Summary: Optimal intake of type B procyanidins, a class of polyphenols found in apples, cocoa, and red wine, is related to metabolism and hormone responses in the blood.
source: Shibura Institute of Technology
Type B procyanidins, made from oligomers of catechins, are a class of polyphenols found abundantly in foods such as cocoa, apples, grape seeds, and red wine.
Several studies have demonstrated the benefits of this micronutrient in reducing the risk of cardiovascular disease and stroke. Type B procyanidins are also successful in controlling hypertension, dyslipidemia, and glucose intolerance.
Studies attest to the physiological benefits of its intake on the central nervous system (CNS), i.e. an improvement in cognitive functions.
These physiological changes follow a hormonal pattern – a phenomenon in which the peak benefits of a substance are achieved at mid-range doses, and become progressively less at lower and higher doses.
The dose-response relationship for most bioactive compounds follows a monotonic pattern, with a higher dose showing a greater response. However, in some exceptional cases, a U-shaped dose-response curve is seen.
This U-shaped curve indicates hormones – an adaptive response in which a low dose of a normally harmful compound causes the body to resist its higher doses. This means that exposure to low levels of harmful stimuli can lead to activation of stress-resistant pathways, resulting in increased repair and regeneration capabilities.
In the case of type B procyanidins, there are several in the laboratory Studies support its hormonal effects, but these results have not been proven in vivo.
To address this knowledge gap, researchers from the Shibura Institute of Technology (SIT) in Japan, led by Professor Naomi Osakabe from the Department of Biological Sciences and Engineering, reviewed data from intervention trials that support hormonal responses to ingestion of type B procyanidins.
The team composed of Taiki Fushimi and Yasuyuki Fujii of the Graduate School of Engineering and Science (SIT) also conducted in vivo Experiments to understand potential links between procyanidin-type B hormonal responses and CNS neurotransmitter receptor activation.
Their article was published online on June 15, 2022 and is published in Volume 9 of Nutrition limits On September 7, 2022.
The researchers noted that oral administration of a single dose of cocoa flavanols temporarily increased blood pressure and heart rate in mice. But hemodynamics did not change when the dose was increased or decreased. Administration of procyanidin-type B monomer and different oligomers gave similar results.
According to Professor Osakabe, “These findings are consistent with results from intervention studies after a single intake of food rich in type B procyanidins, and support the theory of U-shaped dose response, or polyphenol hormones.”
To observe whether the sympathetic nervous system (SNS) was involved in the hemodynamic changes induced by type B procyanidins, the team administered epinephrine blockers to test mice.
This succeeded in reducing the temporary increase in heart rate caused by the optimal dose of cocoa flavanols. A different type of blocker – an A1 blocker – inhibits transient rise in blood pressure.
This suggests that the SNS, which control the action of adrenaline blockers, are responsible for the hemodynamic and metabolic changes induced by a single oral dose of type B procyanidin.
Next, the researchers ascertained why optimum doses, not higher doses, were responsible for the thermogenic and metabolic responses. They co-administered high-dose cocoa flavanols and yohimbine (α2 blockers) and observed a temporary but distinct increase in blood pressure in test animals. Similar observations were made using type B procyanidin oligomer and yohimbine.
Prof. Osakabe speculates, “Because α2-blockers are associated with down-regulation of SNS, the reduced metabolic and thermal metabolites with high-dose B-type procyanidins seen in our study may cause activation of endogenous α2 receptors. Thus, SNS inactivation may occur by high-dose procyanidins. type B”.
Previous studies have demonstrated the role of the gut axis in controlling responses related to hormonal stress. Activation of the hypothalamic-pituitary-adrenal (HPA) axis by optimal stress has a powerful effect on memory, cognition and stress tolerance.
This article highlights how HPA activation occurs after a single dose of type B procyanidin, suggesting that stimulation with an oral dose of type B procyanidin may be a stress factor in mammals and cause SNS activation.
Hormesis and its stimulating biochemical pathways provide protection against various pathological and aging processes, enhancing our overall health and making us resilient in the face of future stress.
Although the exact relationship between type B procyanidins and the central nervous system needs further research, the health benefits of foods rich in type B procyanidins remain undisputed.
This study was supported by JSPS KAKENHI (grant number: 19H04036).
About this diet and neuroscience research news
author: Wang Yu
source: Shibura Institute of Technology
Contact: Wang Yu – Shibura Institute of Technology
picture: The image is in the public domain
original search: open access.
“The hormonal response to ingestion of type B procyanidins involves stress-related neuromodulation across the gut axis: preclinical and clinical observations.Written by Taiki Fushimi et al. Frontiers in Nutrition
The hormonal response to ingestion of type B procyanidins involves stress-related neuromodulation across the gut axis: preclinical and clinical observations.
Type B procyanidins, a series of catechin oligomers, are among the polyphenols most commonly ingested in the human diet.
The results of meta-analyses indicated that taking B-type procyanidins reduces the risk of cardiovascular disease.
Another recent focus has been on the effects of type B procyanidins on central nervous system (CNS) function.
Although long-term administration of type B procyanidins is associated with health benefits, a single oral dose has been reported to cause physiological changes in the circulatory system, metabolism, and central nervous system.
Comprehensive analyzes of previous reports indicate an optimal mid-range dose for the hemodynamic effects of type B procyanidins, with null responses at lower or higher doses, indicating hormone formation.
Indeed, polyphenols, including type B procyanidins, elicit hormonal responses in the laboratoryHowever, clinical and animal studies are limited. The modulation of hemodynamic and metabolic responses to B-type procyanidins has recently been confirmed in animal studies, and our work has linked these effects to the central nervous system.
Here, we evaluate the hormonal response elicited by type B procyanidins, and reformulate the results of intervention trials. In addition, we discuss the possibility that this hormonal response to B-type procyanidins may arise via CNS neurotransmitter receptors.
We have verified the direction of future research for type B procyanidins in this review.