Early Detection of Alzheimer’s: Key Blood Markers

Alzheimer’s is a brain disease. It affects memory, thinking, and behavior. It usually starts after age 65. This disease is a type of dementia. It causes abnormal proteins to build up in the brain. These proteins kill nerve cells. They also disrupt brain communication. Alzheimer’s cannot be reversed. Symptoms worsen over time. But, certain blood markers can predict Alzheimer’s. Early detection is key. It helps slow the disease’s progress.

Key Blood Markers for Alzheimer’s Detection

Fasting Insulin

Insulin is a hormone. It regulates blood sugar. Studies show that very low or very high fasting insulin levels can increase dementia risk. This includes Alzheimer’s. Low insulin levels may indicate a different risk of dementia. This risk is not related to diabetes. Monitoring fasting insulin helps. It identifies people at risk, even without diabetes.

High-Sensitivity C-Reactive Protein (hs-CRP)

Hs-CRP is a marker. It shows inflammation in the body. Inflammation is linked to brain changes in Alzheimer’s. Some studies suggest that higher hs-CRP levels might protect brain structure. This is true for people with cognitive impairment. It could be due to activating repair mechanisms. Still, abnormal hs-CRP levels signal that inflammation should be monitored. Managing inflammation can reduce Alzheimer’s risk.

Homocysteine

Homocysteine is an amino acid. High levels can increase Alzheimer’s risk. High homocysteine levels can damage blood vessels and brain cells. This worsens cognitive decline. Studies show Alzheimer’s patients often have about 30% higher homocysteine than healthy people. Lowering homocysteine by improving folate intake and other B vitamins may help. It can reduce this risk.

Omega-3 Index

Our brain is almost 60% fat. Omega-3 fatty acids are essential for brain health. Especially EPA and DHA found in fish oil. A higher omega-3 index in blood is linked to better memory, learning, and brain blood flow. Taking omega-3 improves cognitive function. This is particularly true for older adults. It can help prevent dementia. Omega-3s also reduce brain inflammation. They protect nerve cells from damage.

Vitamin D (25-Hydroxyvitamin D)

Low vitamin D levels are linked to a higher risk of dementia and Alzheimer’s disease. Research shows that for every 10 nmol/L increase in vitamin D levels, the risk of dementia decreases by about 5-7%. Maintaining adequate vitamin D supports brain health. It may help prevent Alzheimer’s. You can get vitamin D through sunlight exposure, diet, or supplements.

ApoE Genotype and Lipid Panel

The ApoE gene comes in different forms. The ε4 variant is a major genetic risk factor for late-onset Alzheimer’s. ApoE helps transport cholesterol and fats in the body and brain. People with the ε4 allele have a higher Alzheimer’s risk. The ε2 variant is protective. Along with genetic testing, checking blood lipids can also be a marker. This includes cholesterol and triglycerides. It can indicate early dementia risk.

Gamma-Glutamyl Transferase (GGT)

GGT is an enzyme. It is linked to liver function and oxidative stress. Elevated GGT levels in blood are associated with an increased risk of dementia and Alzheimer’s. High GGT may reflect harmful oxidative damage and inflammation affecting the brain. Monitoring GGT can help. It identifies people at risk.

Sources

• Highly accurate blood test diagnoses Alzheimer’s disease, Washington University & Lund University, 2025
• Association of hs-CRP and Alzheimer’s disease, PMC, 2018
• Plasma homocysteine levels and risk of Alzheimer disease, Neurology, 2004
• The omega-3 index in Alzheimer’s disease, PMC, 2022