Obesity reduces white matter in the human brain

Overweight causes the brain to age faster?
Obesity has consequences for the entire organism. This does not exclude the brain. Thus, overweight and obese people in middle age show a marked decrease in the volume of so-called white matter in their brain. This has been discovered by scientists from the Universities of Cambridge and Yale in a recent study. The brain of people with obesity shows according to the researchers changes, as they occur in normal weight only ten years later.

The volume of white matter naturally decreases with age. However, in recent years there has been some evidence that obesity may have an impact on this process, according to the University of Cambridge Communication. Obesity, which has already been clearly linked to an increased risk of diabetes, cancer and cardiovascular disease, may accelerate the decline in white matter. British scientists have now reviewed this in their latest study. Their results were published in the journal "Neurobiology of Aging".

Comparison of gray matter (brown) and white matter (yellow) in a 56-year-old normal weight (left) and a 50-year-old adipose subject. (Image: Dr. Lisa Ronan / University of Cambridge)

Striking differences in the volume of white matter
The research team used 473 people, ages 20 to 87, to investigate possible effects of obesity on the structure of the brain. Using a body mass index (BMI), the scientists divided the volunteers into a normal-weight control group (246 people), obese people (150) and obese patients (77 people), and checked their brain structure using MRI scans. In the overweight and obese study participants were here compared to the normal weight "striking differences in the volume of white matter," the researchers report.

Deviations in the middle age particularly large
Overweight and obese individuals, according to the scientists, showed a widespread reduction in white matter compared to the control group. White matter is the tissue that connects the areas of the brain and allows the transfer of information between regions, the researchers explain. This goes back naturally with the age.

In people with overweight but obviously a little faster. The differences in white matter volume were particularly dramatic between middle-aged subjects, suggesting "that our brains may be vulnerable during this period of aging," explains study author Professor Paul Fletcher of Cambridge University.

Impact of altered brain structures unclear
The researchers report that overweight individuals over the age of 50 had comparable levels of white matter in the tests as a slim person at the age of 60 years. However, despite the significant differences in white matter volume between lean and overweight individuals, the researchers found no association between overweight or obesity and the cognitive abilities of study participants. The consequences of the differences remain open.

Examine the relationship between brain structures and obesity in more detail
Why "people who are overweight show a greater reduction in the amount of white matter," according to co-study author Dr. Lisa Ronan from the University of Cambridge "so far unclear".

The researchers say they can only "speculate about whether obesity in any way causes these changes, or whether obesity is a consequence of brain changes." The question also arises as to whether the changes might be reversible in a weight reduction. In any case, the relationship between the brain structure and obesity or obesity must be examined in more detail in further studies. (Fp)