As studies continue to give us the finger wag for foods we love to eat, sometimes researchers surprise us and give us a thumbs-up instead.

Such was the case this week when a group of benevolent researchers at Harvard Medical School published their findings on the salubrious effects of drinking hot chocolate. They found that drinking two cups of the hot confection a day may work to boost brain health and prevent memory decline in aging people. The cocoa magic seems to work by preserving blood flow in working areas of the brain.

Previous research has proven chocolate to have potent health benefits; the Harvard team was interested in furthering the investigations by looking at the effect of cocoa on thinking and memory performance. They were also looking at neurovascular coupling, which is the change of blood flow in the brain in response to local brain activity.

As Farzaneh A. Sorond, lead author and member of the American Academy of Neurology, explains, "As different areas of the brain need more energy to complete their tasks, they also need greater blood flow. This relationship, called neurovascular coupling, may play an important role in diseases such as Alzheimer's."

For the study, the researchers gathered 60 people over the age of 73 who were dementia-free and had them drink two cups of hot cocoa daily for 30 days; they were instructed to not eat any other products with chocolate during the time.

Participants' were given a set of standard tests before and after to assess memory and thinking skills. The researchers also measured neurovascular coupling by ultrasound.

At the beginning of the study, 18 of the participants had impaired neurovascular coupling; after the 60 cups of hot chocolate, that number had improved by 8.3 percent.

These participants also showed significant improvement on working memory speed tests. At the beginning of the study, it took them 167 seconds to complete the test; at the end they did it in 116 seconds.

Interestingly, the 42 participants with regular neurovascular coupling at the start of the study experienced no change either in blood flow measures or working memory, suggesting that the cocoa benefits in this context applied only to those with initial impairment.

The study concluded that, "There is a strong correlation between neurovascular coupling and cognitive function, and both can be improved by regular cocoa consumption in individuals with baseline impairments.”

The findings were published online in Neurology.

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