Obesity has long been linked to many health conditions, including cardiovascular disease, Type 2 diabetes, and some cancers. New research adds another concern: cognitive decline.
Obesity Causes Similar Changes to Brain as Alzheimer’s Disease
Researchers compared patterns of brain atrophy and amyloid-β/tau protein accumulation (hallmarks of Alzheimer’s) in patients with obesity and Alzheimer’s disease. They used a sample of over 1,300 individuals from four groups—Alzheimer’s disease patients, healthy people, obese but otherwise healthy people, and lean people.The study was conducted using two large cohorts: the UK Biobank and the Alzheimer’s Disease Neuroimaging Initiative (ADNI).
Researchers used PET brain scans to investigate what mechanisms might be responsible for similarities between obesity-related brain atrophy and Alzheimer’s-related amyloid-beta accumulation. They also looked for overlapping areas among patients with these conditions.
The scans showed these groups experienced similar brain thinning in areas associated with learning, memory, and judgment.
Obesity is related to many health problems, such as Type 2 diabetes, hypertension, and high cholesterol.
How Obesity Increases Risk for Neurodegenerative Diseases
Obesity rates have increased alarmingly in the last decades, reaching global epidemic levels.In the same period, the prevalence of severe obesity also nearly doubled.
Obesity is believed to increase neurodegenerative disease risk by two means—“promoting insulin resistance and the production of inflammatory molecules in the body called cytokines,” said Dr. Jonathan J. Rasouli, director of complex and adult spinal deformity surgery at Staten Island University Hospital, part of Northwell Health in New York.
The combination of these factors can mean an increased risk of cardiovascular, pulmonary, musculoskeletal, and neurologic diseases, he continued.
There’s evidence showing insulin plays a role in brain health, and insulin resistance, which is associated with overweight and obesity, is significantly associated with Alzheimer’s risk.
When the brain can’t use insulin properly, cognition can become impaired.
‘An Ounce of Prevention Is Worth a Pound of Cure’
Can weight loss reverse or prevent cognitive decline; is it ever too late? The impact of weight loss on cognitive function in older adults, specifically, is still not understood fully, and it’s likely that more research will be needed.However, there is encouraging evidence that it may help.
When it comes to cognitive decline, “an ounce of prevention is worth a pound of cure,” said Rasouli.
Although the progression of cognitive decline—including memory loss—can be slowed or temporarily stopped, he warned that as soon as the process starts, it is very difficult to fully “return to normal” afterward.
Reducing sources of inflammation is one of the things Rasouli encourages patients to do.
Normal aging is associated with increased and prolonged inflammation throughout the body—and the brain.
Morys said the “key takeaway” is that obesity is a major risk factor for Alzheimer’s disease and other types of dementia.
“In line with this, we think that obesity prevention and weight loss might play a very important role in decreasing the risk for Alzheimer’s disease,” he concluded.