Dementia is a devastating disease, and while the underlying cause remains to be determined, decreased blood flow to the brain may play a role. Improving blood flow may therefore prevent the development of, or slow the progression of, dementia.
A decreased supply of blood to the brain, called cerebral ischemia, can be caused by many different factors, including common diseases such as atherosclerosis. Cerebral ischemia is known to increase with aging.
...[M]en and women who ingested a cocoa flavanoid-rich beverage experienced a 10% improved blood flow to the brain after two weeks.
Cocoa flavanoids are compounds that are found in the cocoa plant among many other foods; flavanols are a subclass of flavanoids, and are better known as antioxidants. In the study, published in the August issue of Neuropsychiatric Disease and Treatment, healthy elderly men and women who ingested a cocoa flavanoid-rich beverage experienced a 10% improved blood flow to the brain after two weeks. Researchers suggest that, if this increased blood flow is sustained, it would decrease the risk of developing dementia, and may slow progression in people who already have it.
Increasing blood flow to the brain would also decrease the risk of stroke, which in some people is due to rapid onset of cerebral ischemia (inadequate blood flow).
Interestingly, study participants who ingested a cocoa beverage with little or no flavanoids showed significantly less improvement in brain blood flow. This supports the role of flavanoids as the specific compound in cocoa that is responsible for this beneficial effect.
While this correlational study does demonstrate the benefits of cocoa on blood flow, whether this really translates into a decreased risk of dementia or stroke remains to be seen.
The findings of this most recent trial add to the body of evidence linking cocoa to health benefits. Cocoa is rich in antioxidants, which may prevent cancer, although this remains to be proven. Other cocoa benefits that have been reported include immune-boosting and heart-protective effects.