Study Shows Link Between Obesity and Brain Function

Correlation found between increased body mass and decreased white matter

A study published in the journal of the Public Library of Science examines the association between body mass (BMI), vascular and inflammatory markers, and white matter integrity in the corpus callosum of the brain.

White matter is made up of neuron fiber bundles, and it helps carry signals quickly through the brain. As a result, white matter actively affects how the brain functions. The corpus callosum (CC) is the largest white matter structure in the brain. The CC connects the right and left brain hemispheres and facilitates communication between them.

135 healthy older adults participated in the study at the UCSF Memory and Aging Center, which included a blood draw, brain imaging, and a self-reported health evaluation.


Body Mass Index (BMI)

  • 45% of participants were in a healthy weight range (BMI: 18.5–24.9)
  • 43% overweight (BMI: 25.0–29.9)
  • 1% underweight (BMI: <18.5)
  • 11% obese (BMI: ≥30.0)

BMI was calculated as: [weight (kg)/height (m)2 ].


Vascular risk factors

This information came from participants’ self-reports, including questions about smoking history, high blood pressure, high cholesterol levels, and diabetes.


Diffusion tension imaging (DTI)

This MRI scan sequence measures white matter fiber integrity. In this study, it measured the CC.


Laboratory measures

For the purpose of this study, vascular and inflammatory markers were selected based on those already linked to obesity.


After controlling for the age of participants, links were made between blood markers, age and gender, and white matter regions of interest (ROIs) in the brain.

A larger BMI was associated with the male gender, a history of smoking, high blood pressure, and high cholesterol levels.


Models BMI White Matter
includes the genu (outer section of the CC), the body, and the splenium (inner section of the CC)
Model 1: BMI and white matter integrity in CC

Model 2: BMI and white matter integrity, controlling for age and gender

Model 3: BMI and white matter integrity, controlling for age and gender, and vascular risk factors

Model 4: BMI and white matter integrity, controlling for age and gender, vascular risk factors, and vascular and inflammatory blood markers (those linked to obesity)

(but only in the genu of the CC, not the body or splenium)


The findings of this study propose a connection between BMI and lower white matter integrity in the brain.

In certain regions, the BMI-white matter correlation was so influenced by vascular and inflammatory risk factors that statistically controlling for those factors and their markers completely eliminated the connection between BMI and the ROI. In contrast, BMI remained connected with other regions, such that the BMI-white matter correlation was beyond age, gender, and vascular and inflammatory markers.

These connections show a complex link between BMI and white matter integrity, as the two are linked in some regions of the brain but not in others. These inconsistencies suggest that there may be another influence for the BMI-white matter relationship, and that more research needs to be done to understand this connection.

BMI and obesity have often been associated with cardiovascular risk, but this study shows a significant link between BMI, cardiovascular markers, and brain health. Scientists, researchers, and doctors maintain that physical exercise, and a consequently lower BMI, is the best thing a person can do to preserve a healthy brain.


By Anna Milter

Related Links:

Bettcher BM, Walsh CM, Watson C, Miller JW, Green R, Patel N, Miller BL, Neuhaus J, Yaffe K, Kramer JH. Body mass and white matter integrity: the influence of vascular and inflammatory markers. PLoS One. 2013 Oct 16;8(10):e77741. doi: 10.1371/journal.pone.0077741. eCollection 2013.

Speech and Language Rehab for PPA Patients

Word retrieval therapy shows promise for patients with primary progressive aphasia

A November 2013 article from the journal Brain and Language discusses a treatment that might help improve language performance in patients diagnosed with primary progressive aphasia (PPA). PPA causes deterioration in areas of the brain that control speech and language, causing a gradual decline in communication abilities. Read more

The Art of Coping

How to address the behavioral changes in patients with Alzheimer’s disease

photo of mother and daughter
The formal definition of a caregiver is “a person providing direct care to an individual (adult or child)”—Webster’s Dictionary. Read more