Ratting out the truth on GMOs: Seralini vs Science.

Here goes - my first post for The Life of Sci and I'm going straight in at the deep end with a LONG post on one of the most contentious studies of our generation - 
"Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize", Seralini et al., 2012. 

Incidentally, this has since been retracted but people are still using it as justification for being anti-GMO.

[Edit from the author, Oct 2014; this has been re-published again since I wrote this post and is available at - http://www.enveurope.com/content/26/1/14 ] 

Before I start, I'm going to include a disclaimer right here - 
I hate this study with a passion. More so than any other article or meme or anything else that exists out there. 

So let's start at the top - the title. 

Well, this title sure sets the tone for the piece. Note it's not "Long term assessment of toxicity" but "long term toxicity", why do I point this out? "Long term toxicity" implies that it is toxic for a long time rather than that the assessment was carried out over a long time. First red flag.


Let's look at the methods...

The basic method for GMO toxicity analysis appears to be:

• Rats were fed varying amounts of GM corn in their diet.
• Rats were fed varying amounts of Roundup (aka glyphosate) in their water.

Thats my second red flag right there. 

By using varying amounts of GM corn you are making your test groups very small. The issue with this is that it makes things that are insignificant, look significant. I'll explain how...

You have 4 rats. You put them in two groups - treatment vs control. One of the treatment group dies - 50% death rate for that treatment. 

Someone else does the same experiment but with 10 rats, treatment vs control, TWO die which is DOUBLE your estimate but oh! It's only a 20% death rate! And suddenly, your significant result is much less so!

So which estimate is right? Neither, the groups are too small to be statistically significant. 

Statistically insignificant group numbers do more harm than good. For a start - there is no excuse for it as maths wizards have created a whole suite of stats programmes that can calculate the minimum number of subjects and controls you need for it to be significant. Secondly - whenever you do an animal study, particularly a vivisection like this one, if your data is not statistically viable then frankly, animals have died for no good reason. 

And it gets worse when you vary your experiment as much as the Seralini study did...

• Some of the animals were fed non GM corn, some were given GM corn - three differing percentages of GM corn within their diet... So we're at 4 groups already...
• Some of each of those groups were also given Roundup in their water, some were not - and again, 3 differing levels of Roundup... 
• Oh and they were also split by sex!

Frankly it is now impossible to work out which rats were in which damn group!

Secondly each time you split your study into smaller groups, you are either using animals for no good reason or you need to use more animals. 

I am pro-vivisection but only when the "3 Rs" are applied -

1. REPLACE. Use other studies where possible such as testing on cell lines (in vitro). 
2. REDUCE. Use the lowest number of animals required to get a statistically robust result. Too many is unnecessary, too few is pointless.
3. REFINE. Make sure your study meets the above requirements and does not subject the animals to excessive suffering.

Which actually brings me onto my next set of red flags...

The rats used in this study are a breed known as Sprague-Dawley. 

MASSIVE SET OF RED FLAGS.

Why does this demand such a large warning? Well, this is basically the entire reason I HATE this study as all the points I hate go back to this one...

Sprague-Dawley rats were bred for use in labs - they're the pink-eyed albino ones everybody imagines when you think "lab rat" and they became popular because they're generally calm (read: not so bitey!) and produce lots of offspring (average litter is 11 pups).

Here's the downsides - 

1. they have a shorter than average lifespan, most rats live about 3-5 years and SD rats live at most 2 years.
2. they tend to die of cancer and are more prone to developing cancer. 

Which means guess what they're not great for?!

Studies based on cancer development and studies lasting 2 years.

Guess what?

The Seralini study,

• took place over two years - RED FLAG.
• used tumour progression and growth as an indicator of toxicity - RED FLAG.

So that really skews the data this study has produced as it suggests that most of these poor rats would have gotten cancer anyway and died from it within those two years. From a science perspective, this means that at best the data presented is inconclusive and at worst it is a false study whereby the natural lifespan and predisposition were not accounted for. Unfortunately, I'd say it is the latter.

The use of SD rats also raises further issues about the ethics of this study.

The study contains gory, infamous images of these poor rats with massive tumours. In the ethical section of the study, it is stated that the animals were only put-down during the study if they experienced "25% body weight loss, tumors over 25% body weight, hemorrhagic bleeding or prostration". This raises a number of red flags with me...

1. You measure the initial weight of the animal, lets say 30g. How can you distinguish a 25% body weight loss if the tumour weighs a similar amount? Red flag.
2. Why are there no behavioural indicators of distress or pain included within that list such as  behavioural changes, reduced food and/or water consumption? Surely all of those should be grounds for putting an animal out of its misery? Red flag. 
3. Prostration in this context means collapse - so absolutely no activity from the animal. What about reduced activity or difficulty moving or feeding due to the tumours? Red flag.

The answer is simple - the first point about weight goes unanswered, the second and third points were used by the researchers as indicators of toxicity. They chose animals prone to developing tumours and allowed these animals to suffer in order to make their point.

There's a few things to think about here...

• Option 1: do not euthanise the rats and instead allow them to die naturally - downside is obvious cruelty, upside is "truthful" mortality data. 
• Option 2: euthanise the rats when suffering is apparent - downside is a lack of mortality data, upside is lack of cruelty.

Neither option is perfect but I would've preferred as many of the rats to be euthanised as possible than to have suffered. The mortality data in doing this is still useful as it indicates the point at which euthanasia was necessary and gives an indicator of disease development. 

It's also worth pointing out at this point that rats are highly sociable creatures and like to be in groups - hell wild rats live in colonies of hundreds! - these were kept in pairs during "acclimatisation" and unspecified thereafter - a minor red flag but a red flag none the less.

And wait! Theres still more unethical practices in this study!

In order to study the toxicity of Roundup aka glyphosate itself, the researchers fed some groups of rats the normal diet but gave them water supplemented with the herbicide. I'm not even joking. The justification? The maximum amount given was "half of the minimal agricultural working dilution". WOW - RED FLAG AND A HALF.

In agriculture, whether you use organic or standard pesticides and herbicides - workers are often geared up in protective suits as when it comes to toxicity of anything, the dose makes the poison and they are regularly exposed to the chemicals they use. By the time this reaches the water table - it has diluted out considerably. Tap water contains around 50ng/litre, the amount given to some of the rats was 2.25g/litre (2500mg/l) or for a direct comparison, the amount they gave them was 2,250,000,000ng/litre! 

A necessary concentration? Absolutely not on the basis that nobody will ever be exposed to that level of glyphosate especially not through fluid consumption, it is an extreme dose, so there was nothing to be gained from that element of the study (which goes back to my point about the 3 Rs).

So, so far - no evidence that GMOs were to blame for the deaths - just genetic predisposition and malpractice. 

Let's now take a look at the results section!

Going back to my earlier point about groups - it becomes very difficult to work out what results are what. And in fact, different groups are grouped together and compared on different graphs... It may not be falsifying data but it is definitely massaging it to the point where the raw data is unclear and therefore indeterminate - a total RED FLAG!

What there is clear evidence for though, is quite interesting! I say "clear" in a very loose way because Seralini's graphs are very cleverly designed to mask certain results (red flag!)! For a start, if you look closely, the male glyphosate treatment groups actually all lived longer than the control group and had fewer deaths during the study! No, really! And the GM fed males lived a similar timeframe to the controls as did all of the females! So zero effect if not a protective effect!

And in fact - looking at the graphs of humane euthanasia vs spontaneous death vs survived to the end... The moderate treatment groups had more incidences of death during the study than the highest treatment groups...

So eating a little GMO in your diet is worse for you than eating a lot of it!? That makes no sense. As with anything, the dose makes the poison so eating a lot of GMOs, if it is worse for you, should have a worse effect than eating a little of it.

When you look at the tumour data - the females appear to be more susceptible to the supposed effects than the males. Nope - female SD rats are more likely to develop cancer than their male counterparts, often developing mammary tumours and well... We all know why the boys don't! And in fact, later in the paper, it is even stated that mammary tumours were the most common type in the females, so yeah - still all correlating with the genetic predisposition of SD rats.

Going back to the gory images - theres a whole lovely bunch of tumour images. Guess what? Pictures of the rats with tumours and of the dissected tumours are included for the control groups but no pictures at all of any control rats! What are they trying to hide?! Every decent paper shows the control images too. R.E.D. F.L.A.G.

The next set of data are the biochemical analyses and their use as indicators of kidney and liver damage. I'm not even going to go into these, I'm just going to state the obvious... When any animal has cancer and is that sick - their hormone levels and other plasma component levels change dramatically. Ours does too. So much so that certain changes are being looked into as early biomarkers for cancer detection. Enough said. Red flag.

In conclusion - 

The statements made in this paper regarding the supposed toxic effects of GM corn and glyphosate, both individually and in tandem, come from data which has been doctored to the point where it may as well have been falsified. This data is statistically invalid and therefore 200 animals died without us learning anything valuable. 

Short lived rats prone to developing cancer were used and unsurprisingly, the study found a short lifespan and cancer.

I personally believe that GMOs are safe, because many studies have been carried out with robust methods and data that says there is no statistically significant difference between control animals and animals fed GMO diets.

I cannot decide for you whether or not you choose to believe in the wealth of evidence out there that is in favour of GMOs but what I at least hope to have achieved is this:

An understanding that the Seralini study is seriously flawed - methodologically, statistically and ethically and therefore should NOT be used as the basis of any argument that GMOs are unsafe.