Overview: Optimal intake of B-type procyanidins, a class of polyphenols found in apples, cocoa and red wine, is associated with hormesis of metabolic and hemodynamic responses.
sauce: Shibaura Institute of Technology
B-type procyanidins are made up of catechin oligomers and are a class of polyphenols abundant in foods such as cocoa, apples, grape seeds, and red wine.
Several studies have established the benefits of these micronutrients in reducing the risk of cardiovascular disease and stroke.B-type procyanidins also successfully control hypertension, dyslipidemia, and impaired glucose tolerance. doing.
Studies have demonstrated physiological benefits of consumption on the central nervous system (CNS), namely improved cognitive function.
These physiological changes follow the pattern of hormesis. Hormesis is a phenomenon in which the effect of a substance is maximized at moderate doses and gradually diminishes at lower or higher doses.
The dose-response relationship for most bioactive compounds follows a monotonic pattern, with higher doses leading to greater responses. However, in some exceptional cases, a U-shaped dose-response curve is seen.
This U-shaped curve signifies hormesis. Hormesis is an adaptive response in which low doses of normally harmful compounds induce resistance in the body to high doses. This means that exposure to low-level noxious triggers induces activation of stress tolerance pathways, enhancing their capacity for repair and regeneration.
For B-type procyanidins, some in vitro Studies support hormetic effects, but these results have not been substantiated in vivo.
To address this knowledge gap, researchers at Shibaura Institute of Technology (SIT) in Japan, led by Professor Naomi Osakabe of the Department of Life Science and Engineering, reviewed data from an intervention trial supporting hormetic responses to B-type procyanidin intake. Did.
In addition, a team consisting of Daiki Fushimi and Yasuyuki Fujii from the Graduate School of Engineering (SIT) of in vivo Experiments to understand possible relationships between B-type procyanidin hormetic responses and CNS neurotransmitter receptor activation.
Their article was published online on June 15, 2022 in Volume 9. The forefront of nutrition science September 7, 2022.
The researchers noted that a single oral administration of optimal doses of cocoa flavanols transiently increased blood pressure and heart rate in rats. I did. Administration of B-type procyanidin monomers and various oligomers produced similar results.
According to Professor Osakabe, “These results are consistent with the results of intervention studies after a single intake of foods rich in B-type procyanidins, and support the U-shaped dose-response theory of polyphenols, or hormesis.” I have.”
To see if the sympathetic nervous system (SNS) is involved in the hemodynamic changes induced by B-type procyanidins, the researchers administered an adrenergic blocker to rats.
This successfully reduced the transient increase in heart rate caused by optimal doses of cocoa flavanols.
This suggests that SNSs, which control the action of adrenergic blockers, are responsible for the hemodynamic and metabolic changes induced by a single oral dose of B-type procyanidins.
The researchers next determined why optimal doses, rather than high doses, are responsible for thermogenic and metabolic responses. They co-administered high doses of cocoa flavanols and yohimbine (an α2 blocker) and noted a temporary but distinct increase in blood pressure in the test animals. Similar observations were made using B-type procyanidin oligomers and yohimbine.
Professor Osakabe said, “Because α2-blockers are associated with downregulation of the SNS, the decrease in metabolic and thermogenic output seen in our study at high doses of B-type procyanidins is likely to be related to α2-autoreceptor activity. SNS inactivation may therefore be induced by high doses of B-type procyanidins.”
Previous studies have demonstrated a role for the gut-brain axis in regulating hormetic stress-related responses. Activation of the hypothalamic-pituitary-adrenal (HPA) axis by optimal stress has profound effects on memory, cognition, and stress tolerance.
This article highlights how HPA activation occurs after a single dose of B-type procyanidins, suggesting that stimulation by oral administration of B-type procyanidins can be a stressor in mammals and cause SNS activation. suggests that
Hormesis and the biochemical pathways that trigger it provide protection against a variety of pathological and aging processes, enhancing our general health and making us more resilient to future stress.
Although the exact relationship between B-type procyanidins and the CNS requires further research, the health benefits of foods rich in B-type procyanidins remain controversial.
This research was supported by JSPS KAKENHI (grant number: 19H04036).
About this diet and neuroscience research news
Original research: open access.
“Hormetic responses to type-B procyanidin ingestion involve stress-related neuroregulation via the gut-brain axis: preclinical and clinical observations.Daiki Fushimi and others The forefront of nutrition science
Hormetic responses to type-B procyanidin ingestion involve stress-related neuroregulation via the gut-brain axis: preclinical and clinical observations.
B-type procyanidins, a series of catechin oligomers, are among the most abundant polyphenols in the human diet.
Results from a meta-analysis suggest that intake of B-type procyanidins reduces the risk of cardiovascular disease.
Another recent focus has been on the effects of B-type procyanidins on central nervous system (CNS) function.
Long-term intake of B-type procyanidins has been associated with health benefits, but a single oral intake has been reported to cause physiological changes in circulation, metabolism, and the CNS.
A comprehensive analysis of previous reports indicates optimal mid-range doses for hemodynamic effects of B-type procyanidins, with ineffective responses at low or high doses suggestive of hormesis.
Indeed, polyphenols, including B-type procyanidins, induce hormetic responses in vitro, but animal and clinical studies are limited. However, hormesis of hemodynamic and metabolic responses to B-type procyanidins has recently been confirmed in animal studies.
Here, we assess hormetic responses induced by B-type procyanidins and recontextualize the results of intervention trials. In addition, we discuss the possibility that hormetic responses to B-type procyanidins are mediated through CNS neurotransmitter receptors.
In this review, we validated future research directions for B-type procyanidins.