In a new study from the University of Pittsburgh, researchers found a metabolite produced following consumption of dietary soy may decrease a key risk factor for dementia.
They found that elderly Japanese men and women who produce equol — a metabolite of dietary soy created by certain types of gut bacteria — display lower levels of white matter lesions within the brain.
White matter lesions are strong risk factors for cognitive decline, dementia, and all-cause mortality.
in the study, the team found 50% more white matter lesions in people who cannot produce equol compared to people who can produce it, which is a surprisingly huge effect.
To obtain this result, the team measured equol levels within the blood of 91 elderly Japanese participants with normal cognition.
Participants were sorted by their equol production status, and then six to nine years later underwent brain imaging to detect levels of white matter lesions and deposits of amyloid-beta, which is the suspected molecular cause of Alzheimer’s disease.
The researchers found that while equol production did not appear to impact levels of amyloid-beta deposited within the brain, it was linked to reduced white matter lesion volumes.
They also discovered that high levels of isoflavones — soy nutrients that are metabolized into equol — had no effect on levels of white matter lesions or amyloid-beta when equol wasn’t produced.
According to the team, the ability to produce equol from soy isoflavones may be the key to unlocking protective health benefits from a soy-rich diet.
They had previously shown that equol production is associated with a lower risk of heart disease.
As heart disease is strongly associated with cognitive decline and dementia, equol production could help protect the aging brain as well as the heart.
Studies in Japan, where soy is regularly consumed, have shown that dietary intake of soy isoflavones has been linked to a lower risk for heart disease and dementia.
However, most clinical trials in America have failed to show this.
The team believes that this discrepancy may be due to the microbiome — 40-70% of Japanese harbor gut bacteria that can convert dietary isoflavones into equol compared to only 20-30% of Americans.
They say that equol supplements could one day be combined with existing diet-based prevention strategies that appear to lower the risk of dementia, particularly the Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets.
If you care about dementia, please read studies about how unhealthy blood pressure increases your dementia risk and findings of why people with type 2 diabetes develop dementia.
For more information about dementia and your health, please see recent studies about this healthy diet may strongly prevent memory loss and dementia and results showing that this eye problem may signal higher risk of dementia.
The study is published in Alzheimer’s & Dementia: Translational Research & Clinical Interventions. One author of the study is Akira Sekikawa, M.D., Ph.D.
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