The news keeps getting sweeter about dark chocolate and other cocoa products. Since we last reviewed the research, several studies have further highlighted its potential for bettering cardiovascular health—by improving arterial function, for instance, which can help lower blood pressure. The latest research finds that cocoa can also aid the brain.

Chocolate’s health benefits are largely attributed to compounds called flavonoids—related to those in tea, red wine, grape juice and many other plant foods. The new study, done by Italian researchers and published in Hypertension, involved 90 people over 65 with mild cognitive impairment (MCI).

This condition causes memory problems more serious than those seen with normal aging, but less severe than those of dementia. It’s estimated that 20 percent of people over 70 have MCI and that 5 percent of those with MCI progress to dementia each year.

Every day the subjects drank a cocoa beverage, which contained either high, intermediate or low levels of flavanols (a key subclass of flavonoids). Their diets were controlled to eliminate other sources of flavanols. After eight weeks, the high-flavanol group did better on a series of memory, verbal fluency and other cognition tests, followed by the intermediate-flavanol group. Their blood pressure, blood sugar control and oxidative stress levels also improved.

Though flavonoids may have direct effects on neurons and neurodegenerative processes, the researchers concluded that the cognitive benefits were related primarily to better insulin sensitivity, which affects blood sugar control as well as brain function.

But the benefits may also derive from the cocoa’s effects on cardiovascular health in general—and blood pressure and blood flow in particular—since so much of what’s good for the heart is also good for the brain.

What to keep in mind

Not all chocolate or cocoa is rich in flavonoids. In general, the darker the chocolate, the more flavonoids, but it’s hard to judge. The “percent cocoa” listed on some labels is not a reliable gauge. When cocoa powder is highly processed—called Dutch or alkali processed—flavonoids are destroyed. The low-flavonoid drink used in the study contained such highly processed cocoa. The flavonoid-rich cocoa, supplied by Mars, was processed to retain more of these compounds. (Mars also funded the study, and one author worked for the company.)

Other flavonoid-rich foods and beverages, such as grape juice and tea, have also been linked to cognitive benefits in observational, lab and animal studies. The new study may be the best clinical trial so far testing the effect of a specific food on cognitive function.

But don’t assume that chocolate is the only, let alone best, way to protect your aging brain or that it’s a cure for MCI. No one knows what level of flavonoids are needed to improve or maintain brain health, or if the effect would continue in the longer term.

Bottom line: This research is even more reason to like dark chocolate. Just keep an eye on the calories and sugar content.