B-type procyanidins, a series of catechin oligomers, are among the most ingested polyphenols in the human diet. This is found abundantly in foods like cocoa, apples, grape seeds, and red wine.
Results of meta-analyses have suggested that intake of foods rich in B-type procyanidins is linked to reduced risk for cardiovascular disease, including coronary heart disease, myocardial infarction, and stroke. Randomized controlled trials and subsequent meta-analyses have confirmed that dark chocolate containing large amounts of B-type procyanidins can mitigate states related to the metabolic syndrome, including hypertension.
In addition, the latest large-scale randomized trial found a 27% reduction in cardiovascular death by ingestion of cocoa flavanol fraction, which is rich in B-type procyanidin monomer and oligomers, for 3.6 years.
Recent studies have focused on the benefit of B-type procyanidin ingestion for the central nervous system (CNS). A few intervention trials have reported that B-type procyanidin might be effective in improving cognitive function
Almost all B-type procyanidins ingested in food move into the colon, and some are degraded by the microbiome. Consequently, changes in the gut microbiome induced by ingestion of B-type procyanidins for a comparatively long period may alter the composition of metabolites in the colon . One hypothesis is that these colon changes associated with gut microbiota contribute to the beneficial effects of B-type procyanidins.
Polyphenols, including B-type procyanidins, elicit hormetic responses in cell culture . Cellular proliferation occurs at relatively low concentrations, but cytotoxicity is detected at high concentrations .
Multiple health benefits of b-type procyanidin-rich foods
Researchers from Shibaura Institute of Technology (SIT), Japan, led by Professor Naomi Osakabe from the Department of Bioscience and Engineering, reviewed the data from intervention trials supporting hormetic responses of B-type procyanidin ingestion. The team, comprising Taiki Fushimi and Yasuyuki Fujii from the Graduate School of Engineering and Science (SIT), also conducted in vivo experiments to understand possible connections between B-type procyanidin hormetic responses and CNS neurotransmitter receptor activation.
The researchers noted that a single oral administration of an optimal dose of cocoa flavanol temporarily increased the blood pressure and heart rate in rats. But the hemodynamics did not change when the dose was increased or decreased. Administration of B-type procyanidin monomers and various oligomers produced similar results.
To observe whether the sympathetic nervous system (SNS) is involved in the hemodynamic changes induced by B-type procyanidins, the team administered adrenaline blockers in test rats. This successfully decreased the temporary increase in heart rate induced by the optimal dose of cocoa flavanol. A different kind of blocker ,a1 blocker, inhibited the transient rise in blood pressure. This suggested that the SNS, which controls the action of adrenaline blockers, is responsible for the hemodynamic and metabolic changes induced by a single oral dose of B-type procyanidin.
The researchers next ascertained why optimal doses, and not high doses, are responsible for the thermogenic and metabolic responses. They co-administered a high dose of cocoa flavanol and yohimbine (an α2 blocker) and noted a temporary but distinct increase in blood pressure in test animals.
As we can see, the consumption of b-type procyanidin-rich foods may give us protection against various pathological and aging processes, enhancing our general health and making us resilient to future stress. Though the exact relation between B-type procyanidins and the CNS needs more research.
Naomi Osakabe, Taiki Fushimi, Yasuyuki Fujii (September 7, 2022). Hormetic response to B-type procyanidin ingestion involves stress-related neuromodulation via the gut-brain axis: Preclinical and clinical observations. Frontiers in Nutrition. Retrieved from : https://www.frontiersin.org/articles/10.3389/fnut.2022.969823/full