Isoflavone intake is associated with longitudinal changes in hippocampal volume, but not total grey matter volume, in Japanese middle-aged and older community dwellers

Mariko Nakamoto ^1,2, Yukiko Nishita ³, Chikako Tange ³

⁰Department of Public Health and Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima city, Tokushima, 770-8503, Japan. nakamoto@tokushima-u.ac.jp.

European Journal of Nutrition +

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April 9, 2025

View abstract on PubMed

Summary

Increased isoflavone intake may help prevent hippocampal atrophy in older adults (≥65 years). This dietary strategy shows potential for preserving brain volume in aging Japanese populations.

Area Of Science

Neuroscience
Nutrition Science
Gerontology

Background

Brain aging is associated with volume loss, particularly in regions like the hippocampus.
Dietary factors, including isoflavones, are being investigated for their neuroprotective potential.
Longitudinal studies are crucial for understanding the impact of diet on brain structure over time.

Purpose Of The Study

To investigate the association between dietary isoflavone intake and longitudinal changes in hippocampal and total grey matter (TGM) volume.
To examine these associations over a 10-year period in Japanese middle-aged and older adults.
To determine if age modifies the relationship between isoflavone intake and brain volume changes.

Main Methods

Analysis of data from the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA).
Dietary isoflavone intake assessed via 3-day records and categorized into quintiles.
Brain volumes (hippocampus, TGM) measured using MRI and FreeSurfer; longitudinal changes analyzed with general linear models, stratified by age (<65 and ≥65 years).

Main Results

No significant association between isoflavone intake and brain volume changes in the overall cohort.
In individuals aged ≥65 years, higher isoflavone intake was significantly associated with preserved hippocampal volume over time (p for trend = 0.009 for difference, p for trend = 0.012 for % change).
No significant associations were found between isoflavone intake and total grey matter volume changes in either age group.

Conclusions

Increased total isoflavone intake may be a potential nutritional strategy to mitigate hippocampal atrophy in older Japanese adults (≥65 years).
Isoflavones may play a role in preserving specific brain structures related to aging.
Further research is warranted to confirm these findings and explore mechanisms.

Keywords:

Hippocampus Isoflavones Japanese community dwellers Nutritional epidemiology