Field of Science

GM corn causes cancer in rats: a study in bad science


Last week a scientific paper appeared that reported that eating genetically modified (GM) corn causes cancer in rats.  Specifically, the scientists fed Roundup Ready® corn, or maize, to rats for two years, and reported that both females and males developed cancer and died at higher rates than controls.  

This is very surprising.  If GM corn causes cancer, why aren't Americans "dropping like flies," as one scientist asked?  We've been eating Monsanto's Roundup Ready® corn for over a decade, even if most of us aren't aware of it.  But our rates of cancer haven't increased more than Europeans, who eat far less GM corn.  Maybe the effect is limited to rats - in which case we should also have seen dramatic increases in cancer in lab rats.  But we haven't seen that either.

So what's wrong?  The best way to find out is to read the paper, which I did.  It turns out to be a very badly designed study, and the report itself omits many crucial details that may (and probably do) completely invalidate the findings.  The scientists leading the study have a strongly biases agenda and a conflict of interest, which they failed to reveal. I'll explain below, but meanwhile this study has already been taken up by politicians as proof (proof!) that GMO crops are harmful.  As Forbes blogger Tim Worstall explained, this paper is more politics than science.

Let's look at the study itself, which was led by Gilles-Eric Seralini (more on him below) and published last week in Food and Chemical Toxicology.  (A copy of the full paper is here.)

The authors studied 200 rats for 2 years, dividing them into 20 group of 10 rats each.  The test rats were fed a variety of diets:
  1. Non-GM corn comprising 33% of the diet (this was the control group).
  2. Roundup Ready corn comprising 11%, 22%, or 33% of the food.
  3. Roundup Ready corn that had been treated with Roundup during cultivation.
  4. Non-GM corn but with Roundup itself added to the rats' water.
So what happened?  Well, in some groups, the rats got more cancer than controls.  But not always.  In fact, the authors had to cherry-pick their own data to support their conclusions.

One major problem is that only 10% of the rats were controls - 10 male, 10 female. The study's main claim is that rates of cancer were significantly higher in the rats fed GM corn.  Martina Newell-McGloughlin from UC Davis, in an interview with Discovery News, said 
"The type of statistical analysis they used is really a type of fishing expedition.  One individual referred to it as 'fantasy statistics.' "
Another major problem is that there's no dosage effect.  In other words, if Seralini is right and GM food is bad for you, then more of it should be worse.  But the study's results actually contradict this hypothesis: rats fed the highest levels of GM corn lived longer than rats fed the lowest level.

A third problem, as Discovery News and other sources reported, is that the rats used in this study are a special laboratory strain that is highly prone to cancer.

Perhaps most damning, though, is the fact that rats fed Roundup directly had the longest survival times.  As Seralini's own Figure 1 shows, the longest-living rats in the entire study, out of all the conditions, where those that drank Roundup in their water.  These rats outlived the control rats.

Yum!  Maybe Perrier should start selling Roundup-enhanced spring water?

Seralini and colleagues struggle to explain the internal contradictions in their study.  They write, 
"Interestingly, in the groups of animals fed with the NK603 [Roundup Ready corn] without R[oundup] application, similar effects with respect to enhanced tumor incidence and mortality rates were observed."  
This tortured English is their way of admitting that rats did worse ("similar effects") when fed GM corn that was grown without Roundup.  They don't want to admit that this result contradicts their central hypothesis.

The study was designed to fail: the sample sizes (10 rats in each group) are so small that all the results are likely just due to chance, and none of the differences are meaningful.  It's exceedingly unlikely that the Roundup in the rats' water made them live longer, just as it's unlikely that Roundup Ready corn had any effect on the incidence of cancer.

I know that ad hominem attacks aren't valid, but I can't resist pointing out that Seralini's co-author, Joel de Vendomois, is a homeopath, with a "Homeopathy and Acupuncture Diploma", a double dose of quackery in a single degree.  Seralini has also published a book about the supposed dangers of GMOs, and he and de Vendomois are the lead scientists at CRIIGEN, an organization devoted to lobbying against GMOs. Of course, even if Seralini and de Vendomois are bad scientists, and even if they have a strong bias, their paper isn't necessarily wrong.  It's wrong simply because the science is wrong.

Not surprisingly, an anti-GMO group in California has gleefully embraced the claims of this dreadful paper to argue in favor of Proposition 37, a ballot initiative that will require labelling of genetically modified foods.  And Jose Bove of the European Parliament has used it to claim that all GM crops are harmful to human health.

Let's be clear about the science here.  Genetic modification of foods is a powerful technology that can be incredibly beneficial.  The recent development of salmon that can grow faster is an example: these salmon (developed by a company called AquaBounty) will make fish farming more efficient, and thereby help preserve the perilously endangered wild fish species in our oceans.  On the other hand, GM technology can be used, as Monsanto has done, simply to allow farmers to use more pesticides, which doesn't seem to benefit anyone other than the pesticide producers.  It's unfortunate that Monsanto's behavior has been used as an excuse to give all GMOs a bad name.

Now we have a bad study done by anti-GMO scientists who have allowed their political agenda to trump their scientific judgment.  What a mess.

Stabbing kids with needles: malpractice, or just a very bad idea?


Yesterday's Washington Post featured a terribly researched article titled "Kids and needles is sometimes a good match: Acupuncture can help with pain."

Imagine: a one-year-old boy arrives at an emergency room in New York at 3 a.m. with an asthma attack.  He is slow to respond to a nebulizer treatment.  Enter Dr. Stephen Cowan, who decides to use acupuncture.  That's right, he stabs a one-year-old baby with multiple needles to treat asthma.  According to Dr. Cowan, the boy "reacted calmly" and improved.  The article doesn't provide any more details.

This is appalling.  Sticking needles into a baby has never been shown to have any effectiveness at treating asthma, and we do have treatments that work.  In all likelihood, the nebulizer did work, in the case that Dr. Cowan related to the reporter, but Dr. Cowan mistakenly credits his acupuncture treatment.

Stephen Cowan is a aggressively self-promoting doctor, who claims on his website that he can treat both autism and ADHD with acupuncture and other forms of Chinese Medicine.  He also describes how he convinces children to let him stick needles into them.  He states his belief in mystical "vital energy" or qi, one of the wacky pseudoscientific notions at the core of acupuncture beliefs.  His claims are little more than a modern, mystical version of the claims made by 19th-century snake oil salesman.

The Washington Post story also revealed that Children's National Medical Center in Washington, D.C. recently treated a 17-year-old girl with pancreatitis by stabbing needles into her stomach and other places.  There is no evidence that this works, but the girl's doctor believes it does.  The girl reportedly wasn't harmed, fortunately.

The doctor at Children's Hospital, Jennifer Anderson, is an anesthesiologist who is also an acupuncturist.  In the story, she said "I often treat patients with chronic issues" with acupuncture.  This is frightening: a doctor at a major medical center is telling children, most of whom are too young to even think of questioning the wisdom of a doctor, that sticking them with needles will help their pain.  Dr. Anderson admitted that "she often does two to three treatments a week at first on a child."  So she admits to stabbing many sharp needles into children and telling them that the treatments will help their pain.  She argues that the children report that this is "helpful."

This is perilously close to child abuse.  Children want to please adults, and if an adult tells them something is good for them, especially if an authority figure tells them, they are extremely unlikely to disagree. They'll just swallow the medicine, or endure the treatment, and then tell the adult what she wants to hear.  Dr. Anderson seems unaware of this.  And Children's National Medical Center, a generally outstanding hospital, should be seriously concerned that one of its anesthesiologists is practicing quack medicine on children, who are perhaps the most vulnerable of all patients.

Let's be clear: acupuncture is based on nonsense.  Scientists have gone to great pains to study it, and the conclusion can be stated simply: acupuncture does not work.  (And yes, I know about the latest meta-analysis claiming that acupuncture works.  Dr. Steven Novella has already explained why that analysis is "completely useless.")  If acupuncture were a drug being tested by a pharmaceutical company, it would have been abandoned long ago.  Its proponents are no better than any big pharma company that pushes a drug that it knows to be ineffective.

Acupuncture is worse than ineffective: because it's an invasive procedure, there is a small but real risk of harm.  As I wrote last year in The Atlantic, acupuncturist sometimes cause infections, which can lead to rare but serious complications.  Acupuncturists protest (often) that they use sterile needles, but this very protest reveals their ignorance: most infections are caused by bacteria already present on the skin, which enter through the puncture wound.

Parents: don't let an acupuncturist stick needles into your kids.  Read the science first, and avoid - no, run screaming from - any practitioner who claims that he can adjust the "qi" in your child.

British Health Minister believes in magic water


Well, this is one way to save money on health care.  The new British Minister of Health, Jeremy Hunt, is a firm believer in homeopathy, which treats disease using magic water solutions that contain - well, only water.

Just a few days ago, British prime minister David Cameron shuffled his cabinet, moving Hunt from Minister of Culture to his new position in charge of health.  Within hours, Tom Chivers, a science editor at the Telegraph, reported on Hunt's belief in homeopathy:
"The man put in charge of the nation's health policy is on record as supporting spending public money on magic water to cure disease." 
He went on to add:
"This is not unlike putting someone who thinks the Second World War began in 1986 in charge of the Department of Education."
Not surprisingly, Chivers' blog post was flooded with hundreds of comments, many of them from upset defenders of homeopathy.  Most of their arguments boiled down to "I think it works for me, so there."

Homeopathy is one of the most absurd, wildly implausible forms of quack medicine. I've written about it many times (for example, about the bogus flu pills sold as oscillococcinum,
about NCCAM's embarrassing funding of studies of homeopathy, and about how homeopaths offer strychnine to cure children's colds), so I'll try not to repeat myself.  Homeopathy is founded on two basic notinos, both of them dead wrong:

  1. Infinitely diluted substances are more potent than substances at higher concentrations, and
  2. "Like cures like," meaning that if a substance causes a symptom, you can use that substance to cure the symptom.  

Thus caffeine can be used to help you sleep, and poison ivy can cure itching.  No, I'm not making this up; homeopaths really believe this stuff.

Homeopathy is simply magical thinking.  There has never been a shred of scientific evidence to support it, and the British Medical Association declared in 2010 that homeopathy is witchcraft.  After pressure from science bloggers, NIH's NCCAM has corrected its website to state that
"it is not possible to explain in scientific terms how a remedy containing little or no active ingredient can have any effect."
But homeopaths make a lot of money selling homeopathic potions, and through clever marketing they keep themselves in business.  Now they have a new ally, the UK Minister of Health. Andy Coghlan, writing in The New Scientist, called him "the new minister for magic."  Brilliant!  As Coghlan pointed out, magic is much cheaper than real medicine:
"Think of the savings if all those expensive proven treatments and drugs are phased out, and patients are offered cheap little vials of water instead."
We're desperately looking for ways to control health care costs here in the U.S. as well.  The UK Minister of Magic may have a solution for us.  I wonder, though, if it works for muggles?

What did the ENCODE project discover about the genome? A quick shout-out.

Does top-down science work as well as bottom-up science?

This is just a quick link-over to my friends at Simply Statistics, who interviewed me on their blog (and vodcast) about the just-published set of papers on the human genome known as the ENCODE project.  Check it out here, and then follow the discussion and comments further on their follow-up post here.