The horror of science continues with the terrifying news that chocolate is once again good for you and this time it helps the brain and may – gasp – stave off Alzheimers. We’ll detail this new research in a minute, but first consider the news reports.
In a small study out this week, people with high blood pressure, diabetes and some memory challenges performed better on cognitive tests after drinking hot cocoa for a month. Drinking the cocoa also appeared to increase blood flow to their brains, according to ultrasounds. Vascular dementia, which can include confusion, trouble speaking and vision loss in addition to memory loss, is caused by reduced blood flow to the brain that deprives brain cells of oxygen and nutrients.
Small? It was an experimental design where participants got randomized to different cocoa treatments for 30 days. Brain and cognitive functions were tested at baseline, Day 1 and Day 30. There were 60 people. Small’s got nothing to do with much here. You need to replicate this research and kick all the cans you can infer from it. But small is no problem. This research is in the stream of an active river of research on brain function. But worse than small, this study is – gasp – preliminary.
The study was small and preliminary, so it should not encourage people to drink cocoa thinking it will save them from dementia, warned Heather Snyder, director of medical and scientific operations at the Alzheimer’s Association. “I don’t think we can draw any conclusions from this study about whether drinking cocoa is a potential therapy,” she said.
We’ve seen people jump off the cliff for Fairy Tales and Windowpanes that are barely cracked open and here we’ve got a randomized controlled experiment that shows both physiological and cognitive improvements from cocoa consumption. We can draw conclusions from Fairy Tales, but not experiments? Is chocolate that big a threat?
Remember the hilarious research which showed that consuming sugary drinks increased WATTage thus enabling Other Guys to hit the Central Route? Jeepers, you gotta do something bad like drink sugary soda pop to understand that drinking sugary soda pop is bad for you! Now, it appears if you consume evil cocoa for 30 days your brain works better and your mind solves puzzles faster which means consuming chocolate helps you understand why consuming chocolate is dangerous for you!
What are people supposed to do?
Let’s start with the actual research. The results are much more complicated than any of the news reports understand. Researchers recruited 60 older Other Guys for the study which required them to show up for testing and to drink cocoa twice a day for 30 days. The researchers provided all the cocoa in easy to use packets and therein lies the experiment with randomization and control.
See, while everyone got normal cocoa, half the Other Guys got a flavanol-enhanced dose. A considerable amount of prior science demonstrates that some of the chocolate effect comes from the flavanol, so the researchers increased that amount to see what kind of boost you’d get.
(Experimental Side Bar: Why not cocoa without flavanol instead? That could be reasonably interpreted as harming people. Flavanol helps. You could have done this study with either reducing or enhancing the flavanol amount and you’d get a reasonable control. However, cutting the flavanol would be some kind of unethical. Does that make sense?)
So. You’ve got an experiment with older Other Guys all drinking cocoa twice a day with half randomly getting that flavanol boost. And, we’ve tested everyone before, Day 1 and Day 30 on a variety of physiological and cognitive measures. Now it gets complicated.
The experimental variable with flavanol did nothing. The experiment is blown and did not work. The extra flavanol had no effect on brain function or cognitive testing. Now, it gets simple.
Just run the analysis on all Other Guys making this a longitudinal observational Fairy Tale with 60 participants. Now concerns about sample size and preliminary results come flying in. This ain’t the plan and we’re testing post hoc hypotheses. Now, it gets complicated again.
The researchers “adjust” the analysis for the participants neurovascular coupling status. This is a standard Tooth Fairy play where you start diddling your analysis with different combination of variables. This was designed as a simple experimental t-test, but that blew up. Now, let’s add other variables. What is neurovascular coupling?
Neuronal activity is linked to oxygen and glucose delivery. An increase in metabolic demand leads to an increase in blood flow. The close functional and spatial relationship between neuronal activity and cerebral blood flow has been termed neurovascular coupling (NVC) or functional hyperemia. Impaired NVC has been associated with significant pathology.
So, let’s now divide the Other Guys – not on the experimental variable of flavanol amount – but on their NVC score and break everyone into two groups, Intact and Impaired NVC. Now, look at the effect of 30 days of drinking cocoa (with or without extra flavanol). Here’s a pretty picture.
Cocoa had no impact on cognitive outcomes for people with Intact NVC function (the left side). Cocoa did have a beneficial effect on cognitive function for people with Impaired NVC status (the bars on the right side). In this case, the lower scores are better because it means you are getting faster on this measure of cognition called Trails B which requires you to connect a bunch of dots scattered on a page. The faster you go the better the test.
So, the pretty picture looks good, but there are a big buncha buts with it. See, only 17 people had Impaired NVC function. And, yeah, whoopee, the effect is significant at p < .007 which is a kinda cool number, but come on. We start with 60 people, randomize into groups of 30, but that blows up. We then adjust the data and find 17 people who are 007 at connecting dots.
And, the Other Guys took 3 measures of cognitive function: Mini-Mental State Examination and Trail Making Test A and B. The pretty picture shows the results from Trail B, but the report is silent on the other 2 measures. Think about that. Start with 60 people, randomize and control, but, oops. Now find 17 with a good story on NVC, run 3 tests of cognitive function on them and report the one that delivers and omit the others.
Yeah. Cocoa drinking reduces Alzheimers. Probably. Maybe if you have impaired NVS function and are connecting a lot of dots on a daily basis in the Local called Trails B. Then. Yeah. There’s a significant relationship between cocoa drinking and cognitive function.
The most interesting element of this story is not the science, but the persuasion. I have no idea why this thing hit journalists as something to tout as the New New Thing, but they sure did. And, if you do a search on Goggle News you can find all those cheerfully stupid press reports about chocolate and Alzheimers.
And even more persuasion interesting was the response of folks who represent science. Our more careful look at Methods and Results shows that this is an interesting little study with some tantalizing outcomes that are obviously weak and shaky, but consistent with the literature and suggest more focus on NVS status and cocoa consumption. The Need For Future Research here shouts for experiments with impaired NVS participants randomly assigned to cocoa conditions with measures of physiological and cognitive function. If I was on that study section or running a grant funding operation, I’d be favorably disposed toward that given this study.
But, the media statements of these science guys didn’t take that tack. Instead they all worried about people eating chocolate for diet and weight gain reasons. Here’s the lead author.
“I do not recommend that people add chocolate or cocoa to their diet at this point,” Sorond told The Salt via email. “Our results are preliminary and adding the extra calories, sugar and fat that comes with chocolate and cocoa carries additional health hazards which may offset any possible brain benefits.”
You could put it like that. Or even like this from the actual Discussion of the paper.
Moreover, we show that NVC may be modifiable. Four weeks of cocoa consumption resulted in improved NVC and Trails B scores in those with impaired function at baseline . . . Our study shows that cocoa consumption resulted in higher NVC and that individuals with higher NVC had better cognitive function and greater cerebral white matter structural integrity.
Hmmm. So the results are preliminary and hazardous while showing that NVC can be modified with cocoa which then improves NVC function and cognitive function.
No persuasion here. Just science.
Farzaneh A. Sorond, Shelley Hurwitz, David H. Salat, et al. Neurovascular coupling, cerebral white matter integrity, and response to cocoa in older people. Neurology published online August 7, 2013.
P.S. When you do science with a PR kit you will always find persuasion.
P.P.S. And just for fun read this.
The healing power of chocolate. The researchers weren’t quite ready to call chocolate a health food — they cruelly reminded the audience of its fatty content — but they did have good news about the flavanols found in cocoa (particularly some dark chocolates).
Norman Hollenberg of Harvard Medical School has documented that central American Indians who consume large quantities of cocoa have low rates of hypertension and of vascular dementia (caused by restriction of blood flow in the brain). At the AAAS meeting, he reported on a experiment showing people given flavanol-rich cocoa enjoyed a “a significant increase” in cerebral blood flow. “We hope,” he noted, “to explore the potential of flavanol-rich cocoa in preventing or ameliorating the vascular dementias.”
Another researcher, Ian Macdonald of the University of Nottingham, scanned the brains of women who’d been given flavanol-rich cocoa. He found it increased “cerebral blood flow to gray matter.” He and Dr. Hollenberg didn’t urge listeners to go out and gorge on chocolate, but they did raise the possibility of flavanols being used to help aging brains, perhaps being administered in the form of vitamins. Let’s hope these vitamins are the chewable variety.
So says a New York Times report from . . . 2007, six years prior to this paper.