New Lipid Biomarkers for Mild Cognitive Impairment

Researchers have identified specific lipid biomarkers in saliva, plasma, and fecal samples that may help detect mild cognitive impairment (MCI), an early stage in the progression toward dementia. The findings, from the Microbiome in Aging Gut and Brain (MiaGB) consortium, reveal distinct lipidomic alterations in individuals with MCI compared to healthy controls.

Compared to controls, MCI patients exhibited increased oxidized triacylglycerols (oxTGs) in saliva, reduced cholesteryl linoleate (CE 18:2) in plasma, and decreased fatty acid esters of hydroxy fatty acids (FAHFAs) in feces. These changes were detected using high-performance liquid chromatography coupled with high-resolution mass spectrometry (LC/MS), which profiled over 200 molecular species across five major lipid classes.

Biomarkers with Diagnostic Potential

Receiver operating characteristic (ROC) analysis identified three metabolites as discriminatory biomarkers with notable diagnostic performance: α-linolenic acid (FA 18:3), docosapentaenoic acid (FA 22:5), and cholesteryl linoleate (CE 18:2). These lipids showed consistent differences between MCI patients and healthy older adults in the study.

Fecal Lipids and Metabolic Clues

In addition to decreased FAHFAs, researchers observed elevated levels of fecal triacylglycerols containing medium-chain fatty acids (TG-MCFAs) in individuals with MCI. This finding suggests possible impairments in lipid absorption or altered lipid metabolism in the gastrointestinal tract among those with early cognitive decline.

Study Context and Implications

The research was conducted as part of the Microbiome in Aging Gut and Brain (MiaGB) consortium, which collected saliva, plasma, and fecal samples from older adults with MCI and healthy controls. Samples were analyzed using LC/MS to profile lipidomic alterations and identify candidate biomarkers for early detection.

While lipids are known to play a central role in neurodegeneration, the biomarker potential of lipidomics from saliva, plasma, and feces has been underexplored. This multi-sample approach highlights the potential of TG-MCFAs as fecal biomarkers for MCI detection, though the authors note that further mechanistic and longitudinal validation is needed to confirm their utility in clinical or screening settings.

The study was published in Translational Psychiatry on February 16, 2026, and includes authors from Hokkaido University, the University of South Florida, and other institutions affiliated with the MiaGB consortium. No conflicts of interest were reported in relation to the work presented, although one author disclosed affiliations with biotechnology companies unrelated to this specific study.