Obesity causes the brain to shrink

Being overweight is particularly damaging to the brain of women

19/04/2011

Obesity and obesity (obesity) cause a decrease in brain volume and a reduction in tissue density. Leipzig researchers have now discovered together with London colleagues that the negative effects of obesity on the brain of women are far stronger than in men.

It has been known for some time that being overweight has negative effects on the brain. The researchers at the Leipzig Max Planck Institute for Human Cognitive and Brain Sciences have now carried out a comprehensive study in collaboration with the Department of Endocrinology at the University of Leipzig, the Integrated Disease Research Center Leipzig and the University College in London clearly identified gender differences in the negative effects of obesity on the brain.

Brain volume and tissue density decreased by obesity
The fact that obesity decreases both brain volume and tissue density in the brain has been clearly and scientifically proven for a long time. But the gender differences found are an absolute novelty. For the first time, various effects of obesity on male and female brains were found. For example, in overweight women in the brain region of the corpus callosum, more massive changes than in male subjects, the researchers reported in the journal „PLoS ONE“. The international team of scientists studied the brains of normal-weight to severely overweight women and men using diffusion-weighted magnetic resonance imaging (MRI). The movement of water molecules in the brain, which is significantly influenced by barriers in the tissue such as the nerve fibers, served as an indication of tissue density and brain volume. The so-called white substance consisting of nerve fibers is a component of the central nervous system and forms the opposite pole to the so-called gray matter, the nerve cell bodies.

Gender differences in the negative effects
The international team of researchers attributes the detected gender differences in the negative effects of obesity on brain structure to the fact that the linkages of nerve fibers between the two hemispheres are different in men and women. According to the scientists, in the MRI images, a clear weakening of the white matter - with the contained nerve fibers consisting of signal-transmitting extensions of the nerve cells (axons) and an insulating membrane layer (myelin) - could be detected. The changed in a certain way „Mobility of water molecules in brain tissue“ of the corpus callosum in the women have pointed out, „that damaged axons or myelin“ and negative effects on the brain are to be feared, explained study author Karsten Müller. The higher the body mass index (BMI) was, the more the mobility of the water molecules had changed, the scientists explained. The effects occurred in both male and female brains, but the effect on women has taken on a much more massive scale

Possible connection with the occurrence of other diseases
The results of the international team of researchers are of particular importance when linking the negative effects of obesity on the brain to other diseases that can be significantly influenced by changes in brain volume or tissue density. Recent studies have found a link between Alzheimer's disease and the diminishing brain substance. Even years before the onset of the disease Alzheimer's can be read by reducing the brain mass in certain brain areas, reported earlier this month US scientists at Harvard Medical School / Boston, the Massachusetts General Hospital / Boston and the Rush University Medical Center / Chicago in the journal „Neurology“. (Fp)

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Picture: Gerd Altmann