Consumption of flavanols, naturally occurring compounds found in plants, is associated with cognitive and cerebrovascular benefits in healthy adults, according to new research published in Scientific reports. The study provides evidence that flavanol intake results in greater and faster oxygenation of the brain in response to the buildup of carbon dioxide in the blood.
“For the past 10-12 years, I have been interested in the health benefits of plant-based flavonoids, particularly their effects on the brain and cognitive function,” said study author Catarina Rendeiro, professor of nutritional sciences at the School of Sport, Exercise and Rehabilitation Sciences at the University of Birmingham.
“We have known for many years that cocoa flavanols (in particular) can improve vascular function in humans by improving vascular / arterial function. These benefits are evident even after a single dose. However, the extent to which some of these benefits could translate into cerebral vascularity was less clear. “
As we have more and more people suffering from cognitive impairments and neurodegenerative diseases later in life (and for the most part we are living longer), it is imperative that we make the lifestyle choices (exercise, diet) that can maximize they protect the brain and help delay the onset of cognitive dysfunction as we age, ”Rendeiro explained.
For their study, which used a double-blind methodology, the researchers tested 18 healthy male participants in two separate trials, one in which the subjects received flavanol-rich cocoa and another during which they consumed processed cocoa with very low levels of flavanols. Cocoa rich in flavanols contained 150 mg of epicatechin and 35.5 mg of catechin, while cocoa low in flavanols contained less than 4 mg of both flavanols.
Participants underwent a standard procedure to challenge the blood circulation of the brain that involves breathing in 5% carbon dioxide – about 100 times the normal concentration in the air, producing an effect called hypercapnia. Non-invasive near-infrared spectroscopy, a technique that uses light to capture changes in blood oxygenation levels, has been used to monitor increases in brain oxygenation in the frontal cortex, a region of the brain that plays a key role in planning, behavior regulation and decision-making.
Participants were then asked to complete a series of progressively complex cognitive tests.
The researchers found that participants who took the flavanol-enriched drink tended to have more efficient tissue oxygenation responses in the frontal cortex. Improved brain oxygenation also seemed to translate into improvements in cognitive performance on tasks of greater complexity (but not on tasks of lesser complexity).
The findings indicate that “consuming foods rich in flavanols, such as grapes, green tea, apples, berries and unprocessed cocoa powder can provide levels of flavanols that are beneficial for brain oxygenation and cognitive function,” he said. Rendeiro to PsyPost.
“The fact that flavanols can also be effective in a healthy brain (where physiology works exactly as it should) is a remarkable discovery and means we can potentially all benefit from diets rich in flavanols.”
But as with all research, the study includes some caveats.
Women were not included in the study to ensure a more homogeneous sample and to minimize the impact of hormonal fluctuations. “The impact of flavanols in women was not addressed in this study, so it is possible that women respond differently. This is something that needs to be considered in the future, “Rendeiro explained.
“We also need to better understand the mechanisms behind these beneficial effects. How do these compounds affect oxygenation levels? “
“Efficient oxygenation of the brain is critical to cognition, and impairments in this process are common in people of advanced age or at high risk for cardiovascular disease or dementia. So, in the future it would be important to check whether these beneficial effects we see in young people can be translated into at-risk populations, as it is likely that they will benefit the most, “Rendeiro added.
Although the study looked at flavanols from natural cocoa powders, ingesting chocolate probably wouldn’t have produced the same effect.
“Many people tend to associate the benefits of cocoa with chocolate, but they are two very different things. Cocoas that contain flavanols are normally not processed. However, when cocoa beans are processed to make chocolate (roasting, alkalizing, etc.), the flavanol content decreases, “explained Rendeiro.
“Unfortunately, it is difficult to know what the flavanol content is in chocolate products as these are not declared on the label. In general, scientific papers that have measured the flavanol content in commercially available chocolates do not seem to find any relationship between cocoa solids content and flavanol levels. “
“So having more solid cocoa doesn’t necessarily mean more flavanol content. Importantly, even chocolates that have the highest amount of flavanols are still a bit far from effective doses. You should consume a substantial portion of chocolate to reach the desired doses and this would not be advisable given the simultaneous intake of sugar and fat. Producing chocolate in ways that maintain flavanol content should be a goal, so that effective doses of flavanols can be obtained from small amounts of chocolate (1 to 2 squares), ”Rendeiro said.
“The good news is that consuming a variety of flavanol-rich foods, such as grapes, green tea, apples, berries, legumes can provide levels of flavanols that are beneficial for the brain and vascular function.”
The study, “Diet Flavanols Improve Cerebral Cortical Oxygenation and Cognition in Healthy Adults”, was written by Gabriele Gratton, Samuel R. Weaver, Claire V. Burley, Kathy A. Low, Edward L. Maclin, Paul W Johns, Quang S Pham, Samuel JE Lucas, Monica Fabiani and Catarina Rendeiro.