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NVC -- Cerebral Blood Flow and Mental Processing: The Case for Cocoa
When it comes to its need for fuel, your brain is like a Maserati. It uses 20% of the body’s energy, but accounts for only 2% of its weight. Given what the brain makes possible — every thought, action and memory we have — the demand for energy is easy to understand.
Blood is what brings this energy to our brains, and new research demonstrates that boosting blood flow can improve elderly brains' performance. And one good way to do this is to…drink cocoa.
It's a little like tuning up your car's fuel injection system.
Better Blood Flow Means Better, Faster, Mental Performance
When a team of researchers at Harvard studied elderly people at risk for vascular dementia, the loss of brain function that results from impaired blood flow, they found that cocoa improved blood flow to the area of the brain involved in cognitive functions such as memory and thinking.
“We're learning more about blood flow in the brain and its effect on thinking skills,” lead author Farzaneh Sorond told TheDoctor. As areas of the brain need energy to complete their tasks, they require greater blood flow.
This close relationship between neuronal activity and cerebral blood flow has been called neurovascular coupling (NVC), and may play an important role in neurodegenerative diseases such as Alzheimer's.
Sorond and her team enrolled 60 people with an average age of 73 in their study. None of the participants had dementia, but 18 of the 60 participants had slightly impaired blood flow to their brain.
Everyone in the study drank two cups of hot cocoa per day for 30 days. They did not consume any other chocolate during the study. Half of the participants received cocoa that was rich in the antioxidant flavanol, while the other half received cocoa that contained little flavanol.
Participants were given tests of their memory and thinking skills, and their brains were imaged via ultrasound as they completed these tests, to measure changes in the amount of blood flow.
Those who began the study with impaired blood flow had an 8.3 percent improvement in the blood flow to the working areas of their brain by the end of the study. No improvement was seen among those who began with regular blood flow.
Those with improved blood flow also improved their times on a test of working memory. Their processing speed dropped from 167 seconds at the beginning of the study to 116 seconds at the end. No change in test times was seen among people with regular blood flow.
Interestingly, no differences between the flavanol-rich and flavanol-poor groups were noted. “We had hypothesized that cocoa would improve NVC, and that the effect would be related to the flavanols,” Sorond said. She also said that cocoa did improve NVC, but it seems that flavanol had nothing to with it, unless just a little flavanol was enough since the flavanol-poor cocoa used in the study still had 13 mg/serving.
So while it is still unclear exactly what is behind cocoa's benefits, they are there.
Previous studies have linked the flavanols in cocoa to improved cognitive function in the elderly and the flavonoids in berries to a reduced risk of a heart attack. “This study was one of the first to suggest that flavanols have nothing to do with any benefits seen by drinking cocoa,” Paul Rosenberg, an author of an editorial that accompanied the study, told TheDoctor.
So should you go clean out the candy aisle at the supermarket? Not quite yet, said Sorond. “…[T]he scientific significance of our study is not so much that cocoa improves neurovascular coupling, but that we have a biomarker (neurovascular coupling) which may be useful in identifying individuals at risk of cognitive impairment in the pre-clinical state, when interventions such as cocoa and other potential agents may prevent disease progression.”
She and her colleagues hope to expand their study to include more people and a longer duration of treatment. They also intend to have different control arms to better understand what in cocoa may be related to its health benefits. And they also plan to test other interventions that have shown some promise for prevention of cognitive impairment.
August 20, 2013