Flavanol-Rich Cacao Increases Cerebral Blood Flow

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Brain ischemia, also known as cerebral ischemia or cerebrovascular ischemia is a condition in which there is insufficient blood flow to the brain. This condition leads to poor oxygen supply to the brain and consequently death of brain tissue or cerebral infarction.

Brain ischemia is commonly accompanied by cognitive decline and can lead to vascular dementia.

Vascular dementia, also known as multi-infarct dementia (MID) and vascular cognitive impairment (VCI), is a form of dementia caused by a lack of supply of blood to the brain.  This ongoing condition leads to cognitive decline.  1

According to the University of Cincinnati’s Memory Disorders Center at the UC Neuroscience Institute, vascular cognitive impairment is defined as:

“Vascular cognitive impairment (VCI) is if a form of dementia  that is believed to be caused by  damaged blood vessels in the brain, or cerebrovascular disease. When blood vessels lose their effectiveness, either because of age or other factors, such as high blood pressure or smoking, the brain can suffer reduction of blood flow. 

Vascular cognitive impairment is widely viewed as the second leading cause of dementia (Alzheimer’s disease is the first). Vascular cognitive impairment is thought to be the dominant cause of dementia in up to 20 percent of people who develop dementia after age 65, and pathological changes suggest that VCI contributes to dementia in 33 to 40 percent of people over age 65.”   2

Two important studies recently indicated that there are vascular health benefits of flavanol-rich cacao (or cocoa) for the treatment and prevention of cerebral ischemia.

The first study from 2006 entitled, Chronic consumption of flavanol-rich cocoa improves endothelial function and decreases vascular cell adhesion molecule in hypercholesterolemic postmenopausal women, J Cardiovasc Pharmacol. 2006;47 Suppl 2:S177-86, was the first study to identify beneficial vascular effects of flavanol-rich cocoa consumption in hypercholesterolemic postmenopausal women. 

The purpose of the study was to determine if consumption of flavanol-rich cacao improves endothelial function and markers of cardiovascular health in hypercholesterolemic postmenopausal women. The postmenopausal hypercholesterolemic women consumed a high-flavanol cocoa beverage for 6 weeks in a double-blind study.

The results of the study were promising, in that, brachial artery hyperemic blood flow increased significantly by 76% after the 6-week period in the women consuming high-flavanol cocoa, whereas the low-flavanol cocoa group of women only increased by 32%.   3 

The second study from 2008 entitled, Cerebral blood flow response to flavanol-rich cocoa in healthy elderly humans, Neuropsychiatr Dis Treat. 2008 Apr; 4(2): 433–440. Published online 2008 Apr., was designed to investigate the effects of flavanol-rich cocoa (FRC) consumption on cerebral blood flow in older healthy volunteers.  This particular study was the first to investigate the consumption of flavanol-rich cacao on cerebral blood flow.

The study illustrated that after 2 weeks of regular consumption of flavanol-rich cacao (providing 900 mg of cocoa flavanols daily), resulted in a significant increase in peak cerebral blood flow response in the MCA.    4

The authors of the study concluded:

“In summary, we show that dietary intake of FRC is associated with a significant increase in cerebral blood flow velocity in the MCA as measured by TCD. Our data suggest a promising role for regular cocoa flavanol’s consumption in the treatment of cerebrovascular ischemic syndromes, including dementias and stroke.”    5


Choosing a proper cacao product is important because the goal is to consume a flavanol-rich cacao (FRC) product and not one that is highly processed with low levels of flavanols, or what is known as a flavanol-poor cacao (FPC).

Most cocoa or chocolate on the market today is highly processed by a method called Dutch-treated or Dutching.  With the Dutching process, the cacao powder is treated with an alkalizing agent to modify its color and give it a milder taste.  The Dutching process improves the flavor of the cocoa powder, but unfortunately removes the beneficial flavanols and other polyphenols in the natural cacao bean.

Cacao that has not been processed by the Dutching method is considered nonalkalizing cocoa.

In a 2008 study published in the Journal of Agricultural and Food Chemistry, the authors determined that 60% of natural cocoa’s original antioxidants (flavanols and polyphenols) were destroyed by even light dutching, and 90% were destroyed by heavy dutching.  6

The preferred form of cacao is raw cacao that is not heavily processed using the Dutching method.  With raw cacao, the cacao beans are milled at low temperature to protect the nutrients and flavor and 100% of the natural flavanols of the bean are preserved.


Resources:

Raw Cacao Beans

Raw Cacao Nibs

Cacao Liquor/Paste

Raw Cacao Powder


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