Keen Cuisine: The Flavor of Cleverness

Food of the gods—and that's merely the formal name of the plant that yields the seductive lusciousness of theobroma cacao, otherwise known as chocolate. Its cocoa-bearing seeds were so prized that the Aztecs of Mexico used them as currency.

In the modern world, chocolate is more often a currency of love and affection. Yet, as science sinks its teeth into the links between what we eat and the state of our health, it is serving up some particularly sweet reasons to savor the confection.

Cocoa turns out to be rich in a specific class of antioxidants that boost blood flow to both the heart and the brain. Researchers have found that chocolate processed to retain high levels of these antioxidants known as flavanols helps even healthy adults shift their mental resources to quickly and accurately meet the demands of complex cognitive tasks.

"Our study showed that acute consumption of [a] flavanol-rich cocoa beverage was associated with increased blood flow to gray matter for two to three hours," reports Ian A. Macdonald of the University of Nottingham Medical School. "This raises the possibility that certain food components like cocoa flavanols may be beneficial in increasing brain blood flow and enhancing brain function among older adults or for others in situations where they may be cognitively impaired, such as fatigue or sleep deprivation."

In earlier studies, Macdonald found that the improvement in blood flow seen in people given a flavanol-rich cocoa beverage stimulates the production of nitric oxide, a critical biological messenger prompting even the tiniest blood vessels to relax and deliver a bounty of blood. That may explain why cocoa has particular benefits to the brain.

A number of vegetable-based foods—among them tea, purple grapes, cranberries, as well as cocoa—are rich in antioxidants. But chocolate has its own unique profile of flavanols. German scientists recently found that cocoa—but not green or black tea—lowers blood pressure in people being treated for hypertension. Even moderate degrees of high blood pressure, researchers believe, are at the root of the cognitive decline seen in aging.

Not all chocolate is created equal. The key ingredient is cocoa, which is naturally low in fat and which varies dramatically in antioxidant content depending on processing methods. Macdonald relied on cocoa specially processed to enhance flavanol content. Dark chocolate has the highest cocoa content, and candy manufacturers are engaged in a virtual arms race to turn it into a health food by boosting its flavanol power even beyond nature's largesse. Not only does milk dilute the overall cocoa content of chocolate, it increases saturated fat levels too, countering cocoa's blood-borne benefits. Still, studies have found that even the fats in dark chocolate may help lower cholesterol levels—and preliminary studies suggest that they may even aid diabetics by boosting insulin sensitivity.