Study links bacterial metabolism of dietary soy with dementia

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

A metabolite produced following consumption of dietary soy may decrease a key risk factor for dementia–with the help of the right bacteria.  According to a new discovery led by the University of Pittsburgh Graduate School of Public Health in the US, published in the journal Alzheimer’s & Dementia: Translational Research & Clinical Interventions, 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.

The researchers found that while equol production did not appear to impact levels of amyloid-beta deposited within the brain, it was associated with reduced white matter lesion volumes.

The research team 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 researchers, the ability to produce equol from soy isoflavones may be the key to unlocking protective health benefits from a soy-rich diet, and his team has 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.

The researchers believe that this type of study always catches people’s attention, but it cannot prove that equol protects against dementia until they get a randomized clinical trial with sufficient evidence.