Why we want to believe chocolate makes us smarter

Eat chocolate, win Nobel Prize?

The New England Journal of Medicine published a study two weeks ago showing, amazingly, that eating chocolate might make you smarter.  To be precise, the author, Franz Messerli, was wondering if chocolate consumption might be correlated with the overall cognitive function of a population.  He couldn't find any data on national intelligence, so instead he used the total number of Nobel prize winners per capita.  The correlation between chocolate consumption and Nobels is remarkably strong, with a p-value less than 0.0001, meaning that the odds that this is due to chance are less than 1 in 10,000.

Ha ha! Dr. Messerli was just kidding.  Or was he?

The article itself reads like almost any science paper.  It includes a straight-faced presentation of the data and scholarly references suggesting that the brain-enhancing effect of chocolate might be due to flavanols, which may be "effective in slowing down or even reversing the reductions in cognitive performance that occur with aging."

In fact the entire article appears to be dead serious until the end, where Messerli makes the wry comment that

"The cumulative dose of chocolate that is needed to sufficiently increase the odds of being asked to travel to Stockholm [where the Nobels are awarded] is uncertain."

And then, in his disclosure of conflicts of interest, he reports "daily chocolate consumption, mostly but not exclusively in the form of Lindt's dark varieties."  Hmmm, this doesn't seem like a serious science paper after all.

Word of this article swept through the halls of academia the day after it was published.  I heard it being discussed among my colleagues, who were concerned that NEJM had published yet another example of misleading statistics.  It took a couple of days for us to realize that it was a joke - based on real data, but a joke nonetheless.

The media reported the story widely, and a few reporters figured out the ruse, but the parody was just too subtle for most.  Reuters wasn't fooled, as reported on their own site and on Fox News. They reached Messerli by phone, who confessed that

"the whole idea is absurd, although the data are legitimate and contain a few lessons about the fallibility of science."

The Associated Press reporters were slightly suspicious, opening with "take this with a grain of salt." But they went on to report it as straight news, and their story appeared on CBS News, the Huffington Post, and elsewhere.

Larry Husten, my fellow columnist at at Forbes, reported it as straight news with the headline "Chocolate and Nobel Prizes Linked in Study." Time magazine fell for it too.

Two medical websites, Medical News Today and WebMD, not only took the story seriously, but also bought into the explanation that the effect is caused by flavanols, which are found not just in cocoa, but also in red wine and green tea.  Sounds like an ideal diet to me.

Slate's Brian Palmer had an interesting angle. He reported the story as straight news, but then investigated why the Swiss eat so much chocolate.  (Answer: innovation in chocolate-making, and wealth.)

Why do we want to believe chocolate makes us smarter?  Well, obviously because we'd love for it to be true.  And as Messerli points out, there have been some serious studies linking flavonoids to better health and cognitive function.  But the notion that chocolate leads to Nobel prizes is a little too good to be true.  I'm reminded of the study that I wrote about back in April that claimed chocolate would help you lose weight - which was little more than wishful thinking masquerading as science.

Still, with Halloween just past, many parents are probably wondering how much to let their kids eat.  Those Nobel-champion Swiss consume about 11 kilograms per year, about 30 g (1 ounce) per day.  That's 3 of those little mini-chocolate bars.  And parents, maybe you should have a few too - just in case Messerli is right.

Multivitamins and cancer: a mixed bag

A major new study published this week in the Journal of the American Medical Association (JAMA)  came to the surprising conclusion that

"daily multivitamin supplementation modestly but significantly reduced the risk of total cancer."

The report included some caveats, such as the fact that all 14,641 participants were healthy male physicians.

But the result is still surprising, because other recent studies, some of them even larger, have concluded that vitamin supplements do not provide any significant health benefits.  On the contrary, some studies found that supplements could actually be harmful.  As I wrote last year, a very large study of 38,772 older women, who were followed for 25 years, showed that the risk of death INCREASED with long-term use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc, and copper.  That's death, not just cancer.  The authors of that study, Jaakko Mursu and colleagues, concluded that there is

"little justification for the general and widespread use of dietary supplements."

The new study, PHS II (Physicians' Health Study II) looked at overall death rates as well as cancer, and found that men on a daily multivitamin had fewer deaths, but too few to be statistically significant.

So we have a large study in men showing that multivitamins seem to reduce overall cancer, and maybe even death, but an even larger study in women showing the opposite effect.

A second study from last year, in 35,533 men, looked at vitamin E and selenium supplements. That study, also published in JAMA, found that risk of cancer INCREASED for men taking vitamin E, selenium, or both.

The media reports aren't helping to clarify things.  The NY Times proclaimed "Multivitamin use linked to lowered cancer risk, and the Wall St. Journal reported that "Multivitamin cuts cancer risk, large study finds."  Bloomberg News went right for the business angle, announcing that "Pfizer multivitamin reduces cancer 8% in men, study finds."

Compared to Bloomberg news, Pfizer's own website was remarkably restrained, saying only

"Centrum Silver was part of the recently published landmark study evaluating the long-term benefits of multivitamins."  

No claims about reducing the risk of cancer - surprisingly, the independent media made far stronger statements than Pfizer.  Not true of supplement manufacturer GNC, which was flashing a pop-up headline that "Taking a daily multivitamin could cut cancer risk", linking to a news article at the Boston Herald.

So what do we make of this new study?  Are multivitamins good for you after all?

The new JAMA study appears to be very well done.  It's a double-blind, placebo-controlled study in which half of the physicians received a daily multivitamin, Centrum Silver, and half received a placebo.  The participants didn't know if the pill they were taking was a vitamin or a sugar pill.  The authors report some minor conflicts of interest, but none of them work for or received major funding from Pfizer (PFE, the manufacturer of Centrum).  So how to explain the seeming contradiction with two larger studies published only a year ago?

To answer this question, we must look at the details of the study itself.  This study looked at 21 different types of cancer risk.  For most cancers - colon cancer, prostate cancer, lung cancer, pancreatic cancer, lymphoma, leukemia, melanoma, and others - multivitamins did not provide a benefit.  But when all the numbers were added up, the effect was just large enough to be "significant", at a level of p=0.04.  More on that in a moment.

Here are the raw numbers: among the 7,317 men who took a daily multivitamin, there were 1,290 cases of cancer over the 11-year study.  Among the 7,324 men who took a placebo pill, there were 1,379 cases.  That's about 1.2% more - far less than the 8% reported by Bloomberg News. The statistical analysis showed that this difference had a p-value of 0.04, a result the authors considered significant. When the authors looked only at men with no history of cancer, the effect was smaller, and not statistically significant.

One explanation of the new finding is that the effects were indeed due to chance. Let's look at that p-value of 0.04. In much of the scientific literature, any p-value below 0.05 is considered "significant," but this has been widely criticized, in part because it encourages binary "true, false" thinking that is not the way scientists actually think. Also, the "0.05 threshold actually represents evidence much weaker than the number "0.05" suggests. A back-of-the-envelope Bayesian calculation shows that if the cancer-preventing power of multivitamins was a 50:50 proposition before this study, then after this study there is still a 10-26% chance that the cancer prevention claim is wrong. If we thought that prior evidence made this effect less than 50:50, (say 25:75), then the study has roughly a 25-50% chance of being wrong.* Either way, I won't be stocking up on Centrum Silver anytime soon.

Looking at this small effect, and at the contradictory results from other studies, neurologist Steven Novella writes in his blog that

"About the only thing we can say with a high degree of confidence is that there is no large risk or benefit from taking a multivitamin. There may be a small benefit, no benefit, or even a small harm."

That's a good summary.  So should men take a multivitamin?  Well, it's your money, but if you don't have a vitamin deficiency, it's probably not worth it.  Should women?  The evidence still says no.

*Thanks to Stanford biostatistician Steven Goodman (formerly of Johns Hopkins University) for crunching some numbers to produce Bayes factors.

What do the Presidential candidates think about science?

ScienceDebate.org recently posed 14 questions to President Obama and Republican presidential nominee Mitt Romney, and just a few days ago, the candidates answered all 14.  Can we learn what they actually think about science from these answers?  Well, maybe just a little bit.  

My first inclination, on going to the ScienceDebate2012 website, was to look for the candidates' positions on the two biggest scientific topics in the political arena today: evolution and global warming.  Somehow, ScienceDebate2012 only asked about one of these, which I'll get to in a minute.

The ScienceDebate2012 organization calls its list "the top American science questions: 2012", but the questions themselves are a disappointment.  They're what you'd expect from a committee: lots of nice-sounding, polite questions, but nothing that really challenges the candidates.  I guess SD2012 was afraid that the candidates might get all offended, or maybe that fewer scientists would sign their petition.  But if you read the answers, you'll see that the candidates just answered the question they wanted to hear, as politicians love to do.  Most of the answers describe policies we already know (for those who are paying attention to the campaigns), but an interesting surprise popped up: Mitt Romney has no fondness for NASA.  Jump to the bottom to learn more.

Most of the questions are big fat softballs, starting with the first one: "What policies will best ensure that America remains a world leader in innovation?" http://www.sciencedebate.org/debate12/   Good tough question, guys!  We only have 14 questions, and you waste one on this?  Unsurprisingly, the answers to this one just repeated campaign talking points.

Before looking at some real answers, let's start with the howlingly obvious question that ScienceDebate2012 failed to ask.  

The Un-asked Question: do you believe that evolution should be taught in public schools, and that it should be presented as the only explanation for how species arose?  

This question has only one right answer, as any biologist worthy of the name knows.  Evolution is the foundation of all of modern biology, genetics, infectious disease research, you name it.  And the U.S. is one of the few advanced countries where a significant number of its citizens don't accept evolution, opting instead for an archaic religious position that claims Earth is only a few thousand years old.  

We should know the candidates' answers.  In 2008, ten Republican presidential candidates were asked if they believe in the theory of evolution.  Only 7 said yes--but one was Governor Romney.  Back in 2007, he told the New York Times that "the science class is where to teach evolution," and that intelligent design was "for the religion class or philosophy class."  President Obama also supports evolution, and opposes teaching creationism in the science classroom. 

So the candidates agree on this one - at least they did in the past.  But Romney's fellow Republicans don't all agree. In particular, we need to ask Governor Romney: do you support the crazy religious extremism of your fellow Republican, Congressman Paul Broun from Georgia, who just announced that evolution, embryology, and the Big Bang theory are

 "lies straight from the pit of hell"?  

And Broun also stated that the Bible - and his wacko interpretation of it - should be used to run our government.  Any candidate for president should denounce this call for theocratic rule.

And by the way, if a Democratic Congressman said anything like this, I'd throw the same question at President Obama.

Now on to one of the real questions, on global warming. ScienceDebate2012 posed the question this way:

"The Earth’s climate is changing and there is concern about the potentially adverse effects of these changes on life on the planet. What is your position on cap-and-trade, carbon taxes, and other policies proposed to address global climate change—and what steps can we take to improve our ability to tackle challenges like climate change that cross national boundaries?"  

Obama's short answer acknowledges that "climate change is one of the biggest issues of this generation," and goes on to say he will "continue efforts to reduce our dependence on oil and lower our greenhouse gas emissions."  Vague generalities, and nothing he hasn't said before, but consistent at least.

Romney's answer, though, tries to have it both ways.  He first says that global warming is indeed happening and then says, basically, we need more research because it's controversial.  Here's how his lengthy answer begins: 

"My best assessment of the data is that the world is getting warmer, that human activity contributes to that warming, and that policymakers should therefore consider the risk of negative consequences."  

But then he pivots in the very next sentence and claims 

"there remains a lack of scientific consensus on the issue ... and I believe we must supported continued debate and investigation within the scientific community."  

So there you go: yes, global warming is a problem, but let's study it rather than do something.  At the end of his answer, Romney recovers a bit by saying he supports "robust government funding for research on efficient, low-emissions technologies."  So it appears he would support some action on global warming.  But his answer offers a troubling false claim about a lack of scientific consensus: the consensus is rock solid.

Now, I promised one surprise: a bit of new information.  Question 12 covers space exploration and is another softball: 

"What should America's space exploration and utilization goals be in the 21st century and what steps should the government take to help achieve them?" 

I expected some vague answers about how great America is (and both candidates did indeed deliver on that), but Romney surprised me with his answer.

Here's the surprise: Romney comes right out and says he will probably cut the NASA budget.  What he actually said in his answer was: 

"A strong and successful NASA does not require more funding, it needs clearer priorities."

In Washington-speak, this means "NASA has too much money and I will probably cut it."

So at least we know where Romney stands on space exploration.  He wants to downsize it and, apparently, outsource it to other countries.  Here's how he puts it later in his answer: 

"Part of leadership is also engaging and working with our allies and the international community. I will be clear about the nation’s space objectives and will invite friends and allies to cooperate with America in achieving mutually beneficial goals."  

If I worked for NASA, I'd be worried.  

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.