The dry, puckering sensation felt after eating cocoa, berries, or red wine may do more than affect taste-it could also stimulate the brain, according to new research from Japan. Scientists suggest that flavanols, natural plant compounds found in these foods, may activate brain function through sensory nerves in the mouth rather than through absorption into the bloodstream.
Flavanols belong to a group of compounds called polyphenols and have long been linked to benefits such as better heart health, improved memory, and protection against brain cell damage. However, researchers have been puzzled by the fact that only a small amount of flavanols is absorbed during digestion. Despite this low bioavailability, their effects on the brain appear significant.
To investigate this, researchers led by Dr. Yasuyuki Fujii and Professor Naomi Osakabe at Shibaura Institute of Technology focused on astringency—the dry, rough mouthfeel caused by flavanols. They proposed that this sensation itself may act as a signal, sending messages directly to the brain via sensory nerves.
The study, published in Current Research in Food Science, tested the idea in mice. Animals given flavanols showed increased physical activity, more exploratory behavior, and better performance in learning and memory tests compared to mice given only water.
Further analysis revealed increased activity in key brain chemicals linked to attention, motivation, and stress regulation, including dopamine and norepinephrine. The researchers also observed activation of brain regions involved in stress responses, along with higher levels of stress-related hormones. These responses were similar to those seen after physical exercise.
The findings suggest that flavanols act as a mild, beneficial stressor, stimulating the brain in a way that enhances alertness and cognitive performance. Importantly, this effect appears to occur through taste perception rather than digestion alone.
Researchers say the study highlights the growing importance of “sensory nutrition,” a field that examines how the sensory experience of food affects health. Understanding how taste and mouthfeel influence the nervous system could help guide the development of foods that support brain health while remaining enjoyable to eat.
REFERENCE: Yasuyuki Fujii, Shu Taira, Keisuke Shinoda, Yuki Yamato, Kazuki Sakata, Orie Muta, Yuta Osada, Ashiyu Ono, Toshiya Matsushita, Mizuki Azumi, Hitomi Shikano, Keiko Abe, Vittorio Calabrese, Naomi Osakabe. Astringent flavanol fires the locus-noradrenergic system, regulating neurobehavior and autonomic nerves. Current Research in Food Science, 2025; 11: 101195 DOI: 10.1016/j.crfs.2025.101195
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