Brown Rice and Rice Bran Fermented Food (FBRA) Suppresses Cognitive Decline

A research group from the Department of Endocrinology, Metabolism, Hematology, Rheumatology (Second Department of Internal Medicine), Graduate School of Medicine, University of the Ryukyus, has discovered that the intake of fermented brown rice and rice bran food (FBRA: Fermented Brown rice and Rice bran with Aspergillus oryzae) effectively suppresses cognitive decline in aged obese mice.

These aged obese mice are analogous to slightly overweight obese men around 65 years old, mimicking a state of mild cognitive impairment (MCI).

Furthermore, they elucidated that the expression of gene groups (IEGs) important for memory and learning in the "hippocampus," a crucial brain region, was specifically induced as part of the molecular mechanism.

These research findings were published in the "Journal of Food Bioactives," Volume 34 (2026), the official medical journal of the International Society for Nutraceuticals and Functional Foods.

[Background]

The prevalence of cognitive impairment is increasing globally. While various new treatments have begun in recent years, many challenges remain regarding safety, efficacy, and economic burden. Furthermore, there is a lack of intervention methods for prevention from the stage of mild cognitive impairment (MCI).

Against this backdrop, expectations are growing for safe and sustainable brain health maintenance using familiar food components.

This study investigated the possibility that feeding FBRA, a fermented brown rice food that allows easy intake of functional components of brown rice, contributes to the improvement of cognitive function decline in aged obese mice models with cognitive impairment.

FBRA is a food produced by fermenting brown rice and rice bran with Aspergillus oryzae. While its functionalities such as improvement of intestinal environment, antioxidant effects, anti-inflammatory effects, and cancer-preventive effects have been reported, its effects and impact on cognitive function remained unknown.

This research was conducted by the research group of Professor Hiroaki Masuzaki (researcher Taiki Teruya) from the Graduate School of Medicine (Second Department of Internal Medicine), University of the Ryukyus, which has achieved numerous world-first research results in the functional research of brown rice and brain science.

[Research Outline]

The mice used in the study were aged obese mice models with cognitive impairment, raised for a long period on a diet rich in animal fats with high caloric content.

Analogous to humans, they mimic the state of slightly overweight obese men around 65 years old experiencing mild cognitive impairment (MCI).

Using these model mice, the research group conducted a long-term feeding study of 50 weeks with FBRA, revealing the following results:

1 Improvement in Cognitive Function

The cognitive function of aged obese mice that consumed FBRA long-term was evaluated using two types of behavioral tests (NOL test, Y-maze test) to assess spatial recognition memory.

As a result, mice that consumed FBRA showed a significant suppression of cognitive decline compared to mice that did not.

2 Induction of Specific Gene Group Expression in the Hippocampus

Comprehensive analysis of the molecular mechanisms involved in cognitive function improvement using microarrays and qPCR revealed that FBRA intake significantly and specifically increased the expression levels of Egr1 and Nr4a1, which are immediate early genes (IEGs) induced by learning and neural activity in the hippocampus.

These genes are known to be involved in the regulation of synaptic plasticity and long-term memory formation.

3 Safety and Specificity

No adverse events were observed from long-term intake of FBRA.

Furthermore, as there was no impact on the suppression of neuroinflammation or neurogenesis, it was suggested that FBRA exerts its cognitive function-suppressing effects by regulating intracellular signal transduction pathways related to neural transmission or neuronal activation.

[Future Prospects]

This research provides important scientific evidence that FBRA, a fermented food made from brown rice and Aspergillus oryzae, familiar to Japanese people, has the potential to contribute to the maintenance and improvement of cognitive function in old age.

Future expectations include clinical trials targeting humans and further elucidation of the molecular mechanisms by which the diverse functional components in FBRA exert synergistic effects, thereby contributing to the extension of healthy life expectancy.

[Publication Information]

Title: Brown rice bran fermented with Aspergillus oryzae attenuates cognitive decline in aged mice accompanied by induction of immediate early genes in hippocampus

Authors: Taiki Teruya, Chie Horiguchi, Eri Nakamine, Yuhi Nemoto, Tsugumi Uema, Keita Tamaki, Hideyuki Nemoto, Yukiko Horie, Masafumi Mayama, Masataka Shikanai, Hiroaki Masuzaki

Journal: J. Food Bioactives 2026;34:75-86

[PDF File of This Release]

https://www.genmaikoso.co.jp/data/m/20260630.pdf

[What is Brown Rice and Rice Bran Fermented Food (FBRA)?]

It is a "fermented food that allows easy intake of the healthy components of brown rice" made by fermenting brown rice, germ, and bran with Aspergillus oryzae.

As a result of approximately 30 years of academic research, ・Function to suppress cancer development in various organs ・Function to suppress inflammation ・Function to improve intestinal environment ・Function to suppress oxidation have been demonstrated, with over 40 academic papers published.

Research data can be viewed on the academic research explanation site "fubolab." fubolab: https://fbra.jp/

[About Genmaikoso Co., Ltd.]

Since its establishment in 1971, Genmaikoso Co., Ltd. has focused not only on the manufacturing and research of brown rice and rice bran fermented food (FBRA) but also on food education activities based on natural brown rice diets.

They have contributed to the health promotion of the nation by holding seminars and natural food cooking classes nationwide, and by operating natural brown rice restaurants and organic farms.

Recently, they have been focusing on health business through collaboration with doctors and medical professionals, with over 600 doctors and dentists utilizing FBRA and online seminars inviting doctors as lecturers.

[Contact Information]

Genmaikoso Co., Ltd. (Academic Research Department, Tomomitsu Mizuno)

Address: Kita 12-jo Nishi 1-chome 1-1, Kita-ku, Sapporo

Phone: 011-736-2345

Email: mizuno@genmaikoso.co.jp