Obesity is associated with reduced blood flow to the brain, a new study has found, and this may help explain why obesity is associated with an increased risk for Alzheimer’s disease.
Researchers did brain scans on 17,721 men and women, average age 41, tracking blood flow in 128 regions of the brain. They classified the participants into weight categories: underweight (a body mass index less than 18), normal (18.5 to 24.9) overweight (24.9 to 29.9), obese (B.M.I. greater than 30), and morbidly obese (B.M.I. of 40 or higher).
They found that the higher the B.M.I., the lower the blood flow to five regions of the brain that are especially vulnerable in Alzheimer’s disease: the temporal lobes, the parietal lobes, the hippocampus, the posterior cingulate and the precuneus. The study is in the Journal of Alzheimer’s Disease.
The link between B.M.I. and blood flow persisted even after controlling for bipolar disorder, anxiety disorder, traumatic brain injury, alcohol use disorder and other factors that can affect blood flow in the brain. The association of B.M.I. with brain blood perfusion was evident even in younger members of the group.
“Weight hurts the brain,” said the lead author, Dr. Daniel G. Amen, founder of Amen Clinics. “I want people to care enough about their brains that they will work to get their bodies healthy.”
In lowering the risk for Alzheimer’s disease, he added, “you have way more control than you may think.”
