Dark chocolate improves blood flow to brain, study
Unsweetened dark chocolate may improve attention and help consumers beat the ‘midday slump’, according to new research from North Arizona University (NAU).
The study, published in the journal NeuroRegulation and sponsored by confectionery company the Hershey Company, is the first to examine the acute effects of chocolate on attentional characteristics of the brain and the first study of chocolate consumption performed using electroencephalography (EEG). EEG studies take images of the brain to measure brain activity while it is performing a cognitive task.
“Chocolate is indeed a stimulant and it activates the brain in a really special way,” said Larry Stevens, a Professor of Psychological Sciences at NAU. “It can increase brain characteristics of attention, and it also significantly affects blood pressure levels.”
Chocolate as a stimulant
Historically, chocolate has been recognised as a vasodilator, meaning that it widens blood vessels and lowers blood pressure in the long run, but chocolate also contains some powerful stimulants. Professor Stevens said his team wanted to investigate if people who consume chocolate would see an immediate stimulant effect.
Professor Stevens and his colleagues in the Department of Psychological Sciences performed the EEG study with 122 participants between the ages of 18 and 25 years old. The researchers examined the EEG levels and blood pressure effects of consuming a 60 percent cacao confection compared with five control conditions.
Michelle Montopoli, an NAU alumna and student at the time of the study, led the EEG testing phase which included measuring serving sizes of the samples based on participant weight and packaging them so the participants were blind to what they were tasting. Constance Smith, Professor of Psychological Sciences, assisted with the physiological analyses.
The results for the participants who consumed the 60 percent cacao chocolate showed that the brain was more alert and attentive after consumption. Their blood pressure also increased for a short time.
“A lot of us in the afternoon get a little fuzzy and can’t pay attention, particularly students, so we could have a higher cacao content chocolate bar and it would increase attention,” Professor Stevens said.
Professor Stevens said that a regular chocolate bar with high sugar and milk content would not be as good — it is the high-cacao content chocolate that can be found from most manufacturers that will have these effects.
Cacao and green tea extract combination
The researchers said the most interesting results came from one of the control conditions, a 60 percent cacao chocolate which included L-theanine, an amino acid found in green tea that acts as a relaxant. This combination has not been introduced to the market yet, so is not available in food products currently.
“L-theanine is a really fascinating product that lowers blood pressure and produces what we call alpha waves in the brain that are very calm and peaceful,” Professor Stevens said. “We thought that if chocolate acutely elevates blood pressure, and L-theanine lowers blood pressure, then maybe the L-theanine would counteract the short-term hypertensive effects of chocolate,” he said.
For participants who consumed the high-cacao content chocolate with L-theanine, researchers recorded an immediate drop in blood pressure.
“It’s remarkable,” Professor Stevens said. “The potential here is for a heart healthy chocolate confection that contains a high level of cacao with L-theanine that is good for your heart, lowers blood pressure and helps you pay attention,” he said.
Professor Stevens said he hoped the results of this study would encourage manufacturers to investigate further and consider the health benefits of developing a chocolate bar made with high-cacao content and L-theanine.
“People don’t generally eat chocolate and think it’s going to be healthy for them,” Professor Stevens said.
He said that there was a possibility of developing a “heart healthy” chocolate bar that could help hypertension patients to keep their blood pressure in the normal range.