Gut bacteria molecule imidazole propionate linked to faster cognitive decline in Alzheimer's study

October 3, 2026 at 05:24 PM2 min

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A molecule produced by gut bacteria, imidazole propionate (ImP), is associated with faster cognitive decline and Alzheimer's disease markers, according to a University of Wisconsin-Madison study published in Nature Communications. Researchers found that higher blood levels of ImP in nearly 1,200 participants correlated with abnormal amyloid and tau proteins and impaired neuron function. The findings suggest a potential treatment strategy targeting ImP to lower Alzheimer's risk.

Key Facts

Imidazole propionate (ImP) is a compound produced by certain gut bacteria and was previously linked to type 2 diabetes and coronary artery disease.
In mice, ImP reaching the brain increased accumulation of abnormal beta amyloid and tau proteins, hallmarks of Alzheimer's disease.
The study examined blood samples from almost 1,200 people enrolled in the Wisconsin Registry for Alzheimer's Prevention and Wisconsin Alzheimer's Disease Research Center studies.
Participants with higher blood ImP concentrations were more likely to show biological markers of abnormal proteins and impaired neuron function.
People with the highest ImP levels experienced much faster cognitive decline over time, according to cognitive test results.

Gut-Brain Connection

Nearly a decade ago, University of Wisconsin-Madison professors Barbara Bendlin and Federico Rey found that gut microorganism mixes differ between people with Alzheimer's disease and healthy individuals. Bendlin, a professor of medicine, said the team has since tried to determine how this gut difference leads to brain changes. The recent study focused on imidazole propionate (ImP), a compound produced by certain gut bacteria, and its potential contribution to Alzheimer's-related brain changes. ImP production varies considerably from person to person, with some people generating relatively large amounts and others very little. Rey, a professor of bacteriology, noted that ImP-producing bacteria are present in a large fraction of people but not very abundant in most, and a microbe does not have to be abundant to affect the host.

ImP and Alzheimer's Markers

Once produced in the gut, ImP can enter circulation and reach other parts of the body, with previous research linking it to type 2 diabetes and coronary artery disease. In mice, ImP reaching the brain increased accumulation of abnormal beta amyloid and tau proteins, two major hallmarks associated with Alzheimer's disease. Rey said that process eventually results in neuron death, a key feature of Alzheimer's disease in humans. Researchers examined blood samples from almost 1,200 people enrolled in the Wisconsin Registry for Alzheimer's Prevention and Wisconsin Alzheimer's Disease Research Center studies. Participants with higher ImP concentrations in blood were much more likely to show biological markers associated with abnormal proteins and impaired neuron function in dementia.

Cognitive Decline Link

Because volunteers had completed cognitive testing over time, researchers compared ImP levels with changes in thinking and memory. Rey stated that people with the highest ImP levels also experienced much faster cognitive decline. The finding could point scientists toward a potential treatment strategy aimed at lowering Alzheimer's risk.