybean.

OK, here's my first comment: without even reading the paper, I can tell you that they're going to find DNA fragments from the soybean. As I've outlined in several other articles, DNA from all our food (be it organic, conventional, meat, veggies, etc) gets chopped up in our digestive system and then we find bit and pieces of it in our organs and blood. There are MANY papers that have discussed this so why is this paper going to sacrifice animals to investigate a matter that is already well established?

Regardless, let's continue.

Materials and methods. The authors state that they performed the experiment on 20 male kids born from goats fed a soybean extract from conventional or RoundUp Ready soy. After this point, nothing else really matters because the authors didn't do an analysis of the feed.

If you are going to do an experiment to determine if a single variable impacts a system (in this case, that the presence of the protein that confers RoundUp Ready resistance causes harm in goats), then you have to be pretty dang sure that nothing else is different. Previously, I've described several studies that outline that the location where the crop is grown and the environment create greater variability in a crop than whether or not the crop is transgenic. For example, if I take an ear of corn from Northern Ontario and compare it to an ear of corn from Southern Ontario (of the same variety), they will be more different in terms of nutrients/amino-acids/minerals than taking an ear of corn from Southern Ontario that's a GMO and comparing it to a non-GMO ear of corn of the same variety grown in Southern Ontario.

The paper that I'm reviewing here didn't do an analysis on the composition of the soybeans used in the study. It has no information on the variety of soybean used, the location where they were grown, or even if they were from the same season, etc. In general, feeding studies that I've examined do an analysis of the composition of the feed that is given and then make the feed equivalent by adding supplements, so that the ONLY different component in the feed is the presence/absence of the transgenic protein (and the gene that encodes for it).

Here's a hypothetical example: the scientists conducting a study buy regular soybeans and transgenic soy beans and do a nutritional analysis. They find that the regular soybeans have 12% less calcium and that the transgenic soybeans have 8% less of the amino acid lysine. Maybe it rained a bit more in the farm where the regular soybeans were grown, causing this difference. Maybe they added more fertilizer to the soil where the transgenic soybeans were grown, leading to these differences. Anyway, the researchers will add calcium to the feed that consists of regular soy and add lysine to the feed that consists of transgenic soy. Otherwise, they won't be able to conclude if any differences observed are due to the calcium, the lysine, or the transgenic protein.

So, that's where the paper falls apart.

As expected, the authors detected the presence of DNA from the transgene in organs and blood. Does it matter? Not really: if I took two people and fed one strawberries and the other blueberries, I'd detect small pieces of DNA from the cells of the strawberry in the blood of one person and small pieces of DNA from the cells of the blueberry in the blood of the other person. Does it mean that the individual will turn blue or red? No. So why would DNA from a transgenic crop be any different?

To conclude, the authors detected increased levels of GGT in several tissues, but without the compositional analysis, you can't draw any conclusions.

Final comment: I'm not a very strong animal advocate. I believe that they should be treated with care, but I'm not a vegetarian, let alone a vegan. I'm not a member of PETA. But I believe that scientists have a responsibility to perform animal studies judiciously. If it's not necessary, if there's another way to reach the same conclusion, then give it a shot before you resort to animals. I used animals in my PhD and I hated it. The mice I used were so cute and cuddly, that I'd have nightmares when I had to sacrifice them. I'm so glad I don't have to use model organisms anymore. Unfortunately, this experiment was not an example of the judicious use of animals.

@GMOtruths, I think your concern about this particular paper may be unfounded. What do you think?

UPDATE (Jan 16, 2016): the paper was retracted due to plagiarism. To read more about this, see:

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