A new study has found that being overweight appears to be related to reduced levels of a molecule that reflects brain cell health in the hippocampus, a part of the brain involved in memory, learning, and emotions, and likely also involved in appetite control.

Jeremy D. Coplan, MD, professor of psychiatry at SUNY Downstate Medical Center, led a multicenter team that visualized the molecule, N-acetyl-aspartate (NAA), using magnetic resonance spectroscopy, a non-invasive magnetic resonance imaging (MRI) application.

NAA is associated with brain cell health. Overweight study participants exhibited lower levels of NAA in the hippocampus than normal weight subjects. The effect was independent of age, sex, and psychiatric diagnoses.

The importance of the hippocampus - a seahorse-shaped organ deep within the brain - to the formation and preservation of memory and to emotional control is well known, Dr. Coplan said, but its role in appetite control is less established.

"The relevance of the finding is that being overweight is associated with specific changes in a part of the brain that is crucial to memory formation and emotions, and probably to appetite," Dr. Coplan said.

The study is believed to be the first human research documenting the association of NAA with body weight.

"Whether low NAA is a consequence of being overweight, causes being overweight, or a combination of both remains to be determined," he added.

The findings are published in the journal Neuroimage: Clinical.