Does obesity speed up Alzheimer’s disease? Recent research shows that people with obesity experience much faster changes in the brain linked to Alzheimer’s compared to those without obesity.
Scientists looked at this question by studying blood tests and brain scans from 407 people over five years. These people were part of a large project called the Alzheimer’s Disease Neuroimaging Initiative. The blood tests measured special proteins that signal Alzheimer’s problems, like pTau217 and NfL. These proteins build up as the disease worsens. Brain scans checked for amyloid plaques, sticky clumps in the brain that harm thinking and memory.
At the start of the study, people with obesity had lower levels of these proteins in their blood. This happened because obese people often have more blood volume, which dilutes the proteins. It might make it seem like they have less Alzheimer’s trouble at first glance. But as time went on, the real picture changed.
Over the five years, those with obesity saw their pTau217 levels rise 29 to 95 percent faster than in non-obese people. Baseline obesity also meant a 24 percent faster jump in NfL levels and a 3.7 percent quicker buildup of amyloid on scans. Blood tests picked up these speed-ups better than the scans did.
Experts like Dr. Cyrus Raji and Dr. Soheil Mohammadi from Washington University School of Medicine led the work. They shared results at the Radiological Society of North America meeting. Dr. Raji noted this is the first time blood tests have clearly shown obesity’s push on Alzheimer’s. Dr. Mohammadi pointed out that tracking changes over time is key, not just one snapshot.
Why does this matter? Obesity is one of 14 changeable risks for Alzheimer’s. A 2024 report from the Lancet Commission says these risks explain nearly half of all cases. Cutting obesity could slow things down or delay the disease. Doctors might need to watch blood tests more closely in obese patients and push weight control harder.
Other experts agree. Dr. Dung Trinh, who runs a brain clinic, says obesity does not just link to Alzheimer’s, it ramps up brain changes. This could mean earlier checks and stronger steps for at-risk people. Dr. Marc Siegel adds that obesity sparks inflammation and insulin issues, which fuel brain damage in Alzheimer’s.
The study stresses that obesity speeds the disease’s hidden steps, even if symptoms do not show right away. Losing weight might help protect the brain.
Sources
https://clpmag.com/disease-states/dementias-alzheimer/blood-biomarker-tests-obesity-accelerates-alzheimers-disease-progression/
https://www.sciencedaily.com/releases/2025/12/251210092019.htm
https://www.medicalnewstoday.com/articles/obesity-may-hasten-alzheimers-disease-development
https://www.nutritioninsight.com/news/obesity-alzheimers-disease-brain-health-weight.html
https://www.foxnews.com/health/alzheimers-risk-could-rise-common-condition-affecting-millions-study-finds
https://onlinelibrary.wiley.com/doi/10.1111/obr.70078?af=R
https://pubmed.ncbi.nlm.nih.gov/41439648/?fc=None&ff=20251228133601&v=2.18.0.post22+67771e2
