5. YKL-40 (Chitinase-3-like Protein 1)
YKL-40, also known as chitinase-3-like protein 1, is closely linked to neuroinflammation—a key process in Alzheimer’s development. Studies have detected elevated YKL-40 levels in both cerebrospinal fluid and blood among individuals with early-stage Alzheimer’s disease. According to research published in Frontiers in Aging Neuroscience, this biomarker may serve as an early warning sign and offers insight into inflammatory mechanisms at play.