Anne Robbs, Columnist & Editor,
NEW STUDY: Cocoa, Even With Few Flavonoids, Boosts Cognition
Drinking cocoa, whether rich in flavonoids or not, appears to boost the effect of blood flow on neuronal activity in the brain, known as neurovascular coupling (NVC).
A new study shows not only that drinking flavonoid-rich or flavonoid-poor cocoa improves NVC but also that higher NVC is associated with better cognitive performance and greater cerebral white matter structural integrity in elderly patients with vascular risk factors.
As researchers search for ways to detect dementia at the earliest possible stage, the study results could pave the way for using NVC as a biomarker for vascular function in those at high risk for dementia, said lead author Farzaneh A. Sorond, MD, PhD, Department of Neurology, Stroke Division, Brigham and Women's Hospital, Boston, Massachusetts.
"Our study shows that NVC is modifiable and can be enhanced with cocoa consumption," said Dr. Sorond.
The study is published online August 7 in Neurology.
The authors were surprised at the lack of effect of flavonoids because previous research had indicated a dose-response with respect to cognitive performance. It could be something other than flavonoids in the cocoa, possibly caffeine, that improves NVC, or it could be that the 13 mg in the low-flavonoid cocoa group was enough to have an effect.
"I think there are effects of flavonol on brain blood flow no matter how low it is," said Dr. Sorond, adding that perhaps only a tiny amount is needed to activate an enzyme or some other trigger.
It's important to identify the component or mechanism, whatever it is, because just telling patients to drink cocoa could be risky, said Dr. Sorond. "Patients with diabetes or hypertension really don't need the extra sugar, extra calories, and extra fat that come with it."
Dr. Sorond thinks NVC could be measured in high-risk patients seen in the clinic. "I think this could be an easy, in-clinic quick test of vascular brain function that pertains to cognitive performance."
The ideal next step would be to carry out a larger study in patients with mild cognitive impairment that includes more detailed cognitive profiles and more control groups. "We need a cocoa arm; we need a caffeine arm; we need maybe other arms, to make sure that we understand this, and maybe look at some of the metabolites in the blood as a result of cocoa consumption that correlates with these things," said Dr. Sorond.
Remarkable First Step
In an accompanying editorial, Paul B. Rosenberg, MD, associate professor of psychiatry and behavioral sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, and Can Ozan Tan, PhD, Harvard Medical School, Boston, write that in many ways, the study represents a "remarkable first step."
For one thing, it demonstrates the practical utility of a simple, inexpensive, and noninvasive technique for measuring NVC that has several advantages over functional MRI and other means of measuring blood brain flow during cognitive tasks.
In demonstrating a link between NVC and cerebral white matter structural integrity, the study provides an important validation for the association between vascular and cognitive function, according to Dr. Rosenberg.
The study demonstrates that NVC "hangs together" as a measure of vascular function, which could be used in studies targeting vascular interventions, said Dr. Rosenberg in an interview with Medscape Medical News. In this way, he added, the study is "promising for the development of new treatments for vascular dementia."
The study suggests that the vascular effects of cocoa are not due to its flavonol content, noted Dr. Rosenberg."It could be a placebo effect."
Dr. Rosenberg pointed out several strengths of the study, including its relatively large size for a pilot study and its "well-chosen" measures. READ MORE