Not so fast, says Catherine Kwik-Uribe. She's the director of research and development for Mars Symbioscience – a unit of the candy-making giant that studies flavanols, a type of antioxidant in cocoa beans.

As she notes, there's a solid body of research showing that cocoa flavanols can help control blood pressure and generally improve cardiovascular health. Plenty of evidence has linked cardiovascular health to cognition and, more recently, researchers have been asking whether cocoa flavanols can also boost brain health.

"Our knowledge is just beginning to emerge," says Kwik-Uribe. But you can't conclude much from the Neurology study, Kwik-Uribe told me.

The researchers in the study, she notes, didn't find a difference between those who drank cocoa with high levels of flavanols and those with very low levels. The authors also failed to keep track of what else the participants were eating that might have influenced their improved cognitive test scores.

In fact, cocoa's impact on the brain wasn't really the main point of the study anyway, as study author Farzaneh Sorond, a neurologist at Brigham and Women's Hospital in Boston, points out. She and her colleagues were mostly interested in investigating the link between poorer performance on thinking and memory tests and lower blood flow to the brain. The chocolate bit was really more of an aside.

Cocoa beans are naturally rich in flavanols, but these compounds can get stripped out by the time you get to a chocolate bar. Researchers use cocoa powder specially prepared to preserve the flavanols to figure out how they affect the brain. Photo: Courtesy of Mars

"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."

But don't fret just yet, chocoholics: While this study may not tell us all that much, other research on cocoa flavanols and brain health, while preliminary, is more promising.

Scientists have homed in on one particular flavanol, (-)epicatechin (it's pronounced minus epicatechin), as the likely source of the brain benefits seen from cocoa. For example, studies have found that mice fed (-)epicatechin had better spatial memory and formed more new blood vessels than mice who weren't given the compound. And research in snails has found the slimy crawlers were able to remember a trained task for at least a day when given the flavanol, compared to less than three hours without it.

As for humans, last year, Kwik-Uribe and her colleagues published a study that looked at 90 elderly patients with mild memory problems. Those who drank cocoa with medium levels (520 mg) to high levels (990 mg) of flavanols daily for eight weeks showed major improvements on tests that measured factors such as attention, verbal fluency and working memory, compared to those whose cocoa had low flavanol levels (45 mg).

So how do cocoa flavanols confer their brain benefits? Researchers don't know for sure, though there are plenty of ideas.

It might be that flavanols promote better brain blood flow and help generate new blood vessels (the more oxygen your noggin gets, the better it performs). Or maybe flavanols encourage the expression of proteins that protect the brain and promote neuron connections. Cocoa flavanols also help control blood sugar, which might be protecting the brain from declines associated with insulin resistance.

The data, says Kwik-Uribe, is still emerging: "You have to stay tuned."

Copyright 2013 NPR.

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Can Chocolate Boost Brain Health? Don't Binge Just Yet